Kernel: Turn Thread::current and Process::current into functions

This allows us to query the current thread and process on a
per processor basis

AK/LogStream.cpp

@@ -125,8 +125,8 @@ DebugLogStream dbg()
         stream << "\033[33;1m" << process_name_buffer << '(' << getpid() << ")\033[0m: ";
 #endif
 #if defined(__serenity__) && defined(KERNEL)
-    if (Kernel::Thread::current)
+    if (Kernel::Processor::is_initialized() && Kernel::Thread::current())
-        stream << "\033[34;1m[" << *Kernel::Thread::current << "]\033[0m: ";
+        stream << "\033[34;1m[" << *Kernel::Thread::current() << "]\033[0m: ";
     else
         stream << "\033[36;1m[Kernel]\033[0m: ";
 #endif
@@ -137,8 +137,8 @@ DebugLogStream dbg()
 KernelLogStream klog()
 {
     KernelLogStream stream;
-    if (Kernel::Thread::current)
+    if (Kernel::Processor::is_initialized() && Kernel::Thread::current())
-        stream << "\033[34;1m[" << *Kernel::Thread::current << "]\033[0m: ";
+        stream << "\033[34;1m[" << *Kernel::Thread::current() << "]\033[0m: ";
     else
         stream << "\033[36;1m[Kernel]\033[0m: ";
     return stream;

Kernel/Arch/i386/CPU.cpp

@@ -113,7 +113,8 @@ static void dump(const RegisterState& regs)
 {
     u16 ss;
     u32 esp;
-    if (!Process::current || Process::current->is_ring0()) {
+    auto process = Process::current();
+    if (!process || process->is_ring0()) {
         ss = regs.ss;
         esp = regs.esp;
     } else {
@@ -139,7 +140,7 @@ static void dump(const RegisterState& regs)
         : "=a"(cr4));
     klog() << "cr0=" << String::format("%08x", cr0) << " cr2=" << String::format("%08x", cr2) << " cr3=" << String::format("%08x", cr3) << " cr4=" << String::format("%08x", cr4);
 
-    if (Process::current && Process::current->validate_read((void*)regs.eip, 8)) {
+    if (process && process->validate_read((void*)regs.eip, 8)) {
         SmapDisabler disabler;
         u8* codeptr = (u8*)regs.eip;
         klog() << "code: " << String::format("%02x", codeptr[0]) << " " << String::format("%02x", codeptr[1]) << " " << String::format("%02x", codeptr[2]) << " " << String::format("%02x", codeptr[3]) << " " << String::format("%02x", codeptr[4]) << " " << String::format("%02x", codeptr[5]) << " " << String::format("%02x", codeptr[6]) << " " << String::format("%02x", codeptr[7]);
@@ -148,26 +149,27 @@ static void dump(const RegisterState& regs)
 
 void handle_crash(RegisterState& regs, const char* description, int signal, bool out_of_memory)
 {
-    if (!Process::current) {
+    auto process = Process::current();
+    if (!process) {
         klog() << description << " with !current";
         hang();
     }
 
     // If a process crashed while inspecting another process,
     // make sure we switch back to the right page tables.
-    MM.enter_process_paging_scope(*Process::current);
+    MM.enter_process_paging_scope(*process);
 
-    klog() << "CRASH: CPU #" << Processor::current().id() << " " << description << ". Ring " << (Process::current->is_ring0() ? 0 : 3) << ".";
+    klog() << "CRASH: CPU #" << Processor::current().id() << " " << description << ". Ring " << (process->is_ring0() ? 0 : 3) << ".";
     dump(regs);
 
-    if (Process::current->is_ring0()) {
+    if (process->is_ring0()) {
         klog() << "Crash in ring 0 :(";
         dump_backtrace();
         hang();
     }
 
     cli();
-    Process::current->crash(signal, regs.eip, out_of_memory);
+    process->crash(signal, regs.eip, out_of_memory);
 }
 
 EH_ENTRY_NO_CODE(6, illegal_instruction);
@@ -226,7 +228,8 @@ void page_fault_handler(TrapFrame* trap)
 #endif
 
     bool faulted_in_userspace = (regs.cs & 3) == 3;
-    if (faulted_in_userspace && !MM.validate_user_stack(*Process::current, VirtualAddress(regs.userspace_esp))) {
+    auto current_thread = Thread::current();
+    if (faulted_in_userspace && !MM.validate_user_stack(current_thread->process(), VirtualAddress(regs.userspace_esp))) {
         dbg() << "Invalid stack pointer: " << VirtualAddress(regs.userspace_esp);
         handle_crash(regs, "Bad stack on page fault", SIGSTKFLT);
         ASSERT_NOT_REACHED();
@@ -236,8 +239,8 @@ void page_fault_handler(TrapFrame* trap)
 
     if (response == PageFaultResponse::ShouldCrash || response == PageFaultResponse::OutOfMemory) {
         if (response != PageFaultResponse::OutOfMemory) {
-            if (Thread::current->has_signal_handler(SIGSEGV)) {
+            if (current_thread->has_signal_handler(SIGSEGV)) {
-                Thread::current->send_urgent_signal_to_self(SIGSEGV);
+                current_thread->send_urgent_signal_to_self(SIGSEGV);
                 return;
             }
         }
@@ -284,7 +287,8 @@ void debug_handler(TrapFrame* trap)
 {
     clac();
     auto& regs = *trap->regs;
-    if (!Process::current || (regs.cs & 3) == 0) {
+    auto current_thread = Thread::current();
+    if (&current_thread->process() == nullptr || (regs.cs & 3) == 0) {
         klog() << "Debug Exception in Ring0";
         hang();
         return;
@@ -294,10 +298,10 @@ void debug_handler(TrapFrame* trap)
     if (!is_reason_singlestep)
         return;
 
-    if (Thread::current->tracer()) {
+    if (current_thread->tracer()) {
-        Thread::current->tracer()->set_regs(regs);
+        current_thread->tracer()->set_regs(regs);
     }
-    Thread::current->send_urgent_signal_to_self(SIGTRAP);
+    current_thread->send_urgent_signal_to_self(SIGTRAP);
 }
 
 EH_ENTRY_NO_CODE(3, breakpoint);
@@ -305,15 +309,16 @@ void breakpoint_handler(TrapFrame* trap)
 {
     clac();
     auto& regs = *trap->regs;
-    if (!Process::current || (regs.cs & 3) == 0) {
+    auto current_thread = Thread::current();
+    if (&current_thread->process() == nullptr || (regs.cs & 3) == 0) {
         klog() << "Breakpoint Trap in Ring0";
         hang();
         return;
     }
-    if (Thread::current->tracer()) {
+    if (current_thread->tracer()) {
-        Thread::current->tracer()->set_regs(regs);
+        current_thread->tracer()->set_regs(regs);
     }
-    Thread::current->send_urgent_signal_to_self(SIGTRAP);
+    current_thread->send_urgent_signal_to_self(SIGTRAP);
 }
 
 #define EH(i, msg)                                                                                                                                                             \
@@ -797,6 +802,7 @@ u32 read_dr6()
 FPUState Processor::s_clean_fpu_state;
 
 static Vector<Processor*>* s_processors;
+static SpinLock s_processor_lock;
 
 Vector<Processor*>& Processor::processors()
 {
@@ -806,6 +812,10 @@ Vector<Processor*>& Processor::processors()
 
 Processor& Processor::by_id(u32 cpu)
 {
+    // s_processors does not need to be protected by a lock of any kind.
+    // It is populated early in the boot process, and the BSP is waiting
+    // for all APs to finish, after which this array never gets modified
+    // again, so it's safe to not protect access to it here
     auto& procs = processors();
     ASSERT(procs[cpu] != nullptr);
     ASSERT(procs.size() > cpu);
@@ -819,6 +829,9 @@ void Processor::initialize(u32 cpu)
     m_cpu = cpu;
     m_in_irq = 0;
 
+    m_idle_thread = nullptr;
+    m_current_thread = nullptr;
+
     gdt_init();
     if (cpu == 0)
         idt_init();
@@ -836,11 +849,15 @@ void Processor::initialize(u32 cpu)
 
     m_info = new ProcessorInfo(*this);
 
-    if (!s_processors)
+    {
-        s_processors = new Vector<Processor*>();
+        ScopedSpinLock lock(s_processor_lock);
-    if (cpu >= s_processors->size())
+        // We need to prevent races between APs starting up at the same time
-        s_processors->resize(cpu + 1);
+        if (!s_processors)
-    (*s_processors)[cpu] = this;
+            s_processors = new Vector<Processor*>();
+        if (cpu >= s_processors->size())
+            s_processors->resize(cpu + 1);
+        (*s_processors)[cpu] = this;
+    }
 
     klog() << "CPU #" << cpu << " using Processor at " << VirtualAddress(FlatPtr(this));
 }
@@ -894,6 +911,10 @@ extern "C" void enter_thread_context(Thread* from_thread, Thread* to_thread)
 {
     ASSERT(from_thread == to_thread || from_thread->state() != Thread::Running);
     ASSERT(to_thread->state() == Thread::Running);
+
+    auto& processor = Processor::current();
+    processor.set_current_thread(*to_thread);
+
     auto& from_tss = from_thread->tss();
     auto& to_tss = to_thread->tss();
     asm volatile("fxsave %0"
@@ -904,7 +925,6 @@ extern "C" void enter_thread_context(Thread* from_thread, Thread* to_thread)
     set_fs(to_tss.fs);
     set_gs(to_tss.gs);
 
-    auto& processor = Processor::current();
     auto& tls_descriptor = processor.get_gdt_entry(GDT_SELECTOR_TLS);
     tls_descriptor.set_base(to_thread->thread_specific_data().as_ptr());
     tls_descriptor.set_limit(to_thread->thread_specific_region_size());
@@ -1250,8 +1270,9 @@ void __assertion_failed(const char* msg, const char* file, unsigned line, const
 
     // Switch back to the current process's page tables if there are any.
     // Otherwise stack walking will be a disaster.
-    if (Process::current)
+    auto process = Process::current();
-        MM.enter_process_paging_scope(*Process::current);
+    if (process)
+        MM.enter_process_paging_scope(*process);
 
     Kernel::dump_backtrace();
     asm volatile("hlt");

Kernel/Arch/i386/CPU.h

@@ -626,6 +626,8 @@ class Processor {
     static FPUState s_clean_fpu_state;
 
     ProcessorInfo* m_info;
+    Thread* m_current_thread;
+    Thread* m_idle_thread;
 
     bool m_invoke_scheduler_async;
 
@@ -661,6 +663,33 @@ public:
         return *(Processor*)read_fs_u32(0);
     }
 
+    ALWAYS_INLINE static bool is_initialized()
+    {
+        return get_fs() == GDT_SELECTOR_PROC && read_fs_u32(0) != 0;
+    }
+
+    ALWAYS_INLINE Thread* idle_thread() const
+    {
+        return m_idle_thread;
+    }
+
+    ALWAYS_INLINE void set_idle_thread(Thread& idle_thread)
+    {
+        m_idle_thread = &idle_thread;
+    }
+
+    ALWAYS_INLINE Thread* current_thread() const
+    {
+        // NOTE: NOT safe to call from another processor!
+        ASSERT(&Processor::current() == this);
+        return m_current_thread;
+    }
+
+    ALWAYS_INLINE void set_current_thread(Thread& current_thread)
+    {
+        m_current_thread = &current_thread;
+    }
+
     ALWAYS_INLINE u32 id()
     {
         return m_cpu;

Kernel/Devices/BXVGADevice.cpp

@@ -198,14 +198,14 @@ int BXVGADevice::ioctl(FileDescription&, unsigned request, FlatPtr arg)
     switch (request) {
     case FB_IOCTL_GET_SIZE_IN_BYTES: {
         auto* out = (size_t*)arg;
-        if (!Process::current->validate_write_typed(out))
+        if (!Process::current()->validate_write_typed(out))
             return -EFAULT;
         *out = framebuffer_size_in_bytes();
         return 0;
     }
     case FB_IOCTL_GET_BUFFER: {
         auto* index = (int*)arg;
-        if (!Process::current->validate_write_typed(index))
+        if (!Process::current()->validate_write_typed(index))
             return -EFAULT;
         *index = m_y_offset == 0 ? 0 : 1;
         return 0;
@@ -218,7 +218,7 @@ int BXVGADevice::ioctl(FileDescription&, unsigned request, FlatPtr arg)
     }
     case FB_IOCTL_GET_RESOLUTION: {
         auto* resolution = (FBResolution*)arg;
-        if (!Process::current->validate_write_typed(resolution))
+        if (!Process::current()->validate_write_typed(resolution))
             return -EFAULT;
         resolution->pitch = m_framebuffer_pitch;
         resolution->width = m_framebuffer_width;
@@ -227,7 +227,7 @@ int BXVGADevice::ioctl(FileDescription&, unsigned request, FlatPtr arg)
     }
     case FB_IOCTL_SET_RESOLUTION: {
         auto* resolution = (FBResolution*)arg;
-        if (!Process::current->validate_read_typed(resolution) || !Process::current->validate_write_typed(resolution))
+        if (!Process::current()->validate_read_typed(resolution) || !Process::current()->validate_write_typed(resolution))
             return -EFAULT;
         if (resolution->width > MAX_RESOLUTION_WIDTH || resolution->height > MAX_RESOLUTION_HEIGHT)
             return -EINVAL;

Kernel/Devices/MBVGADevice.cpp

@@ -79,21 +79,21 @@ int MBVGADevice::ioctl(FileDescription&, unsigned request, FlatPtr arg)
     switch (request) {
     case FB_IOCTL_GET_SIZE_IN_BYTES: {
         auto* out = (size_t*)arg;
-        if (!Process::current->validate_write_typed(out))
+        if (!Process::current()->validate_write_typed(out))
             return -EFAULT;
         *out = framebuffer_size_in_bytes();
         return 0;
     }
     case FB_IOCTL_GET_BUFFER: {
         auto* index = (int*)arg;
-        if (!Process::current->validate_write_typed(index))
+        if (!Process::current()->validate_write_typed(index))
             return -EFAULT;
         *index = 0;
         return 0;
     }
     case FB_IOCTL_GET_RESOLUTION: {
         auto* resolution = (FBResolution*)arg;
-        if (!Process::current->validate_write_typed(resolution))
+        if (!Process::current()->validate_write_typed(resolution))
             return -EFAULT;
         resolution->pitch = m_framebuffer_pitch;
         resolution->width = m_framebuffer_width;
@@ -102,7 +102,7 @@ int MBVGADevice::ioctl(FileDescription&, unsigned request, FlatPtr arg)
     }
     case FB_IOCTL_SET_RESOLUTION: {
         auto* resolution = (FBResolution*)arg;
-        if (!Process::current->validate_read_typed(resolution) || !Process::current->validate_write_typed(resolution))
+        if (!Process::current()->validate_read_typed(resolution) || !Process::current()->validate_write_typed(resolution))
             return -EFAULT;
         resolution->pitch = m_framebuffer_pitch;
         resolution->width = m_framebuffer_width;

Kernel/Devices/PATAChannel.cpp

@@ -177,7 +177,7 @@ static void print_ide_status(u8 status)
 
 void PATAChannel::wait_for_irq()
 {
-    Thread::current->wait_on(m_irq_queue);
+    Thread::current()->wait_on(m_irq_queue);
     disable_irq();
 }
 

Kernel/Devices/SB16.cpp

@@ -222,7 +222,7 @@ void SB16::handle_irq(const RegisterState&)
 
 void SB16::wait_for_irq()
 {
-    Thread::current->wait_on(m_irq_queue);
+    Thread::current()->wait_on(m_irq_queue);
     disable_irq();
 }
 

Kernel/FileSystem/FIFO.cpp

@@ -133,7 +133,7 @@ ssize_t FIFO::read(FileDescription&, size_t, u8* buffer, ssize_t size)
 ssize_t FIFO::write(FileDescription&, size_t, const u8* buffer, ssize_t size)
 {
     if (!m_readers) {
-        Thread::current->send_signal(SIGPIPE, Process::current);
+        Thread::current()->send_signal(SIGPIPE, Process::current());
         return -EPIPE;
     }
 #ifdef FIFO_DEBUG

Kernel/FileSystem/InodeFile.cpp

@@ -48,7 +48,7 @@ ssize_t InodeFile::read(FileDescription& description, size_t offset, u8* buffer,
 {
     ssize_t nread = m_inode->read_bytes(offset, count, buffer, &description);
     if (nread > 0)
-        Thread::current->did_file_read(nread);
+        Thread::current()->did_file_read(nread);
     return nread;
 }
 
@@ -57,7 +57,7 @@ ssize_t InodeFile::write(FileDescription& description, size_t offset, const u8*
     ssize_t nwritten = m_inode->write_bytes(offset, count, data, &description);
     if (nwritten > 0) {
         m_inode->set_mtime(kgettimeofday().tv_sec);
-        Thread::current->did_file_write(nwritten);
+        Thread::current()->did_file_write(nwritten);
     }
     return nwritten;
 }

Kernel/FileSystem/ProcFS.cpp

@@ -296,7 +296,7 @@ Optional<KBuffer> procfs$pid_vm(InodeIdentifier identifier)
     KBufferBuilder builder;
     JsonArraySerializer array { builder };
     for (auto& region : process.regions()) {
-        if (!region.is_user_accessible() && !Process::current->is_superuser())
+        if (!region.is_user_accessible() && !Process::current()->is_superuser())
             continue;
         auto region_object = array.add_object();
         region_object.add("readable", region.is_readable());
@@ -439,7 +439,7 @@ Optional<KBuffer> procfs$profile(InodeIdentifier)
     object.add("executable", Profiling::executable_path());
 
     auto array = object.add_array("events");
-    bool mask_kernel_addresses = !Process::current->is_superuser();
+    bool mask_kernel_addresses = !Process::current()->is_superuser();
     Profiling::for_each_sample([&](auto& sample) {
         auto object = array.add_object();
         object.add("type", "sample");
@@ -677,7 +677,7 @@ Optional<KBuffer> procfs$pid_root(InodeIdentifier identifier)
 Optional<KBuffer> procfs$self(InodeIdentifier)
 {
     char buffer[16];
-    sprintf(buffer, "%u", Process::current->pid());
+    sprintf(buffer, "%u", Process::current()->pid());
     return KBuffer::copy((const u8*)buffer, strlen(buffer));
 }
 
@@ -807,7 +807,7 @@ Optional<KBuffer> procfs$memstat(InodeIdentifier)
 
 Optional<KBuffer> procfs$all(InodeIdentifier)
 {
-    InterruptDisabler disabler;
+    ScopedSpinLock lock(g_scheduler_lock);
     auto processes = Process::all_processes();
     KBufferBuilder builder;
     JsonArraySerializer array { builder };

Kernel/FileSystem/VirtualFileSystem.cpp

@@ -220,7 +220,8 @@ KResult VFS::utime(StringView path, Custody& base, time_t atime, time_t mtime)
         return custody_or_error.error();
     auto& custody = *custody_or_error.value();
     auto& inode = custody.inode();
-    if (!Process::current->is_superuser() && inode.metadata().uid != Process::current->euid())
+    auto current_process = Process::current();
+    if (!current_process->is_superuser() && inode.metadata().uid != current_process->euid())
         return KResult(-EACCES);
     if (custody.is_readonly())
         return KResult(-EROFS);
@@ -272,18 +273,19 @@ KResultOr<NonnullRefPtr<FileDescription>> VFS::open(StringView path, int options
 
     bool should_truncate_file = false;
 
-    if ((options & O_RDONLY) && !metadata.may_read(*Process::current))
+    auto current_process = Process::current();
+    if ((options & O_RDONLY) && !metadata.may_read(*current_process))
         return KResult(-EACCES);
 
     if (options & O_WRONLY) {
-        if (!metadata.may_write(*Process::current))
+        if (!metadata.may_write(*current_process))
             return KResult(-EACCES);
         if (metadata.is_directory())
             return KResult(-EISDIR);
         should_truncate_file = options & O_TRUNC;
     }
     if (options & O_EXEC) {
-        if (!metadata.may_execute(*Process::current) || (custody.mount_flags() & MS_NOEXEC))
+        if (!metadata.may_execute(*current_process) || (custody.mount_flags() & MS_NOEXEC))
             return KResult(-EACCES);
     }
 
@@ -333,14 +335,15 @@ KResult VFS::mknod(StringView path, mode_t mode, dev_t dev, Custody& base)
     if (existing_file_or_error.error() != -ENOENT)
         return existing_file_or_error.error();
     auto& parent_inode = parent_custody->inode();
-    if (!parent_inode.metadata().may_write(*Process::current))
+    auto current_process = Process::current();
+    if (!parent_inode.metadata().may_write(*current_process))
         return KResult(-EACCES);
     if (parent_custody->is_readonly())
         return KResult(-EROFS);
 
     LexicalPath p(path);
     dbg() << "VFS::mknod: '" << p.basename() << "' mode=" << mode << " dev=" << dev << " in " << parent_inode.identifier();
-    return parent_inode.create_child(p.basename(), mode, dev, Process::current->uid(), Process::current->gid()).result();
+    return parent_inode.create_child(p.basename(), mode, dev, current_process->uid(), current_process->gid()).result();
 }
 
 KResultOr<NonnullRefPtr<FileDescription>> VFS::create(StringView path, int options, mode_t mode, Custody& parent_custody, Optional<UidAndGid> owner)
@@ -355,7 +358,8 @@ KResultOr<NonnullRefPtr<FileDescription>> VFS::create(StringView path, int optio
     }
 
     auto& parent_inode = parent_custody.inode();
-    if (!parent_inode.metadata().may_write(*Process::current))
+    auto current_process = Process::current();
+    if (!parent_inode.metadata().may_write(*current_process))
         return KResult(-EACCES);
     if (parent_custody.is_readonly())
         return KResult(-EROFS);
@@ -364,8 +368,8 @@ KResultOr<NonnullRefPtr<FileDescription>> VFS::create(StringView path, int optio
 #ifdef VFS_DEBUG
     dbg() << "VFS::create: '" << p.basename() << "' in " << parent_inode.identifier();
 #endif
-    uid_t uid = owner.has_value() ? owner.value().uid : Process::current->uid();
+    uid_t uid = owner.has_value() ? owner.value().uid : current_process->uid();
-    gid_t gid = owner.has_value() ? owner.value().gid : Process::current->gid();
+    gid_t gid = owner.has_value() ? owner.value().gid : current_process->gid();
     auto inode_or_error = parent_inode.create_child(p.basename(), mode, 0, uid, gid);
     if (inode_or_error.is_error())
         return inode_or_error.error();
@@ -396,7 +400,8 @@ KResult VFS::mkdir(StringView path, mode_t mode, Custody& base)
         return result.error();
 
     auto& parent_inode = parent_custody->inode();
-    if (!parent_inode.metadata().may_write(*Process::current))
+    auto current_process = Process::current();
+    if (!parent_inode.metadata().may_write(*current_process))
         return KResult(-EACCES);
     if (parent_custody->is_readonly())
         return KResult(-EROFS);
@@ -405,7 +410,7 @@ KResult VFS::mkdir(StringView path, mode_t mode, Custody& base)
 #ifdef VFS_DEBUG
     dbg() << "VFS::mkdir: '" << p.basename() << "' in " << parent_inode.identifier();
 #endif
-    return parent_inode.create_child(p.basename(), S_IFDIR | mode, 0, Process::current->uid(), Process::current->gid()).result();
+    return parent_inode.create_child(p.basename(), S_IFDIR | mode, 0, current_process->uid(), current_process->gid()).result();
 }
 
 KResult VFS::access(StringView path, int mode, Custody& base)
@@ -416,18 +421,19 @@ KResult VFS::access(StringView path, int mode, Custody& base)
     auto& custody = *custody_or_error.value();
     auto& inode = custody.inode();
     auto metadata = inode.metadata();
+    auto current_process = Process::current();
     if (mode & R_OK) {
-        if (!metadata.may_read(*Process::current))
+        if (!metadata.may_read(*current_process))
             return KResult(-EACCES);
     }
     if (mode & W_OK) {
-        if (!metadata.may_write(*Process::current))
+        if (!metadata.may_write(*current_process))
             return KResult(-EACCES);
         if (custody.is_readonly())
             return KResult(-EROFS);
     }
     if (mode & X_OK) {
-        if (!metadata.may_execute(*Process::current))
+        if (!metadata.may_execute(*current_process))
             return KResult(-EACCES);
     }
     return KSuccess;
@@ -442,7 +448,7 @@ KResultOr<NonnullRefPtr<Custody>> VFS::open_directory(StringView path, Custody&
     auto& inode = custody.inode();
     if (!inode.is_directory())
         return KResult(-ENOTDIR);
-    if (!inode.metadata().may_execute(*Process::current))
+    if (!inode.metadata().may_execute(*Process::current()))
         return KResult(-EACCES);
     return custody;
 }
@@ -451,7 +457,8 @@ KResult VFS::chmod(Custody& custody, mode_t mode)
 {
     auto& inode = custody.inode();
 
-    if (Process::current->euid() != inode.metadata().uid && !Process::current->is_superuser())
+    auto current_process = Process::current();
+    if (current_process->euid() != inode.metadata().uid && !current_process->is_superuser())
         return KResult(-EPERM);
     if (custody.is_readonly())
         return KResult(-EROFS);
@@ -492,14 +499,15 @@ KResult VFS::rename(StringView old_path, StringView new_path, Custody& base)
     if (&old_parent_inode.fs() != &new_parent_inode.fs())
         return KResult(-EXDEV);
 
-    if (!new_parent_inode.metadata().may_write(*Process::current))
+    auto current_process = Process::current();
+    if (!new_parent_inode.metadata().may_write(*current_process))
         return KResult(-EACCES);
 
-    if (!old_parent_inode.metadata().may_write(*Process::current))
+    if (!old_parent_inode.metadata().may_write(*current_process))
         return KResult(-EACCES);
 
     if (old_parent_inode.metadata().is_sticky()) {
-        if (!Process::current->is_superuser() && old_inode.metadata().uid != Process::current->euid())
+        if (!current_process->is_superuser() && old_inode.metadata().uid != current_process->euid())
             return KResult(-EACCES);
     }
 
@@ -515,7 +523,7 @@ KResult VFS::rename(StringView old_path, StringView new_path, Custody& base)
         if (&new_inode == &old_inode)
             return KSuccess;
         if (new_parent_inode.metadata().is_sticky()) {
-            if (!Process::current->is_superuser() && new_inode.metadata().uid != Process::current->euid())
+            if (!current_process->is_superuser() && new_inode.metadata().uid != current_process->euid())
                 return KResult(-EACCES);
         }
         if (new_inode.is_directory() && !old_inode.is_directory())
@@ -541,19 +549,20 @@ KResult VFS::chown(Custody& custody, uid_t a_uid, gid_t a_gid)
     auto& inode = custody.inode();
     auto metadata = inode.metadata();
 
-    if (Process::current->euid() != metadata.uid && !Process::current->is_superuser())
+    auto current_process = Process::current();
+    if (current_process->euid() != metadata.uid && !current_process->is_superuser())
         return KResult(-EPERM);
 
     uid_t new_uid = metadata.uid;
     gid_t new_gid = metadata.gid;
 
     if (a_uid != (uid_t)-1) {
-        if (Process::current->euid() != a_uid && !Process::current->is_superuser())
+        if (current_process->euid() != a_uid && !current_process->is_superuser())
             return KResult(-EPERM);
         new_uid = a_uid;
     }
     if (a_gid != (gid_t)-1) {
-        if (!Process::current->in_group(a_gid) && !Process::current->is_superuser())
+        if (!current_process->in_group(a_gid) && !current_process->is_superuser())
             return KResult(-EPERM);
         new_gid = a_gid;
     }
@@ -603,7 +612,7 @@ KResult VFS::link(StringView old_path, StringView new_path, Custody& base)
     if (parent_inode.fsid() != old_inode.fsid())
         return KResult(-EXDEV);
 
-    if (!parent_inode.metadata().may_write(*Process::current))
+    if (!parent_inode.metadata().may_write(*Process::current()))
         return KResult(-EACCES);
 
     if (old_inode.is_directory())
@@ -633,11 +642,12 @@ KResult VFS::unlink(StringView path, Custody& base)
     ASSERT(parent_custody);
 
     auto& parent_inode = parent_custody->inode();
-    if (!parent_inode.metadata().may_write(*Process::current))
+    auto current_process = Process::current();
+    if (!parent_inode.metadata().may_write(*current_process))
         return KResult(-EACCES);
 
     if (parent_inode.metadata().is_sticky()) {
-        if (!Process::current->is_superuser() && inode.metadata().uid != Process::current->euid())
+        if (!current_process->is_superuser() && inode.metadata().uid != current_process->euid())
             return KResult(-EACCES);
     }
 
@@ -662,14 +672,15 @@ KResult VFS::symlink(StringView target, StringView linkpath, Custody& base)
     if (existing_custody_or_error.error() != -ENOENT)
         return existing_custody_or_error.error();
     auto& parent_inode = parent_custody->inode();
-    if (!parent_inode.metadata().may_write(*Process::current))
+    auto current_process = Process::current();
+    if (!parent_inode.metadata().may_write(*current_process))
         return KResult(-EACCES);
     if (parent_custody->is_readonly())
         return KResult(-EROFS);
 
     LexicalPath p(linkpath);
     dbg() << "VFS::symlink: '" << p.basename() << "' (-> '" << target << "') in " << parent_inode.identifier();
-    auto inode_or_error = parent_inode.create_child(p.basename(), S_IFLNK | 0644, 0, Process::current->uid(), Process::current->gid());
+    auto inode_or_error = parent_inode.create_child(p.basename(), S_IFLNK | 0644, 0, current_process->uid(), current_process->gid());
     if (inode_or_error.is_error())
         return inode_or_error.error();
     auto& inode = inode_or_error.value();
@@ -700,7 +711,7 @@ KResult VFS::rmdir(StringView path, Custody& base)
 
     auto& parent_inode = parent_custody->inode();
 
-    if (!parent_inode.metadata().may_write(*Process::current))
+    if (!parent_inode.metadata().may_write(*Process::current()))
         return KResult(-EACCES);
 
     if (inode.directory_entry_count() != 2)
@@ -778,7 +789,7 @@ Custody& VFS::root_custody()
 
 const UnveiledPath* VFS::find_matching_unveiled_path(StringView path)
 {
-    for (auto& unveiled_path : Process::current->unveiled_paths()) {
+    for (auto& unveiled_path : Process::current()->unveiled_paths()) {
         if (path == unveiled_path.path)
             return &unveiled_path;
         if (path.starts_with(unveiled_path.path) && path.length() > unveiled_path.path.length() && path[unveiled_path.path.length()] == '/')
@@ -789,7 +800,7 @@ const UnveiledPath* VFS::find_matching_unveiled_path(StringView path)
 
 KResult VFS::validate_path_against_process_veil(StringView path, int options)
 {
-    if (Process::current->veil_state() == VeilState::None)
+    if (Process::current()->veil_state() == VeilState::None)
         return KSuccess;
 
     // FIXME: Figure out a nicer way to do this.
@@ -865,7 +876,8 @@ KResultOr<NonnullRefPtr<Custody>> VFS::resolve_path_without_veil(StringView path
         return KResult(-EINVAL);
 
     auto parts = path.split_view('/', true);
-    auto& current_root = Process::current->root_directory();
+    auto current_process = Process::current();
+    auto& current_root = current_process->root_directory();
 
     NonnullRefPtr<Custody> custody = path[0] == '/' ? current_root : base;
 
@@ -875,7 +887,7 @@ KResultOr<NonnullRefPtr<Custody>> VFS::resolve_path_without_veil(StringView path
         if (!parent_metadata.is_directory())
             return KResult(-ENOTDIR);
         // Ensure the current user is allowed to resolve paths inside this directory.
-        if (!parent_metadata.may_execute(*Process::current))
+        if (!parent_metadata.may_execute(*current_process))
             return KResult(-EACCES);
 
         auto& part = parts[i];

Kernel/KSyms.cpp

@@ -130,8 +130,9 @@ NEVER_INLINE void dump_backtrace_impl(FlatPtr base_pointer, bool use_ksyms)
     }
 
     OwnPtr<Process::ELFBundle> elf_bundle;
-    if (Process::current)
+    auto current_process = Process::current();
-        elf_bundle = Process::current->elf_bundle();
+    if (current_process)
+        elf_bundle = current_process->elf_bundle();
 
     struct RecognizedSymbol {
         FlatPtr address;
@@ -142,13 +143,13 @@ NEVER_INLINE void dump_backtrace_impl(FlatPtr base_pointer, bool use_ksyms)
     size_t recognized_symbol_count = 0;
     if (use_ksyms) {
         for (FlatPtr* stack_ptr = (FlatPtr*)base_pointer;
-             (Process::current ? Process::current->validate_read_from_kernel(VirtualAddress(stack_ptr), sizeof(void*) * 2) : 1) && recognized_symbol_count < max_recognized_symbol_count; stack_ptr = (FlatPtr*)*stack_ptr) {
+             (current_process ? current_process->validate_read_from_kernel(VirtualAddress(stack_ptr), sizeof(void*) * 2) : 1) && recognized_symbol_count < max_recognized_symbol_count; stack_ptr = (FlatPtr*)*stack_ptr) {
             FlatPtr retaddr = stack_ptr[1];
             recognized_symbols[recognized_symbol_count++] = { retaddr, symbolicate_kernel_address(retaddr) };
         }
     } else {
         for (FlatPtr* stack_ptr = (FlatPtr*)base_pointer;
-             (Process::current ? Process::current->validate_read_from_kernel(VirtualAddress(stack_ptr), sizeof(void*) * 2) : 1); stack_ptr = (FlatPtr*)*stack_ptr) {
+             (current_process ? current_process->validate_read_from_kernel(VirtualAddress(stack_ptr), sizeof(void*) * 2) : 1); stack_ptr = (FlatPtr*)*stack_ptr) {
             FlatPtr retaddr = stack_ptr[1];
             dbg() << String::format("%x", retaddr) << " (next: " << String::format("%x", (stack_ptr ? (u32*)*stack_ptr : 0)) << ")";
         }

Kernel/Lock.cpp

@@ -49,29 +49,31 @@ void Lock::lock(Mode mode)
         dump_backtrace();
         hang();
     }
+    auto current_thread = Thread::current();
     for (;;) {
         bool expected = false;
         if (m_lock.compare_exchange_strong(expected, true, AK::memory_order_acq_rel)) {
             // FIXME: Do not add new readers if writers are queued.
             bool modes_dont_conflict = !modes_conflict(m_mode, mode);
-            bool already_hold_exclusive_lock = m_mode == Mode::Exclusive && m_holder == Thread::current;
+            bool already_hold_exclusive_lock = m_mode == Mode::Exclusive && m_holder == current_thread;
             if (modes_dont_conflict || already_hold_exclusive_lock) {
                 // We got the lock!
                 if (!already_hold_exclusive_lock)
                     m_mode = mode;
-                m_holder = Thread::current;
+                m_holder = current_thread;
                 m_times_locked++;
                 m_lock.store(false, AK::memory_order_release);
                 return;
             }
             timeval* timeout = nullptr;
-            Thread::current->wait_on(m_queue, timeout, &m_lock, m_holder, m_name);
+            current_thread->wait_on(m_queue, timeout, &m_lock, m_holder, m_name);
         }
     }
 }
 
 void Lock::unlock()
 {
+    auto current_thread = Thread::current();
     for (;;) {
         bool expected = false;
         if (m_lock.compare_exchange_strong(expected, true, AK::memory_order_acq_rel)) {
@@ -80,8 +82,8 @@ void Lock::unlock()
 
             ASSERT(m_mode != Mode::Unlocked);
             if (m_mode == Mode::Exclusive)
-                ASSERT(m_holder == Thread::current);
+                ASSERT(m_holder == current_thread);
-            if (m_holder == Thread::current && (m_mode == Mode::Shared || m_times_locked == 0))
+            if (m_holder == current_thread && (m_mode == Mode::Shared || m_times_locked == 0))
                 m_holder = nullptr;
 
             if (m_times_locked > 0) {
@@ -101,7 +103,7 @@ bool Lock::force_unlock_if_locked()
 {
     ASSERT(m_mode != Mode::Shared);
     InterruptDisabler disabler;
-    if (m_holder != Thread::current)
+    if (m_holder != Thread::current())
         return false;
     ASSERT(m_times_locked == 1);
     m_holder = nullptr;

Kernel/Net/E1000NetworkAdapter.cpp

@@ -416,7 +416,7 @@ void E1000NetworkAdapter::send_raw(const u8* data, size_t length)
             sti();
             break;
         }
-        Thread::current->wait_on(m_wait_queue);
+        Thread::current()->wait_on(m_wait_queue);
     }
 #ifdef E1000_DEBUG
     klog() << "E1000: Sent packet, status is now " << String::format("%b", descriptor.status) << "!";

Kernel/Net/IPv4Socket.cpp

@@ -111,9 +111,9 @@ KResult IPv4Socket::bind(const sockaddr* user_address, socklen_t address_size)
         return KResult(-EINVAL);
 
     auto requested_local_port = ntohs(address.sin_port);
-    if (!Process::current->is_superuser()) {
+    if (!Process::current()->is_superuser()) {
         if (requested_local_port < 1024) {
-            dbg() << "UID " << Process::current->uid() << " attempted to bind " << class_name() << " to port " << requested_local_port;
+            dbg() << "UID " << Process::current()->uid() << " attempted to bind " << class_name() << " to port " << requested_local_port;
             return KResult(-EACCES);
         }
     }
@@ -232,7 +232,7 @@ ssize_t IPv4Socket::sendto(FileDescription&, const void* data, size_t data_lengt
 
     int nsent = protocol_send(data, data_length);
     if (nsent > 0)
-        Thread::current->did_ipv4_socket_write(nsent);
+        Thread::current()->did_ipv4_socket_write(nsent);
     return nsent;
 }
 
@@ -246,7 +246,7 @@ ssize_t IPv4Socket::receive_byte_buffered(FileDescription& description, void* bu
             return -EAGAIN;
 
         locker.unlock();
-        auto res = Thread::current->block<Thread::ReadBlocker>(description);
+        auto res = Thread::current()->block<Thread::ReadBlocker>(description);
         locker.lock();
 
         if (!m_can_read) {
@@ -261,7 +261,7 @@ ssize_t IPv4Socket::receive_byte_buffered(FileDescription& description, void* bu
     ASSERT(!m_receive_buffer.is_empty());
     int nreceived = m_receive_buffer.read((u8*)buffer, buffer_length);
     if (nreceived > 0)
-        Thread::current->did_ipv4_socket_read((size_t)nreceived);
+        Thread::current()->did_ipv4_socket_read((size_t)nreceived);
 
     m_can_read = !m_receive_buffer.is_empty();
     return nreceived;
@@ -296,7 +296,7 @@ ssize_t IPv4Socket::receive_packet_buffered(FileDescription& description, void*
         }
 
         locker.unlock();
-        auto res = Thread::current->block<Thread::ReadBlocker>(description);
+        auto res = Thread::current()->block<Thread::ReadBlocker>(description);
         locker.lock();
 
         if (!m_can_read) {
@@ -354,7 +354,7 @@ ssize_t IPv4Socket::recvfrom(FileDescription& description, void* buffer, size_t
         nreceived = receive_packet_buffered(description, buffer, buffer_length, flags, addr, addr_length);
 
     if (nreceived > 0)
-        Thread::current->did_ipv4_socket_read(nreceived);
+        Thread::current()->did_ipv4_socket_read(nreceived);
     return nreceived;
 }
 
@@ -468,7 +468,7 @@ int IPv4Socket::ioctl(FileDescription&, unsigned request, FlatPtr arg)
 
     auto ioctl_route = [request, arg]() {
         auto* route = (rtentry*)arg;
-        if (!Process::current->validate_read_typed(route))
+        if (!Process::current()->validate_read_typed(route))
             return -EFAULT;
 
         char namebuf[IFNAMSIZ + 1];
@@ -481,7 +481,7 @@ int IPv4Socket::ioctl(FileDescription&, unsigned request, FlatPtr arg)
 
         switch (request) {
         case SIOCADDRT:
-            if (!Process::current->is_superuser())
+            if (!Process::current()->is_superuser())
                 return -EPERM;
             if (route->rt_gateway.sa_family != AF_INET)
                 return -EAFNOSUPPORT;
@@ -500,7 +500,7 @@ int IPv4Socket::ioctl(FileDescription&, unsigned request, FlatPtr arg)
 
     auto ioctl_interface = [request, arg]() {
         auto* ifr = (ifreq*)arg;
-        if (!Process::current->validate_read_typed(ifr))
+        if (!Process::current()->validate_read_typed(ifr))
             return -EFAULT;
 
         char namebuf[IFNAMSIZ + 1];
@@ -513,7 +513,7 @@ int IPv4Socket::ioctl(FileDescription&, unsigned request, FlatPtr arg)
 
         switch (request) {
         case SIOCSIFADDR:
-            if (!Process::current->is_superuser())
+            if (!Process::current()->is_superuser())
                 return -EPERM;
             if (ifr->ifr_addr.sa_family != AF_INET)
                 return -EAFNOSUPPORT;
@@ -521,7 +521,7 @@ int IPv4Socket::ioctl(FileDescription&, unsigned request, FlatPtr arg)
             return 0;
 
         case SIOCSIFNETMASK:
-            if (!Process::current->is_superuser())
+            if (!Process::current()->is_superuser())
                 return -EPERM;
             if (ifr->ifr_addr.sa_family != AF_INET)
                 return -EAFNOSUPPORT;
@@ -529,14 +529,14 @@ int IPv4Socket::ioctl(FileDescription&, unsigned request, FlatPtr arg)
             return 0;
 
         case SIOCGIFADDR:
-            if (!Process::current->validate_write_typed(ifr))
+            if (!Process::current()->validate_write_typed(ifr))
                 return -EFAULT;
             ifr->ifr_addr.sa_family = AF_INET;
             ((sockaddr_in&)ifr->ifr_addr).sin_addr.s_addr = adapter->ipv4_address().to_u32();
             return 0;
 
         case SIOCGIFHWADDR:
-            if (!Process::current->validate_write_typed(ifr))
+            if (!Process::current()->validate_write_typed(ifr))
                 return -EFAULT;
             ifr->ifr_hwaddr.sa_family = AF_INET;
             {

Kernel/Net/LocalSocket.cpp

@@ -63,8 +63,9 @@ LocalSocket::LocalSocket(int type)
     LOCKER(all_sockets().lock());
     all_sockets().resource().append(this);
 
-    m_prebind_uid = Process::current->uid();
+    auto current_process = Process::current();
-    m_prebind_gid = Process::current->gid();
+    m_prebind_uid = current_process->uid();
+    m_prebind_gid = current_process->gid();
     m_prebind_mode = 0666;
 
 #ifdef DEBUG_LOCAL_SOCKET
@@ -110,7 +111,7 @@ KResult LocalSocket::bind(const sockaddr* user_address, socklen_t address_size)
 
     mode_t mode = S_IFSOCK | (m_prebind_mode & 04777);
     UidAndGid owner { m_prebind_uid, m_prebind_gid };
-    auto result = VFS::the().open(path, O_CREAT | O_EXCL | O_NOFOLLOW_NOERROR, mode, Process::current->current_directory(), owner);
+    auto result = VFS::the().open(path, O_CREAT | O_EXCL | O_NOFOLLOW_NOERROR, mode, Process::current()->current_directory(), owner);
     if (result.is_error()) {
         if (result.error() == -EEXIST)
             return KResult(-EADDRINUSE);
@@ -148,7 +149,7 @@ KResult LocalSocket::connect(FileDescription& description, const sockaddr* addre
     dbg() << "LocalSocket{" << this << "} connect(" << safe_address << ")";
 #endif
 
-    auto description_or_error = VFS::the().open(safe_address, O_RDWR, 0, Process::current->current_directory());
+    auto description_or_error = VFS::the().open(safe_address, O_RDWR, 0, Process::current()->current_directory());
     if (description_or_error.is_error())
         return KResult(-ECONNREFUSED);
 
@@ -175,7 +176,7 @@ KResult LocalSocket::connect(FileDescription& description, const sockaddr* addre
         return KSuccess;
     }
 
-    if (Thread::current->block<Thread::ConnectBlocker>(description) != Thread::BlockResult::WokeNormally) {
+    if (Thread::current()->block<Thread::ConnectBlocker>(description) != Thread::BlockResult::WokeNormally) {
         m_connect_side_role = Role::None;
         return KResult(-EINTR);
     }
@@ -265,7 +266,7 @@ ssize_t LocalSocket::sendto(FileDescription& description, const void* data, size
         return -EPIPE;
     ssize_t nwritten = send_buffer_for(description).write((const u8*)data, data_size);
     if (nwritten > 0)
-        Thread::current->did_unix_socket_write(nwritten);
+        Thread::current()->did_unix_socket_write(nwritten);
     return nwritten;
 }
 
@@ -299,7 +300,7 @@ ssize_t LocalSocket::recvfrom(FileDescription& description, void* buffer, size_t
             return -EAGAIN;
         }
     } else if (!can_read(description, 0)) {
-        auto result = Thread::current->block<Thread::ReadBlocker>(description);
+        auto result = Thread::current()->block<Thread::ReadBlocker>(description);
         if (result != Thread::BlockResult::WokeNormally)
             return -EINTR;
     }
@@ -308,7 +309,7 @@ ssize_t LocalSocket::recvfrom(FileDescription& description, void* buffer, size_t
     ASSERT(!buffer_for_me.is_empty());
     int nread = buffer_for_me.read((u8*)buffer, buffer_size);
     if (nread > 0)
-        Thread::current->did_unix_socket_read(nread);
+        Thread::current()->did_unix_socket_read(nread);
     return nread;
 }
 
@@ -389,7 +390,8 @@ KResult LocalSocket::chown(FileDescription&, uid_t uid, gid_t gid)
     if (m_file)
         return m_file->chown(uid, gid);
 
-    if (!Process::current->is_superuser() && (Process::current->euid() != uid || !Process::current->in_group(gid)))
+    auto current_process = Process::current();
+    if (!current_process->is_superuser() && (current_process->euid() != uid || !current_process->in_group(gid)))
         return KResult(-EPERM);
 
     m_prebind_uid = uid;

Kernel/Net/NetworkTask.cpp

@@ -113,7 +113,7 @@ void NetworkTask_main()
     for (;;) {
         size_t packet_size = dequeue_packet(buffer, buffer_size);
         if (!packet_size) {
-            Thread::current->wait_on(packet_wait_queue);
+            Thread::current()->wait_on(packet_wait_queue);
             continue;
         }
         if (packet_size < sizeof(EthernetFrameHeader)) {

Kernel/Net/Routing.cpp

@@ -135,7 +135,7 @@ RoutingDecision route_to(const IPv4Address& target, const IPv4Address& source, c
     request.set_sender_protocol_address(adapter->ipv4_address());
     adapter->send({ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff }, request);
 
-    (void)Thread::current->block_until("Routing (ARP)", [next_hop_ip] {
+    (void)Thread::current()->block_until("Routing (ARP)", [next_hop_ip] {
         return arp_table().resource().get(next_hop_ip).has_value();
     });
 

Kernel/Net/Socket.cpp

@@ -55,7 +55,7 @@ Socket::Socket(int domain, int type, int protocol)
     , m_type(type)
     , m_protocol(protocol)
 {
-    auto& process = *Process::current;
+    auto& process = *Process::current();
     m_origin = { process.pid(), process.uid(), process.gid() };
 }
 
@@ -82,7 +82,7 @@ RefPtr<Socket> Socket::accept()
 #endif
     auto client = m_pending.take_first();
     ASSERT(!client->is_connected());
-    auto& process = *Process::current;
+    auto& process = *Process::current();
     client->m_acceptor = { process.pid(), process.uid(), process.gid() };
     client->m_connected = true;
     client->m_role = Role::Accepted;

Kernel/Net/TCPSocket.cpp

@@ -372,7 +372,7 @@ KResult TCPSocket::protocol_connect(FileDescription& description, ShouldBlock sh
     m_direction = Direction::Outgoing;
 
     if (should_block == ShouldBlock::Yes) {
-        if (Thread::current->block<Thread::ConnectBlocker>(description) != Thread::BlockResult::WokeNormally)
+        if (Thread::current()->block<Thread::ConnectBlocker>(description) != Thread::BlockResult::WokeNormally)
             return KResult(-EINTR);
         ASSERT(setup_state() == SetupState::Completed);
         if (has_error()) {

Kernel/PerformanceEventBuffer.cpp

@@ -67,11 +67,12 @@ KResult PerformanceEventBuffer::append(int type, FlatPtr arg1, FlatPtr arg2)
     asm volatile("movl %%ebp, %%eax"
                  : "=a"(ebp));
     FlatPtr eip;
-    copy_from_user(&eip, (FlatPtr*)&Thread::current->get_register_dump_from_stack().eip);
+    auto current_thread = Thread::current();
+    copy_from_user(&eip, (FlatPtr*)&current_thread->get_register_dump_from_stack().eip);
     Vector<FlatPtr> backtrace;
     {
         SmapDisabler disabler;
-        backtrace = Thread::current->raw_backtrace(ebp, eip);
+        backtrace = current_thread->raw_backtrace(ebp, eip);
     }
     event.stack_size = min(sizeof(event.stack) / sizeof(FlatPtr), static_cast<size_t>(backtrace.size()));
     memcpy(event.stack, backtrace.data(), event.stack_size * sizeof(FlatPtr));

Kernel/Process.cpp

@@ -84,10 +84,10 @@
 #include <LibELF/Validation.h>
 #include <LibKeyboard/CharacterMapData.h>
 
-//#define PROCESS_DEBUG
+#define PROCESS_DEBUG
 //#define DEBUG_POLL_SELECT
 //#define DEBUG_IO
-//#define TASK_DEBUG
+#define TASK_DEBUG
 //#define FORK_DEBUG
 //#define EXEC_DEBUG
 //#define SIGNAL_DEBUG
@@ -97,9 +97,8 @@ namespace Kernel {
 
 static void create_signal_trampolines();
 
-Process* Process::current;
+RecursiveSpinLock g_processes_lock;
-
+static Atomic<pid_t> next_pid;
-static pid_t next_pid;
 InlineLinkedList<Process>* g_processes;
 static String* s_hostname;
 static Lock* s_hostname_lock;
@@ -108,15 +107,14 @@ HashMap<String, OwnPtr<Module>>* g_modules;
 
 pid_t Process::allocate_pid()
 {
-    InterruptDisabler disabler;
+    return next_pid.fetch_add(1, AK::MemoryOrder::memory_order_acq_rel);
-    return next_pid++;
 }
 
 void Process::initialize()
 {
     g_modules = new HashMap<String, OwnPtr<Module>>;
 
-    next_pid = 0;
+    next_pid.store(0, AK::MemoryOrder::memory_order_release);
     g_processes = new InlineLinkedList<Process>;
     s_hostname = new String("courage");
     s_hostname_lock = new Lock;
@@ -127,7 +125,7 @@ void Process::initialize()
 Vector<pid_t> Process::all_pids()
 {
     Vector<pid_t> pids;
-    InterruptDisabler disabler;
+    ScopedSpinLock lock(g_processes_lock);
     pids.ensure_capacity((int)g_processes->size_slow());
     for (auto& process : *g_processes)
         pids.append(process.pid());
@@ -137,7 +135,7 @@ Vector<pid_t> Process::all_pids()
 Vector<Process*> Process::all_processes()
 {
     Vector<Process*> processes;
-    InterruptDisabler disabler;
+    ScopedSpinLock lock(g_processes_lock);
     processes.ensure_capacity((int)g_processes->size_slow());
     for (auto& process : *g_processes)
         processes.append(&process);
@@ -234,7 +232,7 @@ Region* Process::allocate_region_with_vmobject(VirtualAddress vaddr, size_t size
 
 bool Process::deallocate_region(Region& region)
 {
-    InterruptDisabler disabler;
+    ScopedSpinLock lock(m_lock);
     if (m_region_lookup_cache.region == &region)
         m_region_lookup_cache.region = nullptr;
     for (size_t i = 0; i < m_regions.size(); ++i) {
@@ -248,6 +246,7 @@ bool Process::deallocate_region(Region& region)
 
 Region* Process::region_from_range(const Range& range)
 {
+    ScopedSpinLock lock(m_lock);
     if (m_region_lookup_cache.range == range && m_region_lookup_cache.region)
         return m_region_lookup_cache.region;
 
@@ -264,6 +263,7 @@ Region* Process::region_from_range(const Range& range)
 
 Region* Process::region_containing(const Range& range)
 {
+    ScopedSpinLock lock(m_lock);
     for (auto& region : m_regions) {
         if (region.contains(range))
             return &region;
@@ -738,17 +738,6 @@ pid_t Process::sys$fork(RegisterState& regs)
     dbg() << "fork: child=" << child;
 #endif
 
-    for (auto& region : m_regions) {
-#ifdef FORK_DEBUG
-        dbg() << "fork: cloning Region{" << &region << "} '" << region.name() << "' @ " << region.vaddr();
-#endif
-        auto& child_region = child->add_region(region.clone());
-        child_region.map(child->page_directory());
-
-        if (&region == m_master_tls_region)
-            child->m_master_tls_region = child_region.make_weak_ptr();
-    }
-
     child->m_extra_gids = m_extra_gids;
 
     auto& child_tss = child_first_thread->m_tss;
@@ -773,8 +762,20 @@ pid_t Process::sys$fork(RegisterState& regs)
     dbg() << "fork: child will begin executing at " << String::format("%w", child_tss.cs) << ":" << String::format("%x", child_tss.eip) << " with stack " << String::format("%w", child_tss.ss) << ":" << String::format("%x", child_tss.esp) << ", kstack " << String::format("%w", child_tss.ss0) << ":" << String::format("%x", child_tss.esp0);
 #endif
 
+    ScopedSpinLock lock(m_lock);
+    for (auto& region : m_regions) {
+#ifdef FORK_DEBUG
+        dbg() << "fork: cloning Region{" << &region << "} '" << region.name() << "' @ " << region.vaddr();
+#endif
+        auto& child_region = child->add_region(region.clone());
+        child_region.map(child->page_directory());
+
+        if (&region == m_master_tls_region)
+            child->m_master_tls_region = child_region.make_weak_ptr();
+    }
+
     {
-        InterruptDisabler disabler;
+        ScopedSpinLock lock(g_processes_lock);
         g_processes->prepend(child);
     }
 #ifdef TASK_DEBUG
@@ -789,11 +790,12 @@ void Process::kill_threads_except_self()
 {
     InterruptDisabler disabler;
 
-    if (m_thread_count <= 1)
+    if (thread_count() <= 1)
         return;
 
+    auto current_thread = Thread::current();
     for_each_thread([&](Thread& thread) {
-        if (&thread == Thread::current
+        if (&thread == current_thread
             || thread.state() == Thread::State::Dead
             || thread.state() == Thread::State::Dying)
             return IterationDecision::Continue;
@@ -857,7 +859,8 @@ int Process::do_exec(NonnullRefPtr<FileDescription> main_program_description, Ve
 
     // Mark this thread as the current thread that does exec
     // No other thread from this process will be scheduled to run
-    m_exec_tid = Thread::current->tid();
+    auto current_thread = Thread::current();
+    m_exec_tid = current_thread->tid();
 
     RefPtr<PageDirectory> old_page_directory;
     NonnullOwnPtrVector<Region> old_regions;
@@ -905,7 +908,7 @@ int Process::do_exec(NonnullRefPtr<FileDescription> main_program_description, Ve
     RefPtr<ELF::Loader> loader;
     {
         ArmedScopeGuard rollback_regions_guard([&]() {
-            ASSERT(Process::current == this);
+            ASSERT(Process::current() == this);
             // Need to make sure we don't swap contexts in the middle
             InterruptDisabler disabler;
             m_page_directory = move(old_page_directory);
@@ -1005,9 +1008,9 @@ int Process::do_exec(NonnullRefPtr<FileDescription> main_program_description, Ve
             m_egid = m_sgid = main_program_metadata.gid;
     }
 
-    Thread::current->set_default_signal_dispositions();
+    current_thread->set_default_signal_dispositions();
-    Thread::current->m_signal_mask = 0;
+    current_thread->m_signal_mask = 0;
-    Thread::current->m_pending_signals = 0;
+    current_thread->m_pending_signals = 0;
 
     m_futex_queues.clear();
 
@@ -1024,8 +1027,8 @@ int Process::do_exec(NonnullRefPtr<FileDescription> main_program_description, Ve
     }
 
     Thread* new_main_thread = nullptr;
-    if (Process::current == this) {
+    if (&current_thread->process() == this) {
-        new_main_thread = Thread::current;
+        new_main_thread = current_thread;
     } else {
         for_each_thread([&](auto& thread) {
             new_main_thread = &thread;
@@ -1041,7 +1044,7 @@ int Process::do_exec(NonnullRefPtr<FileDescription> main_program_description, Ve
     // We cli() manually here because we don't want to get interrupted between do_exec() and Processor::assume_context().
     // The reason is that the task redirection we've set up above will be clobbered by the timer IRQ.
     // If we used an InterruptDisabler that sti()'d on exit, we might timer tick'd too soon in exec().
-    if (Process::current == this)
+    if (&current_thread->process() == this)
         cli();
 
     // NOTE: Be careful to not trigger any page faults below!
@@ -1253,16 +1256,17 @@ int Process::exec(String path, Vector<String> arguments, Vector<String> environm
     if (rc < 0)
         return rc;
 
+    auto current_thread = Thread::current();
     if (m_wait_for_tracer_at_next_execve) {
-        ASSERT(Thread::current->state() == Thread::State::Skip1SchedulerPass);
+        ASSERT(current_thread->state() == Thread::State::Skip1SchedulerPass);
         // State::Skip1SchedulerPass is irrelevant since we block the thread
-        Thread::current->set_state(Thread::State::Running);
+        current_thread->set_state(Thread::State::Running);
-        Thread::current->send_urgent_signal_to_self(SIGSTOP);
+        current_thread->send_urgent_signal_to_self(SIGSTOP);
     }
 
-    if (Process::current == this) {
+    if (&current_thread->process() == this) {
-        Thread::current->set_state(Thread::State::Running);
+        current_thread->set_state(Thread::State::Running);
-        Processor::assume_context(*Thread::current);
+        Processor::assume_context(*current_thread);
         ASSERT_NOT_REACHED();
     }
     return 0;
@@ -1282,7 +1286,7 @@ int Process::sys$execve(const Syscall::SC_execve_params* user_params)
         return -E2BIG;
 
     if (m_wait_for_tracer_at_next_execve)
-        Thread::current->send_urgent_signal_to_self(SIGSTOP);
+        Thread::current()->send_urgent_signal_to_self(SIGSTOP);
 
     String path;
     {
@@ -1331,7 +1335,7 @@ Process* Process::create_user_process(Thread*& first_thread, const String& path,
     RefPtr<Custody> cwd;
     RefPtr<Custody> root;
     {
-        InterruptDisabler disabler;
+        ScopedSpinLock lock(g_processes_lock);
         if (auto* parent = Process::from_pid(parent_pid)) {
             cwd = parent->m_cwd;
             root = parent->m_root_directory;
@@ -1361,7 +1365,7 @@ Process* Process::create_user_process(Thread*& first_thread, const String& path,
     }
 
     {
-        InterruptDisabler disabler;
+        ScopedSpinLock lock(g_processes_lock);
         g_processes->prepend(process);
     }
 #ifdef TASK_DEBUG
@@ -1371,19 +1375,20 @@ Process* Process::create_user_process(Thread*& first_thread, const String& path,
     return process;
 }
 
-Process* Process::create_kernel_process(Thread*& first_thread, String&& name, void (*e)())
+Process* Process::create_kernel_process(Thread*& first_thread, String&& name, void (*e)(), u32 affinity)
 {
     auto* process = new Process(first_thread, move(name), (uid_t)0, (gid_t)0, (pid_t)0, Ring0);
     first_thread->tss().eip = (FlatPtr)e;
 
     if (process->pid() != 0) {
-        InterruptDisabler disabler;
+        ScopedSpinLock lock(g_processes_lock);
         g_processes->prepend(process);
 #ifdef TASK_DEBUG
         klog() << "Kernel process " << process->pid() << " (" << process->name().characters() << ") spawned @ " << String::format("%p", first_thread->tss().eip);
 #endif
     }
 
+    first_thread->set_affinity(affinity);
     first_thread->set_state(Thread::State::Runnable);
     return process;
 }
@@ -1414,7 +1419,7 @@ Process::Process(Thread*& first_thread, const String& name, uid_t uid, gid_t gid
 
     if (fork_parent) {
         // NOTE: fork() doesn't clone all threads; the thread that called fork() becomes the only thread in the new process.
-        first_thread = Thread::current->clone(*this);
+        first_thread = Thread::current()->clone(*this);
     } else {
         // NOTE: This non-forked code path is only taken when the kernel creates a process "manually" (at boot.)
         first_thread = new Thread(*this);
@@ -1449,7 +1454,7 @@ void Process::sys$exit(int status)
     m_termination_status = status;
     m_termination_signal = 0;
     die();
-    Thread::current->die_if_needed();
+    Thread::current()->die_if_needed();
     ASSERT_NOT_REACHED();
 }
 
@@ -1513,7 +1518,7 @@ int Process::sys$sigreturn(RegisterState& registers)
     //pop the stored eax, ebp, return address, handler and signal code
     stack_ptr += 5;
 
-    Thread::current->m_signal_mask = *stack_ptr;
+    Thread::current()->m_signal_mask = *stack_ptr;
     stack_ptr++;
 
     //pop edi, esi, ebp, esp, ebx, edx, ecx and eax
@@ -1534,7 +1539,7 @@ void Process::crash(int signal, u32 eip, bool out_of_memory)
 {
     ASSERT_INTERRUPTS_DISABLED();
     ASSERT(!is_dead());
-    ASSERT(Process::current == this);
+    ASSERT(Process::current() == this);
 
     if (out_of_memory) {
         dbg() << "\033[31;1mOut of memory\033[m, killing: " << *this;
@@ -1555,13 +1560,14 @@ void Process::crash(int signal, u32 eip, bool out_of_memory)
     die();
     // We can not return from here, as there is nowhere
     // to unwind to, so die right away.
-    Thread::current->die_if_needed();
+    Thread::current()->die_if_needed();
     ASSERT_NOT_REACHED();
 }
 
 Process* Process::from_pid(pid_t pid)
 {
     ASSERT_INTERRUPTS_DISABLED();
+    ScopedSpinLock lock(g_processes_lock);
     for (auto& process : *g_processes) {
         if (process.pid() == pid)
             return &process;
@@ -1713,7 +1719,7 @@ ssize_t Process::do_write(FileDescription& description, const u8* data, int data
 #ifdef IO_DEBUG
             dbg() << "block write on " << description.absolute_path();
 #endif
-            if (Thread::current->block<Thread::WriteBlocker>(description) != Thread::BlockResult::WokeNormally) {
+            if (Thread::current()->block<Thread::WriteBlocker>(description) != Thread::BlockResult::WokeNormally) {
                 if (nwritten == 0)
                     return -EINTR;
             }
@@ -1776,7 +1782,7 @@ ssize_t Process::sys$read(int fd, u8* buffer, ssize_t size)
         return -EISDIR;
     if (description->is_blocking()) {
         if (!description->can_read()) {
-            if (Thread::current->block<Thread::ReadBlocker>(*description) != Thread::BlockResult::WokeNormally)
+            if (Thread::current()->block<Thread::ReadBlocker>(*description) != Thread::BlockResult::WokeNormally)
                 return -EINTR;
             if (!description->can_read())
                 return -EAGAIN;
@@ -2323,6 +2329,7 @@ KResult Process::do_killall(int signal)
     KResult error = KSuccess;
 
     // Send the signal to all processes we have access to for.
+    ScopedSpinLock lock(g_processes_lock);
     for (auto& process : *g_processes) {
         KResult res = KSuccess;
         if (process.pid() == m_pid)
@@ -2346,9 +2353,10 @@ KResult Process::do_killself(int signal)
     if (signal == 0)
         return KSuccess;
 
-    if (!Thread::current->should_ignore_signal(signal)) {
+    auto current_thread = Thread::current();
-        Thread::current->send_signal(signal, this);
+    if (!current_thread->should_ignore_signal(signal)) {
-        (void)Thread::current->block<Thread::SemiPermanentBlocker>(Thread::SemiPermanentBlocker::Reason::Signal);
+        current_thread->send_signal(signal, this);
+        (void)current_thread->block<Thread::SemiPermanentBlocker>(Thread::SemiPermanentBlocker::Reason::Signal);
     }
 
     return KSuccess;
@@ -2373,7 +2381,7 @@ int Process::sys$kill(pid_t pid, int signal)
     if (pid == m_pid) {
         return do_killself(signal);
     }
-    InterruptDisabler disabler;
+    ScopedSpinLock lock(g_processes_lock);
     auto* peer = Process::from_pid(pid);
     if (!peer)
         return -ESRCH;
@@ -2385,7 +2393,7 @@ int Process::sys$usleep(useconds_t usec)
     REQUIRE_PROMISE(stdio);
     if (!usec)
         return 0;
-    u64 wakeup_time = Thread::current->sleep(usec / 1000);
+    u64 wakeup_time = Thread::current()->sleep(usec / 1000);
     if (wakeup_time > g_uptime)
         return -EINTR;
     return 0;
@@ -2396,7 +2404,7 @@ int Process::sys$sleep(unsigned seconds)
     REQUIRE_PROMISE(stdio);
     if (!seconds)
         return 0;
-    u64 wakeup_time = Thread::current->sleep(seconds * TimeManagement::the().ticks_per_second());
+    u64 wakeup_time = Thread::current()->sleep(seconds * TimeManagement::the().ticks_per_second());
     if (wakeup_time > g_uptime) {
         u32 ticks_left_until_original_wakeup_time = wakeup_time - g_uptime;
         return ticks_left_until_original_wakeup_time / TimeManagement::the().ticks_per_second();
@@ -2519,23 +2527,22 @@ siginfo_t Process::reap(Process& process)
         siginfo.si_code = CLD_EXITED;
     }
 
-    {
+    ASSERT(g_processes_lock.is_locked());
-        InterruptDisabler disabler;
 
-        if (process.ppid()) {
+    if (process.ppid()) {
-            auto* parent = Process::from_pid(process.ppid());
+        auto* parent = Process::from_pid(process.ppid());
-            if (parent) {
+        if (parent) {
-                parent->m_ticks_in_user_for_dead_children += process.m_ticks_in_user + process.m_ticks_in_user_for_dead_children;
+            parent->m_ticks_in_user_for_dead_children += process.m_ticks_in_user + process.m_ticks_in_user_for_dead_children;
-                parent->m_ticks_in_kernel_for_dead_children += process.m_ticks_in_kernel + process.m_ticks_in_kernel_for_dead_children;
+            parent->m_ticks_in_kernel_for_dead_children += process.m_ticks_in_kernel + process.m_ticks_in_kernel_for_dead_children;
-            }
         }
+    }
 
 #ifdef PROCESS_DEBUG
-        dbg() << "Reaping process " << process;
+    dbg() << "Reaping process " << process;
 #endif
-        ASSERT(process.is_dead());
+    ASSERT(process.is_dead());
-        g_processes->remove(&process);
+    g_processes->remove(&process);
-    }
+
     delete &process;
     return siginfo;
 }
@@ -2543,7 +2550,7 @@ siginfo_t Process::reap(Process& process)
 KResultOr<siginfo_t> Process::do_waitid(idtype_t idtype, int id, int options)
 {
     if (idtype == P_PID) {
-        InterruptDisabler disabler;
+        ScopedSpinLock lock(g_processes_lock);
         if (idtype == P_PID && !Process::from_pid(id))
             return KResult(-ECHILD);
     }
@@ -2560,10 +2567,10 @@ KResultOr<siginfo_t> Process::do_waitid(idtype_t idtype, int id, int options)
         return KResult(-EINVAL);
     }
 
-    if (Thread::current->block<Thread::WaitBlocker>(options, waitee_pid) != Thread::BlockResult::WokeNormally)
+    if (Thread::current()->block<Thread::WaitBlocker>(options, waitee_pid) != Thread::BlockResult::WokeNormally)
         return KResult(-EINTR);
 
-    InterruptDisabler disabler;
+    ScopedSpinLock lock(g_processes_lock);
 
     // NOTE: If waitee was -1, m_waitee_pid will have been filled in by the scheduler.
     Process* waitee_process = Process::from_pid(waitee_pid);
@@ -2660,7 +2667,7 @@ pid_t Process::sys$getsid(pid_t pid)
     REQUIRE_PROMISE(proc);
     if (pid == 0)
         return m_sid;
-    InterruptDisabler disabler;
+    ScopedSpinLock lock(g_processes_lock);
     auto* process = Process::from_pid(pid);
     if (!process)
         return -ESRCH;
@@ -2691,7 +2698,7 @@ pid_t Process::sys$getpgid(pid_t pid)
     REQUIRE_PROMISE(proc);
     if (pid == 0)
         return m_pgid;
-    InterruptDisabler disabler; // FIXME: Use a ProcessHandle
+    ScopedSpinLock lock(g_processes_lock); // FIXME: Use a ProcessHandle
     auto* process = Process::from_pid(pid);
     if (!process)
         return -ESRCH;
@@ -2706,7 +2713,7 @@ pid_t Process::sys$getpgrp()
 
 static pid_t get_sid_from_pgid(pid_t pgid)
 {
-    InterruptDisabler disabler;
+    ScopedSpinLock lock(g_processes_lock);
     auto* group_leader = Process::from_pid(pgid);
     if (!group_leader)
         return -1;
@@ -2716,7 +2723,7 @@ static pid_t get_sid_from_pgid(pid_t pgid)
 int Process::sys$setpgid(pid_t specified_pid, pid_t specified_pgid)
 {
     REQUIRE_PROMISE(proc);
-    InterruptDisabler disabler; // FIXME: Use a ProcessHandle
+    ScopedSpinLock lock(g_processes_lock); // FIXME: Use a ProcessHandle
     pid_t pid = specified_pid ? specified_pid : m_pid;
     if (specified_pgid < 0) {
         // The value of the pgid argument is less than 0, or is not a value supported by the implementation.
@@ -2790,10 +2797,11 @@ int Process::sys$dup2(int old_fd, int new_fd)
 int Process::sys$sigprocmask(int how, const sigset_t* set, sigset_t* old_set)
 {
     REQUIRE_PROMISE(sigaction);
+    auto current_thread = Thread::current();
     if (old_set) {
         if (!validate_write_typed(old_set))
             return -EFAULT;
-        copy_to_user(old_set, &Thread::current->m_signal_mask);
+        copy_to_user(old_set, &current_thread->m_signal_mask);
     }
     if (set) {
         if (!validate_read_typed(set))
@@ -2802,13 +2810,13 @@ int Process::sys$sigprocmask(int how, const sigset_t* set, sigset_t* old_set)
         copy_from_user(&set_value, set);
         switch (how) {
         case SIG_BLOCK:
-            Thread::current->m_signal_mask &= ~set_value;
+            current_thread->m_signal_mask &= ~set_value;
             break;
         case SIG_UNBLOCK:
-            Thread::current->m_signal_mask |= set_value;
+            current_thread->m_signal_mask |= set_value;
             break;
         case SIG_SETMASK:
-            Thread::current->m_signal_mask = set_value;
+            current_thread->m_signal_mask = set_value;
             break;
         default:
             return -EINVAL;
@@ -2822,7 +2830,7 @@ int Process::sys$sigpending(sigset_t* set)
     REQUIRE_PROMISE(stdio);
     if (!validate_write_typed(set))
         return -EFAULT;
-    copy_to_user(set, &Thread::current->m_pending_signals);
+    copy_to_user(set, &Thread::current()->m_pending_signals);
     return 0;
 }
 
@@ -2834,7 +2842,7 @@ int Process::sys$sigaction(int signum, const sigaction* act, sigaction* old_act)
     if (!validate_read_typed(act))
         return -EFAULT;
     InterruptDisabler disabler; // FIXME: This should use a narrower lock. Maybe a way to ignore signals temporarily?
-    auto& action = Thread::current->m_signal_action_data[signum];
+    auto& action = Thread::current()->m_signal_action_data[signum];
     if (old_act) {
         if (!validate_write_typed(old_act))
             return -EFAULT;
@@ -2988,9 +2996,10 @@ int Process::sys$select(const Syscall::SC_select_params* params)
         select_has_timeout = true;
     }
 
-    ScopedValueRollback scoped_sigmask(Thread::current->m_signal_mask);
+    auto current_thread = Thread::current();
+    ScopedValueRollback scoped_sigmask(current_thread->m_signal_mask);
     if (sigmask)
-        Thread::current->m_signal_mask = *sigmask;
+        current_thread->m_signal_mask = *sigmask;
 
     Thread::SelectBlocker::FDVector rfds;
     Thread::SelectBlocker::FDVector wfds;
@@ -3023,7 +3032,7 @@ int Process::sys$select(const Syscall::SC_select_params* params)
 #endif
 
     if (!timeout || select_has_timeout) {
-        if (Thread::current->block<Thread::SelectBlocker>(computed_timeout, select_has_timeout, rfds, wfds, efds) != Thread::BlockResult::WokeNormally)
+        if (current_thread->block<Thread::SelectBlocker>(computed_timeout, select_has_timeout, rfds, wfds, efds) != Thread::BlockResult::WokeNormally)
             return -EINTR;
         // While we blocked, the process lock was dropped. This gave other threads
         // the opportunity to mess with the memory. For example, it could free the
@@ -3099,16 +3108,17 @@ int Process::sys$poll(const Syscall::SC_poll_params* params)
         has_timeout = true;
     }
 
-    ScopedValueRollback scoped_sigmask(Thread::current->m_signal_mask);
+    auto current_thread = Thread::current();
+    ScopedValueRollback scoped_sigmask(current_thread->m_signal_mask);
     if (sigmask)
-        Thread::current->m_signal_mask = *sigmask;
+        current_thread->m_signal_mask = *sigmask;
 
 #if defined(DEBUG_IO) || defined(DEBUG_POLL_SELECT)
     dbg() << "polling on (read:" << rfds.size() << ", write:" << wfds.size() << "), timeout=" << timeout;
 #endif
 
     if (!timeout || has_timeout) {
-        if (Thread::current->block<Thread::SelectBlocker>(actual_timeout, has_timeout, rfds, wfds, Thread::SelectBlocker::FDVector()) != Thread::BlockResult::WokeNormally)
+        if (current_thread->block<Thread::SelectBlocker>(actual_timeout, has_timeout, rfds, wfds, Thread::SelectBlocker::FDVector()) != Thread::BlockResult::WokeNormally)
             return -EINTR;
     }
 
@@ -3245,7 +3255,7 @@ int Process::sys$chown(const Syscall::SC_chown_params* user_params)
 
 void Process::finalize()
 {
-    ASSERT(Thread::current == g_finalizer);
+    ASSERT(Thread::current() == g_finalizer);
 #ifdef PROCESS_DEBUG
     dbg() << "Finalizing process " << *this;
 #endif
@@ -3460,7 +3470,7 @@ int Process::sys$accept(int accepting_socket_fd, sockaddr* user_address, socklen
 
     if (!socket.can_accept()) {
         if (accepting_socket_description->is_blocking()) {
-            if (Thread::current->block<Thread::AcceptBlocker>(*accepting_socket_description) != Thread::BlockResult::WokeNormally)
+            if (Thread::current()->block<Thread::AcceptBlocker>(*accepting_socket_description) != Thread::BlockResult::WokeNormally)
                 return -EINTR;
         } else {
             return -EAGAIN;
@@ -3663,7 +3673,7 @@ int Process::sys$sched_setparam(int tid, const struct sched_param* param)
     copy_from_user(&desired_priority, &param->sched_priority);
 
     InterruptDisabler disabler;
-    auto* peer = Thread::current;
+    auto* peer = Thread::current();
     if (tid != 0)
         peer = Thread::from_tid(tid);
 
@@ -3687,7 +3697,7 @@ int Process::sys$sched_getparam(pid_t pid, struct sched_param* param)
         return -EFAULT;
 
     InterruptDisabler disabler;
-    auto* peer = Thread::current;
+    auto* peer = Thread::current();
     if (pid != 0)
         peer = Thread::from_tid(pid);
 
@@ -3808,7 +3818,7 @@ int Process::sys$shbuf_allow_pid(int shbuf_id, pid_t peer_pid)
     if (!shared_buffer.is_shared_with(m_pid))
         return -EPERM;
     {
-        InterruptDisabler disabler;
+        ScopedSpinLock lock(g_processes_lock);
         auto* peer = Process::from_pid(peer_pid);
         if (!peer)
             return -ESRCH;
@@ -3987,14 +3997,35 @@ int Process::sys$create_thread(void* (*entry)(void*), const Syscall::SC_create_t
     return thread->tid();
 }
 
+Thread* Process::create_kernel_thread(void (*entry)(), u32 priority, const String& name, u32 affinity, bool joinable)
+{
+    ASSERT((priority >= THREAD_PRIORITY_MIN) && (priority <= THREAD_PRIORITY_MAX));
+
+    // FIXME: Do something with guard pages?
+
+    auto* thread = new Thread(*this);
+
+    thread->set_name(name);
+    thread->set_affinity(affinity);
+    thread->set_priority(priority);
+    thread->set_joinable(joinable);
+
+    auto& tss = thread->tss();
+    tss.eip = (FlatPtr)entry;
+
+    thread->set_state(Thread::State::Runnable);
+    return thread;
+}
+
 void Process::sys$exit_thread(void* exit_value)
 {
     REQUIRE_PROMISE(thread);
     cli();
-    Thread::current->m_exit_value = exit_value;
+    auto current_thread = Thread::current();
-    Thread::current->set_should_die();
+    current_thread->m_exit_value = exit_value;
+    current_thread->set_should_die();
     big_lock().force_unlock_if_locked();
-    Thread::current->die_if_needed();
+    current_thread->die_if_needed();
     ASSERT_NOT_REACHED();
 }
 
@@ -4024,13 +4055,14 @@ int Process::sys$join_thread(int tid, void** exit_value)
     if (!thread || thread->pid() != pid())
         return -ESRCH;
 
-    if (thread == Thread::current)
+    auto current_thread = Thread::current();
+    if (thread == current_thread)
         return -EDEADLK;
 
-    if (thread->m_joinee == Thread::current)
+    if (thread->m_joinee == current_thread)
         return -EDEADLK;
 
-    ASSERT(thread->m_joiner != Thread::current);
+    ASSERT(thread->m_joiner != current_thread);
     if (thread->m_joiner)
         return -EINVAL;
 
@@ -4041,15 +4073,15 @@ int Process::sys$join_thread(int tid, void** exit_value)
 
     // NOTE: pthread_join() cannot be interrupted by signals. Only by death.
     for (;;) {
-        auto result = Thread::current->block<Thread::JoinBlocker>(*thread, joinee_exit_value);
+        auto result = current_thread->block<Thread::JoinBlocker>(*thread, joinee_exit_value);
         if (result == Thread::BlockResult::InterruptedByDeath) {
             // NOTE: This cleans things up so that Thread::finalize() won't
             //       get confused about a missing joiner when finalizing the joinee.
             InterruptDisabler disabler_t;
 
-            if (Thread::current->m_joinee) {
+            if (current_thread->m_joinee) {
-                Thread::current->m_joinee->m_joiner = nullptr;
+                current_thread->m_joinee->m_joiner = nullptr;
-                Thread::current->m_joinee = nullptr;
+                current_thread->m_joinee = nullptr;
             }
 
             break;
@@ -4107,7 +4139,7 @@ int Process::sys$get_thread_name(int tid, char* buffer, size_t buffer_size)
 int Process::sys$gettid()
 {
     REQUIRE_PROMISE(stdio);
-    return Thread::current->tid();
+    return Thread::current()->tid();
 }
 
 int Process::sys$donate(int tid)
@@ -4528,12 +4560,12 @@ int Process::sys$clock_nanosleep(const Syscall::SC_clock_nanosleep_params* user_
         u64 wakeup_time;
         if (is_absolute) {
             u64 time_to_wake = (requested_sleep.tv_sec * 1000 + requested_sleep.tv_nsec / 1000000);
-            wakeup_time = Thread::current->sleep_until(time_to_wake);
+            wakeup_time = Thread::current()->sleep_until(time_to_wake);
         } else {
             u32 ticks_to_sleep = (requested_sleep.tv_sec * 1000 + requested_sleep.tv_nsec / 1000000);
             if (!ticks_to_sleep)
                 return 0;
-            wakeup_time = Thread::current->sleep(ticks_to_sleep);
+            wakeup_time = Thread::current()->sleep(ticks_to_sleep);
         }
         if (wakeup_time > g_uptime) {
             u32 ticks_left = wakeup_time - g_uptime;
@@ -4571,14 +4603,14 @@ int Process::sys$sync()
 int Process::sys$yield()
 {
     REQUIRE_PROMISE(stdio);
-    Thread::current->yield_without_holding_big_lock();
+    Thread::current()->yield_without_holding_big_lock();
     return 0;
 }
 
 int Process::sys$beep()
 {
     PCSpeaker::tone_on(440);
-    u64 wakeup_time = Thread::current->sleep(100);
+    u64 wakeup_time = Thread::current()->sleep(100);
     PCSpeaker::tone_off();
     if (wakeup_time > g_uptime)
         return -EINTR;
@@ -4738,7 +4770,7 @@ int Process::sys$module_unload(const char* user_name, size_t name_length)
 int Process::sys$profiling_enable(pid_t pid)
 {
     REQUIRE_NO_PROMISES;
-    InterruptDisabler disabler;
+    ScopedSpinLock lock(g_processes_lock);
     auto* process = Process::from_pid(pid);
     if (!process)
         return -ESRCH;
@@ -4753,7 +4785,7 @@ int Process::sys$profiling_enable(pid_t pid)
 
 int Process::sys$profiling_disable(pid_t pid)
 {
-    InterruptDisabler disabler;
+    ScopedSpinLock lock(g_processes_lock);
     auto* process = Process::from_pid(pid);
     if (!process)
         return -ESRCH;
@@ -4811,7 +4843,7 @@ int Process::sys$futex(const Syscall::SC_futex_params* user_params)
         }
 
         // FIXME: This is supposed to be interruptible by a signal, but right now WaitQueue cannot be interrupted.
-        Thread::BlockResult result = Thread::current->wait_on(wait_queue, optional_timeout);
+        Thread::BlockResult result = Thread::current()->wait_on(wait_queue, optional_timeout);
         if (result == Thread::BlockResult::InterruptedByTimeout) {
             return -ETIMEDOUT;
         }
@@ -4854,7 +4886,7 @@ int Process::sys$set_process_boost(pid_t pid, int amount)
     REQUIRE_PROMISE(proc);
     if (amount < 0 || amount > 20)
         return -EINVAL;
-    InterruptDisabler disabler;
+    ScopedSpinLock lock(g_processes_lock);
     auto* process = Process::from_pid(pid);
     if (!process || process->is_dead())
         return -ESRCH;
@@ -4976,6 +5008,7 @@ int Process::sys$pledge(const Syscall::SC_pledge_params* user_params)
 Region& Process::add_region(NonnullOwnPtr<Region> region)
 {
     auto* ptr = region.ptr();
+    ScopedSpinLock lock(m_lock);
     m_regions.append(move(region));
     return *ptr;
 }
@@ -5091,7 +5124,7 @@ int Process::sys$get_stack_bounds(FlatPtr* user_stack_base, size_t* user_stack_s
     if (!validate_write_typed(user_stack_size))
         return -EFAULT;
 
-    FlatPtr stack_pointer = Thread::current->get_register_dump_from_stack().userspace_esp;
+    FlatPtr stack_pointer = Thread::current()->get_register_dump_from_stack().userspace_esp;
     auto* stack_region = MM.region_from_vaddr(*this, VirtualAddress(stack_pointer));
     if (!stack_region) {
         ASSERT_NOT_REACHED();

Kernel/Process.h

@@ -111,15 +111,21 @@ class Process : public InlineLinkedListNode<Process> {
     friend class Thread;
 
 public:
-    static Process* current;
+    inline static Process* current()
+    {
+        auto current_thread = Processor::current().current_thread();
+        return current_thread ? &current_thread->process() : nullptr;
+    }
 
-    static Process* create_kernel_process(Thread*& first_thread, String&& name, void (*entry)());
+    static Process* create_kernel_process(Thread*& first_thread, String&& name, void (*entry)(), u32 affinity = THREAD_AFFINITY_DEFAULT);
     static Process* create_user_process(Thread*& first_thread, const String& path, uid_t, gid_t, pid_t ppid, int& error, Vector<String>&& arguments = Vector<String>(), Vector<String>&& environment = Vector<String>(), TTY* = nullptr);
     ~Process();
 
     static Vector<pid_t> all_pids();
     static Vector<Process*> all_processes();
 
+    Thread* create_kernel_thread(void (*entry)(), u32 priority, const String& name, u32 affinity = THREAD_AFFINITY_DEFAULT, bool joinable = true);
+
     bool is_profiling() const { return m_profiling; }
     void set_profiling(bool profiling) { m_profiling = profiling; }
 
@@ -417,7 +423,7 @@ public:
     void terminate_due_to_signal(u8 signal);
     KResult send_signal(u8 signal, Process* sender);
 
-    u16 thread_count() const { return m_thread_count; }
+    u16 thread_count() const { return m_thread_count.load(AK::MemoryOrder::memory_order_consume); }
 
     Lock& big_lock() { return m_big_lock; }
 
@@ -518,7 +524,7 @@ private:
     RingLevel m_ring { Ring0 };
     u8 m_termination_status { 0 };
     u8 m_termination_signal { 0 };
-    u16 m_thread_count { 0 };
+    Atomic<u16> m_thread_count { 0 };
 
     bool m_dead { false };
     bool m_profiling { false };
@@ -550,6 +556,7 @@ private:
     size_t m_master_tls_alignment { 0 };
 
     Lock m_big_lock { "Process" };
+    SpinLock<u32> m_lock;
 
     u64 m_alarm_deadline { 0 };
 
@@ -581,14 +588,14 @@ public:
     ProcessInspectionHandle(Process& process)
         : m_process(process)
     {
-        if (&process != Process::current) {
+        if (&process != Process::current()) {
             InterruptDisabler disabler;
             m_process.increment_inspector_count({});
         }
     }
     ~ProcessInspectionHandle()
     {
-        if (&m_process != Process::current) {
+        if (&m_process != Process::current()) {
             InterruptDisabler disabler;
             m_process.decrement_inspector_count({});
         }
@@ -613,11 +620,13 @@ private:
 };
 
 extern InlineLinkedList<Process>* g_processes;
+extern RecursiveSpinLock g_processes_lock;
 
 template<typename Callback>
 inline void Process::for_each(Callback callback)
 {
     ASSERT_INTERRUPTS_DISABLED();
+    ScopedSpinLock lock(g_processes_lock);
     for (auto* process = g_processes->head(); process;) {
         auto* next_process = process->next();
         if (callback(*process) == IterationDecision::Break)
@@ -631,6 +640,7 @@ inline void Process::for_each_child(Callback callback)
 {
     ASSERT_INTERRUPTS_DISABLED();
     pid_t my_pid = pid();
+    ScopedSpinLock lock(g_processes_lock);
     for (auto* process = g_processes->head(); process;) {
         auto* next_process = process->next();
         if (process->ppid() == my_pid || process->has_tracee_thread(m_pid)) {
@@ -649,7 +659,14 @@ inline void Process::for_each_thread(Callback callback) const
 
     if (my_pid == 0) {
         // NOTE: Special case the colonel process, since its main thread is not in the global thread table.
-        callback(*g_colonel);
+        Processor::for_each(
+            [&](Processor& proc) -> IterationDecision
+            {
+                auto idle_thread = proc.idle_thread();
+                if (idle_thread != nullptr)
+                    return callback(*idle_thread);
+                return IterationDecision::Continue;
+            });
         return;
     }
 
@@ -665,6 +682,7 @@ template<typename Callback>
 inline void Process::for_each_in_pgrp(pid_t pgid, Callback callback)
 {
     ASSERT_INTERRUPTS_DISABLED();
+    ScopedSpinLock lock(g_processes_lock);
     for (auto* process = g_processes->head(); process;) {
         auto* next_process = process->next();
         if (!process->is_dead() && process->pgid() == pgid) {
@@ -705,25 +723,25 @@ inline u32 Thread::effective_priority() const
     return m_priority + m_process.priority_boost() + m_priority_boost + m_extra_priority;
 }
 
-#define REQUIRE_NO_PROMISES                      \
+#define REQUIRE_NO_PROMISES                        \
-    do {                                         \
+    do {                                           \
-        if (Process::current->has_promises()) {  \
+        if (Process::current()->has_promises()) {  \
-            dbg() << "Has made a promise";       \
+            dbg() << "Has made a promise";         \
-            cli();                               \
+            cli();                                 \
-            Process::current->crash(SIGABRT, 0); \
+            Process::current()->crash(SIGABRT, 0); \
-            ASSERT_NOT_REACHED();                \
+            ASSERT_NOT_REACHED();                  \
-        }                                        \
+        }                                          \
     } while (0)
 
-#define REQUIRE_PROMISE(promise)                                   \
+#define REQUIRE_PROMISE(promise)                                     \
-    do {                                                           \
+    do {                                                             \
-        if (Process::current->has_promises()                       \
+        if (Process::current()->has_promises()                       \
-            && !Process::current->has_promised(Pledge::promise)) { \
+            && !Process::current()->has_promised(Pledge::promise)) { \
-            dbg() << "Has not pledged " << #promise;               \
+            dbg() << "Has not pledged " << #promise;                 \
-            cli();                                                 \
+            cli();                                                   \
-            Process::current->crash(SIGABRT, 0);                   \
+            Process::current()->crash(SIGABRT, 0);                   \
-            ASSERT_NOT_REACHED();                                  \
+            ASSERT_NOT_REACHED();                                    \
-        }                                                          \
+        }                                                            \
     } while (0)
 
 }

Kernel/Ptrace.cpp

@@ -36,7 +36,7 @@ namespace Ptrace {
 KResultOr<u32> handle_syscall(const Kernel::Syscall::SC_ptrace_params& params, Process& caller)
 {
     if (params.request == PT_TRACE_ME) {
-        if (Thread::current->tracer())
+        if (Thread::current()->tracer())
             return KResult(-EBUSY);
 
         caller.set_wait_for_tracer_at_next_execve(true);

Kernel/Random.cpp

@@ -69,7 +69,7 @@ KernelRng::KernelRng()
 void KernelRng::wait_for_entropy()
 {
     if (!resource().is_ready()) {
-        Thread::current->wait_on(m_seed_queue);
+        Thread::current()->wait_on(m_seed_queue);
     }
 }
 

Kernel/Scheduler.cpp

@@ -43,6 +43,7 @@ namespace Kernel {
 
 SchedulerData* g_scheduler_data;
 timeval g_timeofday;
+RecursiveSpinLock g_scheduler_lock;
 
 void Scheduler::init_thread(Thread& thread)
 {
@@ -63,7 +64,7 @@ void Scheduler::update_state_for_thread(Thread& thread)
 static u32 time_slice_for(const Thread& thread)
 {
     // One time slice unit == 1ms
-    if (&thread == g_colonel)
+    if (&thread == Processor::current().idle_thread())
         return 1;
     return 10;
 }
@@ -74,7 +75,6 @@ timeval Scheduler::time_since_boot()
 }
 
 Thread* g_finalizer;
-Thread* g_colonel;
 WaitQueue* g_finalizer_wait_queue;
 Atomic<bool> g_finalizer_has_work{false};
 static Process* s_colonel_process;
@@ -85,8 +85,9 @@ Thread::JoinBlocker::JoinBlocker(Thread& joinee, void*& joinee_exit_value)
     , m_joinee_exit_value(joinee_exit_value)
 {
     ASSERT(m_joinee.m_joiner == nullptr);
-    m_joinee.m_joiner = Thread::current;
+    auto current_thread = Thread::current();
-    Thread::current->m_joinee = &joinee;
+    m_joinee.m_joiner = current_thread;
+    current_thread->m_joinee = &joinee;
 }
 
 bool Thread::JoinBlocker::should_unblock(Thread& joiner, time_t, long)
@@ -268,7 +269,6 @@ bool Thread::WaitBlocker::should_unblock(Thread& thread, time_t, long)
             return IterationDecision::Continue;
 
         m_waitee_pid = child.pid();
-        dbg() << "Unblocking thread " << thread << " process " << thread.process() << " child exited: " << m_waitee_pid;
         should_unblock = true;
         return IterationDecision::Break;
     });
@@ -317,15 +317,16 @@ void Thread::consider_unblock(time_t now_sec, long now_usec)
 void Scheduler::start()
 {
     ASSERT_INTERRUPTS_DISABLED();
-    ASSERT(!Thread::current);
+    auto& processor = Processor::current();
-    Thread::current = g_colonel;
+    ASSERT(processor.current_thread() == nullptr);
-    Process::current = &g_colonel->process();
+    auto& idle_thread = *processor.idle_thread();
-    g_colonel->set_ticks_left(time_slice_for(*g_colonel));
+    processor.set_current_thread(idle_thread);
-    g_colonel->did_schedule();
+    idle_thread.set_ticks_left(time_slice_for(idle_thread));
-    g_colonel->set_initialized(true);
+    idle_thread.did_schedule();
-    Processor::init_context(*g_colonel);
+    idle_thread.set_initialized(true);
-    g_colonel->set_state(Thread::Running);
+    Processor::init_context(idle_thread);
-    Processor::current().initialize_context_switching(*g_colonel);
+    idle_thread.set_state(Thread::Running);
+    processor.initialize_context_switching(idle_thread);
     ASSERT_NOT_REACHED();
 }
 
@@ -333,12 +334,14 @@ bool Scheduler::pick_next()
 {
     ASSERT_INTERRUPTS_DISABLED();
 
-    ASSERT(Thread::current);
+    auto current_thread = Thread::current();
     auto now = time_since_boot();
 
     auto now_sec = now.tv_sec;
     auto now_usec = now.tv_usec;
 
+    ScopedSpinLock lock(g_scheduler_lock);
+
     // Check and unblock threads whose wait conditions have been met.
     Scheduler::for_each_nonrunnable([&](Thread& thread) {
         thread.consider_unblock(now_sec, now_usec);
@@ -347,7 +350,7 @@ bool Scheduler::pick_next()
 
     Process::for_each([&](Process& process) {
         if (process.is_dead()) {
-            if (Process::current->pid() != process.pid() && (!process.ppid() || !Process::from_pid(process.ppid()))) {
+            if (current_thread->process().pid() != process.pid() && (!process.ppid() || !Process::from_pid(process.ppid()))) {
                 auto name = process.name();
                 auto pid = process.pid();
                 auto exit_status = Process::reap(process);
@@ -363,13 +366,13 @@ bool Scheduler::pick_next()
     });
 
     // Dispatch any pending signals.
-    Thread::for_each_living([](Thread& thread) -> IterationDecision {
+    Thread::for_each_living([&](Thread& thread) -> IterationDecision {
         if (!thread.has_unmasked_pending_signals())
             return IterationDecision::Continue;
         // FIXME: It would be nice if the Scheduler didn't have to worry about who is "current"
         //        For now, avoid dispatching signals to "current" and do it in a scheduling pass
         //        while some other process is interrupted. Otherwise a mess will be made.
-        if (&thread == Thread::current)
+        if (&thread == current_thread)
             return IterationDecision::Continue;
         // We know how to interrupt blocked processes, but if they are just executing
         // at some random point in the kernel, let them continue.
@@ -433,32 +436,33 @@ bool Scheduler::pick_next()
     }
 
     if (!thread_to_schedule)
-        thread_to_schedule = g_colonel;
+        thread_to_schedule = Processor::current().idle_thread();
 
 #ifdef SCHEDULER_DEBUG
     dbg() << "Scheduler: Switch to " << *thread_to_schedule << " @ " << String::format("%04x:%08x", thread_to_schedule->tss().cs, thread_to_schedule->tss().eip);
 #endif
 
+    lock.unlock();
     return context_switch(*thread_to_schedule);
 }
 
 bool Scheduler::yield()
 {
-//#ifdef SCHEDULER_DEBUG
+    auto& proc = Processor::current();
-#if 0
+    auto current_thread = Thread::current();
-    dbg() << "Scheduler: yielding thread " << *Thread::current << " in_trap: " << Processor::current().in_trap() << " in_irq: " << Processor::current().in_irq();
+#ifdef SCHEDULER_DEBUG
+    dbg() << "Scheduler: yielding thread " << *current_thread << " in_trap: " << proc.in_trap() << " in_irq: " << proc.in_irq();
 #endif
     InterruptDisabler disabler;
-    ASSERT(Thread::current);
+    ASSERT(current_thread != nullptr);
-    if (Processor::current().in_irq()) {
+    if (proc.in_irq()) {
         // If we're handling an IRQ we can't switch context, delay until
         // exiting the trap
-        Processor::current().invoke_scheduler_async();
+        proc.invoke_scheduler_async();
     } else if (!Scheduler::pick_next())
         return false;
-//#ifdef SCHEDULER_DEBUG
+#ifdef SCHEDULER_DEBUG
-#if 0
+    dbg() << "Scheduler: yield returns to thread " << *current_thread << " in_trap: " << proc.in_trap() << " in_irq: " << proc.in_irq();
-    dbg() << "Scheduler: yield returns to thread " << *Thread::current << " in_trap: " << Processor::current().in_trap() << " in_irq: " << Processor::current().in_irq();
 #endif
     return true;
 }
@@ -471,7 +475,7 @@ bool Scheduler::donate_to(Thread* beneficiary, const char* reason)
         return false;
 
     (void)reason;
-    unsigned ticks_left = Thread::current->ticks_left();
+    unsigned ticks_left = Thread::current()->ticks_left();
     if (!beneficiary || beneficiary->state() != Thread::Runnable || ticks_left <= 1)
          return Scheduler::yield();
 
@@ -489,30 +493,28 @@ bool Scheduler::context_switch(Thread& thread)
     thread.set_ticks_left(time_slice_for(thread));
     thread.did_schedule();
 
-    if (Thread::current == &thread)
+    auto current_thread = Thread::current();
+    if (current_thread == &thread)
         return false;
 
-    if (Thread::current) {
+    if (current_thread) {
         // If the last process hasn't blocked (still marked as running),
         // mark it as runnable for the next round.
-        if (Thread::current->state() == Thread::Running)
+        if (current_thread->state() == Thread::Running)
-            Thread::current->set_state(Thread::Runnable);
+            current_thread->set_state(Thread::Runnable);
 
 #ifdef LOG_EVERY_CONTEXT_SWITCH
-        dbg() << "Scheduler: " << *Thread::current << " -> " << thread << " [" << thread.priority() << "] " << String::format("%w", thread.tss().cs) << ":" << String::format("%x", thread.tss().eip);
+        dbg() << "Scheduler: " << *current_thread << " -> " << thread << " [" << thread.priority() << "] " << String::format("%w", thread.tss().cs) << ":" << String::format("%x", thread.tss().eip);
 #endif
     }
 
-    Thread* from = Thread::current;
-    Thread::current = &thread;
-    Process::current = &thread.process();
     if (!thread.is_initialized()) {
         Processor::init_context(thread);
         thread.set_initialized(true);
     }
     thread.set_state(Thread::Running);
 
-    Processor::current().switch_context(from, &thread);
+    Processor::current().switch_context(current_thread, &thread);
     return true;
 }
 
@@ -527,11 +529,21 @@ void Scheduler::initialize(u32 cpu)
     g_scheduler_data = new SchedulerData;
     g_finalizer_wait_queue = new WaitQueue;
 
+    Thread* idle_thread = nullptr;
     if (cpu == 0) {
         g_finalizer_has_work.store(false, AK::MemoryOrder::memory_order_release);
-        s_colonel_process = Process::create_kernel_process(g_colonel, "colonel", idle_loop);
+        s_colonel_process = Process::create_kernel_process(idle_thread, "colonel", idle_loop);
-        g_colonel->set_priority(THREAD_PRIORITY_MIN);
+        ASSERT(s_colonel_process);
+        ASSERT(idle_thread);
+        idle_thread->set_priority(THREAD_PRIORITY_MIN);
+        idle_thread->set_name(String::format("idle thread #%u", cpu));
+    } else {
+        ASSERT(s_colonel_process);
+        idle_thread = s_colonel_process->create_kernel_thread(idle_loop, THREAD_PRIORITY_MIN, String::format("idle thread #%u", cpu), false);
+        ASSERT(idle_thread);
     }
+
+    Processor::current().set_idle_thread(*idle_thread);
 }
 
 void Scheduler::timer_tick(const RegisterState& regs)
@@ -539,19 +551,20 @@ void Scheduler::timer_tick(const RegisterState& regs)
     ASSERT_INTERRUPTS_DISABLED();
     ASSERT(Processor::current().in_irq());
 
-    if (!Thread::current)
+    auto current_thread = Processor::current().current_thread();
+    if (!current_thread)
         return;
 
     ++g_uptime;
 
     g_timeofday = TimeManagement::now_as_timeval();
 
-    if (Process::current->is_profiling()) {
+    if (current_thread->process().is_profiling()) {
         SmapDisabler disabler;
-        auto backtrace = Thread::current->raw_backtrace(regs.ebp, regs.eip);
+        auto backtrace = current_thread->raw_backtrace(regs.ebp, regs.eip);
         auto& sample = Profiling::next_sample_slot();
-        sample.pid = Process::current->pid();
+        sample.pid = current_thread->process().pid();
-        sample.tid = Thread::current->tid();
+        sample.tid = current_thread->tid();
         sample.timestamp = g_uptime;
         for (size_t i = 0; i < min(backtrace.size(), Profiling::max_stack_frame_count); ++i) {
             sample.frames[i] = backtrace[i];
@@ -560,7 +573,7 @@ void Scheduler::timer_tick(const RegisterState& regs)
 
     TimerQueue::the().fire();
 
-    if (Thread::current->tick())
+    if (current_thread->tick())
         return;
 
     ASSERT_INTERRUPTS_DISABLED();

Kernel/Scheduler.h

@@ -30,6 +30,7 @@
 #include <AK/Function.h>
 #include <AK/IntrusiveList.h>
 #include <AK/Types.h>
+#include <Kernel/SpinLock.h>
 #include <Kernel/UnixTypes.h>
 
 namespace Kernel {
@@ -41,12 +42,12 @@ struct RegisterState;
 struct SchedulerData;
 
 extern Thread* g_finalizer;
-extern Thread* g_colonel;
 extern WaitQueue* g_finalizer_wait_queue;
 extern Atomic<bool> g_finalizer_has_work;
 extern u64 g_uptime;
 extern SchedulerData* g_scheduler_data;
 extern timeval g_timeofday;
+extern RecursiveSpinLock g_scheduler_lock;
 
 class Scheduler {
 public:

Kernel/Syscall.cpp

@@ -87,8 +87,9 @@ static Handler s_syscall_table[] = {
 int handle(RegisterState& regs, u32 function, u32 arg1, u32 arg2, u32 arg3)
 {
     ASSERT_INTERRUPTS_ENABLED();
-    auto& process = *Process::current;
+    auto current_thread = Thread::current();
-    Thread::current->did_syscall();
+    auto& process = current_thread->process();
+    current_thread->did_syscall();
 
     if (function == SC_exit || function == SC_exit_thread) {
         // These syscalls need special handling since they never return to the caller.
@@ -126,15 +127,17 @@ void syscall_handler(TrapFrame* trap)
     auto& regs = *trap->regs;
     // Special handling of the "gettid" syscall since it's extremely hot.
     // FIXME: Remove this hack once userspace locks stop calling it so damn much.
+    auto current_thread = Thread::current();
+    auto& process = current_thread->process();
     if (regs.eax == SC_gettid) {
-        regs.eax = Process::current->sys$gettid();
+        regs.eax = process.sys$gettid();
-        Thread::current->did_syscall();
+        current_thread->did_syscall();
         return;
     }
 
-    if (Thread::current->tracer() && Thread::current->tracer()->is_tracing_syscalls()) {
+    if (current_thread->tracer() && current_thread->tracer()->is_tracing_syscalls()) {
-        Thread::current->tracer()->set_trace_syscalls(false);
+        current_thread->tracer()->set_trace_syscalls(false);
-        Thread::current->tracer_trap(regs);
+        current_thread->tracer_trap(regs);
     }
 
     // Make sure SMAP protection is enabled on syscall entry.
@@ -146,8 +149,6 @@ void syscall_handler(TrapFrame* trap)
     asm volatile(""
                  : "=m"(*ptr));
 
-    auto& process = *Process::current;
-
     if (!MM.validate_user_stack(process, VirtualAddress(regs.userspace_esp))) {
         dbg() << "Invalid stack pointer: " << String::format("%p", regs.userspace_esp);
         handle_crash(regs, "Bad stack on syscall entry", SIGSTKFLT);
@@ -174,18 +175,18 @@ void syscall_handler(TrapFrame* trap)
     u32 arg3 = regs.ebx;
     regs.eax = (u32)Syscall::handle(regs, function, arg1, arg2, arg3);
 
-    if (Thread::current->tracer() && Thread::current->tracer()->is_tracing_syscalls()) {
+    if (current_thread->tracer() && current_thread->tracer()->is_tracing_syscalls()) {
-        Thread::current->tracer()->set_trace_syscalls(false);
+        current_thread->tracer()->set_trace_syscalls(false);
-        Thread::current->tracer_trap(regs);
+        current_thread->tracer_trap(regs);
     }
 
     process.big_lock().unlock();
 
     // Check if we're supposed to return to userspace or just die.
-    Thread::current->die_if_needed();
+    current_thread->die_if_needed();
 
-    if (Thread::current->has_unmasked_pending_signals())
+    if (current_thread->has_unmasked_pending_signals())
-        (void)Thread::current->block<Thread::SemiPermanentBlocker>(Thread::SemiPermanentBlocker::Reason::Signal);
+        (void)current_thread->block<Thread::SemiPermanentBlocker>(Thread::SemiPermanentBlocker::Reason::Signal);
 }
 
 }

Kernel/TTY/MasterPTY.cpp

@@ -42,8 +42,9 @@ MasterPTY::MasterPTY(unsigned index)
     , m_index(index)
 {
     m_pts_name = String::format("/dev/pts/%u", m_index);
-    set_uid(Process::current->uid());
+    auto process = Process::current();
-    set_gid(Process::current->gid());
+    set_uid(process->uid());
+    set_gid(process->gid());
 }
 
 MasterPTY::~MasterPTY()

Kernel/TTY/SlavePTY.cpp

@@ -39,8 +39,9 @@ SlavePTY::SlavePTY(MasterPTY& master, unsigned index)
     , m_index(index)
 {
     sprintf(m_tty_name, "/dev/pts/%u", m_index);
-    set_uid(Process::current->uid());
+    auto process = Process::current();
-    set_gid(Process::current->gid());
+    set_uid(process->uid());
+    set_gid(process->gid());
     DevPtsFS::register_slave_pty(*this);
     set_size(80, 25);
 }

Kernel/TTY/TTY.cpp

@@ -282,7 +282,7 @@ void TTY::set_termios(const termios& t)
 int TTY::ioctl(FileDescription&, unsigned request, FlatPtr arg)
 {
     REQUIRE_PROMISE(tty);
-    auto& process = *Process::current;
+    auto& current_process = *Process::current();
     pid_t pgid;
     termios* tp;
     winsize* ws;
@@ -290,7 +290,7 @@ int TTY::ioctl(FileDescription&, unsigned request, FlatPtr arg)
 #if 0
     // FIXME: When should we block things?
     //        How do we make this work together with MasterPTY forwarding to us?
-    if (process.tty() && process.tty() != this) {
+    if (current_process.tty() && current_process.tty() != this) {
         return -ENOTTY;
     }
 #endif
@@ -308,14 +308,14 @@ int TTY::ioctl(FileDescription&, unsigned request, FlatPtr arg)
                 return -EPERM;
             if (pgid != process->pgid())
                 return -EPERM;
-            if (Process::current->sid() != process->sid())
+            if (current_process.sid() != process->sid())
                 return -EPERM;
         }
         m_pgid = pgid;
         return 0;
     case TCGETS:
         tp = reinterpret_cast<termios*>(arg);
-        if (!process.validate_write(tp, sizeof(termios)))
+        if (!current_process.validate_write(tp, sizeof(termios)))
             return -EFAULT;
         *tp = m_termios;
         return 0;
@@ -323,7 +323,7 @@ int TTY::ioctl(FileDescription&, unsigned request, FlatPtr arg)
     case TCSETSF:
     case TCSETSW:
         tp = reinterpret_cast<termios*>(arg);
-        if (!process.validate_read(tp, sizeof(termios)))
+        if (!current_process.validate_read(tp, sizeof(termios)))
             return -EFAULT;
         set_termios(*tp);
         if (request == TCSETSF)
@@ -331,14 +331,14 @@ int TTY::ioctl(FileDescription&, unsigned request, FlatPtr arg)
         return 0;
     case TIOCGWINSZ:
         ws = reinterpret_cast<winsize*>(arg);
-        if (!process.validate_write(ws, sizeof(winsize)))
+        if (!current_process.validate_write(ws, sizeof(winsize)))
             return -EFAULT;
         ws->ws_row = m_rows;
         ws->ws_col = m_columns;
         return 0;
     case TIOCSWINSZ:
         ws = reinterpret_cast<winsize*>(arg);
-        if (!process.validate_read(ws, sizeof(winsize)))
+        if (!current_process.validate_read(ws, sizeof(winsize)))
             return -EFAULT;
         if (ws->ws_col == m_columns && ws->ws_row == m_rows)
             return 0;
@@ -347,10 +347,10 @@ int TTY::ioctl(FileDescription&, unsigned request, FlatPtr arg)
         generate_signal(SIGWINCH);
         return 0;
     case TIOCSCTTY:
-        process.set_tty(this);
+        current_process.set_tty(this);
         return 0;
     case TIOCNOTTY:
-        process.set_tty(nullptr);
+        current_process.set_tty(nullptr);
         return 0;
     }
     ASSERT_NOT_REACHED();

Kernel/Tasks/FinalizerTask.cpp

@@ -32,10 +32,10 @@ namespace Kernel {
 void FinalizerTask::spawn()
 {
     Process::create_kernel_process(g_finalizer, "FinalizerTask", [] {
-        Thread::current->set_priority(THREAD_PRIORITY_LOW);
+        Thread::current()->set_priority(THREAD_PRIORITY_LOW);
         for (;;) {
 			dbg() << "Finalizer task is running";
-            Thread::current->wait_on(*g_finalizer_wait_queue);
+            Thread::current()->wait_on(*g_finalizer_wait_queue);
             
             bool expected = true;
             if (g_finalizer_has_work.compare_exchange_strong(expected, false, AK::MemoryOrder::memory_order_acq_rel))

Kernel/Tasks/SyncTask.cpp

@@ -38,7 +38,7 @@ void SyncTask::spawn()
         dbg() << "SyncTask is running";
         for (;;) {
             VFS::the().sync();
-            Thread::current->sleep(1 * TimeManagement::the().ticks_per_second());
+            Thread::current()->sleep(1 * TimeManagement::the().ticks_per_second());
         }
     });
 }

Kernel/Thread.cpp

@@ -46,8 +46,6 @@
 
 namespace Kernel {
 
-Thread* Thread::current;
-
 HashTable<Thread*>& thread_table()
 {
     ASSERT_INTERRUPTS_DISABLED();
@@ -61,13 +59,12 @@ Thread::Thread(Process& process)
     : m_process(process)
     , m_name(process.name())
 {
-    if (m_process.m_thread_count == 0) {
+    if (m_process.m_thread_count.fetch_add(1, AK::MemoryOrder::memory_order_acq_rel) == 0) {
         // First thread gets TID == PID
         m_tid = process.pid();
     } else {
         m_tid = Process::allocate_pid();
     }
-    process.m_thread_count++;
 #ifdef THREAD_DEBUG
     dbg() << "Created new thread " << process.name() << "(" << process.pid() << ":" << m_tid << ")";
 #endif
@@ -127,14 +124,14 @@ Thread::~Thread()
         thread_table().remove(this);
     }
 
-    ASSERT(m_process.m_thread_count);
+    auto thread_cnt_before = m_process.m_thread_count.fetch_sub(1, AK::MemoryOrder::memory_order_acq_rel);
-    m_process.m_thread_count--;
+    ASSERT(thread_cnt_before != 0);
 }
 
 void Thread::unblock()
 {
     m_blocker = nullptr;
-    if (current == this) {
+    if (Thread::current() == this) {
         if (m_should_die)
             set_state(Thread::Dying);
         else
@@ -179,7 +176,7 @@ void Thread::set_should_die()
 
 void Thread::die_if_needed()
 {
-    ASSERT(current == this);
+    ASSERT(Thread::current() == this);
 
     if (!m_should_die)
         return;
@@ -213,7 +210,7 @@ u64 Thread::sleep(u32 ticks)
 {
     ASSERT(state() == Thread::Running);
     u64 wakeup_time = g_uptime + ticks;
-    auto ret = Thread::current->block<Thread::SleepBlocker>(wakeup_time);
+    auto ret = Thread::current()->block<Thread::SleepBlocker>(wakeup_time);
     if (wakeup_time > g_uptime) {
         ASSERT(ret != Thread::BlockResult::WokeNormally);
     }
@@ -223,7 +220,7 @@ u64 Thread::sleep(u32 ticks)
 u64 Thread::sleep_until(u64 wakeup_time)
 {
     ASSERT(state() == Thread::Running);
-    auto ret = Thread::current->block<Thread::SleepBlocker>(wakeup_time);
+    auto ret = Thread::current()->block<Thread::SleepBlocker>(wakeup_time);
     if (wakeup_time > g_uptime)
         ASSERT(ret != Thread::BlockResult::WokeNormally);
     return wakeup_time;
@@ -261,7 +258,7 @@ const char* Thread::state_string() const
 
 void Thread::finalize()
 {
-    ASSERT(current == g_finalizer);
+    ASSERT(Thread::current() == g_finalizer);
 
 #ifdef THREAD_DEBUG
     dbg() << "Finalizing thread " << *this;
@@ -283,7 +280,7 @@ void Thread::finalize()
 
 void Thread::finalize_dying_threads()
 {
-    ASSERT(current == g_finalizer);
+    ASSERT(Thread::current() == g_finalizer);
     Vector<Thread*, 32> dying_threads;
     {
         InterruptDisabler disabler;
@@ -296,7 +293,7 @@ void Thread::finalize_dying_threads()
         auto& process = thread->process();
         thread->finalize();
         delete thread;
-        if (process.m_thread_count == 0)
+        if (process.m_thread_count.load(AK::MemoryOrder::memory_order_consume) == 0)
             process.finalize();
     }
 }
@@ -770,7 +767,7 @@ String Thread::backtrace_impl() const
     Vector<RecognizedSymbol, 128> recognized_symbols;
 
     u32 start_frame;
-    if (current == this) {
+    if (Thread::current() == this) {
         asm volatile("movl %%ebp, %%eax"
                      : "=a"(start_frame));
     } else {
@@ -853,7 +850,7 @@ Thread::BlockResult Thread::wait_on(WaitQueue& queue, timeval* timeout, Atomic<b
         if (lock)
             *lock = false;
         set_state(State::Queued);
-        queue.enqueue(*current);
+        queue.enqueue(*Thread::current());
 
     
         if (timeout) {
@@ -888,7 +885,7 @@ Thread::BlockResult Thread::wait_on(WaitQueue& queue, timeval* timeout, Atomic<b
 void Thread::wake_from_queue()
 {
     ASSERT(state() == State::Queued);
-    if (this != Thread::current)
+    if (this != Thread::current())
         set_state(State::Runnable);
     else
         set_state(State::Running);

Kernel/Thread.h

@@ -63,6 +63,8 @@ struct ThreadSpecificData {
 #define THREAD_PRIORITY_HIGH 50
 #define THREAD_PRIORITY_MAX 99
 
+#define THREAD_AFFINITY_DEFAULT 0xffffffff
+
 class Thread {
     AK_MAKE_NONCOPYABLE(Thread);
     AK_MAKE_NONMOVABLE(Thread);
@@ -71,7 +73,10 @@ class Thread {
     friend class Scheduler;
 
 public:
-    static Thread* current;
+    inline static Thread* current()
+    {
+        return Processor::current().current_thread();
+    }
 
     explicit Thread(Process&);
     ~Thread();
@@ -275,6 +280,8 @@ public:
 
     u32 cpu() const { return m_cpu.load(AK::MemoryOrder::memory_order_consume); }
     void set_cpu(u32 cpu) { m_cpu.store(cpu, AK::MemoryOrder::memory_order_release); }
+    u32 affinity() const { return m_cpu_affinity; }
+    void set_affinity(u32 affinity) { m_cpu_affinity = affinity; }
 
     u32 frame_ptr() const { return m_tss.ebp; }
     u32 stack_ptr() const { return m_tss.esp; }
@@ -470,6 +477,7 @@ private:
     TSS32 m_tss;
     FarPtr m_far_ptr;
     Atomic<u32> m_cpu { 0 };
+    u32 m_cpu_affinity { THREAD_AFFINITY_DEFAULT };
     u32 m_ticks { 0 };
     u32 m_ticks_left { 0 };
     u32 m_times_scheduled { 0 };
@@ -539,6 +547,7 @@ template<typename Callback>
 inline IterationDecision Thread::for_each(Callback callback)
 {
     ASSERT_INTERRUPTS_DISABLED();
+    ScopedSpinLock lock(g_scheduler_lock);
     auto ret = Scheduler::for_each_runnable(callback);
     if (ret == IterationDecision::Break)
         return ret;
@@ -549,6 +558,7 @@ template<typename Callback>
 inline IterationDecision Thread::for_each_in_state(State state, Callback callback)
 {
     ASSERT_INTERRUPTS_DISABLED();
+    ScopedSpinLock lock(g_scheduler_lock);
     auto new_callback = [=](Thread& thread) -> IterationDecision {
         if (thread.state() == state)
             return callback(thread);
@@ -579,6 +589,7 @@ template<typename Callback>
 inline IterationDecision Scheduler::for_each_runnable(Callback callback)
 {
     ASSERT_INTERRUPTS_DISABLED();
+    ASSERT(g_scheduler_lock.is_locked());
     auto& tl = g_scheduler_data->m_runnable_threads;
     for (auto it = tl.begin(); it != tl.end();) {
         auto& thread = *it;
@@ -594,6 +605,7 @@ template<typename Callback>
 inline IterationDecision Scheduler::for_each_nonrunnable(Callback callback)
 {
     ASSERT_INTERRUPTS_DISABLED();
+    ASSERT(g_scheduler_lock.is_locked());
     auto& tl = g_scheduler_data->m_nonrunnable_threads;
     for (auto it = tl.begin(); it != tl.end();) {
         auto& thread = *it;

Kernel/VM/MemoryManager.cpp

@@ -267,7 +267,7 @@ Region* MemoryManager::region_from_vaddr(VirtualAddress vaddr)
 PageFaultResponse MemoryManager::handle_page_fault(const PageFault& fault)
 {
     ASSERT_INTERRUPTS_DISABLED();
-    ASSERT(Thread::current);
+    ASSERT(Thread::current() != nullptr);
     ScopedSpinLock lock(s_lock);
     if (Processor::current().in_irq()) {
         dbg() << "CPU[" << Processor::current().id() << "] BUG! Page fault while handling IRQ! code=" << fault.code() << ", vaddr=" << fault.vaddr() << ", irq level: " << Processor::current().in_irq();
@@ -519,10 +519,11 @@ RefPtr<PhysicalPage> MemoryManager::allocate_supervisor_physical_page()
 
 void MemoryManager::enter_process_paging_scope(Process& process)
 {
-    ASSERT(Thread::current);
+    auto current_thread = Thread::current();
+    ASSERT(current_thread != nullptr);
     ScopedSpinLock lock(s_lock);
 
-    Thread::current->tss().cr3 = process.page_directory().cr3();
+    current_thread->tss().cr3 = process.page_directory().cr3();
     write_cr3(process.page_directory().cr3());
 }
 

Kernel/VM/ProcessPagingScope.cpp

@@ -31,7 +31,7 @@ namespace Kernel {
 
 ProcessPagingScope::ProcessPagingScope(Process& process)
 {
-    ASSERT(Thread::current);
+    ASSERT(Thread::current() != nullptr);
     m_previous_cr3 = read_cr3();
     MM.enter_process_paging_scope(process);
 }
@@ -39,7 +39,7 @@ ProcessPagingScope::ProcessPagingScope(Process& process)
 ProcessPagingScope::~ProcessPagingScope()
 {
     InterruptDisabler disabler;
-    Thread::current->tss().cr3 = m_previous_cr3;
+    Thread::current()->tss().cr3 = m_previous_cr3;
     write_cr3(m_previous_cr3);
 }
 

Kernel/VM/Region.cpp

@@ -67,7 +67,7 @@ Region::~Region()
 
 NonnullOwnPtr<Region> Region::clone()
 {
-    ASSERT(Process::current);
+    ASSERT(Process::current());
 
     if (m_inherit_mode == InheritMode::ZeroedOnFork) {
         ASSERT(m_mmap);
@@ -367,8 +367,9 @@ PageFaultResponse Region::handle_zero_fault(size_t page_index_in_region)
         return PageFaultResponse::Continue;
     }
 
-    if (Thread::current)
+    auto current_thread = Thread::current();
-        Thread::current->did_zero_fault();
+    if (current_thread != nullptr)
+        current_thread->did_zero_fault();
 
     auto page = MM.allocate_user_physical_page(MemoryManager::ShouldZeroFill::Yes);
     if (page.is_null()) {
@@ -397,8 +398,9 @@ PageFaultResponse Region::handle_cow_fault(size_t page_index_in_region)
         return PageFaultResponse::Continue;
     }
 
-    if (Thread::current)
+    auto current_thread = Thread::current();
-        Thread::current->did_cow_fault();
+    if (current_thread)
+        current_thread->did_cow_fault();
 
 #ifdef PAGE_FAULT_DEBUG
     dbg() << "    >> It's a COW page and it's time to COW!";
@@ -446,8 +448,9 @@ PageFaultResponse Region::handle_inode_fault(size_t page_index_in_region)
         return PageFaultResponse::Continue;
     }
 
-    if (Thread::current)
+    auto current_thread = Thread::current();
-        Thread::current->did_inode_fault();
+    if (current_thread)
+        current_thread->did_inode_fault();
 
 #ifdef MM_DEBUG
     dbg() << "MM: page_in_from_inode ready to read from inode";

Kernel/init.cpp

@@ -310,7 +310,7 @@ void init_stage2()
         hang();
     }
 
-    Process::current->set_root_directory(VFS::the().root_custody());
+    Process::current()->set_root_directory(VFS::the().root_custody());
 
     load_kernel_symbol_table();
 
@@ -329,7 +329,7 @@ void init_stage2()
 
     NetworkTask::spawn();
 
-    Process::current->sys$exit(0);
+    Process::current()->sys$exit(0);
     ASSERT_NOT_REACHED();
 }