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Kernel: Remove allocate_region() functions that don't take a Range

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Let's force callers to provide a VM range when allocating a region.
This makes ENOMEM error handling more visible and removes implicit
VM allocation which felt a bit magical.
This commit is contained in:
Andreas Kling 2021-01-26 14:13:57 +01:00
parent d697d33fa6
commit 1e25d2b734
5 changed files with 41 additions and 25 deletions
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16
Kernel/Process.cpp
View file

@ -150,14 +150,6 @@ KResultOr<Region*> Process::allocate_region(const Range& range, const String& na
return &add_region(move(region));
}
KResultOr<Region*> Process::allocate_region(VirtualAddress vaddr, size_t size, const String& name, int prot, AllocationStrategy strategy)
{
auto range = allocate_range(vaddr, size);
if (!range.is_valid())
return ENOMEM;
return allocate_region(range, name, prot, strategy);
}
KResultOr<Region*> Process::allocate_region_with_vmobject(const Range& range, NonnullRefPtr<VMObject> vmobject, size_t offset_in_vmobject, const String& name, int prot, bool shared)
{
ASSERT(range.is_valid());
@ -183,14 +175,6 @@ KResultOr<Region*> Process::allocate_region_with_vmobject(const Range& range, No
return &region;
}
KResultOr<Region*> Process::allocate_region_with_vmobject(VirtualAddress vaddr, size_t size, NonnullRefPtr<VMObject> vmobject, size_t offset_in_vmobject, const String& name, int prot, bool shared)
{
auto range = allocate_range(vaddr, size);
if (!range.is_valid())
return ENOMEM;
return allocate_region_with_vmobject(range, move(vmobject), offset_in_vmobject, name, prot, shared);
}
bool Process::deallocate_region(Region& region)
{
OwnPtr<Region> region_protector;

2
Kernel/Process.h
View file

@ -437,8 +437,6 @@ public:
return m_euid == 0;
}
KResultOr<Region*> allocate_region_with_vmobject(VirtualAddress, size_t, NonnullRefPtr<VMObject>, size_t offset_in_vmobject, const String& name, int prot, bool shared);
KResultOr<Region*> allocate_region(VirtualAddress, size_t, const String& name, int prot = PROT_READ | PROT_WRITE, AllocationStrategy strategy = AllocationStrategy::Reserve);
KResultOr<Region*> allocate_region_with_vmobject(const Range&, NonnullRefPtr<VMObject>, size_t offset_in_vmobject, const String& name, int prot, bool shared);
KResultOr<Region*> allocate_region(const Range&, const String& name, int prot = PROT_READ | PROT_WRITE, AllocationStrategy strategy = AllocationStrategy::Reserve);
bool deallocate_region(Region& region);

30
Kernel/Syscalls/execve.cpp
View file

@ -184,7 +184,13 @@ KResultOr<Process::LoadResult> Process::load_elf_object(FileDescription& object_
return IterationDecision::Break;
}
auto region_or_error = allocate_region({}, program_header.size_in_memory(), String::formatted("{} (master-tls)", elf_name), PROT_READ | PROT_WRITE, AllocationStrategy::Reserve);
auto range = allocate_range({}, program_header.size_in_memory());
if (!range.is_valid()) {
ph_load_result = ENOMEM;
return IterationDecision::Break;
}
auto region_or_error = allocate_region(range, String::formatted("{} (master-tls)", elf_name), PROT_READ | PROT_WRITE, AllocationStrategy::Reserve);
if (region_or_error.is_error()) {
ph_load_result = region_or_error.error();
return IterationDecision::Break;
@ -219,7 +225,12 @@ KResultOr<Process::LoadResult> Process::load_elf_object(FileDescription& object_
if (program_header.is_writable())
prot |= PROT_WRITE;
auto region_name = String::formatted("{} (data-{}{})", elf_name, program_header.is_readable() ? "r" : "", program_header.is_writable() ? "w" : "");
auto region_or_error = allocate_region(program_header.vaddr().offset(load_offset), program_header.size_in_memory(), move(region_name), prot, AllocationStrategy::Reserve);
auto range = allocate_range(program_header.vaddr().offset(load_offset), program_header.size_in_memory());
if (!range.is_valid()) {
ph_load_result = ENOMEM;
return IterationDecision::Break;
}
auto region_or_error = allocate_region(range, region_name, prot, AllocationStrategy::Reserve);
if (region_or_error.is_error()) {
ph_load_result = region_or_error.error();
return IterationDecision::Break;
@ -251,7 +262,12 @@ KResultOr<Process::LoadResult> Process::load_elf_object(FileDescription& object_
prot |= PROT_WRITE;
if (program_header.is_executable())
prot |= PROT_EXEC;
auto region_or_error = allocate_region_with_vmobject(program_header.vaddr().offset(load_offset), program_header.size_in_memory(), *vmobject, program_header.offset(), elf_name, prot, true);
auto range = allocate_range(program_header.vaddr().offset(load_offset), program_header.size_in_memory());
if (!range.is_valid()) {
ph_load_result = ENOMEM;
return IterationDecision::Break;
}
auto region_or_error = allocate_region_with_vmobject(range, *vmobject, program_header.offset(), elf_name, prot, true);
if (region_or_error.is_error()) {
ph_load_result = region_or_error.error();
return IterationDecision::Break;
@ -271,7 +287,13 @@ KResultOr<Process::LoadResult> Process::load_elf_object(FileDescription& object_
return ENOEXEC;
}
auto stack_region_or_error = allocate_region(VirtualAddress(), Thread::default_userspace_stack_size, "Stack (Main thread)", PROT_READ | PROT_WRITE, AllocationStrategy::Reserve);
auto stack_range = allocate_range({}, Thread::default_userspace_stack_size);
if (!stack_range.is_valid()) {
dbgln("do_exec: Failed to allocate VM range for stack");
return ENOMEM;
}
auto stack_region_or_error = allocate_region(stack_range, "Stack (Main thread)", PROT_READ | PROT_WRITE, AllocationStrategy::Reserve);
if (stack_region_or_error.is_error())
return stack_region_or_error.error();
auto& stack_region = *stack_region_or_error.value();

12
Kernel/Syscalls/mmap.cpp
View file

@ -404,10 +404,14 @@ void* Process::sys$mremap(Userspace<const Syscall::SC_mremap_params*> user_param
auto old_name = old_region->name();
auto old_prot = region_access_flags_to_prot(old_region->access());
NonnullRefPtr inode = static_cast<SharedInodeVMObject&>(old_region->vmobject()).inode();
// Unmap without deallocating the VM range since we're going to reuse it.
old_region->unmap(Region::ShouldDeallocateVirtualMemoryRange::No);
deallocate_region(*old_region);
auto new_vmobject = PrivateInodeVMObject::create_with_inode(inode);
auto new_region_or_error = allocate_region_with_vmobject(range.base(), range.size(), new_vmobject, 0, old_name, old_prot, false);
auto new_region_or_error = allocate_region_with_vmobject(range, new_vmobject, 0, old_name, old_prot, false);
if (new_region_or_error.is_error())
return (void*)new_region_or_error.error().error();
auto& new_region = *new_region_or_error.value();
@ -439,7 +443,11 @@ void* Process::sys$allocate_tls(size_t size)
});
ASSERT(main_thread);
auto region_or_error = allocate_region({}, size, String(), PROT_READ | PROT_WRITE);
auto range = allocate_range({}, size);
if (!range.is_valid())
return (void*)-ENOMEM;
auto region_or_error = allocate_region(range, String(), PROT_READ | PROT_WRITE);
if (region_or_error.is_error())
return (void*)region_or_error.error().error();

6
Kernel/Thread.cpp
View file

@ -1041,7 +1041,11 @@ KResult Thread::make_thread_specific_region(Badge<Process>)
if (!process().m_master_tls_region)
return KSuccess;
auto region_or_error = process().allocate_region({}, thread_specific_region_size(), "Thread-specific", PROT_READ | PROT_WRITE);
auto range = process().allocate_range({}, thread_specific_region_size());
if (!range.is_valid())
return ENOMEM;
auto region_or_error = process().allocate_region(range, "Thread-specific", PROT_READ | PROT_WRITE);
if (region_or_error.is_error())
return region_or_error.error();