Everywhere: Make the codebase more architecture aware

Kernel/Coredump.cpp

@@ -85,8 +85,10 @@ ErrorOr<void> Coredump::write_elf_header()
     elf_file_header.e_ident[EI_MAG3] = 'F';
 #if ARCH(I386)
     elf_file_header.e_ident[EI_CLASS] = ELFCLASS32;
-#else
+#elif ARCH(X86_64) || ARCH(AARCH64)
     elf_file_header.e_ident[EI_CLASS] = ELFCLASS64;
+#else
+#    error Unknown architecture
 #endif
     elf_file_header.e_ident[EI_DATA] = ELFDATA2LSB;
     elf_file_header.e_ident[EI_VERSION] = EV_CURRENT;
@@ -101,8 +103,12 @@ ErrorOr<void> Coredump::write_elf_header()
     elf_file_header.e_type = ET_CORE;
 #if ARCH(I386)
     elf_file_header.e_machine = EM_386;
-#else
+#elif ARCH(X86_64)
     elf_file_header.e_machine = EM_X86_64;
+#elif ARCH(AARCH64)
+    elf_file_header.e_machine = EM_AARCH64;
+#else
+#    error Unknown architecture
 #endif
     elf_file_header.e_version = 1;
     elf_file_header.e_entry = 0;

Kernel/Heap/kmalloc.cpp

@@ -20,8 +20,10 @@
 
 #if ARCH(I386)
 static constexpr size_t CHUNK_SIZE = 32;
-#else
+#elif ARCH(X86_64) || ARCH(AARCH64)
 static constexpr size_t CHUNK_SIZE = 64;
+#else
+#    error Unknown architecture
 #endif
 static_assert(is_power_of_two(CHUNK_SIZE));
 

Kernel/Process.cpp

@@ -191,8 +191,10 @@ RefPtr<Process> Process::create_kernel_process(RefPtr<Thread>& first_thread, Non
     first_thread->regs().set_ip((FlatPtr)entry);
 #if ARCH(I386)
     first_thread->regs().esp = FlatPtr(entry_data); // entry function argument is expected to be in regs.esp
-#else
+#elif ARCH(X86_64)
     first_thread->regs().rdi = FlatPtr(entry_data); // entry function argument is expected to be in regs.rdi
+#else
+#    error Unknown architecture
 #endif
 
     if (do_register == RegisterProcess::Yes)

Kernel/Syscalls/execve.cpp

@@ -149,10 +149,12 @@ static ErrorOr<FlatPtr> make_userspace_context_for_main_thread([[maybe_unused]]
     push_on_new_stack(envp);
     push_on_new_stack(argv);
     push_on_new_stack(argv_entries.size());
-#else
+#elif ARCH(X86_64)
     regs.rdi = argv_entries.size();
     regs.rsi = argv;
     regs.rdx = envp;
+#else
+#    error Unknown architecture
 #endif
 
     VERIFY(new_sp % 16 == 0);

Kernel/Syscalls/fork.cpp

@@ -89,7 +89,7 @@ ErrorOr<FlatPtr> Process::sys$fork(RegisterState& regs)
 
     dbgln_if(FORK_DEBUG, "fork: child will begin executing at {:#04x}:{:p} with stack {:#04x}:{:p}, kstack {:#04x}:{:p}",
         child_regs.cs, child_regs.eip, child_regs.ss, child_regs.esp, child_regs.ss0, child_regs.esp0);
-#else
+#elif ARCH(X86_64)
     auto& child_regs = child_first_thread->m_regs;
     child_regs.rax = 0; // fork() returns 0 in the child :^)
     child_regs.rbx = regs.rbx;
@@ -113,6 +113,8 @@ ErrorOr<FlatPtr> Process::sys$fork(RegisterState& regs)
 
     dbgln_if(FORK_DEBUG, "fork: child will begin executing at {:#04x}:{:p} with stack {:p}, kstack {:p}",
         child_regs.cs, child_regs.rip, child_regs.rsp, child_regs.rsp0);
+#else
+#    error Unknown architecture
 #endif
 
     {

Kernel/Syscalls/uname.cpp

@@ -19,8 +19,12 @@ ErrorOr<FlatPtr> Process::sys$uname(Userspace<utsname*> user_buf)
     memcpy(buf.version, "FIXME", 6);
 #if ARCH(I386)
     memcpy(buf.machine, "i686", 5);
-#else
+#elif ARCH(X86_64)
     memcpy(buf.machine, "x86_64", 7);
+#elif ARCH(AARCH64)
+    memcpy(buf.machine, "AArch64", 7);
+#else
+#    error Unknown architecture
 #endif
 
     hostname().with_shared([&](auto const& name) {

Kernel/Thread.cpp

@@ -96,11 +96,13 @@ Thread::Thread(NonnullRefPtr<Process> process, NonnullOwnPtr<Memory::Region> ker
         m_regs.ss = GDT_SELECTOR_DATA3 | 3;
         m_regs.gs = GDT_SELECTOR_TLS | 3;
     }
-#else
+#elif ARCH(X86_64)
     if (m_process->is_kernel_process())
         m_regs.cs = GDT_SELECTOR_CODE0;
     else
         m_regs.cs = GDT_SELECTOR_CODE3 | 3;
+#else
+#    error Unknown architecture
 #endif
 
     m_regs.cr3 = m_process->address_space().page_directory().cr3();

Kernel/Time/HPET.cpp

@@ -93,7 +93,7 @@ static u64 read_register_safe64(HPETRegister const& reg)
 {
 #if ARCH(X86_64)
     return reg.full;
-#else
+#elif ARCH(I386)
     // As per 2.4.7 this reads the 64 bit value in a consistent manner
     // using only 32 bit reads
     u32 low, high = reg.high;
@@ -105,6 +105,8 @@ static u64 read_register_safe64(HPETRegister const& reg)
         high = new_high;
     }
     return ((u64)high << 32) | (u64)low;
+#else
+#    error Unknown architecture
 #endif
 }