Kernel/riscv64: Make the kernel compile

This commits inserts TODOs into all necessary places to make the kernel
compile on riscv64!

Kernel/Syscalls/SyscallHandler.cpp

@@ -107,6 +107,8 @@ NEVER_INLINE void syscall_handler(TrapFrame* trap)
     clac();
 #elif ARCH(AARCH64)
     // FIXME: Implement the security mechanism for aarch64
+#elif ARCH(RISCV64)
+    // FIXME: Implement the security mechanism for riscv64
 #else
 #    error Unknown architecture
 #endif
@@ -148,6 +150,8 @@ NEVER_INLINE void syscall_handler(TrapFrame* trap)
     }
 #elif ARCH(AARCH64)
     // FIXME: Implement the security mechanism for aarch64
+#elif ARCH(RISCV64)
+    // FIXME: Implement the security mechanism for riscv64
 #else
 #    error Unknown architecture
 #endif

Kernel/Syscalls/execve.cpp

@@ -156,6 +156,10 @@ static ErrorOr<FlatPtr> make_userspace_context_for_main_thread([[maybe_unused]]
     regs.x[0] = argv_entries.size();
     regs.x[1] = argv;
     regs.x[2] = envp;
+#elif ARCH(RISCV64)
+    (void)argv;
+    (void)envp;
+    TODO_RISCV64();
 #else
 #    error Unknown architecture
 #endif
@@ -737,6 +741,8 @@ static Array<ELF::AuxiliaryValue, auxiliary_vector_size> generate_auxiliary_vect
         { ELF::AuxiliaryValue::HwCap, (long)CPUID(1).edx() },
 #elif ARCH(AARCH64)
         { ELF::AuxiliaryValue::HwCap, (long)0 },
+#elif ARCH(RISCV64)
+        { ELF::AuxiliaryValue::HwCap, (long)0 }, // TODO
 #else
 #    error "Unknown architecture"
 #endif

Kernel/Syscalls/fork.cpp

@@ -150,6 +150,10 @@ ErrorOr<FlatPtr> Process::sys$fork(RegisterState& regs)
     child_regs.spsr_el1 = regs.spsr_el1;
     child_regs.elr_el1 = regs.elr_el1;
     child_regs.sp_el0 = regs.sp_el0;
+#elif ARCH(RISCV64)
+    (void)child_regs;
+    (void)regs;
+    TODO_RISCV64();
 #else
 #    error Unknown architecture
 #endif

Kernel/Syscalls/ptrace.cpp

@@ -258,6 +258,9 @@ ErrorOr<FlatPtr> Thread::peek_debug_register(u32 register_index)
 #elif ARCH(AARCH64)
     (void)register_index;
     TODO_AARCH64();
+#elif ARCH(RISCV64)
+    (void)register_index;
+    TODO_RISCV64();
 #else
 #    error "Unknown architecture"
 #endif
@@ -290,6 +293,10 @@ ErrorOr<void> Thread::poke_debug_register(u32 register_index, FlatPtr data)
     (void)register_index;
     (void)data;
     TODO_AARCH64();
+#elif ARCH(RISCV64)
+    (void)register_index;
+    (void)data;
+    TODO_RISCV64();
 #else
 #    error "Unknown architecture"
 #endif

Kernel/Syscalls/thread.cpp

@@ -76,6 +76,8 @@ ErrorOr<FlatPtr> Process::sys$create_thread(void* (*entry)(void*), Userspace<Sys
     regs.x[1] = (FlatPtr)params.entry_argument;
     regs.x[2] = (FlatPtr)params.stack_location;
     regs.x[3] = (FlatPtr)params.stack_size;
+#elif ARCH(RISCV64)
+    TODO_RISCV64();
 #else
 #    error Unknown architecture
 #endif

Kernel/Syscalls/uname.cpp

@@ -15,6 +15,8 @@ namespace Kernel {
 #    define UNAME_MACHINE "x86_64"
 #elif ARCH(AARCH64)
 #    define UNAME_MACHINE "AArch64"
+#elif ARCH(RISCV64)
+#    define UNAME_MACHINE "riscv64"
 #else
 #    error Unknown architecture
 #endif