arm64: Implement kernel thread switching.

Change-Id: I87cca66ad89cfa85ba98a9ec828c5e357d7406b2
Reviewed-on: https://review.haiku-os.org/c/haiku/+/5263
Reviewed-by: Adrien Destugues <[email protected]>
Tested-by: Commit checker robot <[email protected]>

headers/private/kernel/arch/arm64/arch_thread_types.h

@@ -10,12 +10,7 @@
 
 
 struct arch_thread {
-	uint64			x[31];
+	uint64			regs[13]; // x19-x30, sp
-	uint64			pc;
-	uint64			sp;
-	uint64			tpidr_el0;
-	uint64			tpidrro_el0;
-	int				last_vfp_cpu;
 };
 
 struct arch_team {
@@ -26,5 +21,4 @@ struct arch_fork_arg {
 	int			dummy;
 };
 
-
 #endif /* _KERNEL_ARCH_ARM64_ARCH_THREAD_TYPES_H_ */

src/system/kernel/arch/arm64/arch_asm.S

@@ -7,6 +7,31 @@
 
 .text
 
+FUNCTION(_arch_context_swap):
+	stp x19, x20, [x0], #16
+	stp x21, x22, [x0], #16
+	stp x23, x24, [x0], #16
+	stp x25, x26, [x0], #16
+	stp x27, x28, [x0], #16
+	stp x29, x30, [x0], #16
+
+	mov x2, sp
+	str x2, [x0]
+
+	ldp x19, x20, [x1], #16
+	ldp x21, x22, [x1], #16
+	ldp x23, x24, [x1], #16
+	ldp x25, x26, [x1], #16
+	ldp x27, x28, [x1], #16
+	ldp x29, x30, [x1], #16
+
+	ldr x2, [x1]
+	mov sp, x2
+
+	mov x0, x29
+	ret
+FUNCTION_END(_arch_context_swap)
+
 /* status_t arch_cpu_user_memcpy(void *to, const void *from, size_t size, addr_t *faultHandler) */
 FUNCTION(_arch_cpu_user_memcpy):
 	mov		x0, xzr

src/system/kernel/arch/arm64/arch_thread.cpp

@@ -51,6 +51,10 @@ void
 arch_thread_init_kthread_stack(Thread* thread, void* _stack, void* _stackTop,
 	void (*function)(void*), const void* data)
 {
+	memset(&thread->arch_info, 0, sizeof(arch_thread));
+	thread->arch_info.regs[10] = (uint64_t)data;
+	thread->arch_info.regs[11] = (uint64_t)function;
+	thread->arch_info.regs[12] = (uint64_t)_stackTop;
 }
 
 
@@ -61,9 +65,13 @@ arch_thread_init_tls(Thread *thread)
 }
 
 
+extern "C" void _arch_context_swap(arch_thread *from, arch_thread *to);
+
+
 void
 arch_thread_context_switch(Thread *from, Thread *to)
 {
+	_arch_context_swap(&from->arch_info, &to->arch_info);
 }
 
 void