arm64: Add signal handling and forking

Change-Id: I8fd41bf5c540bcb2b9347aae47ad8bb86a6a6964
Reviewed-on: https://review.haiku-os.org/c/haiku/+/10605
Reviewed-by: waddlesplash <[email protected]>
Tested-by: Commit checker robot <[email protected]>

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

@@ -119,34 +119,6 @@ ADDRESS_TRANSLATE_FUNC(s1e1r)
 ADDRESS_TRANSLATE_FUNC(s1e1w)
 
 
-struct aarch64_fpu_state
-{
-	uint64 regs[32 * 2];
-	uint64 fpsr;
-	uint64 fpcr;
-};
-
-
-/* raw exception frames */
-struct iframe {
-	// return info
-	uint64 elr;
-	uint64 spsr;
-	uint64 x[29];
-	uint64 fp;
-	uint64 lr;
-	uint64 sp;
-	uint64 tpidr;
-
-	// exception info
-	uint64 esr;
-	uint64 far;
-
-	// fpu
-	struct aarch64_fpu_state fpu;
-};
-
-
 #ifdef __cplusplus
 namespace BKernel {
 	struct Thread;

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

@@ -11,6 +11,35 @@
 
 #define	IFRAME_TRACE_DEPTH 4
 
+
+struct aarch64_fpu_state
+{
+	uint64 regs[32 * 2];
+	uint64 fpsr;
+	uint64 fpcr;
+};
+
+
+/* raw exception frames */
+struct iframe {
+	// return info
+	uint64 elr;
+	uint64 spsr;
+	uint64 x[29];
+	uint64 fp;
+	uint64 lr;
+	uint64 sp;
+	uint64 tpidr;
+
+	// exception info
+	uint64 esr;
+	uint64 far;
+
+	// fpu
+	struct aarch64_fpu_state fpu;
+};
+
+
 struct iframe_stack {
 	struct iframe *frames[IFRAME_TRACE_DEPTH];
 	int32	index;
@@ -20,17 +49,21 @@ struct iframe_stack {
 struct arch_thread {
 	uint64 regs[14]; // x19-x30, sp, tpidr_el0
 	uint64 fp_regs[8]; // d8-d15
+	uint64 old_x0;
 
 	// used to track interrupts on this thread
 	struct iframe_stack	iframes;
 };
 
+
 struct arch_team {
 	int			dummy;
 };
 
+
 struct arch_fork_arg {
-	int			dummy;
+	struct iframe frame;
 };
 
+
 #endif /* _KERNEL_ARCH_ARM64_ARCH_THREAD_TYPES_H_ */

headers/private/system/arch/arm64/arch_commpage_defs.h

@@ -11,5 +11,6 @@
 #endif
 
 #define COMMPAGE_ENTRY_ARM64_THREAD_EXIT (COMMPAGE_ENTRY_FIRST_ARCH_SPECIFIC + 0)
+#define COMMPAGE_ENTRY_ARM64_SIGNAL_HANDLER (COMMPAGE_ENTRY_FIRST_ARCH_SPECIFIC + 1)
 
 #endif	/* _SYSTEM_ARCH_ARM64_COMMPAGE_DEFS_H */

src/system/kernel/arch/arm64/Jamfile

@@ -49,5 +49,5 @@ KernelMergeObject kernel_arch_arm64.o :
 CreateAsmStructOffsetsHeader asm_offsets.h : asm_offsets.cpp : $(TARGET_KERNEL_ARCH) ;
 
 # syscall headers are generated on the fly, so we need a explicit dependency.
-Includes [ FGristFiles arch_int.cpp arch_asm.S ]
+Includes [ FGristFiles arch_commpage.cpp arch_int.cpp arch_asm.S ]
 	: <syscalls!$(TARGET_PACKAGING_ARCH)>syscall_numbers.h ;

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

@@ -12,10 +12,41 @@
 #include <elf.h>
 #include <smp.h>
 
+#include "syscall_numbers.h"
+
 
 extern "C" void _thread_exit_syscall();
 
 
+extern "C" void __attribute__((noreturn))
+arch_user_signal_handler(signal_frame_data* data)
+{
+	if (data->siginfo_handler) {
+		auto handler = (void (*)(int, siginfo_t*, void*, void*))data->handler;
+		handler(data->info.si_signo, &data->info, &data->context, data->user_data);
+	} else {
+		auto handler = (void (*)(int, void*, vregs*))data->handler;
+		handler(data->info.si_signo, data->user_data, &data->context.uc_mcontext);
+	}
+
+	#define TO_STRING_LITERAL_HELPER(number)	#number
+	#define TO_STRING_LITERAL(number)	TO_STRING_LITERAL_HELPER(number)
+
+	// _kern_restore_signal_frame(data)
+	asm volatile(
+		"mov x0, %0;"
+		"svc #" TO_STRING_LITERAL(((SYSCALL_RESTORE_SIGNAL_FRAME << 5) | 1)) ";"
+		:: "r" (data)
+	);
+
+	#undef TO_STRING_LITERAL_HELPER
+	#undef TO_STRING_LITERAL
+
+	__builtin_unreachable();
+}
+
+
+
 static void
 register_commpage_function(const char* functionName, int32 commpageIndex,
 	const char* commpageSymbolName, addr_t expectedAddress)
@@ -53,5 +84,8 @@ arch_commpage_init_post_cpus(void)
 	register_commpage_function("_thread_exit_syscall", COMMPAGE_ENTRY_ARM64_THREAD_EXIT,
 		"commpage_thread_exit", (addr_t)&_thread_exit_syscall);
 
+	register_commpage_function("arch_user_signal_handler", COMMPAGE_ENTRY_ARM64_SIGNAL_HANDLER,
+		"commpage_signal_handler", (addr_t)&arch_user_signal_handler);
+
 	return B_OK;
 }

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

@@ -311,7 +311,6 @@ do_sync_handler(iframe * frame)
 					return;
 				}
 			} else if (thread->page_faults_allowed != 0) {
-				dprintf("PF: %lx\n", frame->far);
 				enable_interrupts();
 				addr_t ret = 0;
 				vm_page_fault(frame->far, frame->elr, write, isExec, isUser, &ret);
@@ -352,6 +351,7 @@ do_sync_handler(iframe * frame)
 			_fp_save(&frame->fpu);
 
 			thread_at_kernel_entry(system_time());
+			thread_get_current_thread()->arch_info.old_x0 = frame->x[0];
 
 			enable_interrupts();
 			syscall_dispatcher(syscall, (void*)args, &frame->x[0]);
@@ -369,7 +369,13 @@ do_sync_handler(iframe * frame)
 					thread_at_kernel_exit_no_signals();
 				}
 				if ((THREAD_FLAGS_RESTART_SYSCALL & thread_get_current_thread()->flags) != 0) {
-					panic("syscall restart");
+					atomic_and(&thread_get_current_thread()->flags, ~THREAD_FLAGS_RESTART_SYSCALL);
+					atomic_or(&thread_get_current_thread()->flags, THREAD_FLAGS_SYSCALL_RESTARTED);
+
+					// Restore old syscall argument and go
+					// back an instruction
+					frame->x[0] = thread_get_current_thread()->arch_info.old_x0;
+					frame->elr -= 4;
 				}
 			}
 

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

@@ -137,7 +137,32 @@ arch_thread_enter_userspace(Thread *thread, addr_t entry,
 bool
 arch_on_signal_stack(Thread *thread)
 {
-	return false;
+	iframe_stack* iframes = &thread->arch_info.iframes;
+	iframe* frame = iframes->frames[iframes->index - 1];
+
+	return frame->sp >= thread->signal_stack_base
+		&& frame->sp < thread->signal_stack_base
+			+ thread->signal_stack_size;
+}
+
+
+static uint8*
+get_signal_stack(Thread* thread, struct iframe* frame,
+	struct sigaction* action, size_t spaceNeeded)
+{
+	// use the alternate signal stack if we should and can
+	if (
+		thread->signal_stack_enabled &&
+		(action->sa_flags & SA_ONSTACK) != 0 && (
+			frame->sp < thread->signal_stack_base ||
+			frame->sp >= thread->signal_stack_base + thread->signal_stack_size
+		)
+	) {
+		addr_t stackTop = thread->signal_stack_base
+			+ thread->signal_stack_size;
+		return (uint8*)ROUNDDOWN(stackTop - spaceNeeded, 16);
+	}
+	return (uint8*)ROUNDDOWN(frame->sp - spaceNeeded, 16);
 }
 
 
@@ -145,26 +170,81 @@ status_t
 arch_setup_signal_frame(Thread *thread, struct sigaction *sa,
 	struct signal_frame_data *signalFrameData)
 {
-	panic("arch_setup_signal_frame");
+	iframe_stack* iframes = &thread->arch_info.iframes;
-	return B_ERROR;
+	iframe *frame = iframes->frames[iframes->index - 1];
+
+	memcpy(signalFrameData->context.uc_mcontext.x, frame->x, sizeof(frame->x));
+	signalFrameData->context.uc_mcontext.x[29] = frame->fp;
+	signalFrameData->context.uc_mcontext.lr = frame->lr;
+	signalFrameData->context.uc_mcontext.elr = frame->elr;
+	signalFrameData->context.uc_mcontext.spsr = frame->spsr;
+	signalFrameData->context.uc_mcontext.sp = frame->sp;
+	memcpy(signalFrameData->context.uc_mcontext.fp_q, frame->fpu.regs,
+		sizeof(signalFrameData->context.uc_mcontext.fp_q));
+	signalFrameData->context.uc_mcontext.fpsr = frame->fpu.fpsr;
+	signalFrameData->context.uc_mcontext.fpcr = frame->fpu.fpcr;
+	signalFrameData->syscall_restart_return_value = thread->arch_info.old_x0;
+
+	signal_get_user_stack(frame->sp, &signalFrameData->context.uc_stack);
+
+	uint8* userStack = get_signal_stack(thread, frame, sa,
+		sizeof(*signalFrameData));
+	status_t res = user_memcpy(userStack, signalFrameData,
+		sizeof(*signalFrameData));
+	if (res < B_OK)
+		return res;
+
+	addr_t commpageAddr = (addr_t)thread->team->commpage_address;
+	addr_t signalHandlerAddr;
+	ASSERT(user_memcpy(&signalHandlerAddr,
+		&((addr_t*)commpageAddr)[COMMPAGE_ENTRY_ARM64_SIGNAL_HANDLER],
+		sizeof(signalHandlerAddr)) >= B_OK);
+	signalHandlerAddr += commpageAddr;
+
+	frame->lr = frame->elr;
+	frame->sp = (addr_t)userStack;
+	frame->elr = signalHandlerAddr;
+	frame->x[0] = frame->sp;
+
+	return B_OK;
 }
 
 
 int64
 arch_restore_signal_frame(struct signal_frame_data* signalFrameData)
 {
-	return 0;
+	iframe_stack* iframes = &thread_get_current_thread()->arch_info.iframes;
+	iframe *frame = iframes->frames[iframes->index - 1];
+
+	thread_get_current_thread()->arch_info.old_x0
+		= signalFrameData->syscall_restart_return_value;
+
+	memcpy(frame->x, signalFrameData->context.uc_mcontext.x, sizeof(frame->x));
+	frame->fp = signalFrameData->context.uc_mcontext.x[29];
+	frame->lr = signalFrameData->context.uc_mcontext.lr;
+	frame->elr = signalFrameData->context.uc_mcontext.elr;
+	frame->spsr = signalFrameData->context.uc_mcontext.spsr;
+	frame->sp = signalFrameData->context.uc_mcontext.sp;
+	memcpy(frame->fpu.regs, signalFrameData->context.uc_mcontext.fp_q,
+		sizeof(signalFrameData->context.uc_mcontext.fp_q));
+	frame->fpu.fpsr = signalFrameData->context.uc_mcontext.fpsr;
+	frame->fpu.fpcr = signalFrameData->context.uc_mcontext.fpcr;
+
+	return frame->x[0];
 }
 
 
 void
 arch_store_fork_frame(struct arch_fork_arg *arg)
 {
-	panic("arch_store_fork_frame");
+	iframe_stack* iframes = &thread_get_current_thread()->arch_info.iframes;
+	memcpy(&arg->frame, iframes->frames[iframes->index - 1], sizeof(iframe));
+	arg->frame.x[0] = 0;
 }
 
 
 void
 arch_restore_fork_frame(struct arch_fork_arg *arg)
 {
+	_eret_with_iframe(&arg->frame);
 }