kernel: do not use assembly code for commpage signal handler

Unify with x86 and riscv64 implementation.

Change-Id: I2f44575768628eb3a2d4eaaa86f020de582ecd0b
Reviewed-on: https://review.haiku-os.org/c/haiku/+/5203
Tested-by: Commit checker robot <no-reply+buildbot@haiku-os.org>
Reviewed-by: Jérôme Duval <jerome.duval@gmail.com>
Reviewed-by: Fredrik Holmqvist <fredrik.holmqvist@gmail.com>

src/system/kernel/arch/x86/64/signals.cpp

@@ -15,25 +15,66 @@
 #include <elf.h>
 #include <smp.h>
 
+#include "syscall_numbers.h"
 
-extern "C" void x86_64_user_signal_handler(void);
-extern int x86_64_user_signal_handler_end;
+
+extern "C" void __attribute__((noreturn))
+x86_64_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(
+		"movq %0, %%rdi;"
+		"movq $" TO_STRING_LITERAL(SYSCALL_RESTORE_SIGNAL_FRAME) ", %%rax;"
+		"syscall;"
+		:: "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)
+{
+	// get address and size of function
+	elf_symbol_info symbolInfo;
+	if (elf_lookup_kernel_symbol(functionName, &symbolInfo)	!= B_OK) {
+		panic("register_commpage_function(): Failed to find "
+			"signal frame function \"%s\"!", functionName);
+	}
+
+	ASSERT(expectedAddress == symbolInfo.address);
+
+	// fill in the commpage table entry
+	addr_t position = fill_commpage_entry(commpageIndex,
+		(void*)symbolInfo.address, symbolInfo.size);
+
+	// add symbol to the commpage image
+	image_id image = get_commpage_image();
+	elf_add_memory_image_symbol(image, commpageSymbolName, position,
+		symbolInfo.size, B_SYMBOL_TYPE_TEXT);
+}
 
 
 void
 x86_initialize_commpage_signal_handler()
 {
-	void* handlerCode = (void*)&x86_64_user_signal_handler;
-	void* handlerCodeEnd = &x86_64_user_signal_handler_end;
-
-	// Copy the signal handler code to the commpage.
-	size_t len = (size_t)((addr_t)handlerCodeEnd - (addr_t)handlerCode);
-	addr_t position = fill_commpage_entry(COMMPAGE_ENTRY_X86_SIGNAL_HANDLER,
-		handlerCode, len);
-
-	// Add symbol to the commpage image.
-	image_id image = get_commpage_image();
-	elf_add_memory_image_symbol(image, "commpage_signal_handler", position,
-		len, B_SYMBOL_TYPE_TEXT);
+	register_commpage_function("x86_64_user_signal_handler",
+		COMMPAGE_ENTRY_X86_SIGNAL_HANDLER, "commpage_signal_handler",
+		(addr_t)&x86_64_user_signal_handler);
 }
-

src/system/kernel/arch/x86/64/signals_asm.S

@@ -1,56 +0,0 @@
-/*
- * Copyright 2012, Alex Smith, alex@alex-smith.me.uk.
- * Distributed under the terms of the MIT License.
- */
-
-
-#include <asm_defs.h>
-
-#include "asm_offsets.h"
-#include "syscall_numbers.h"
-
-
-.text
-
-
-// Userspace signal handler wrapper, copied to the commpage.
-FUNCTION(x86_64_user_signal_handler):
-	push	%rbp
-	movq	%rsp, %rbp
-
-	// RDI points to the signal_frame_data structure, however we'll overwrite
-	// that with the function arguments, so move it somewhere else. We can use
-	// callee-save registers here without preserving them because the old value
-	// will be restored when the frame is restored.
-	movq	%rdi, %r12
-
-	// Check the handler type.
-	cmpb	$0, SIGNAL_FRAME_DATA_siginfo_handler(%r12)
-	jne		.Lsiginfo_handler
-
-.Lsimple_handler:
-	// Fetch other arguments (user data, vregs).
-	movq	SIGNAL_FRAME_DATA_user_data(%r12), %rsi
-	leaq	SIGNAL_FRAME_DATA_context + UCONTEXT_T_uc_mcontext(%r12), %rdx
-
-.Lcall_handler:
-	// Get the handler address and the signal number first argument.
-	movq	SIGNAL_FRAME_DATA_handler(%r12), %rax
-	movl	SIGNAL_FRAME_DATA_info + SIGINFO_T_si_signo(%r12), %edi
-
-	// Call the handler.
-	callq	*%rax
-
-	// Perform the restore_signal_frame() syscall, should not return.
-	movq	$SYSCALL_RESTORE_SIGNAL_FRAME, %rax
-	movq	%r12, %rdi
-	syscall
-
-.Lsiginfo_handler:
-	// Fetch other arguments (info pointer, context, user data).
-	leaq	SIGNAL_FRAME_DATA_info(%r12), %rsi
-	leaq	SIGNAL_FRAME_DATA_context(%r12), %rdx
-	movq	SIGNAL_FRAME_DATA_user_data(%r12), %rcx
-	jmp		.Lcall_handler
-FUNCTION_END(x86_64_user_signal_handler)
-SYMBOL(x86_64_user_signal_handler_end):

src/system/kernel/arch/x86/Jamfile

@@ -28,7 +28,6 @@ if $(TARGET_ARCH) = x86_64 {
 		errata.cpp
 		interrupts.S
 		signals.cpp
-		signals_asm.S
 		syscalls.cpp
 		thread.cpp