From d776fd53f7fdf12f297838ca476948bc7083c82a Mon Sep 17 00:00:00 2001
From: Alex Smith <alex@alex-smith.me.uk>
Date: Wed, 11 Jul 2012 14:19:19 +0100
Subject: [PATCH] Implemented arch_cpu_user_*() for x86_64, based on the x86
 versions.

---
 src/system/kernel/arch/x86/64/arch.S    | 141 +++++++++++++++++++++++-
 src/system/kernel/arch/x86/64/stubs.cpp |  23 ----
 2 files changed, 140 insertions(+), 24 deletions(-)

diff --git a/src/system/kernel/arch/x86/64/arch.S b/src/system/kernel/arch/x86/64/arch.S
index 4fe65734c1..58b4bcb994 100644
--- a/src/system/kernel/arch/x86/64/arch.S
+++ b/src/system/kernel/arch/x86/64/arch.S
@@ -1,6 +1,12 @@
 /*
  * Copyright 2012, Alex Smith, alex@alex-smith.me.uk.
+ * Copyright 2003-2007, Axel Dörfler, axeld@pinc-software.de.
+ * Copyright 2012, Rene Gollent, rene@gollent.com.
  * Distributed under the terms of the MIT License.
+ *
+ * Copyright 2001, Travis Geiselbrecht. All rights reserved.
+ * Copyright 2002, Michael Noisternig. All rights reserved.
+ * Distributed under the terms of the NewOS License.
  */
 
 
@@ -78,7 +84,7 @@ FUNCTION_END(x86_64_thread_entry)
 
 
 /* void x86_context_switch(struct arch_thread* oldState,
-	struct arch_thread* newState); */
+		struct arch_thread* newState); */
 FUNCTION(x86_context_switch):
 	// Just need to save callee-save registers: RBP, RBX, R12-15.
 	push	%r15
@@ -121,3 +127,136 @@ FUNCTION(x86_reboot):
 done:
 	jmp		done
 FUNCTION_END(x86_reboot)
+
+
+/* status_t arch_cpu_user_memcpy(void* to, const void* from, size_t size,
+		addr_t* faultHandler) */
+FUNCTION(arch_cpu_user_memcpy):
+	// faultHandler -> r8, size -> rcx.
+	movq	%rcx, %r8
+	movq	%rdx, %rcx
+
+	// Set the fault handler, preserve old in rax.
+	movq	(%r8), %rax
+	movq	$.L_user_memcpy_error, (%r8)
+
+	// Move by quadwords.
+	cld
+	movq	%rcx, %r9
+	shrq	$3, %rcx
+	rep
+	movsq
+
+	// Move any remaining data by bytes.
+	movq	%r9, %rcx
+	andq	$7, %rcx
+	rep
+	movsb
+
+	// Restore the old fault handler and return.
+	movq	%rax, (%r8)
+	xorl	%eax, %eax
+	ret
+
+.L_user_memcpy_error:
+	// Restore the old fault handler. Return a generic error, the wrapper
+	// routine will deal with it.
+	movq	%rax, (%r8)
+	movl	$-1, %eax
+	ret
+FUNCTION_END(arch_cpu_user_memcpy)
+
+
+/* status_t arch_cpu_user_memset(void* to, char c, size_t count,
+		addr_t* faultHandler) */
+FUNCTION(arch_cpu_user_memset):
+	// c -> al, faultHandler -> r8, size -> rcx.
+	movw	%si, %ax
+	movq	%rcx, %r8
+	movq	%rdx, %rcx
+
+	// Set the fault handler, preserve old in rdx.
+	movq	(%r8), %rdx
+	movq	$.L_user_memset_error, (%r8)
+
+	rep
+	stosb
+
+	// Restore the old fault handler and return.
+	movq	%rdx, (%r8)
+	xorl	%eax, %eax
+	ret
+
+.L_user_memset_error:
+	// Restore the old fault handler. Return a generic error, the wrapper
+	// routine will deal with it.
+	movq	%rdx, (%r8)
+	movl	$-1, %eax
+	ret
+FUNCTION_END(arch_cpu_user_memset)
+
+
+/* ssize_t arch_cpu_user_strlcpy(void* to, const void* from, size_t size,
+		addr_t* faultHandler) */
+FUNCTION(arch_cpu_user_strlcpy):
+	// faultHandler -> r8, size -> rcx, source -> r9 (original value needed to
+	// calculate return value).
+	movq	%rcx, %r8
+	movq	%rdx, %rcx
+	movq	%rsi, %r9
+
+	// Set the fault handler, preserve old in rax.
+	movq	(%r8), %rax
+	movq	$.L_user_strlcpy_error, (%r8)
+
+	// Check for 0 length.
+	cmp		$0, %rcx
+	je		.L_user_strlcpy_source_count
+
+	// Copy at most count - 1 bytes.
+	dec		%rcx
+
+	// If count is now 0, skip straight to null terminating as our loop will
+	// otherwise overflow.
+	jnz		.L_user_strlcpy_copy_begin
+	movb	$0, (%rdi)
+	jmp		.L_user_strlcpy_source_count
+
+.L_user_strlcpy_copy_begin:
+	cld
+.L_user_strlcpy_copy_loop:
+	// Move data by bytes.
+	lodsb
+	stosb
+	test	%al, %al
+	jz		.L_user_strlcpy_source_done
+	loop	.L_user_strlcpy_copy_loop
+
+	// Null terminate string.
+	movb	$0, (%rdi)
+	dec		%rsi
+
+.L_user_strlcpy_source_count:
+	// Count remaining bytes in src
+	not		%rcx
+	xor		%al, %al
+	repnz
+	scasb
+
+.L_user_strlcpy_source_done:
+	// Restore the old fault handler
+	movq	%rax, (%r8)
+
+	// Calculate total string length and return.
+	movq	%rsi, %rax
+	subq	%r9, %rax
+	dec		%rax
+	ret
+
+.L_user_strlcpy_error:
+	// Restore the old fault handler. Return a generic error, the wrapper
+	// routine will deal with it.
+	movq	%rax, (%r8)
+	movq	$-1, %rax
+	ret
+FUNCTION_END(arch_cpu_user_strlcpy)
diff --git a/src/system/kernel/arch/x86/64/stubs.cpp b/src/system/kernel/arch/x86/64/stubs.cpp
index 2651c32a47..e4a02c973a 100644
--- a/src/system/kernel/arch/x86/64/stubs.cpp
+++ b/src/system/kernel/arch/x86/64/stubs.cpp
@@ -51,29 +51,6 @@ arch_commpage_init_post_cpus(void)
 }
 
 
-ssize_t
-arch_cpu_user_strlcpy(char* to, const char* from, size_t size,
-	addr_t* faultHandler)
-{
-	return B_BAD_ADDRESS;
-}
-
-
-status_t
-arch_cpu_user_memcpy(void* to, const void* from, size_t size,
-	addr_t* faultHandler)
-{
-	return B_BAD_ADDRESS;
-}
-
-
-status_t
-arch_cpu_user_memset(void* s, char c, size_t count, addr_t* faultHandler)
-{
-	return B_BAD_ADDRESS;
-}
-
-
 void
 arch_debug_save_registers(struct arch_debug_registers* registers)
 {