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authorAndré Fabian Silva Delgado <emulatorman@parabola.nu>2016-06-10 05:30:17 -0300
committerAndré Fabian Silva Delgado <emulatorman@parabola.nu>2016-06-10 05:30:17 -0300
commitd635711daa98be86d4c7fd01499c34f566b54ccb (patch)
treeaa5cc3760a27c3d57146498cb82fa549547de06c /arch/x86/lib/memcpy_64.S
parentc91265cd0efb83778f015b4d4b1129bd2cfd075e (diff)
Linux-libre 4.6.2-gnu
Diffstat (limited to 'arch/x86/lib/memcpy_64.S')
-rw-r--r--arch/x86/lib/memcpy_64.S120
1 files changed, 119 insertions, 1 deletions
diff --git a/arch/x86/lib/memcpy_64.S b/arch/x86/lib/memcpy_64.S
index 16698bba8..2ec0b0abb 100644
--- a/arch/x86/lib/memcpy_64.S
+++ b/arch/x86/lib/memcpy_64.S
@@ -1,7 +1,8 @@
/* Copyright 2002 Andi Kleen */
#include <linux/linkage.h>
-#include <asm/cpufeature.h>
+#include <asm/errno.h>
+#include <asm/cpufeatures.h>
#include <asm/alternative-asm.h>
/*
@@ -177,3 +178,120 @@ ENTRY(memcpy_orig)
.Lend:
retq
ENDPROC(memcpy_orig)
+
+#ifndef CONFIG_UML
+/*
+ * memcpy_mcsafe - memory copy with machine check exception handling
+ * Note that we only catch machine checks when reading the source addresses.
+ * Writes to target are posted and don't generate machine checks.
+ */
+ENTRY(memcpy_mcsafe)
+ cmpl $8, %edx
+ /* Less than 8 bytes? Go to byte copy loop */
+ jb .L_no_whole_words
+
+ /* Check for bad alignment of source */
+ testl $7, %esi
+ /* Already aligned */
+ jz .L_8byte_aligned
+
+ /* Copy one byte at a time until source is 8-byte aligned */
+ movl %esi, %ecx
+ andl $7, %ecx
+ subl $8, %ecx
+ negl %ecx
+ subl %ecx, %edx
+.L_copy_leading_bytes:
+ movb (%rsi), %al
+ movb %al, (%rdi)
+ incq %rsi
+ incq %rdi
+ decl %ecx
+ jnz .L_copy_leading_bytes
+
+.L_8byte_aligned:
+ /* Figure out how many whole cache lines (64-bytes) to copy */
+ movl %edx, %ecx
+ andl $63, %edx
+ shrl $6, %ecx
+ jz .L_no_whole_cache_lines
+
+ /* Loop copying whole cache lines */
+.L_cache_w0: movq (%rsi), %r8
+.L_cache_w1: movq 1*8(%rsi), %r9
+.L_cache_w2: movq 2*8(%rsi), %r10
+.L_cache_w3: movq 3*8(%rsi), %r11
+ movq %r8, (%rdi)
+ movq %r9, 1*8(%rdi)
+ movq %r10, 2*8(%rdi)
+ movq %r11, 3*8(%rdi)
+.L_cache_w4: movq 4*8(%rsi), %r8
+.L_cache_w5: movq 5*8(%rsi), %r9
+.L_cache_w6: movq 6*8(%rsi), %r10
+.L_cache_w7: movq 7*8(%rsi), %r11
+ movq %r8, 4*8(%rdi)
+ movq %r9, 5*8(%rdi)
+ movq %r10, 6*8(%rdi)
+ movq %r11, 7*8(%rdi)
+ leaq 64(%rsi), %rsi
+ leaq 64(%rdi), %rdi
+ decl %ecx
+ jnz .L_cache_w0
+
+ /* Are there any trailing 8-byte words? */
+.L_no_whole_cache_lines:
+ movl %edx, %ecx
+ andl $7, %edx
+ shrl $3, %ecx
+ jz .L_no_whole_words
+
+ /* Copy trailing words */
+.L_copy_trailing_words:
+ movq (%rsi), %r8
+ mov %r8, (%rdi)
+ leaq 8(%rsi), %rsi
+ leaq 8(%rdi), %rdi
+ decl %ecx
+ jnz .L_copy_trailing_words
+
+ /* Any trailing bytes? */
+.L_no_whole_words:
+ andl %edx, %edx
+ jz .L_done_memcpy_trap
+
+ /* Copy trailing bytes */
+ movl %edx, %ecx
+.L_copy_trailing_bytes:
+ movb (%rsi), %al
+ movb %al, (%rdi)
+ incq %rsi
+ incq %rdi
+ decl %ecx
+ jnz .L_copy_trailing_bytes
+
+ /* Copy successful. Return zero */
+.L_done_memcpy_trap:
+ xorq %rax, %rax
+ ret
+ENDPROC(memcpy_mcsafe)
+
+ .section .fixup, "ax"
+ /* Return -EFAULT for any failure */
+.L_memcpy_mcsafe_fail:
+ mov $-EFAULT, %rax
+ ret
+
+ .previous
+
+ _ASM_EXTABLE_FAULT(.L_copy_leading_bytes, .L_memcpy_mcsafe_fail)
+ _ASM_EXTABLE_FAULT(.L_cache_w0, .L_memcpy_mcsafe_fail)
+ _ASM_EXTABLE_FAULT(.L_cache_w1, .L_memcpy_mcsafe_fail)
+ _ASM_EXTABLE_FAULT(.L_cache_w3, .L_memcpy_mcsafe_fail)
+ _ASM_EXTABLE_FAULT(.L_cache_w3, .L_memcpy_mcsafe_fail)
+ _ASM_EXTABLE_FAULT(.L_cache_w4, .L_memcpy_mcsafe_fail)
+ _ASM_EXTABLE_FAULT(.L_cache_w5, .L_memcpy_mcsafe_fail)
+ _ASM_EXTABLE_FAULT(.L_cache_w6, .L_memcpy_mcsafe_fail)
+ _ASM_EXTABLE_FAULT(.L_cache_w7, .L_memcpy_mcsafe_fail)
+ _ASM_EXTABLE_FAULT(.L_copy_trailing_words, .L_memcpy_mcsafe_fail)
+ _ASM_EXTABLE_FAULT(.L_copy_trailing_bytes, .L_memcpy_mcsafe_fail)
+#endif