diff options
Diffstat (limited to 'arch/x86/lib/copy_user_64.S')
| -rw-r--r-- | arch/x86/lib/copy_user_64.S | 138 |
1 files changed, 77 insertions, 61 deletions
diff --git a/arch/x86/lib/copy_user_64.S b/arch/x86/lib/copy_user_64.S index 2797e630b9b1..9dec1b38a98f 100644 --- a/arch/x86/lib/copy_user_64.S +++ b/arch/x86/lib/copy_user_64.S @@ -32,14 +32,10 @@ decl %ecx jnz 100b 102: - .section .fixup,"ax" -103: addl %ecx,%edx /* ecx is zerorest also */ - jmp .Lcopy_user_handle_tail - .previous - _ASM_EXTABLE_CPY(100b, 103b) - _ASM_EXTABLE_CPY(101b, 103b) - .endm + _ASM_EXTABLE_CPY(100b, .Lcopy_user_handle_align) + _ASM_EXTABLE_CPY(101b, .Lcopy_user_handle_align) +.endm /* * copy_user_generic_unrolled - memory copy with exception handling. @@ -57,12 +53,12 @@ SYM_FUNC_START(copy_user_generic_unrolled) ASM_STAC cmpl $8,%edx - jb 20f /* less then 8 bytes, go to byte copy loop */ + jb .Lcopy_user_short_string_bytes ALIGN_DESTINATION movl %edx,%ecx andl $63,%edx shrl $6,%ecx - jz .L_copy_short_string + jz copy_user_short_string 1: movq (%rsi),%r8 2: movq 1*8(%rsi),%r9 3: movq 2*8(%rsi),%r10 @@ -83,39 +79,11 @@ SYM_FUNC_START(copy_user_generic_unrolled) leaq 64(%rdi),%rdi decl %ecx jnz 1b -.L_copy_short_string: - movl %edx,%ecx - andl $7,%edx - shrl $3,%ecx - jz 20f -18: movq (%rsi),%r8 -19: movq %r8,(%rdi) - leaq 8(%rsi),%rsi - leaq 8(%rdi),%rdi - decl %ecx - jnz 18b -20: andl %edx,%edx - jz 23f - movl %edx,%ecx -21: movb (%rsi),%al -22: movb %al,(%rdi) - incq %rsi - incq %rdi - decl %ecx - jnz 21b -23: xor %eax,%eax - ASM_CLAC - ret + jmp copy_user_short_string - .section .fixup,"ax" 30: shll $6,%ecx addl %ecx,%edx - jmp 60f -40: leal (%rdx,%rcx,8),%edx - jmp 60f -50: movl %ecx,%edx -60: jmp .Lcopy_user_handle_tail /* ecx is zerorest also */ - .previous + jmp .Lcopy_user_handle_tail _ASM_EXTABLE_CPY(1b, 30b) _ASM_EXTABLE_CPY(2b, 30b) @@ -133,10 +101,6 @@ SYM_FUNC_START(copy_user_generic_unrolled) _ASM_EXTABLE_CPY(14b, 30b) _ASM_EXTABLE_CPY(15b, 30b) _ASM_EXTABLE_CPY(16b, 30b) - _ASM_EXTABLE_CPY(18b, 40b) - _ASM_EXTABLE_CPY(19b, 40b) - _ASM_EXTABLE_CPY(21b, 50b) - _ASM_EXTABLE_CPY(22b, 50b) SYM_FUNC_END(copy_user_generic_unrolled) EXPORT_SYMBOL(copy_user_generic_unrolled) @@ -166,20 +130,16 @@ SYM_FUNC_START(copy_user_generic_string) movl %edx,%ecx shrl $3,%ecx andl $7,%edx -1: rep - movsq +1: rep movsq 2: movl %edx,%ecx -3: rep - movsb +3: rep movsb xorl %eax,%eax ASM_CLAC - ret + RET - .section .fixup,"ax" 11: leal (%rdx,%rcx,8),%ecx 12: movl %ecx,%edx /* ecx is zerorest also */ jmp .Lcopy_user_handle_tail - .previous _ASM_EXTABLE_CPY(1b, 11b) _ASM_EXTABLE_CPY(3b, 12b) @@ -200,19 +160,16 @@ EXPORT_SYMBOL(copy_user_generic_string) */ SYM_FUNC_START(copy_user_enhanced_fast_string) ASM_STAC - cmpl $64,%edx - jb .L_copy_short_string /* less then 64 bytes, avoid the costly 'rep' */ + /* CPUs without FSRM should avoid rep movsb for short copies */ + ALTERNATIVE "cmpl $64, %edx; jb copy_user_short_string", "", X86_FEATURE_FSRM movl %edx,%ecx -1: rep - movsb +1: rep movsb xorl %eax,%eax ASM_CLAC - ret + RET - .section .fixup,"ax" 12: movl %ecx,%edx /* ecx is zerorest also */ jmp .Lcopy_user_handle_tail - .previous _ASM_EXTABLE_CPY(1b, 12b) SYM_FUNC_END(copy_user_enhanced_fast_string) @@ -225,6 +182,7 @@ EXPORT_SYMBOL(copy_user_enhanced_fast_string) * Don't try to copy the tail if machine check happened * * Input: + * eax trap number written by ex_handler_copy() * rdi destination * rsi source * rdx count @@ -233,16 +191,76 @@ EXPORT_SYMBOL(copy_user_enhanced_fast_string) * eax uncopied bytes or 0 if successful. */ SYM_CODE_START_LOCAL(.Lcopy_user_handle_tail) + cmp $X86_TRAP_MC,%eax + je 3f + movl %edx,%ecx 1: rep movsb 2: mov %ecx,%eax ASM_CLAC - ret + RET + +3: + movl %edx,%eax + ASM_CLAC + RET _ASM_EXTABLE_CPY(1b, 2b) + +.Lcopy_user_handle_align: + addl %ecx,%edx /* ecx is zerorest also */ + jmp .Lcopy_user_handle_tail + SYM_CODE_END(.Lcopy_user_handle_tail) /* + * Finish memcpy of less than 64 bytes. #AC should already be set. + * + * Input: + * rdi destination + * rsi source + * rdx count (< 64) + * + * Output: + * eax uncopied bytes or 0 if successful. + */ +SYM_CODE_START_LOCAL(copy_user_short_string) + movl %edx,%ecx + andl $7,%edx + shrl $3,%ecx + jz .Lcopy_user_short_string_bytes +18: movq (%rsi),%r8 +19: movq %r8,(%rdi) + leaq 8(%rsi),%rsi + leaq 8(%rdi),%rdi + decl %ecx + jnz 18b +.Lcopy_user_short_string_bytes: + andl %edx,%edx + jz 23f + movl %edx,%ecx +21: movb (%rsi),%al +22: movb %al,(%rdi) + incq %rsi + incq %rdi + decl %ecx + jnz 21b +23: xor %eax,%eax + ASM_CLAC + RET + +40: leal (%rdx,%rcx,8),%edx + jmp 60f +50: movl %ecx,%edx /* ecx is zerorest also */ +60: jmp .Lcopy_user_handle_tail + + _ASM_EXTABLE_CPY(18b, 40b) + _ASM_EXTABLE_CPY(19b, 40b) + _ASM_EXTABLE_CPY(21b, 50b) + _ASM_EXTABLE_CPY(22b, 50b) +SYM_CODE_END(copy_user_short_string) + +/* * copy_user_nocache - Uncached memory copy with exception handling * This will force destination out of cache for more performance. * @@ -348,9 +366,8 @@ SYM_FUNC_START(__copy_user_nocache) xorl %eax,%eax ASM_CLAC sfence - ret + RET - .section .fixup,"ax" .L_fixup_4x8b_copy: shll $6,%ecx addl %ecx,%edx @@ -366,7 +383,6 @@ SYM_FUNC_START(__copy_user_nocache) .L_fixup_handle_tail: sfence jmp .Lcopy_user_handle_tail - .previous _ASM_EXTABLE_CPY(1b, .L_fixup_4x8b_copy) _ASM_EXTABLE_CPY(2b, .L_fixup_4x8b_copy) |