diff options
Diffstat (limited to 'arch/x86/lib/copy_user_64.S')
| -rw-r--r-- | arch/x86/lib/copy_user_64.S | 55 |
1 files changed, 27 insertions, 28 deletions
diff --git a/arch/x86/lib/copy_user_64.S b/arch/x86/lib/copy_user_64.S index 2797e630b9b1..8ca5ecf16dc4 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. @@ -105,9 +101,8 @@ SYM_FUNC_START(copy_user_generic_unrolled) jnz 21b 23: xor %eax,%eax ASM_CLAC - ret + RET - .section .fixup,"ax" 30: shll $6,%ecx addl %ecx,%edx jmp 60f @@ -115,7 +110,6 @@ SYM_FUNC_START(copy_user_generic_unrolled) jmp 60f 50: movl %ecx,%edx 60: jmp .Lcopy_user_handle_tail /* ecx is zerorest also */ - .previous _ASM_EXTABLE_CPY(1b, 30b) _ASM_EXTABLE_CPY(2b, 30b) @@ -166,20 +160,16 @@ 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 +190,16 @@ 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 .L_copy_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 +212,7 @@ 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 @@ -233,13 +221,26 @@ 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) /* @@ -348,9 +349,8 @@ 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 +366,6 @@ 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) |