The memcpy_mcsafe() implementation handles CPU exceptions when reading from the source address. Before it can be used for user copies it needs to grow support for handling write faults. In preparation for adding that exception handling update the labels for the read cache word X case (.L_cache_rX) and write cache word X case (.L_cache_wX).
Cc: <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Al Viro <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Andrew Morton <[email protected]> Cc: Linus Torvalds <[email protected]> Reported-by: Tony Luck <[email protected]> Signed-off-by: Dan Williams <[email protected]> --- arch/x86/lib/memcpy_64.S | 21 ++++++++++++--------- 1 file changed, 12 insertions(+), 9 deletions(-) diff --git a/arch/x86/lib/memcpy_64.S b/arch/x86/lib/memcpy_64.S index 54c971892db5..5709f3ec22a4 100644 --- a/arch/x86/lib/memcpy_64.S +++ b/arch/x86/lib/memcpy_64.S @@ -204,13 +204,14 @@ ENTRY(__memcpy_mcsafe) subl $8, %ecx negl %ecx subl %ecx, %edx -.L_copy_leading_bytes: +.L_read_leading_bytes: movb (%rsi), %al +.L_write_leading_bytes: movb %al, (%rdi) incq %rsi incq %rdi decl %ecx - jnz .L_copy_leading_bytes + jnz .L_read_leading_bytes .L_8byte_aligned: movl %edx, %ecx @@ -218,13 +219,14 @@ ENTRY(__memcpy_mcsafe) shrl $3, %ecx jz .L_no_whole_words -.L_copy_words: +.L_read_words: movq (%rsi), %r8 +.L_write_words: movq %r8, (%rdi) addq $8, %rsi addq $8, %rdi decl %ecx - jnz .L_copy_words + jnz .L_read_words /* Any trailing bytes? */ .L_no_whole_words: @@ -233,13 +235,14 @@ ENTRY(__memcpy_mcsafe) /* Copy trailing bytes */ movl %edx, %ecx -.L_copy_trailing_bytes: +.L_read_trailing_bytes: movb (%rsi), %al +.L_write_trailing_bytes: movb %al, (%rdi) incq %rsi incq %rdi decl %ecx - jnz .L_copy_trailing_bytes + jnz .L_read_trailing_bytes /* Copy successful. Return zero */ .L_done_memcpy_trap: @@ -256,7 +259,7 @@ EXPORT_SYMBOL_GPL(__memcpy_mcsafe) .previous - _ASM_EXTABLE_FAULT(.L_copy_leading_bytes, .L_memcpy_mcsafe_fail) - _ASM_EXTABLE_FAULT(.L_copy_words, .L_memcpy_mcsafe_fail) - _ASM_EXTABLE_FAULT(.L_copy_trailing_bytes, .L_memcpy_mcsafe_fail) + _ASM_EXTABLE_FAULT(.L_read_leading_bytes, .L_memcpy_mcsafe_fail) + _ASM_EXTABLE_FAULT(.L_read_words, .L_memcpy_mcsafe_fail) + _ASM_EXTABLE_FAULT(.L_read_trailing_bytes, .L_memcpy_mcsafe_fail) #endif
