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Commit bd131544 authored by Dan Williams's avatar Dan Williams Committed by Ingo Molnar
Browse files

x86/asm/memcpy_mcsafe: Add labels for __memcpy_mcsafe() write fault handling 



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).

Reported-by: default avatarTony Luck <tony.luck@intel.com>
Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: hch@lst.de
Cc: linux-fsdevel@vger.kernel.org
Cc: linux-nvdimm@lists.01.org
Link: http://lkml.kernel.org/r/152539237606.31796.6719743548991782264.stgit@dwillia2-desk3.amr.corp.intel.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent da7bc9c5

arch/x86/lib/memcpy_64.S

+12 −9
Original line number Diff line number Diff line
@@ -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