x86/asm/memcpy_mcsafe: Add labels for __memcpy_mcsafe() write fault handling (bd131544) · Commits · 戴 / test

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:

Tony Luck <tony.luck@intel.com> Signed-off-by:

Dan 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:

Ingo Molnar <mingo@kernel.org>

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

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