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

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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 <[email protected]>
Signed-off-by: Dan Williams <[email protected]>
Cc: Al Viro <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Link: http://lkml.kernel.org/r/152539237606.31796.6719743548991782264.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Ingo Molnar <[email protected]>
This commit is contained in:
Dan Williams authored and Ingo Molnar committed 2018-05-15 08:32:42 +02:00
1 parent da7bc9c57e
commit bd131544aa
1 file changed
+12 -9
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arch/x86/lib/memcpy_64.S
+12 -9
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@@ -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