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SubjectRe: [PATCH 2/2] Fix copy_user on x86
Date
Switch copy_user_generic_string(), copy_user_generic_unrolled() and
__copy_user_nocache() from custom tail handlers to generic
copy_user_tail_handle().

diff --git a/arch/x86/lib/copy_user_64.S b/arch/x86/lib/copy_user_64.S
index ee1c3f6..5181653 100644
--- a/arch/x86/lib/copy_user_64.S
+++ b/arch/x86/lib/copy_user_64.S
@@ -1,8 +1,10 @@
-/* Copyright 2002 Andi Kleen, SuSE Labs.
+/*
+ * Copyright 2008 Vitaly Mayatskikh <vmayatsk@redhat.com>
+ * Copyright 2002 Andi Kleen, SuSE Labs.
* Subject to the GNU Public License v2.
- *
- * Functions to copy from and to user space.
- */
+ *
+ * Functions to copy from and to user space.
+ */

#include <linux/linkage.h>
#include <asm/dwarf2.h>
@@ -20,60 +22,88 @@
.long \orig-1f /* by default jump to orig */
1:
.section .altinstr_replacement,"ax"
-2: .byte 0xe9 /* near jump with 32bit immediate */
+2: .byte 0xe9 /* near jump with 32bit immediate */
.long \alt-1b /* offset */ /* or alternatively to alt */
.previous
.section .altinstructions,"a"
.align 8
.quad 0b
.quad 2b
- .byte \feature /* when feature is set */
+ .byte \feature /* when feature is set */
.byte 5
.byte 5
.previous
.endm

-/* Standard copy_to_user with segment limit checking */
+ .macro ALIGN_DESTINATION
+#ifdef FIX_ALIGNMENT
+ /* check for bad alignment of destination */
+ movl %edi,%ecx
+ andl $7,%ecx
+ jz 102f /* already aligned */
+ subl $8,%ecx
+ negl %ecx
+ subl %ecx,%edx
+100: movb (%rsi),%al
+101: movb %al,(%rdi)
+ incq %rsi
+ incq %rdi
+ decl %ecx
+ jnz 100b
+102:
+ .section .fixup,"ax"
+103: addl %r8d,%edx /* ecx is zerorest also */
+ jmp copy_user_handle_tail
+ .previous
+
+ .section __ex_table,"a"
+ .align 8
+ .quad 100b,103b
+ .quad 101b,103b
+ .previous
+#endif
+ .endm
+
+/* Standard copy_to_user with segment limit checking */
ENTRY(copy_to_user)
CFI_STARTPROC
GET_THREAD_INFO(%rax)
movq %rdi,%rcx
addq %rdx,%rcx
- jc bad_to_user
+ jc bad_to_user
cmpq threadinfo_addr_limit(%rax),%rcx
jae bad_to_user
- xorl %eax,%eax /* clear zero flag */
ALTERNATIVE_JUMP X86_FEATURE_REP_GOOD,copy_user_generic_unrolled,copy_user_generic_string
CFI_ENDPROC

-ENTRY(copy_user_generic)
+/* Standard copy_from_user with segment limit checking */
+ENTRY(copy_from_user)
CFI_STARTPROC
- movl $1,%ecx /* set zero flag */
+ GET_THREAD_INFO(%rax)
+ movq %rsi,%rcx
+ addq %rdx,%rcx
+ jc bad_from_user
+ cmpq threadinfo_addr_limit(%rax),%rcx
+ jae bad_from_user
ALTERNATIVE_JUMP X86_FEATURE_REP_GOOD,copy_user_generic_unrolled,copy_user_generic_string
CFI_ENDPROC
+ENDPROC(copy_from_user)

-ENTRY(__copy_from_user_inatomic)
+ENTRY(copy_user_generic)
CFI_STARTPROC
- xorl %ecx,%ecx /* clear zero flag */
ALTERNATIVE_JUMP X86_FEATURE_REP_GOOD,copy_user_generic_unrolled,copy_user_generic_string
CFI_ENDPROC
+ENDPROC(copy_user_generic)

-/* Standard copy_from_user with segment limit checking */
-ENTRY(copy_from_user)
+ENTRY(__copy_from_user_inatomic)
CFI_STARTPROC
- GET_THREAD_INFO(%rax)
- movq %rsi,%rcx
- addq %rdx,%rcx
- jc bad_from_user
- cmpq threadinfo_addr_limit(%rax),%rcx
- jae bad_from_user
- movl $1,%ecx /* set zero flag */
ALTERNATIVE_JUMP X86_FEATURE_REP_GOOD,copy_user_generic_unrolled,copy_user_generic_string
CFI_ENDPROC
-ENDPROC(copy_from_user)
-
+ENDPROC(__copy_from_user_inatomic)
+
.section .fixup,"ax"
/* must zero dest */
+ENTRY(bad_from_user)
bad_from_user:
CFI_STARTPROC
movl %edx,%ecx
@@ -81,271 +111,158 @@ bad_from_user:
rep
stosb
bad_to_user:
- movl %edx,%eax
+ movl %edx,%eax
ret
CFI_ENDPROC
-END(bad_from_user)
+ENDPROC(bad_from_user)
.previous
-
-
+
/*
* copy_user_generic_unrolled - memory copy with exception handling.
- * This version is for CPUs like P4 that don't have efficient micro code for rep movsq
- *
- * Input:
+ * This version is for CPUs like P4 that don't have efficient micro
+ * code for rep movsq
+ *
+ * Input:
* rdi destination
* rsi source
* rdx count
- * ecx zero flag -- if true zero destination on error
*
- * Output:
- * eax uncopied bytes or 0 if successful.
+ * Output:
+ * eax uncopied bytes or 0 if successfull.
*/
ENTRY(copy_user_generic_unrolled)
CFI_STARTPROC
- pushq %rbx
- CFI_ADJUST_CFA_OFFSET 8
- CFI_REL_OFFSET rbx, 0
- pushq %rcx
- CFI_ADJUST_CFA_OFFSET 8
- CFI_REL_OFFSET rcx, 0
- xorl %eax,%eax /*zero for the exception handler */
-
-#ifdef FIX_ALIGNMENT
- /* check for bad alignment of destination */
- movl %edi,%ecx
- andl $7,%ecx
- jnz .Lbad_alignment
-.Lafter_bad_alignment:
-#endif
-
- movq %rdx,%rcx
-
- movl $64,%ebx
- shrq $6,%rdx
- decq %rdx
- js .Lhandle_tail
-
- .p2align 4
-.Lloop:
-.Ls1: movq (%rsi),%r11
-.Ls2: movq 1*8(%rsi),%r8
-.Ls3: movq 2*8(%rsi),%r9
-.Ls4: movq 3*8(%rsi),%r10
-.Ld1: movq %r11,(%rdi)
-.Ld2: movq %r8,1*8(%rdi)
-.Ld3: movq %r9,2*8(%rdi)
-.Ld4: movq %r10,3*8(%rdi)
-
-.Ls5: movq 4*8(%rsi),%r11
-.Ls6: movq 5*8(%rsi),%r8
-.Ls7: movq 6*8(%rsi),%r9
-.Ls8: movq 7*8(%rsi),%r10
-.Ld5: movq %r11,4*8(%rdi)
-.Ld6: movq %r8,5*8(%rdi)
-.Ld7: movq %r9,6*8(%rdi)
-.Ld8: movq %r10,7*8(%rdi)
-
- decq %rdx
-
+ cmpl $8,%edx
+ jb 20f /* less then 8 bytes, go to byte copy loop */
+ ALIGN_DESTINATION
+ movl %edx,%ecx
+ andl $63,%edx
+ shrl $6,%ecx
+ jz 17f
+1: movq (%rsi),%r8
+2: movq 1*8(%rsi),%r9
+3: movq 2*8(%rsi),%r10
+4: movq 3*8(%rsi),%r11
+5: movq %r8,(%rdi)
+6: movq %r9,1*8(%rdi)
+7: movq %r10,2*8(%rdi)
+8: movq %r11,3*8(%rdi)
+9: movq 4*8(%rsi),%r8
+10: movq 5*8(%rsi),%r9
+11: movq 6*8(%rsi),%r10
+12: movq 7*8(%rsi),%r11
+13: movq %r8,4*8(%rdi)
+14: movq %r9,5*8(%rdi)
+15: movq %r10,6*8(%rdi)
+16: movq %r11,7*8(%rdi)
leaq 64(%rsi),%rsi
leaq 64(%rdi),%rdi
-
- jns .Lloop
-
- .p2align 4
-.Lhandle_tail:
- movl %ecx,%edx
- andl $63,%ecx
- shrl $3,%ecx
- jz .Lhandle_7
- movl $8,%ebx
- .p2align 4
-.Lloop_8:
-.Ls9: movq (%rsi),%r8
-.Ld9: movq %r8,(%rdi)
decl %ecx
- leaq 8(%rdi),%rdi
+ jnz 1b
+17: movl %edx,%ecx
+ andl $7,%edx
+ shrl $3,%ecx
+ jz 20f
+18: movq (%rsi),%r8
+19: movq %r8,(%rdi)
leaq 8(%rsi),%rsi
- jnz .Lloop_8
-
-.Lhandle_7:
+ leaq 8(%rdi),%rdi
+ decl %ecx
+ jnz 18b
+20: andl %edx,%edx
+ jz 23f
movl %edx,%ecx
- andl $7,%ecx
- jz .Lende
- .p2align 4
-.Lloop_1:
-.Ls10: movb (%rsi),%bl
-.Ld10: movb %bl,(%rdi)
- incq %rdi
+21: movb (%rsi),%al
+22: movb %al,(%rdi)
incq %rsi
+ incq %rdi
decl %ecx
- jnz .Lloop_1
-
- CFI_REMEMBER_STATE
-.Lende:
- popq %rcx
- CFI_ADJUST_CFA_OFFSET -8
- CFI_RESTORE rcx
- popq %rbx
- CFI_ADJUST_CFA_OFFSET -8
- CFI_RESTORE rbx
+ jnz 21b
+23: xor %eax,%eax
ret
- CFI_RESTORE_STATE

-#ifdef FIX_ALIGNMENT
- /* align destination */
- .p2align 4
-.Lbad_alignment:
- movl $8,%r9d
- subl %ecx,%r9d
- movl %r9d,%ecx
- cmpq %r9,%rdx
- jz .Lhandle_7
- js .Lhandle_7
-.Lalign_1:
-.Ls11: movb (%rsi),%bl
-.Ld11: movb %bl,(%rdi)
- incq %rsi
- incq %rdi
- decl %ecx
- jnz .Lalign_1
- subq %r9,%rdx
- jmp .Lafter_bad_alignment
-#endif
+ .section .fixup,"ax"
+30: shll $6,%ecx
+ addl %ecx,%edx
+ jmp 60f
+40: leal (%edx,%ecx,8),%edx
+ jmp 60f
+50: movl %ecx,%edx
+60: jmp copy_user_handle_tail /* ecx is zerorest also */
+ .previous

- /* table sorted by exception address */
.section __ex_table,"a"
.align 8
- .quad .Ls1,.Ls1e /* Ls1-Ls4 have copied zero bytes */
- .quad .Ls2,.Ls1e
- .quad .Ls3,.Ls1e
- .quad .Ls4,.Ls1e
- .quad .Ld1,.Ls1e /* Ld1-Ld4 have copied 0-24 bytes */
- .quad .Ld2,.Ls2e
- .quad .Ld3,.Ls3e
- .quad .Ld4,.Ls4e
- .quad .Ls5,.Ls5e /* Ls5-Ls8 have copied 32 bytes */
- .quad .Ls6,.Ls5e
- .quad .Ls7,.Ls5e
- .quad .Ls8,.Ls5e
- .quad .Ld5,.Ls5e /* Ld5-Ld8 have copied 32-56 bytes */
- .quad .Ld6,.Ls6e
- .quad .Ld7,.Ls7e
- .quad .Ld8,.Ls8e
- .quad .Ls9,.Le_quad
- .quad .Ld9,.Le_quad
- .quad .Ls10,.Le_byte
- .quad .Ld10,.Le_byte
-#ifdef FIX_ALIGNMENT
- .quad .Ls11,.Lzero_rest
- .quad .Ld11,.Lzero_rest
-#endif
- .quad .Le5,.Le_zero
+ .quad 1b,30b
+ .quad 2b,30b
+ .quad 3b,30b
+ .quad 4b,30b
+ .quad 5b,30b
+ .quad 6b,30b
+ .quad 7b,30b
+ .quad 8b,30b
+ .quad 9b,30b
+ .quad 10b,30b
+ .quad 11b,30b
+ .quad 12b,30b
+ .quad 13b,30b
+ .quad 14b,30b
+ .quad 15b,30b
+ .quad 16b,30b
+ .quad 18b,40b
+ .quad 19b,40b
+ .quad 21b,50b
+ .quad 22b,50b
.previous
-
- /* eax: zero, ebx: 64 */
-.Ls1e: addl $8,%eax /* eax is bytes left uncopied within the loop (Ls1e: 64 .. Ls8e: 8) */
-.Ls2e: addl $8,%eax
-.Ls3e: addl $8,%eax
-.Ls4e: addl $8,%eax
-.Ls5e: addl $8,%eax
-.Ls6e: addl $8,%eax
-.Ls7e: addl $8,%eax
-.Ls8e: addl $8,%eax
- addq %rbx,%rdi /* +64 */
- subq %rax,%rdi /* correct destination with computed offset */
-
- shlq $6,%rdx /* loop counter * 64 (stride length) */
- addq %rax,%rdx /* add offset to loopcnt */
- andl $63,%ecx /* remaining bytes */
- addq %rcx,%rdx /* add them */
- jmp .Lzero_rest
-
- /* exception on quad word loop in tail handling */
- /* ecx: loopcnt/8, %edx: length, rdi: correct */
-.Le_quad:
- shll $3,%ecx
- andl $7,%edx
- addl %ecx,%edx
- /* edx: bytes to zero, rdi: dest, eax:zero */
-.Lzero_rest:
- cmpl $0,(%rsp)
- jz .Le_zero
- movq %rdx,%rcx
-.Le_byte:
- xorl %eax,%eax
-.Le5: rep
- stosb
- /* when there is another exception while zeroing the rest just return */
-.Le_zero:
- movq %rdx,%rax
- jmp .Lende
CFI_ENDPROC
-ENDPROC(copy_user_generic)
+ENDPROC(copy_user_generic_unrolled)

-
- /* Some CPUs run faster using the string copy instructions.
- This is also a lot simpler. Use them when possible.
- Patch in jmps to this code instead of copying it fully
- to avoid unwanted aliasing in the exception tables. */
-
- /* rdi destination
- * rsi source
- * rdx count
- * ecx zero flag
- *
- * Output:
- * eax uncopied bytes or 0 if successfull.
- *
- * Only 4GB of copy is supported. This shouldn't be a problem
- * because the kernel normally only writes from/to page sized chunks
- * even if user space passed a longer buffer.
- * And more would be dangerous because both Intel and AMD have
- * errata with rep movsq > 4GB. If someone feels the need to fix
- * this please consider this.
- */
+/* Some CPUs run faster using the string copy instructions.
+ * This is also a lot simpler. Use them when possible.
+ *
+ * Only 4GB of copy is supported. This shouldn't be a problem
+ * because the kernel normally only writes from/to page sized chunks
+ * even if user space passed a longer buffer.
+ * And more would be dangerous because both Intel and AMD have
+ * errata with rep movsq > 4GB. If someone feels the need to fix
+ * this please consider this.
+ *
+ * Input:
+ * rdi destination
+ * rsi source
+ * rdx count
+ *
+ * Output:
+ * eax uncopied bytes or 0 if successful.
+ */
ENTRY(copy_user_generic_string)
CFI_STARTPROC
- movl %ecx,%r8d /* save zero flag */
+ andl %edx,%edx
+ jz 4f
+ cmpl $8,%edx
+ jb 2f /* less than 8 bytes, go to byte copy loop */
+ ALIGN_DESTINATION
movl %edx,%ecx
shrl $3,%ecx
- andl $7,%edx
- jz 10f
-1: rep
- movsq
- movl %edx,%ecx
-2: rep
- movsb
-9: movl %ecx,%eax
- ret
-
- /* multiple of 8 byte */
-10: rep
+ andl $7,%edx
+1: rep
movsq
- xor %eax,%eax
+2: movl %edx,%ecx
+3: rep
+ movsb
+4: xorl %eax,%eax
ret

- /* exception handling */
-3: lea (%rdx,%rcx,8),%rax /* exception on quad loop */
- jmp 6f
-5: movl %ecx,%eax /* exception on byte loop */
- /* eax: left over bytes */
-6: testl %r8d,%r8d /* zero flag set? */
- jz 7f
- movl %eax,%ecx /* initialize x86 loop counter */
- push %rax
- xorl %eax,%eax
-8: rep
- stosb /* zero the rest */
-11: pop %rax
-7: ret
- CFI_ENDPROC
-END(copy_user_generic_c)
+ .section .fixup,"ax"
+11: leal (%edx,%ecx,8),%ecx
+12: movl %ecx,%edx /* ecx is zerorest also */
+ jmp copy_user_handle_tail
+ .previous

.section __ex_table,"a"
- .quad 1b,3b
- .quad 2b,5b
- .quad 8b,11b
- .quad 10b,3b
+ .align 8
+ .quad 1b,11b
+ .quad 3b,12b
.previous
+ CFI_ENDPROC
+ENDPROC(copy_user_generic_string)
Signed-off-by: Vitaly Mayatskikh <v.mayatskih@gmail.com>
diff --git a/arch/x86/lib/copy_user_nocache_64.S b/arch/x86/lib/copy_user_nocache_64.S
index 9d3d1ab..93353d6 100644
--- a/arch/x86/lib/copy_user_nocache_64.S
+++ b/arch/x86/lib/copy_user_nocache_64.S
@@ -1,4 +1,6 @@
-/* Copyright 2002 Andi Kleen, SuSE Labs.
+/*
+ * Copyright 2008 Vitaly Mayatskikh <vmayatsk@redhat.com>
+ * Copyright 2002 Andi Kleen, SuSE Labs.
* Subject to the GNU Public License v2.
*
* Functions to copy from and to user space.
@@ -12,204 +14,125 @@
#include <asm/current.h>
#include <asm/asm-offsets.h>
#include <asm/thread_info.h>
-#include <asm/cpufeature.h>
-
-/*
- * copy_user_nocache - Uncached memory copy with exception handling
- * This will force destination/source out of cache for more performance.
- *
- * Input:
- * rdi destination
- * rsi source
- * rdx count
- * rcx zero flag when 1 zero on exception
- *
- * Output:
- * eax uncopied bytes or 0 if successful.
- */
-ENTRY(__copy_user_nocache)
- CFI_STARTPROC
- pushq %rbx
- CFI_ADJUST_CFA_OFFSET 8
- CFI_REL_OFFSET rbx, 0
- pushq %rcx /* save zero flag */
- CFI_ADJUST_CFA_OFFSET 8
- CFI_REL_OFFSET rcx, 0
-
- xorl %eax,%eax /* zero for the exception handler */

+ .macro ALIGN_DESTINATION
#ifdef FIX_ALIGNMENT
/* check for bad alignment of destination */
movl %edi,%ecx
andl $7,%ecx
- jnz .Lbad_alignment
-.Lafter_bad_alignment:
-#endif
-
- movq %rdx,%rcx
-
- movl $64,%ebx
- shrq $6,%rdx
- decq %rdx
- js .Lhandle_tail
-
- .p2align 4
-.Lloop:
-.Ls1: movq (%rsi),%r11
-.Ls2: movq 1*8(%rsi),%r8
-.Ls3: movq 2*8(%rsi),%r9
-.Ls4: movq 3*8(%rsi),%r10
-.Ld1: movnti %r11,(%rdi)
-.Ld2: movnti %r8,1*8(%rdi)
-.Ld3: movnti %r9,2*8(%rdi)
-.Ld4: movnti %r10,3*8(%rdi)
-
-.Ls5: movq 4*8(%rsi),%r11
-.Ls6: movq 5*8(%rsi),%r8
-.Ls7: movq 6*8(%rsi),%r9
-.Ls8: movq 7*8(%rsi),%r10
-.Ld5: movnti %r11,4*8(%rdi)
-.Ld6: movnti %r8,5*8(%rdi)
-.Ld7: movnti %r9,6*8(%rdi)
-.Ld8: movnti %r10,7*8(%rdi)
+ jz 102f /* already aligned */
+ subl $8,%ecx
+ negl %ecx
+ subl %ecx,%edx
+100: movb (%rsi),%al
+101: movb %al,(%rdi)
+ incq %rsi
+ incq %rdi
+ decl %ecx
+ jnz 100b
+102:
+ .section .fixup,"ax"
+103: addl %r8d,%edx /* ecx is zerorest also */
+ jmp copy_user_handle_tail
+ .previous

- dec %rdx
+ .section __ex_table,"a"
+ .align 8
+ .quad 100b,103b
+ .quad 101b,103b
+ .previous
+#endif
+ .endm

+/*
+ * copy_user_nocache - Uncached memory copy with exception handling
+ * This will force destination/source out of cache for more performance.
+ */
+ENTRY(__copy_user_nocache)
+ CFI_STARTPROC
+ cmpl $8,%edx
+ jb 20f /* less then 8 bytes, go to byte copy loop */
+ ALIGN_DESTINATION
+ movl %edx,%ecx
+ andl $63,%edx
+ shrl $6,%ecx
+ jz 17f
+1: movq (%rsi),%r8
+2: movq 1*8(%rsi),%r9
+3: movq 2*8(%rsi),%r10
+4: movq 3*8(%rsi),%r11
+5: movnti %r8,(%rdi)
+6: movnti %r9,1*8(%rdi)
+7: movnti %r10,2*8(%rdi)
+8: movnti %r11,3*8(%rdi)
+9: movq 4*8(%rsi),%r8
+10: movq 5*8(%rsi),%r9
+11: movq 6*8(%rsi),%r10
+12: movq 7*8(%rsi),%r11
+13: movnti %r8,4*8(%rdi)
+14: movnti %r9,5*8(%rdi)
+15: movnti %r10,6*8(%rdi)
+16: movnti %r11,7*8(%rdi)
leaq 64(%rsi),%rsi
leaq 64(%rdi),%rdi
-
- jns .Lloop
-
- .p2align 4
-.Lhandle_tail:
- movl %ecx,%edx
- andl $63,%ecx
- shrl $3,%ecx
- jz .Lhandle_7
- movl $8,%ebx
- .p2align 4
-.Lloop_8:
-.Ls9: movq (%rsi),%r8
-.Ld9: movnti %r8,(%rdi)
decl %ecx
- leaq 8(%rdi),%rdi
+ jnz 1b
+17: movl %edx,%ecx
+ andl $7,%edx
+ shrl $3,%ecx
+ jz 20f
+18: movq (%rsi),%r8
+19: movnti %r8,(%rdi)
leaq 8(%rsi),%rsi
- jnz .Lloop_8
-
-.Lhandle_7:
+ leaq 8(%rdi),%rdi
+ decl %ecx
+ jnz 18b
+20: andl %edx,%edx
+ jz 23f
movl %edx,%ecx
- andl $7,%ecx
- jz .Lende
- .p2align 4
-.Lloop_1:
-.Ls10: movb (%rsi),%bl
-.Ld10: movb %bl,(%rdi)
- incq %rdi
+21: movb (%rsi),%al
+22: movb %al,(%rdi)
incq %rsi
+ incq %rdi
decl %ecx
- jnz .Lloop_1
-
- CFI_REMEMBER_STATE
-.Lende:
- popq %rcx
- CFI_ADJUST_CFA_OFFSET -8
- CFI_RESTORE %rcx
- popq %rbx
- CFI_ADJUST_CFA_OFFSET -8
- CFI_RESTORE rbx
+ jnz 21b
+23: xorl %eax,%eax
sfence
ret
- CFI_RESTORE_STATE

-#ifdef FIX_ALIGNMENT
- /* align destination */
- .p2align 4
-.Lbad_alignment:
- movl $8,%r9d
- subl %ecx,%r9d
- movl %r9d,%ecx
- cmpq %r9,%rdx
- jz .Lhandle_7
- js .Lhandle_7
-.Lalign_1:
-.Ls11: movb (%rsi),%bl
-.Ld11: movb %bl,(%rdi)
- incq %rsi
- incq %rdi
- decl %ecx
- jnz .Lalign_1
- subq %r9,%rdx
- jmp .Lafter_bad_alignment
-#endif
+ .section .fixup,"ax"
+30: shll $6,%ecx
+ addl %ecx,%edx
+ jmp 60f
+40: leal (%edx,%ecx,8),%edx
+ jmp 60f
+50: movl %ecx,%edx
+60: sfence
+ movl %r8d,%ecx
+ jmp copy_user_handle_tail
+ .previous

- /* table sorted by exception address */
.section __ex_table,"a"
- .align 8
- .quad .Ls1,.Ls1e /* .Ls[1-4] - 0 bytes copied */
- .quad .Ls2,.Ls1e
- .quad .Ls3,.Ls1e
- .quad .Ls4,.Ls1e
- .quad .Ld1,.Ls1e /* .Ld[1-4] - 0..24 bytes coped */
- .quad .Ld2,.Ls2e
- .quad .Ld3,.Ls3e
- .quad .Ld4,.Ls4e
- .quad .Ls5,.Ls5e /* .Ls[5-8] - 32 bytes copied */
- .quad .Ls6,.Ls5e
- .quad .Ls7,.Ls5e
- .quad .Ls8,.Ls5e
- .quad .Ld5,.Ls5e /* .Ld[5-8] - 32..56 bytes copied */
- .quad .Ld6,.Ls6e
- .quad .Ld7,.Ls7e
- .quad .Ld8,.Ls8e
- .quad .Ls9,.Le_quad
- .quad .Ld9,.Le_quad
- .quad .Ls10,.Le_byte
- .quad .Ld10,.Le_byte
-#ifdef FIX_ALIGNMENT
- .quad .Ls11,.Lzero_rest
- .quad .Ld11,.Lzero_rest
-#endif
- .quad .Le5,.Le_zero
+ .quad 1b,30b
+ .quad 2b,30b
+ .quad 3b,30b
+ .quad 4b,30b
+ .quad 5b,30b
+ .quad 6b,30b
+ .quad 7b,30b
+ .quad 8b,30b
+ .quad 9b,30b
+ .quad 10b,30b
+ .quad 11b,30b
+ .quad 12b,30b
+ .quad 13b,30b
+ .quad 14b,30b
+ .quad 15b,30b
+ .quad 16b,30b
+ .quad 18b,40b
+ .quad 19b,40b
+ .quad 21b,50b
+ .quad 22b,50b
.previous
-
- /* eax: zero, ebx: 64 */
-.Ls1e: addl $8,%eax /* eax: bytes left uncopied: Ls1e: 64 .. Ls8e: 8 */
-.Ls2e: addl $8,%eax
-.Ls3e: addl $8,%eax
-.Ls4e: addl $8,%eax
-.Ls5e: addl $8,%eax
-.Ls6e: addl $8,%eax
-.Ls7e: addl $8,%eax
-.Ls8e: addl $8,%eax
- addq %rbx,%rdi /* +64 */
- subq %rax,%rdi /* correct destination with computed offset */
-
- shlq $6,%rdx /* loop counter * 64 (stride length) */
- addq %rax,%rdx /* add offset to loopcnt */
- andl $63,%ecx /* remaining bytes */
- addq %rcx,%rdx /* add them */
- jmp .Lzero_rest
-
- /* exception on quad word loop in tail handling */
- /* ecx: loopcnt/8, %edx: length, rdi: correct */
-.Le_quad:
- shll $3,%ecx
- andl $7,%edx
- addl %ecx,%edx
- /* edx: bytes to zero, rdi: dest, eax:zero */
-.Lzero_rest:
- cmpl $0,(%rsp) /* zero flag set? */
- jz .Le_zero
- movq %rdx,%rcx
-.Le_byte:
- xorl %eax,%eax
-.Le5: rep
- stosb
- /* when there is another exception while zeroing the rest just return */
-.Le_zero:
- movq %rdx,%rax
- jmp .Lende
CFI_ENDPROC
ENDPROC(__copy_user_nocache)
-
-
Signed-off-by: Vitaly Mayatskikh <v.mayatskih@gmail.com>

--
wbr, Vitaly


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