* Functions to copy from and to user space.
*/
+#include <linux/linkage.h>
+#include <asm/dwarf2.h>
+
#define FIX_ALIGNMENT 1
-
- #include <asm/current.h>
- #include <asm/asm-offsets.h>
- #include <asm/thread_info.h>
- #include <asm/cpufeature.h>
-/* Standard copy_to_user with segment limit checking */
- .globl copy_to_user
- .p2align 4
-copy_to_user:
- GET_THREAD_INFO(%rax)
- movq %rdi,%rcx
- addq %rdx,%rcx
- jc bad_to_user
- cmpq threadinfo_addr_limit(%rax),%rcx
- jae bad_to_user
-2:
+#include <asm/current.h>
+#include <asm/asm-offsets.h>
+#include <asm/thread_info.h>
+#include <asm/cpufeature.h>
+
+ .macro ALTERNATIVE_JUMP feature,orig,alt
+0:
.byte 0xe9 /* 32bit jump */
- .long .Lcug-1f
+ .long \orig-1f /* by default jump to orig */
1:
-
.section .altinstr_replacement,"ax"
-3: .byte 0xe9 /* replacement jmp with 8 bit immediate */
- .long copy_user_generic_c-1b /* offset */
+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
- .quad 3b
- .byte X86_FEATURE_K8_C
+ .byte \feature /* when feature is set */
.byte 5
.byte 5
.previous
+ .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
+ 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)
+ CFI_STARTPROC
+ movl $1,%ecx /* set zero flag */
+ ALTERNATIVE_JUMP X86_FEATURE_REP_GOOD,copy_user_generic_unrolled,copy_user_generic_string
+ CFI_ENDPROC
+
+ENTRY(__copy_from_user_inatomic)
+ CFI_STARTPROC
+ xorl %ecx,%ecx /* clear zero flag */
+ ALTERNATIVE_JUMP X86_FEATURE_REP_GOOD,copy_user_generic_unrolled,copy_user_generic_string
+ CFI_ENDPROC
/* Standard copy_from_user with segment limit checking */
- .globl copy_from_user
- .p2align 4
-copy_from_user:
+ENTRY(copy_from_user)
+ 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
- /* FALL THROUGH to copy_user_generic */
+ 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)
.section .fixup,"ax"
/* must zero dest */
bad_from_user:
+ CFI_STARTPROC
movl %edx,%ecx
xorl %eax,%eax
rep
bad_to_user:
movl %edx,%eax
ret
+ CFI_ENDPROC
+END(bad_from_user)
.previous
/*
- * copy_user_generic - memory copy with exception handling.
+ * 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:
* rdi destination
* rsi source
* rdx count
+ * ecx zero flag -- if true zero destination on error
*
* Output:
* eax uncopied bytes or 0 if successful.
*/
- .globl copy_user_generic
- .p2align 4
-copy_user_generic:
- .byte 0x66,0x66,0x90 /* 5 byte nop for replacement jump */
- .byte 0x66,0x90
-1:
- .section .altinstr_replacement,"ax"
-2: .byte 0xe9 /* near jump with 32bit immediate */
- .long copy_user_generic_c-1b /* offset */
- .previous
- .section .altinstructions,"a"
- .align 8
- .quad copy_user_generic
- .quad 2b
- .byte X86_FEATURE_K8_C
- .byte 5
- .byte 5
- .previous
-.Lcug:
+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
movq %rdx,%rcx
- movl $64,%ebx
+ movl $64,%ebx
shrq $6,%rdx
decq %rdx
js .Lhandle_tail
-
+
.p2align 4
.Lloop:
.Ls1: movq (%rsi),%r11
.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
.Ld6: movq %r8,5*8(%rdi)
.Ld7: movq %r9,6*8(%rdi)
.Ld8: movq %r10,7*8(%rdi)
-
+
decq %rdx
leaq 64(%rsi),%rsi
leaq 64(%rdi),%rdi
-
+
jns .Lloop
.p2align 4
leaq 8(%rdi),%rdi
leaq 8(%rsi),%rsi
jnz .Lloop_8
-
-.Lhandle_7:
- movl %edx,%ecx
+
+.Lhandle_7:
+ movl %edx,%ecx
andl $7,%ecx
jz .Lende
.p2align 4
incq %rsi
decl %ecx
jnz .Lloop_1
-
+
+ CFI_REMEMBER_STATE
.Lende:
+ popq %rcx
+ CFI_ADJUST_CFA_OFFSET -8
+ CFI_RESTORE rcx
popq %rbx
- ret
+ CFI_ADJUST_CFA_OFFSET -8
+ CFI_RESTORE rbx
+ ret
+ CFI_RESTORE_STATE
-#ifdef FIX_ALIGNMENT
+#ifdef FIX_ALIGNMENT
/* align destination */
.p2align 4
.Lbad_alignment:
cmpq %r9,%rdx
jz .Lhandle_7
js .Lhandle_7
-.Lalign_1:
+.Lalign_1:
.Ls11: movb (%rsi),%bl
.Ld11: movb %bl,(%rdi)
incq %rsi
subq %r9,%rdx
jmp .Lafter_bad_alignment
#endif
-
- /* table sorted by exception address */
+
+ /* table sorted by exception address */
.section __ex_table,"a"
.align 8
.quad .Ls1,.Ls1e
.quad .Ls2,.Ls2e
.quad .Ls3,.Ls3e
- .quad .Ls4,.Ls4e
+ .quad .Ls4,.Ls4e
.quad .Ld1,.Ls1e
.quad .Ld2,.Ls2e
.quad .Ld3,.Ls3e
.quad .Ls5,.Ls5e
.quad .Ls6,.Ls6e
.quad .Ls7,.Ls7e
- .quad .Ls8,.Ls8e
+ .quad .Ls8,.Ls8e
.quad .Ld5,.Ls5e
.quad .Ld6,.Ls6e
.quad .Ld7,.Ls7e
.quad .Ld9,.Le_quad
.quad .Ls10,.Le_byte
.quad .Ld10,.Le_byte
-#ifdef FIX_ALIGNMENT
+#ifdef FIX_ALIGNMENT
.quad .Ls11,.Lzero_rest
.quad .Ld11,.Lzero_rest
#endif
.quad .Le5,.Le_zero
.previous
- /* compute 64-offset for main loop. 8 bytes accuracy with error on the
- pessimistic side. this is gross. it would be better to fix the
- interface. */
+ /* compute 64-offset for main loop. 8 bytes accuracy with error on the
+ pessimistic side. this is gross. it would be better to fix the
+ interface. */
/* eax: zero, ebx: 64 */
.Ls1e: addl $8,%eax
.Ls2e: addl $8,%eax
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
+.Le5: rep
stosb
/* when there is another exception while zeroing the rest just return */
-.Le_zero:
+.Le_zero:
movq %rdx,%rax
jmp .Lende
+ CFI_ENDPROC
+ENDPROC(copy_user_generic)
+
- /* C stepping K8 run faster using the string copy instructions.
+ /* 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:
+ * Output:
* eax uncopied bytes or 0 if successfull.
- */
-copy_user_generic_c:
+ *
+ * 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.
+ */
+ENTRY(copy_user_generic_string)
+ CFI_STARTPROC
+ movl %ecx,%r8d /* save zero flag */
movl %edx,%ecx
shrl $3,%ecx
andl $7,%edx
+ jz 10f
1: rep
movsq
movl %edx,%ecx
2: rep
movsb
-4: movl %ecx,%eax
+9: movl %ecx,%eax
ret
-3: lea (%rdx,%rcx,8),%rax
+
+ /* multiple of 8 byte */
+10: rep
+ movsq
+ xor %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 __ex_table,"a"
.quad 1b,3b
- .quad 2b,4b
+ .quad 2b,5b
+ .quad 8b,11b
+ .quad 10b,3b
.previous
git.openpandora.org / pandora-kernel.git / blobdiff