Gitweb: http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=edf101...
Commit: edf10162b2c5ad78ada8e63e960f9d0949c6c219
Parent: f8dd0d3c62164160c59034a96eb17d69ac8a0328
Author: Glauber Costa <gcosta@redhat.com>
AuthorDate: Fri Jun 13 16:35:52 2008 -0300
Committer: Ingo Molnar <mingo@elte.hu>
CommitDate: Wed Jul 9 09:13:59 2008 +0200
x86: don't clobber r8 nor use rcx.
There's really no reason to clobber r8 or pass the address in rcx.
We can safely use only two registers (which we already have to touch anyway)
to do the job.
Signed-off-by: Glauber Costa <gcosta@redhat.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
arch/x86/lib/getuser_64.S | 42 +++++++++++++++++++++---------------------
include/asm-x86/uaccess_64.h | 3 +--
2 files changed, 22 insertions(+), 23 deletions(-)
diff --git a/arch/x86/lib/getuser_64.S b/arch/x86/lib/getuser_64.S
index 5448876..2b003d3 100644
--- a/arch/x86/lib/getuser_64.S
+++ b/arch/x86/lib/getuser_64.S
@@ -36,10 +36,10 @@
.text
ENTRY(__get_user_1)
CFI_STARTPROC
- GET_THREAD_INFO(%r8)
- cmpq threadinfo_addr_limit(%r8),%rcx
+ GET_THREAD_INFO(%rdx)
+ cmpq threadinfo_addr_limit(%rdx),%rax
jae bad_get_user
-1: movzb (%rcx),%edx
+1: movzb (%rax),%edx
xorl %eax,%eax
ret
CFI_ENDPROC
@@ -47,48 +47,48 @@ ENDPROC(__get_user_1)
ENTRY(__get_user_2)
CFI_STARTPROC
- GET_THREAD_INFO(%r8)
- addq $1,%rcx
+ GET_THREAD_INFO(%rdx)
+ addq $1,%rax
jc 20f
- cmpq threadinfo_addr_limit(%r8),%rcx
+ cmpq threadinfo_addr_limit(%rdx),%rax
jae 20f
- decq %rcx
-2: movzwl (%rcx),%edx
+ decq %rax
+2: movzwl (%rax),%edx
xorl %eax,%eax
ret
-20: decq %rcx
+20: decq %rax
jmp bad_get_user
CFI_ENDPROC
ENDPROC(__get_user_2)
ENTRY(__get_user_4)
CFI_STARTPROC
- GET_THREAD_INFO(%r8)
- addq $3,%rcx
+ GET_THREAD_INFO(%rdx)
+ addq $3,%rax
jc 30f
- cmpq threadinfo_addr_limit(%r8),%rcx
+ cmpq threadinfo_addr_limit(%rdx),%rax
jae 30f
- subq $3,%rcx
-3: movl (%rcx),%edx
+ subq $3,%rax
+3: movl (%rax),%edx
xorl %eax,%eax
ret
-30: subq $3,%rcx
+30: subq $3,%rax
jmp bad_get_user
CFI_ENDPROC
ENDPROC(__get_user_4)
ENTRY(__get_user_8)
CFI_STARTPROC
- GET_THREAD_INFO(%r8)
- addq $7,%rcx
+ GET_THREAD_INFO(%rdx)
+ addq $7,%rax
jc 40f
- cmpq threadinfo_addr_limit(%r8),%rcx
+ cmpq threadinfo_addr_limit(%rdx),%rax
jae 40f
- subq $7,%rcx
-4: movq (%rcx),%rdx
+ subq $7,%rax
+4: movq (%rax),%rdx
xorl %eax,%eax
ret
-40: subq $7,%rcx
+40: subq $7,%rax
jmp bad_get_user
CFI_ENDPROC
ENDPROC(__get_user_8)
diff --git a/include/asm-x86/uaccess_64.h b/include/asm-x86/uaccess_64.h
index b8a2f43..a2d4907 100644
--- a/include/asm-x86/uaccess_64.h
+++ b/include/asm-x86/uaccess_64.h
@@ -90,8 +90,7 @@ extern int fixup_exception(struct pt_regs *regs);
#define __get_user_x(size, ret, x, ptr) \
asm volatile("call __get_user_" #size \
: "=a" (ret),"=d" (x) \
- : "c" (ptr) \
- : "r8")
+ : "0" (ptr)) \
/* Careful: we have to cast the result to the type of the pointer
* for sign reasons */
--
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