* __get_user functions.
*
* (C) Copyright 1998 Linus Torvalds
+ * (C) Copyright 2005 Andi Kleen
*
* These functions have a non-standard call interface
* to make them more efficient, especially as they
/*
* __get_user_X
*
- * Inputs: %rax contains the address
+ * Inputs: %rcx contains the address.
+ * The register is modified, but all changes are undone
+ * before returning because the C code doesn't know about it.
*
* Outputs: %rax is error code (0 or -EFAULT)
* %rdx contains zero-extended value
*
- * %rbx is destroyed.
+ * %r8 is destroyed.
*
* These functions should not modify any other registers,
* as they get called from within inline assembly.
#include <linux/linkage.h>
#include <asm/page.h>
#include <asm/errno.h>
-#include <asm/offset.h>
+#include <asm/asm-offsets.h>
#include <asm/thread_info.h>
.text
.p2align 4
.globl __get_user_1
__get_user_1:
- GET_THREAD_INFO(%rbx)
- cmpq threadinfo_addr_limit(%rbx),%rax
+ GET_THREAD_INFO(%r8)
+ cmpq threadinfo_addr_limit(%r8),%rcx
jae bad_get_user
-1: movzb (%rax),%edx
- xorq %rax,%rax
+1: movzb (%rcx),%edx
+ xorl %eax,%eax
ret
.p2align 4
.globl __get_user_2
__get_user_2:
- GET_THREAD_INFO(%rbx)
- addq $1,%rax
- jc bad_get_user
- cmpq threadinfo_addr_limit(%rbx),%rax
- jae bad_get_user
-2: movzwl -1(%rax),%edx
- xorq %rax,%rax
+ GET_THREAD_INFO(%r8)
+ addq $1,%rcx
+ jc 20f
+ cmpq threadinfo_addr_limit(%r8),%rcx
+ jae 20f
+ decq %rcx
+2: movzwl (%rcx),%edx
+ xorl %eax,%eax
ret
+20: decq %rcx
+ jmp bad_get_user
.p2align 4
.globl __get_user_4
__get_user_4:
- GET_THREAD_INFO(%rbx)
- addq $3,%rax
- jc bad_get_user
- cmpq threadinfo_addr_limit(%rbx),%rax
- jae bad_get_user
-3: movl -3(%rax),%edx
- xorq %rax,%rax
+ GET_THREAD_INFO(%r8)
+ addq $3,%rcx
+ jc 30f
+ cmpq threadinfo_addr_limit(%r8),%rcx
+ jae 30f
+ subq $3,%rcx
+3: movl (%rcx),%edx
+ xorl %eax,%eax
ret
+30: subq $3,%rcx
+ jmp bad_get_user
.p2align 4
.globl __get_user_8
__get_user_8:
- GET_THREAD_INFO(%rbx)
- addq $7,%rax
- jc bad_get_user
- cmpq threadinfo_addr_limit(%rbx),%rax
- jae bad_get_user
-4: movq -7(%rax),%rdx
- xorq %rax,%rax
+ GET_THREAD_INFO(%r8)
+ addq $7,%rcx
+ jc 40f
+ cmpq threadinfo_addr_limit(%r8),%rcx
+ jae 40f
+ subq $7,%rcx
+4: movq (%rcx),%rdx
+ xorl %eax,%eax
ret
+40: subq $7,%rcx
+ jmp bad_get_user
-ENTRY(bad_get_user)
bad_get_user:
- xorq %rdx,%rdx
+ xorl %edx,%edx
movq $(-EFAULT),%rax
ret