vserver 2.0 rc7

[linux-2.6.git] / arch / x86_64 / lib / getuser.S

diff --git a/arch/x86_64/lib/getuser.S b/arch/x86_64/lib/getuser.S
index 61a1f75..f80bafe 100644 (file)
--- a/arch/x86_64/lib/getuser.S
+++ b/arch/x86_64/lib/getuser.S
@@ -2,6 +2,7 @@
  * __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
@@ -12,12 +13,14 @@
 /*
  * __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.
@@ -33,52 +36,60 @@
        .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