x86/uaccess: Remove redundant CLACs in getuser/putuser error paths

The same getuser/putuser error paths are used regardless of whether AC
is set.  In non-exception failure cases, this results in an unnecessary
CLAC.

Fixes the following warnings:

  arch/x86/lib/getuser.o: warning: objtool: .altinstr_replacement+0x18: redundant UACCESS disable
  arch/x86/lib/putuser.o: warning: objtool: .altinstr_replacement+0x18: redundant UACCESS disable

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/bc14ded2755ae75bd9010c446079e113dbddb74b.1563413318.git.jpoimboe@redhat.com

diff --git a/arch/x86/lib/getuser.S b/arch/x86/lib/getuser.S
index 74fdff968ea3b14ce05db05f65fe59dc6ae89154..304f958c27b29cd54aed4f736e5e4601bce5ae94 100644 (file)
--- a/arch/x86/lib/getuser.S
+++ b/arch/x86/lib/getuser.S
@@ -115,29 +115,29 @@ ENDPROC(__get_user_8)
 EXPORT_SYMBOL(__get_user_8)
 
 
+bad_get_user_clac:
+       ASM_CLAC
 bad_get_user:
        xor %edx,%edx
        mov $(-EFAULT),%_ASM_AX
-       ASM_CLAC
        ret
-END(bad_get_user)
 
 #ifdef CONFIG_X86_32
+bad_get_user_8_clac:
+       ASM_CLAC
 bad_get_user_8:
        xor %edx,%edx
        xor %ecx,%ecx
        mov $(-EFAULT),%_ASM_AX
-       ASM_CLAC
        ret
-END(bad_get_user_8)
 #endif
 
-       _ASM_EXTABLE_UA(1b, bad_get_user)
-       _ASM_EXTABLE_UA(2b, bad_get_user)
-       _ASM_EXTABLE_UA(3b, bad_get_user)
+       _ASM_EXTABLE_UA(1b, bad_get_user_clac)
+       _ASM_EXTABLE_UA(2b, bad_get_user_clac)
+       _ASM_EXTABLE_UA(3b, bad_get_user_clac)
 #ifdef CONFIG_X86_64
-       _ASM_EXTABLE_UA(4b, bad_get_user)
+       _ASM_EXTABLE_UA(4b, bad_get_user_clac)
 #else
-       _ASM_EXTABLE_UA(4b, bad_get_user_8)
-       _ASM_EXTABLE_UA(5b, bad_get_user_8)
+       _ASM_EXTABLE_UA(4b, bad_get_user_8_clac)
+       _ASM_EXTABLE_UA(5b, bad_get_user_8_clac)
 #endif

diff --git a/arch/x86/lib/putuser.S b/arch/x86/lib/putuser.S
index d2e5c9c396018e7e255ad0cdbfc5d5a1552d6e8c..14bf78341d3c731ab3d3e242003c21dbd8c33a50 100644 (file)
--- a/arch/x86/lib/putuser.S
+++ b/arch/x86/lib/putuser.S
@@ -32,8 +32,6 @@
  */
 
 #define ENTER  mov PER_CPU_VAR(current_task), %_ASM_BX
-#define EXIT   ASM_CLAC ;      \
-               ret
 
 .text
 ENTRY(__put_user_1)
@@ -43,7 +41,8 @@ ENTRY(__put_user_1)
        ASM_STAC
 1:     movb %al,(%_ASM_CX)
        xor %eax,%eax
-       EXIT
+       ASM_CLAC
+       ret
 ENDPROC(__put_user_1)
 EXPORT_SYMBOL(__put_user_1)
 
@@ -56,7 +55,8 @@ ENTRY(__put_user_2)
        ASM_STAC
 2:     movw %ax,(%_ASM_CX)
        xor %eax,%eax
-       EXIT
+       ASM_CLAC
+       ret
 ENDPROC(__put_user_2)
 EXPORT_SYMBOL(__put_user_2)
 
@@ -69,7 +69,8 @@ ENTRY(__put_user_4)
        ASM_STAC
 3:     movl %eax,(%_ASM_CX)
        xor %eax,%eax
-       EXIT
+       ASM_CLAC
+       ret
 ENDPROC(__put_user_4)
 EXPORT_SYMBOL(__put_user_4)
 
@@ -85,19 +86,21 @@ ENTRY(__put_user_8)
 5:     movl %edx,4(%_ASM_CX)
 #endif
        xor %eax,%eax
-       EXIT
+       ASM_CLAC
+       RET
 ENDPROC(__put_user_8)
 EXPORT_SYMBOL(__put_user_8)
 
+bad_put_user_clac:
+       ASM_CLAC
 bad_put_user:
        movl $-EFAULT,%eax
-       EXIT
-END(bad_put_user)
+       RET
 
-       _ASM_EXTABLE_UA(1b, bad_put_user)
-       _ASM_EXTABLE_UA(2b, bad_put_user)
-       _ASM_EXTABLE_UA(3b, bad_put_user)
-       _ASM_EXTABLE_UA(4b, bad_put_user)
+       _ASM_EXTABLE_UA(1b, bad_put_user_clac)
+       _ASM_EXTABLE_UA(2b, bad_put_user_clac)
+       _ASM_EXTABLE_UA(3b, bad_put_user_clac)
+       _ASM_EXTABLE_UA(4b, bad_put_user_clac)
 #ifdef CONFIG_X86_32
-       _ASM_EXTABLE_UA(5b, bad_put_user)
+       _ASM_EXTABLE_UA(5b, bad_put_user_clac)
 #endif