Re: [PATCH 1/8] kasan,x86: Frob kasan_report() in an exception

[Peter Zijlstra]

On Wed, Mar 06, 2019 at 09:59:11AM -0800, Linus Torvalds wrote:
> Maybe we could just get rid of that oddity, and just make __ASM_CLAC
> be a string to begin with.

Seems to work.. I'll add it to the pile.

---
 arch/x86/include/asm/smap.h |   19 +++++++++----------
 1 file changed, 9 insertions(+), 10 deletions(-)

--- a/arch/x86/include/asm/smap.h
+++ b/arch/x86/include/asm/smap.h
@@ -13,13 +13,12 @@
 #ifndef _ASM_X86_SMAP_H
 #define _ASM_X86_SMAP_H
 
-#include <linux/stringify.h>
 #include <asm/nops.h>
 #include <asm/cpufeatures.h>
 
 /* "Raw" instruction opcodes */
-#define __ASM_CLAC     .byte 0x0f,0x01,0xca
-#define __ASM_STAC     .byte 0x0f,0x01,0xcb
+#define __ASM_CLAC     ".byte 0x0f,0x01,0xca"
+#define __ASM_STAC     ".byte 0x0f,0x01,0xcb"
 
 #ifdef __ASSEMBLY__
 
@@ -28,10 +27,10 @@
 #ifdef CONFIG_X86_SMAP
 
 #define ASM_CLAC \
-       ALTERNATIVE "", __stringify(__ASM_CLAC), X86_FEATURE_SMAP
+       ALTERNATIVE "", __ASM_CLAC, X86_FEATURE_SMAP
 
 #define ASM_STAC \
-       ALTERNATIVE "", __stringify(__ASM_STAC), X86_FEATURE_SMAP
+       ALTERNATIVE "", __ASM_STAC, X86_FEATURE_SMAP
 
 #else /* CONFIG_X86_SMAP */
 
@@ -49,20 +48,20 @@
 static __always_inline void clac(void)
 {
        /* Note: a barrier is implicit in alternative() */
-       alternative("", __stringify(__ASM_CLAC), X86_FEATURE_SMAP);
+       alternative("", __ASM_CLAC, X86_FEATURE_SMAP);
 }
 
 static __always_inline void stac(void)
 {
        /* Note: a barrier is implicit in alternative() */
-       alternative("", __stringify(__ASM_STAC), X86_FEATURE_SMAP);
+       alternative("", __ASM_STAC, X86_FEATURE_SMAP);
 }
 
 static __always_inline unsigned long smap_save(void)
 {
        unsigned long flags;
 
-       asm volatile (ALTERNATIVE("", "pushf; pop %0; " __stringify(__ASM_CLAC),
+       asm volatile (ALTERNATIVE("", "pushf; pop %0; " __ASM_CLAC,
                                  X86_FEATURE_SMAP)
                      : "=rm" (flags) : : "memory", "cc");
 
@@ -77,9 +76,9 @@ static __always_inline void smap_restore
 
 /* These macros can be used in asm() statements */
 #define ASM_CLAC \
-       ALTERNATIVE("", __stringify(__ASM_CLAC), X86_FEATURE_SMAP)
+       ALTERNATIVE("", __ASM_CLAC, X86_FEATURE_SMAP)
 #define ASM_STAC \
-       ALTERNATIVE("", __stringify(__ASM_STAC), X86_FEATURE_SMAP)
+       ALTERNATIVE("", __ASM_STAC, X86_FEATURE_SMAP)
 
 #else /* CONFIG_X86_SMAP */