[PATCH] x86: fix percpu_{to,from}_op()

[PATCH] x86: fix percpu_{to,from}_op()

[Jan Beulich]

- the byte operand constraints were wrong for 32-bit
- the to-op's input operands weren't properly parenthesized

[ Impact: compilation problem fix ]

Signed-off-by: Jan Beulich <jbeulich@novell.com>

---
 arch/x86/include/asm/percpu.h |   10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

--- linux-2.6.30-rc5/arch/x86/include/asm/percpu.h	2009-05-11 17:28:25.000000000 +0200
+++ 2.6.30-rc5-x86-percpu-accessors/arch/x86/include/asm/percpu.h	2009-05-07 16:40:11.000000000 +0200
@@ -82,22 +82,22 @@ do {							\
 	case 1:						\
 		asm(op "b %1,"__percpu_arg(0)		\
 		    : "+m" (var)			\
-		    : "ri" ((T__)val));			\
+		    : "qi" ((T__)(val)));		\
 		break;					\
 	case 2:						\
 		asm(op "w %1,"__percpu_arg(0)		\
 		    : "+m" (var)			\
-		    : "ri" ((T__)val));			\
+		    : "ri" ((T__)(val)));		\
 		break;					\
 	case 4:						\
 		asm(op "l %1,"__percpu_arg(0)		\
 		    : "+m" (var)			\
-		    : "ri" ((T__)val));			\
+		    : "ri" ((T__)(val)));		\
 		break;					\
 	case 8:						\
 		asm(op "q %1,"__percpu_arg(0)		\
 		    : "+m" (var)			\
-		    : "re" ((T__)val));			\
+		    : "re" ((T__)(val)));		\
 		break;					\
 	default: __bad_percpu_size();			\
 	}						\
@@ -109,7 +109,7 @@ do {							\
 	switch (sizeof(var)) {				\
 	case 1:						\
 		asm(op "b "__percpu_arg(1)",%0"		\
-		    : "=r" (ret__)			\
+		    : "=q" (ret__)			\
 		    : "m" (var));			\
 		break;					\
 	case 2:						\

Re: [PATCH] x86: fix percpu_{to,from}_op()

[Ingo Molnar]

* Jan Beulich <JBeulich@novell.com> wrote:

> - the byte operand constraints were wrong for 32-bit
> - the to-op's input operands weren't properly parenthesized
> 
> [ Impact: compilation problem fix ]
> 
> Signed-off-by: Jan Beulich <jbeulich@novell.com>
> 
> ---
>  arch/x86/include/asm/percpu.h |   10 +++++-----
>  1 file changed, 5 insertions(+), 5 deletions(-)

applied to x86/urgent, thanks.

Btw., what kind of compilation problem did you experience? Did GCC 
bail out with a constraint error (which version?), or did you get a 
miscompiled kernel?

	Ingo