[PATCH] reorganize <linux/linkage.h>

[PATCH] reorganize <linux/linkage.h>

[Kyle McMartin]

Commit 54a015104136974262afa4b8ddd943ea70dec8a2 adds some new magic
asmlinkage_protect gizmo, but that can only be used from C code, not
assembly. Protect relevant bits of <linux/linkage.h> with !__ASSEMBLY__
so this can't leak into assembly source.

Fixes a couple build errors on my boxes,
  AS      arch/parisc/kernel/pacache.o
In file included from arch/parisc/kernel/pacache.S:40:
include/linux/linkage.h:34: error: syntax error in macro parameter list
make[1]: *** [arch/parisc/kernel/pacache.o] Error 1

(__ALIGN gets used in both kernel and assembly context, so make sure it
is outside of the ifdeffery.)

Signed-off-by: Kyle McMartin <kmcmartin@redhat.com>
---
diff --git a/include/linux/linkage.h b/include/linux/linkage.h
index b163c5c..e848f74 100644
--- a/include/linux/linkage.h
+++ b/include/linux/linkage.h
@@ -3,6 +3,13 @@
 
 #include <asm/linkage.h>
 
+#ifndef __ALIGN
+#define __ALIGN		.align 4,0x90
+#define __ALIGN_STR	".align 4,0x90"
+#endif
+
+#if !defined(__ASSEMBLY__)
+
 #ifdef __cplusplus
 #define CPP_ASMLINKAGE extern "C"
 #else
@@ -34,12 +41,11 @@
 # define asmlinkage_protect(n, ret, args...)	do { } while (0)
 #endif
 
-#ifndef __ALIGN
-#define __ALIGN		.align 4,0x90
-#define __ALIGN_STR	".align 4,0x90"
-#endif
+#define NORET_TYPE    /**/
+#define ATTRIB_NORET  __attribute__((noreturn))
+#define NORET_AND     noreturn,
 
-#ifdef __ASSEMBLY__
+#else
 
 #define ALIGN __ALIGN
 #define ALIGN_STR __ALIGN_STR
@@ -80,10 +86,6 @@
   END(name)
 #endif
 
-#endif
-
-#define NORET_TYPE    /**/
-#define ATTRIB_NORET  __attribute__((noreturn))
-#define NORET_AND     noreturn,
+#endif /*__ASSEMBLY__*/
 
 #endif

Re: [PATCH] reorganize <linux/linkage.h>

[Linus Torvalds]

On Fri, 11 Apr 2008, Kyle McMartin wrote:
>
> Commit 54a015104136974262afa4b8ddd943ea70dec8a2 adds some new magic
> asmlinkage_protect gizmo, but that can only be used from C code, not
> assembly. Protect relevant bits of <linux/linkage.h> with !__ASSEMBLY__
> so this can't leak into assembly source.

Ok, so s390 had a similar issue, and I assumed that they were just usign a 
broken C pre-processor for asm, but now I'm starting to wonder about it.

Why cannot your pre-processor handle that thing?

It doesn't matter if it is C or assembly, the pre-processor should be the 
same. That #define isn't used for asm, so it shouldn't _matter_ for asm. 
What's going on?

I'm starting to suspect that it's the fact that some architectures still 
have

	EXTRA_AFLAGS  := -traditional

or equivalent and I'm wondering whether that is really necessary. IIRC x86 
got rid of the use of --traditional a long time ago, exactly because it 
caused problems with any fancier C preprocessor things.

It would probably be much better to try to lose that -traditional from 
affected architectures, because otherwise issues like this will keep 
popping up just because the most common architecture doesn't use the 
limited preprocessor..

		Linus

Re: [PATCH] reorganize <linux/linkage.h>

[David Miller]

From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Fri, 11 Apr 2008 07:58:56 -0700 (PDT)

> I'm starting to suspect that it's the fact that some architectures still 
> have
> 
> 	EXTRA_AFLAGS  := -traditional
> 
> or equivalent and I'm wondering whether that is really necessary. IIRC x86 
> got rid of the use of --traditional a long time ago, exactly because it 
> caused problems with any fancier C preprocessor things.

A lot of it is probably simply copy and paste from other ports.

When I removed it from Sparc long ago, the only issue I had was that
there were some things using "/**/" concatenation in some sparc
assembler CPP macros, and those were easily fixed.