[PATCH] 2.3.40: <linux/linkage.h> doesn't generate correct cache alignments for 486 and above

[Chris Sears]

On inspection <linux/linkage.h> handles the i686 incorrectly.
Cache line alignments are being set to 4 bytes as per the i386.
This is a bad bad thing for the i686.

However, it is much worse than this. __i386__ is always defined.
BTW, I am running gcc 2.95.1 and I don't have the stomach to
track down where, but __i386__ is always defined for x86.

The patch strips out dependancies on __i*86__ and uses a
combination of CONFIG_X86 and and CONFIG_M386.

I would *strongly* advocate cleansing the kernel of all uses of:

        __WorksWithMyCompilerTodayDoesItWorkWithYours__

And I don't want to hear about Linux being written in gcc.
It is one thing to use gcc as a compiler/code-generator, and
quite another to use it as a configuration management system.


Chris Sears
cbsears en ix.netcom.com

Here is the patch against 2.3.40:

--- linkage.h.orig      Wed Jan 26 14:31:54 2000
+++ linkage.h   Wed Jan 26 15:32:25 2000
@@ -1,6 +1,8 @@
 #ifndef _LINUX_LINKAGE_H
 #define _LINUX_LINKAGE_H

+#include <linux/autoconf.h>
+
 #ifdef __cplusplus
 #define CPP_ASMLINKAGE extern "C"
 #else
@@ -45,13 +47,13 @@
 #define __ALIGN .balign 4
 #define __ALIGN_STR ".balign 4"
 #else
-#if !defined(__i486__) && !defined(__i586__)
-#define __ALIGN .align 4,0x90
-#define __ALIGN_STR ".align 4,0x90"
-#else  /* __i486__/__i586__ */
+#if defined(CONFIG_X86) && !defined(CONFIG_M386)
 #define __ALIGN .align 16,0x90
 #define __ALIGN_STR ".align 16,0x90"
-#endif /* __i486__/__i586__ */
+#else
+#define __ALIGN .align 4,0x90
+#define __ALIGN_STR ".align 4,0x90"
+#endif
 #endif /* __sh__ */
 #endif /* __mc68000__ */
 #endif /* __arm__ */




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