Re: inconsistent kallsyms data [2.6.11-mm2]

[Sam Ravnborg <sam@ravnborg.org>]

On Thu, Mar 10, 2005 at 12:12:22PM +0000, Paulo Marques wrote:
> Paulo Marques wrote:
> >[...]
> >A simple and robust way is to do the sampling on a list of symbols 
> >sorted by symbol name. This way, even if the symbol positions that are 
> >given to scripts/kallsyms change, the symbols sampled will be the same.
> >
> >I'll do the patch to do this and send it ASAP.
> 
> Ok, here it is.
> 
> Dominik can you try the attached patch and see if it solves the problem?
Hi Paulo.

Alexander Stohr had similar problems with down and __sched_text_start.

I figured out that what was causing the troubles was the fact that the
linker generated symbol __sched_text_start changed value from pass 1 to
pass 2. The reason for this was the alingment used within that section.

My stamp on this is attached.

I never came around submitting this since I do not know what the correct
number for function alignment is on different paltforms.

	Sam


===== include/asm-generic/vmlinux.lds.h 1.16 vs edited =====
--- 1.16/include/asm-generic/vmlinux.lds.h	2004-10-06 18:45:06 +02:00
+++ edited/include/asm-generic/vmlinux.lds.h	2004-11-06 21:56:11 +01:00
@@ -6,6 +6,11 @@
 #define VMLINUX_SYMBOL(_sym_) _sym_
 #endif
 
+/* Aling functions to a 8 byte boundary.
+ * This prevents lables defined to mark start/end of section to differ
+ * during pass 1 and pass 2 when generating System.map */
+#define ALIGN_FUNCTION()  . = ALIGN(8)
+
 #define RODATA								\
 	.rodata           : AT(ADDR(.rodata) - LOAD_OFFSET) {		\
 		*(.rodata) *(.rodata.*)					\
@@ -77,11 +82,13 @@
 	}
 
 #define SCHED_TEXT							\
+		ALIGN_FUNCTION();					\
 		VMLINUX_SYMBOL(__sched_text_start) = .;			\
 		*(.sched.text)						\
 		VMLINUX_SYMBOL(__sched_text_end) = .;
 
 #define LOCK_TEXT							\
+		ALIGN_FUNCTION();					\
 		VMLINUX_SYMBOL(__lock_text_start) = .;			\
 		*(.spinlock.text)					\
 		VMLINUX_SYMBOL(__lock_text_end) = .;