linux-kernel - [PATCH] move __attribute__((__cold__)) functions back into final .text section

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Date:	Wed, 18 Jun 2008 12:36:01 +0100
From:	"Jan Beulich" <jbeulich@...ell.com>
To:	<sam@...nborg.org>
Cc:	<stable@...nel.org>, <llipavsky@...e.cz>,
	<linux-kernel@...r.kernel.org>
Subject: [PATCH] move __attribute__((__cold__)) functions back into
	final .text section

Due to the addition of __attribute__((__cold__)) to a few symbols
without adjusting the linker scripts, those symbols currently may end
up outside the [_stext,_etext) range, as they get placed in
.text.unlikely by (at least) gcc 4.3.0. This may confuse code not only
outside of the kernel, symbol_put_addr()'s BUG() could also trigger.
Hence we need to add .text.unlikely (and for future uses of
__attribute__((__hot__)) also .text.hot) to the TEXT_TEXT() macro.

Issue observed by Lukas Lipavsky.

Cc: Lukas Lipavsky <llipavsky@...e.cz>
Signed-off-by: Jan Beulich <jbeulich@...ell.com>

---
 include/asm-generic/vmlinux.lds.h |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

--- linux-2.6.26-rc6/include/asm-generic/vmlinux.lds.h	2008-04-17 04:49:44.000000000 +0200
+++ 2.6.26-rc6-hot-cold-text/include/asm-generic/vmlinux.lds.h	2008-06-18 12:19:22.000000000 +0200
@@ -204,6 +204,7 @@
  * during second ld run in second ld pass when generating System.map */
 #define TEXT_TEXT							\
 		ALIGN_FUNCTION();					\
+		*(.text.hot)						\
 		*(.text)						\
 		*(.ref.text)						\
 		*(.text.init.refok)					\
@@ -213,7 +214,8 @@
 	CPU_KEEP(init.text)						\
 	CPU_KEEP(exit.text)						\
 	MEM_KEEP(init.text)						\
-	MEM_KEEP(exit.text)
+	MEM_KEEP(exit.text)						\
+		*(.text.unlikely)
 
 
 /* sched.text is aling to function alignment to secure we have same



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