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From: Hugh Dickins <hugh@veritas.com>
To: Ingo Molnar <mingo@elte.hu>
Cc: linux-kernel@vger.kernel.org
Subject: [PATCH] x86: vget_cycles() __always_inline
Date: Sun, 27 Apr 2008 00:39:36 +0100 (BST)	[thread overview]
Message-ID: <Pine.LNX.4.64.0804270035200.30877@blonde.site> (raw)

Mark vget_cycles() as __always_inline, so gcc is never tempted to make
the vsyscall vread_tsc() dive into kernel text, with resulting SIGSEGV.

This was a self-inflicted wound: I've not seen that happen with unhacked
sources; but for debug reasons I'd changed my x86/Makefile to compile
no-unit-at-a-time, and that in conjunction with OPTIMIZE_INLINING=y
ended up with vget_cycles() in kernel text.  Perhaps it can happen
in other ways: safer to use __always_inline.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
---

 include/asm-x86/tsc.h |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- 2.6.25-mm1/include/asm-x86/tsc.h	2008-04-18 12:18:34.000000000 +0100
+++ linux/include/asm-x86/tsc.h	2008-04-24 19:12:32.000000000 +0100
@@ -32,7 +32,7 @@ static inline cycles_t get_cycles(void)
 	return ret;
 }
 
-static inline cycles_t vget_cycles(void)
+static __always_inline cycles_t vget_cycles(void)
 {
 	/*
 	 * We only do VDSOs on TSC capable CPUs, so this shouldnt

             reply	other threads:[~2008-04-26 23:39 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-04-26 23:39 Hugh Dickins [this message]
2008-04-28 15:24 ` Ingo Molnar

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