Messages in this thread Patch in this message | | | Date | Sun, 14 Sep 2008 19:03:53 +0200 | Subject | [RFC][PATCH] x86: add memory clobber in switch_to() | From | Vegard Nossum <> |
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There are more places which have segment register reloads without adding memory clobbers. Should we fix them up? Here's one of them:
From 5f135687f7730fbdd979b6fb408fd3ca08a0a678 Mon Sep 17 00:00:00 2001 From: Vegard Nossum <vegard.nossum@gmail.com> Date: Sun, 14 Sep 2008 18:53:22 +0200 Subject: [PATCH] x86: add memory clobber in switch_to()
Segment registers are reloaded, so we should add a memory clobber. The generated assembly code is identical in my tests, but this doesn't mean it is necessarily true for all configurations/compilers.
x86_64 already has the memory clobber.
Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com> --- include/asm-x86/system.h | 5 ++++- 1 files changed, 4 insertions(+), 1 deletions(-)
diff --git a/include/asm-x86/system.h b/include/asm-x86/system.h index 983ce37..fed6482 100644 --- a/include/asm-x86/system.h +++ b/include/asm-x86/system.h @@ -64,7 +64,10 @@ do { \ \ /* regparm parameters for __switch_to(): */ \ [prev] "a" (prev), \ - [next] "d" (next)); \ + [next] "d" (next) \ + \ + : /* reloaded segment registers */ \ + "memory"); \ } while (0) /* -- 1.5.5.1
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