52 lines
1.9 KiB
Diff
52 lines
1.9 KiB
Diff
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From a9f180345f5378ac87d80ed0bea55ba421d83859 Mon Sep 17 00:00:00 2001
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From: Steven Noonan <steven@uplinklabs.net>
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Date: Thu, 13 Feb 2014 07:01:07 +0000
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Subject: compiler/gcc4: Make quirk for asm_volatile_goto() unconditional
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I started noticing problems with KVM guest destruction on Linux
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3.12+, where guest memory wasn't being cleaned up. I bisected it
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down to the commit introducing the new 'asm goto'-based atomics,
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and found this quirk was later applied to those.
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Unfortunately, even with GCC 4.8.2 (which ostensibly fixed the
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known 'asm goto' bug) I am still getting some kind of
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miscompilation. If I enable the asm_volatile_goto quirk for my
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compiler, KVM guests are destroyed correctly and the memory is
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cleaned up.
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So make the quirk unconditional for now, until bug is found
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and fixed.
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Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
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Signed-off-by: Steven Noonan <steven@uplinklabs.net>
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Cc: Peter Zijlstra <peterz@infradead.org>
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Cc: Steven Rostedt <rostedt@goodmis.org>
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Cc: Jakub Jelinek <jakub@redhat.com>
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Cc: Richard Henderson <rth@twiddle.net>
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Cc: Andrew Morton <akpm@linux-foundation.org>
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Cc: Oleg Nesterov <oleg@redhat.com>
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Cc: <stable@vger.kernel.org>
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Link: http://lkml.kernel.org/r/1392274867-15236-1-git-send-email-steven@uplinklabs.net
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Link: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58670
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Signed-off-by: Ingo Molnar <mingo@kernel.org>
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---
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diff --git a/include/linux/compiler-gcc4.h b/include/linux/compiler-gcc4.h
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index ded4299..2507fd2 100644
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--- a/include/linux/compiler-gcc4.h
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+++ b/include/linux/compiler-gcc4.h
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@@ -75,11 +75,7 @@
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*
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* (asm goto is automatically volatile - the naming reflects this.)
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*/
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-#if GCC_VERSION <= 40801
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-# define asm_volatile_goto(x...) do { asm goto(x); asm (""); } while (0)
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-#else
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-# define asm_volatile_goto(x...) do { asm goto(x); } while (0)
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-#endif
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+#define asm_volatile_goto(x...) do { asm goto(x); asm (""); } while (0)
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#ifdef CONFIG_ARCH_USE_BUILTIN_BSWAP
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#if GCC_VERSION >= 40400
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--
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cgit v0.9.2
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