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authorSteven Noonan <steven@uplinklabs.net>2014-02-12 23:01:07 -0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-02-22 12:41:29 -0800
commitfb6b644040b75ae321e23855ac1b9c060c98488f (patch)
treeb49e2f128c444e28e53520b131b267a92f45efa4
parent163d66d4fb1009d51027286cc4b921a5928961fc (diff)
downloadlinux-fb6b644040b75ae321e23855ac1b9c060c98488f.tar.gz
compiler/gcc4: Make quirk for asm_volatile_goto() unconditional
commit a9f180345f5378ac87d80ed0bea55ba421d83859 upstream. I started noticing problems with KVM guest destruction on Linux 3.12+, where guest memory wasn't being cleaned up. I bisected it down to the commit introducing the new 'asm goto'-based atomics, and found this quirk was later applied to those. Unfortunately, even with GCC 4.8.2 (which ostensibly fixed the known 'asm goto' bug) I am still getting some kind of miscompilation. If I enable the asm_volatile_goto quirk for my compiler, KVM guests are destroyed correctly and the memory is cleaned up. So make the quirk unconditional for now, until bug is found and fixed. Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Steven Noonan <steven@uplinklabs.net> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Jakub Jelinek <jakub@redhat.com> Cc: Richard Henderson <rth@twiddle.net> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Link: http://lkml.kernel.org/r/1392274867-15236-1-git-send-email-steven@uplinklabs.net Link: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58670 Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--include/linux/compiler-gcc4.h6
1 files changed, 1 insertions, 5 deletions
diff --git a/include/linux/compiler-gcc4.h b/include/linux/compiler-gcc4.h
index ded429966c1..2507fd2a1eb 100644
--- a/include/linux/compiler-gcc4.h
+++ b/include/linux/compiler-gcc4.h
@@ -75,11 +75,7 @@
*
* (asm goto is automatically volatile - the naming reflects this.)
*/
-#if GCC_VERSION <= 40801
-# define asm_volatile_goto(x...) do { asm goto(x); asm (""); } while (0)
-#else
-# define asm_volatile_goto(x...) do { asm goto(x); } while (0)
-#endif
+#define asm_volatile_goto(x...) do { asm goto(x); asm (""); } while (0)
#ifdef CONFIG_ARCH_USE_BUILTIN_BSWAP
#if GCC_VERSION >= 40400