mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-05 06:46:59 +07:00
a9f180345f
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> Cc: <stable@vger.kernel.org> 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>
89 lines
3.0 KiB
C
89 lines
3.0 KiB
C
#ifndef __LINUX_COMPILER_H
|
|
#error "Please don't include <linux/compiler-gcc4.h> directly, include <linux/compiler.h> instead."
|
|
#endif
|
|
|
|
/* GCC 4.1.[01] miscompiles __weak */
|
|
#ifdef __KERNEL__
|
|
# if GCC_VERSION >= 40100 && GCC_VERSION <= 40101
|
|
# error Your version of gcc miscompiles the __weak directive
|
|
# endif
|
|
#endif
|
|
|
|
#define __used __attribute__((__used__))
|
|
#define __must_check __attribute__((warn_unused_result))
|
|
#define __compiler_offsetof(a,b) __builtin_offsetof(a,b)
|
|
|
|
#if GCC_VERSION >= 40100 && GCC_VERSION < 40600
|
|
# define __compiletime_object_size(obj) __builtin_object_size(obj, 0)
|
|
#endif
|
|
|
|
#if GCC_VERSION >= 40300
|
|
/* Mark functions as cold. gcc will assume any path leading to a call
|
|
to them will be unlikely. This means a lot of manual unlikely()s
|
|
are unnecessary now for any paths leading to the usual suspects
|
|
like BUG(), printk(), panic() etc. [but let's keep them for now for
|
|
older compilers]
|
|
|
|
Early snapshots of gcc 4.3 don't support this and we can't detect this
|
|
in the preprocessor, but we can live with this because they're unreleased.
|
|
Maketime probing would be overkill here.
|
|
|
|
gcc also has a __attribute__((__hot__)) to move hot functions into
|
|
a special section, but I don't see any sense in this right now in
|
|
the kernel context */
|
|
#define __cold __attribute__((__cold__))
|
|
|
|
#define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __COUNTER__)
|
|
|
|
#ifndef __CHECKER__
|
|
# define __compiletime_warning(message) __attribute__((warning(message)))
|
|
# define __compiletime_error(message) __attribute__((error(message)))
|
|
#endif /* __CHECKER__ */
|
|
#endif /* GCC_VERSION >= 40300 */
|
|
|
|
#if GCC_VERSION >= 40500
|
|
/*
|
|
* Mark a position in code as unreachable. This can be used to
|
|
* suppress control flow warnings after asm blocks that transfer
|
|
* control elsewhere.
|
|
*
|
|
* Early snapshots of gcc 4.5 don't support this and we can't detect
|
|
* this in the preprocessor, but we can live with this because they're
|
|
* unreleased. Really, we need to have autoconf for the kernel.
|
|
*/
|
|
#define unreachable() __builtin_unreachable()
|
|
|
|
/* Mark a function definition as prohibited from being cloned. */
|
|
#define __noclone __attribute__((__noclone__))
|
|
|
|
#endif /* GCC_VERSION >= 40500 */
|
|
|
|
#if GCC_VERSION >= 40600
|
|
/*
|
|
* Tell the optimizer that something else uses this function or variable.
|
|
*/
|
|
#define __visible __attribute__((externally_visible))
|
|
#endif
|
|
|
|
/*
|
|
* GCC 'asm goto' miscompiles certain code sequences:
|
|
*
|
|
* http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58670
|
|
*
|
|
* Work it around via a compiler barrier quirk suggested by Jakub Jelinek.
|
|
* Fixed in GCC 4.8.2 and later versions.
|
|
*
|
|
* (asm goto is automatically volatile - the naming reflects this.)
|
|
*/
|
|
#define asm_volatile_goto(x...) do { asm goto(x); asm (""); } while (0)
|
|
|
|
#ifdef CONFIG_ARCH_USE_BUILTIN_BSWAP
|
|
#if GCC_VERSION >= 40400
|
|
#define __HAVE_BUILTIN_BSWAP32__
|
|
#define __HAVE_BUILTIN_BSWAP64__
|
|
#endif
|
|
#if GCC_VERSION >= 40800 || (defined(__powerpc__) && GCC_VERSION >= 40600)
|
|
#define __HAVE_BUILTIN_BSWAP16__
|
|
#endif
|
|
#endif /* CONFIG_ARCH_USE_BUILTIN_BSWAP */
|