mirror of
https://github.com/followmsi/android_kernel_google_msm.git
synced 2024-11-06 23:17:41 +00:00
d19157519c
commit 3f0116c323 upstream.
Fengguang Wu, Oleg Nesterov and Peter Zijlstra tracked down
a kernel crash to a GCC bug: GCC miscompiles certain 'asm goto'
constructs, as outlined here:
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58670
Implement a workaround suggested by Jakub Jelinek.
Reported-and-tested-by: Fengguang Wu <fengguang.wu@intel.com>
Reported-by: Oleg Nesterov <oleg@redhat.com>
Reported-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Suggested-by: Jakub Jelinek <jakub@redhat.com>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
[hq: Backported to 3.4: Adjust context]
Signed-off-by: Qiang Huang <h.huangqiang@huawei.com>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Jianguo Wu <wujianguo@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
42 lines
758 B
C
42 lines
758 B
C
#ifndef _ASM_X86_JUMP_LABEL_H
|
|
#define _ASM_X86_JUMP_LABEL_H
|
|
|
|
#ifdef __KERNEL__
|
|
|
|
#include <linux/types.h>
|
|
#include <asm/nops.h>
|
|
#include <asm/asm.h>
|
|
|
|
#define JUMP_LABEL_NOP_SIZE 5
|
|
|
|
#define STATIC_KEY_INITIAL_NOP ".byte 0xe9 \n\t .long 0\n\t"
|
|
|
|
static __always_inline bool arch_static_branch(struct static_key *key)
|
|
{
|
|
asm_volatile_goto("1:"
|
|
STATIC_KEY_INITIAL_NOP
|
|
".pushsection __jump_table, \"aw\" \n\t"
|
|
_ASM_ALIGN "\n\t"
|
|
_ASM_PTR "1b, %l[l_yes], %c0 \n\t"
|
|
".popsection \n\t"
|
|
: : "i" (key) : : l_yes);
|
|
return false;
|
|
l_yes:
|
|
return true;
|
|
}
|
|
|
|
#endif /* __KERNEL__ */
|
|
|
|
#ifdef CONFIG_X86_64
|
|
typedef u64 jump_label_t;
|
|
#else
|
|
typedef u32 jump_label_t;
|
|
#endif
|
|
|
|
struct jump_entry {
|
|
jump_label_t code;
|
|
jump_label_t target;
|
|
jump_label_t key;
|
|
};
|
|
|
|
#endif
|