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| author | Borislav Petkov <bp@suse.de> | 2013-06-09 10:07:34 (GMT) |
|---|---|---|
| committer | H. Peter Anvin <hpa@linux.intel.com> | 2013-06-21 00:38:22 (GMT) |
| commit | 5f8c4218148822fde6eebbeefc34bd0a6061e031 (patch) | |
| tree | 1490d5de1b80ed71c737a28841cc2dcae930ca71 | |
| parent | 4a90a99c4f8002edaa6be11bd756872ebf3f3d97 (diff) | |
| download | linux-5f8c4218148822fde6eebbeefc34bd0a6061e031.tar.xz | |
x86, fpu: Use static_cpu_has_safe before alternatives
The call stack below shows how this happens: basically eager_fpu_init()
calls __thread_fpu_begin(current) which then does if (!use_eager_fpu()),
which, in turn, uses static_cpu_has.
And we're executing before alternatives so static_cpu_has doesn't work
there yet.
Use the safe variant in this path which becomes optimal after
alternatives have run.
WARNING: at arch/x86/kernel/cpu/common.c:1368 warn_pre_alternatives+0x1e/0x20()
You're using static_cpu_has before alternatives have run!
Modules linked in:
Pid: 0, comm: swapper Not tainted 3.9.0-rc8+ #1
Call Trace:
warn_slowpath_common
warn_slowpath_fmt
? fpu_finit
warn_pre_alternatives
eager_fpu_init
fpu_init
cpu_init
trap_init
start_kernel
? repair_env_string
x86_64_start_reservations
x86_64_start_kernel
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: http://lkml.kernel.org/r/1370772454-6106-6-git-send-email-bp@alien8.de
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
| -rw-r--r-- | arch/x86/include/asm/fpu-internal.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/include/asm/fpu-internal.h b/arch/x86/include/asm/fpu-internal.h index fb808d7..4d0bda7 100644 --- a/arch/x86/include/asm/fpu-internal.h +++ b/arch/x86/include/asm/fpu-internal.h @@ -343,7 +343,7 @@ static inline void __thread_fpu_end(struct task_struct *tsk) static inline void __thread_fpu_begin(struct task_struct *tsk) { - if (!use_eager_fpu()) + if (!static_cpu_has_safe(X86_FEATURE_EAGER_FPU)) clts(); __thread_set_has_fpu(tsk); } |