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| author | Sebastian Andrzej Siewior <bigeasy@linutronix.de> | 2019-04-03 18:41:32 +0200 |
|---|---|---|
| committer | Borislav Petkov <bp@suse.de> | 2019-04-09 19:27:46 +0200 |
| commit | 60e528d6ce3f60a058bbb64f8acb2a07f84b172a (patch) | |
| tree | 687db0d24408bbfa2f318b233724c173aa39d986 /arch/x86 | |
| parent | 6dd677a044e606fd343e31c2108b13d74aec1ca5 (diff) | |
| download | linux-60e528d6ce3f60a058bbb64f8acb2a07f84b172a.tar.bz2 | |
x86/fpu: Remove preempt_disable() in fpu__clear()
The preempt_disable() section was introduced in commit
a10b6a16cdad8 ("x86/fpu: Make the fpu state change in fpu__clear() scheduler-atomic")
and it was said to be temporary.
fpu__initialize() initializes the FPU struct to its initial value and
then sets ->initialized to 1. The last part is the important one.
The content of the state does not matter because it gets set via
copy_init_fpstate_to_fpregs().
A preemption here has little meaning because the registers will always be
set to the same content after copy_init_fpstate_to_fpregs(). A softirq
with a kernel_fpu_begin() could also force to save FPU's registers after
fpu__initialize() without changing the outcome here.
Remove the preempt_disable() section in fpu__clear(), preemption here
does not hurt.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Dave Hansen <dave.hansen@intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "Jason A. Donenfeld" <Jason@zx2c4.com>
Cc: kvm ML <kvm@vger.kernel.org>
Cc: Nicolai Stange <nstange@suse.de>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: x86-ml <x86@kernel.org>
Link: https://lkml.kernel.org/r/20190403164156.19645-4-bigeasy@linutronix.de
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/kernel/fpu/core.c | 2 |
1 files changed, 0 insertions, 2 deletions
diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c index 1d3ae7988f7f..1940319268ae 100644 --- a/arch/x86/kernel/fpu/core.c +++ b/arch/x86/kernel/fpu/core.c @@ -366,11 +366,9 @@ void fpu__clear(struct fpu *fpu) * Make sure fpstate is cleared and initialized. */ if (static_cpu_has(X86_FEATURE_FPU)) { - preempt_disable(); fpu__initialize(fpu); user_fpu_begin(); copy_init_fpstate_to_fpregs(); - preempt_enable(); } } |