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| author | Rik van Riel <riel@surriel.com> | 2019-04-03 18:41:47 +0200 |
|---|---|---|
| committer | Borislav Petkov <bp@suse.de> | 2019-04-11 18:20:04 +0200 |
| commit | a352a3b7b7920212ee4c45a41500c66826318e92 (patch) | |
| tree | 98d1ebae13bec7e07e18f43205bcc1eda2e84246 /arch | |
| parent | 69277c98f5eef0d9839699b7825923c3985f665f (diff) | |
| download | linux-stable-a352a3b7b7920212ee4c45a41500c66826318e92.tar.gz linux-stable-a352a3b7b7920212ee4c45a41500c66826318e92.tar.bz2 linux-stable-a352a3b7b7920212ee4c45a41500c66826318e92.zip | |
x86/fpu: Prepare copy_fpstate_to_sigframe() for TIF_NEED_FPU_LOAD
The FPU registers need only to be saved if TIF_NEED_FPU_LOAD is not set.
Otherwise this has been already done and can be skipped.
[ bp: Massage a bit. ]
Signed-off-by: Rik van Riel <riel@surriel.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-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: Jann Horn <jannh@google.com>
Cc: "Jason A. Donenfeld" <Jason@zx2c4.com>
Cc: kvm ML <kvm@vger.kernel.org>
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/20190403164156.19645-19-bigeasy@linutronix.de
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kernel/fpu/signal.c | 12 |
1 files changed, 11 insertions, 1 deletions
diff --git a/arch/x86/kernel/fpu/signal.c b/arch/x86/kernel/fpu/signal.c index 8f23f5237218..9b9dfdc96285 100644 --- a/arch/x86/kernel/fpu/signal.c +++ b/arch/x86/kernel/fpu/signal.c @@ -171,7 +171,17 @@ int copy_fpstate_to_sigframe(void __user *buf, void __user *buf_fx, int size) sizeof(struct user_i387_ia32_struct), NULL, (struct _fpstate_32 __user *) buf) ? -1 : 1; - copy_fpregs_to_fpstate(fpu); + /* + * If we do not need to load the FPU registers at return to userspace + * then the CPU has the current state and we need to save it. Otherwise, + * it has already been done and we can skip it. + */ + fpregs_lock(); + if (!test_thread_flag(TIF_NEED_FPU_LOAD)) { + copy_fpregs_to_fpstate(fpu); + set_thread_flag(TIF_NEED_FPU_LOAD); + } + fpregs_unlock(); if (using_compacted_format()) { if (copy_xstate_to_user(buf_fx, xsave, 0, size)) |