diff options
| -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)) |