From 1f3171252dc586745bb548d48f3bcedfea34b58d Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Wed, 23 Jun 2021 14:01:51 +0200 Subject: x86/fpu: Get rid of copy_supervisor_to_kernel() If the fast path of restoring the FPU state on sigreturn fails or is not taken and the current task's FPU is active then the FPU has to be deactivated for the slow path to allow a safe update of the tasks FPU memory state. With supervisor states enabled, this requires to save the supervisor state in the memory state first. Supervisor states require XSAVES so saving only the supervisor state requires to reshuffle the memory buffer because XSAVES uses the compacted format and therefore stores the supervisor states at the beginning of the memory state. That's just an overengineered optimization. Get rid of it and save the full state for this case. Signed-off-by: Thomas Gleixner Signed-off-by: Borislav Petkov Reviewed-by: Andy Lutomirski Reviewed-by: Borislav Petkov Link: https://lkml.kernel.org/r/20210623121453.734561971@linutronix.de --- arch/x86/include/asm/fpu/xstate.h | 1 - 1 file changed, 1 deletion(-) (limited to 'arch/x86/include/asm/fpu/xstate.h') diff --git a/arch/x86/include/asm/fpu/xstate.h b/arch/x86/include/asm/fpu/xstate.h index 6e5ba42ffd42..6611e069e834 100644 --- a/arch/x86/include/asm/fpu/xstate.h +++ b/arch/x86/include/asm/fpu/xstate.h @@ -104,7 +104,6 @@ void *get_xsave_addr(struct xregs_state *xsave, int xfeature_nr); int xfeature_size(int xfeature_nr); int copy_kernel_to_xstate(struct xregs_state *xsave, const void *kbuf); int copy_user_to_xstate(struct xregs_state *xsave, const void __user *ubuf); -void copy_supervisor_to_kernel(struct xregs_state *xsave); void copy_dynamic_supervisor_to_kernel(struct xregs_state *xstate, u64 mask); void copy_kernel_to_dynamic_supervisor(struct xregs_state *xstate, u64 mask); -- cgit v1.2.3