x86/fpu: Rename restore_fpu_checking() to copy_fpstate_to_fpregs()

fpu_restore_checking() is a helper function of restore_fpu_checking(),
but this is not apparent from the naming.

Both copy fpstate contents to fpregs, while the fuller variant does
a full copy without leaking information.

So rename them to:

    copy_fpstate_to_fpregs()
  __copy_fpstate_to_fpregs()

Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>

arch/x86/include/asm/fpu/internal.h

@@ -289,7 +289,7 @@ static inline int copy_fpregs_to_fpstate(struct fpu *fpu)
 
 extern void fpu__save(struct fpu *fpu);
 
-static inline int fpu_restore_checking(struct fpu *fpu)
+static inline int __copy_fpstate_to_fpregs(struct fpu *fpu)
 {
 	if (use_xsave())
 		return fpu_xrstor_checking(&fpu->state.xsave);
@@ -299,7 +299,7 @@ static inline int fpu_restore_checking(struct fpu *fpu)
 		return frstor_checking(&fpu->state.fsave);
 }
 
-static inline int restore_fpu_checking(struct fpu *fpu)
+static inline int copy_fpstate_to_fpregs(struct fpu *fpu)
 {
 	/*
 	 * AMD K7/K8 CPUs don't save/restore FDP/FIP/FOP unless an exception is
@@ -314,7 +314,7 @@ static inline int restore_fpu_checking(struct fpu *fpu)
 			: : [addr] "m" (fpu->fpregs_active));
 	}
 
-	return fpu_restore_checking(fpu);
+	return __copy_fpstate_to_fpregs(fpu);
 }
 
 /*
@@ -520,7 +520,7 @@ switch_fpu_prepare(struct fpu *old_fpu, struct fpu *new_fpu, int cpu)
 static inline void switch_fpu_finish(struct fpu *new_fpu, fpu_switch_t fpu_switch)
 {
 	if (fpu_switch.preload) {
-		if (unlikely(restore_fpu_checking(new_fpu)))
+		if (unlikely(copy_fpstate_to_fpregs(new_fpu)))
 			fpu__reset(new_fpu);
 	}
 }

arch/x86/kernel/fpu/core.c

@@ -115,7 +115,7 @@ void __kernel_fpu_end(void)
 	struct fpu *fpu = &current->thread.fpu;
 
 	if (fpu->fpregs_active) {
-		if (WARN_ON(restore_fpu_checking(fpu)))
+		if (WARN_ON(copy_fpstate_to_fpregs(fpu)))
 			fpu__reset(fpu);
 	} else {
 		__fpregs_deactivate_hw();
@@ -338,7 +338,7 @@ void fpu__restore(void)
 	/* Avoid __kernel_fpu_begin() right after fpregs_activate() */
 	kernel_fpu_disable();
 	fpregs_activate(fpu);
-	if (unlikely(restore_fpu_checking(fpu))) {
+	if (unlikely(copy_fpstate_to_fpregs(fpu))) {
 		fpu__reset(fpu);
 		force_sig_info(SIGSEGV, SEND_SIG_PRIV, tsk);
 	} else {

arch/x86/kvm/x86.c

@@ -7030,7 +7030,7 @@ void kvm_load_guest_fpu(struct kvm_vcpu *vcpu)
 	kvm_put_guest_xcr0(vcpu);
 	vcpu->guest_fpu_loaded = 1;
 	__kernel_fpu_begin();
-	fpu_restore_checking(&vcpu->arch.guest_fpu);
+	__copy_fpstate_to_fpregs(&vcpu->arch.guest_fpu);
 	trace_kvm_fpu(1);
 }