x86/fpu: Create 'union thread_xstate' helper for fpstate_init()

fpstate_init() only uses fpu->state, so pass that in to it.

This enables the cleanup we will do in the next patch.

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

@@ -29,7 +29,7 @@ extern void fpu__init_system(struct cpuinfo_x86 *c);
 
 extern void fpu__activate_curr(struct fpu *fpu);
 
-extern void fpstate_init(struct fpu *fpu);
+extern void fpstate_init(union thread_xstate *state);
 #ifdef CONFIG_MATH_EMULATION
 extern void fpstate_init_soft(struct i387_soft_struct *soft);
 #else

arch/x86/kernel/fpu/core.c

@@ -202,19 +202,19 @@ static inline void fpstate_init_fstate(struct i387_fsave_struct *fp)
 	fp->fos = 0xffff0000u;
 }
 
-void fpstate_init(struct fpu *fpu)
+void fpstate_init(union thread_xstate *state)
 {
 	if (!cpu_has_fpu) {
-		fpstate_init_soft(&fpu->state.soft);
+		fpstate_init_soft(&state->soft);
 		return;
 	}
 
-	memset(&fpu->state, 0, xstate_size);
+	memset(state, 0, xstate_size);
 
 	if (cpu_has_fxsr)
-		fpstate_init_fxstate(&fpu->state.fxsave);
+		fpstate_init_fxstate(&state->fxsave);
 	else
-		fpstate_init_fstate(&fpu->state.fsave);
+		fpstate_init_fstate(&state->fsave);
 }
 EXPORT_SYMBOL_GPL(fpstate_init);
 
@@ -282,7 +282,7 @@ void fpu__activate_curr(struct fpu *fpu)
 	WARN_ON_ONCE(fpu != &current->thread.fpu);
 
 	if (!fpu->fpstate_active) {
-		fpstate_init(fpu);
+		fpstate_init(&fpu->state);
 
 		/* Safe to do for the current task: */
 		fpu->fpstate_active = 1;
@@ -321,7 +321,7 @@ static void fpu__activate_stopped(struct fpu *child_fpu)
 	if (child_fpu->fpstate_active) {
 		child_fpu->last_cpu = -1;
 	} else {
-		fpstate_init(child_fpu);
+		fpstate_init(&child_fpu->state);
 
 		/* Safe to do for stopped child tasks: */
 		child_fpu->fpstate_active = 1;

arch/x86/kernel/fpu/xstate.c

@@ -456,7 +456,7 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size)
 
 		if (__copy_from_user(&fpu->state.xsave, buf_fx, state_size) ||
 		    __copy_from_user(&env, buf, sizeof(env))) {
-			fpstate_init(fpu);
+			fpstate_init(&fpu->state);
 			err = -1;
 		} else {
 			sanitize_restored_xstate(tsk, &env, xfeatures, fx_only);

arch/x86/kvm/x86.c

@@ -7004,7 +7004,7 @@ int kvm_arch_vcpu_ioctl_set_fpu(struct kvm_vcpu *vcpu, struct kvm_fpu *fpu)
 
 static void fx_init(struct kvm_vcpu *vcpu)
 {
-	fpstate_init(&vcpu->arch.guest_fpu);
+	fpstate_init(&vcpu->arch.guest_fpu.state);
 	if (cpu_has_xsaves)
 		vcpu->arch.guest_fpu.state.xsave.header.xcomp_bv =
 			host_xcr0 | XSTATE_COMPACTION_ENABLED;