x86/fpu: Use 'struct fpu' in fpu_reset_state()

Migrate this function to pure 'struct fpu' usage.
Reviewed-by: NBorislav Petkov <bp@alien8.de>
Cc: Andy Lutomirski <luto@amacapital.net>
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: NIngo Molnar <mingo@kernel.org>

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

@@ -380,10 +380,8 @@ static inline void restore_init_xstate(void)
  * Reset the FPU state in the eager case and drop it in the lazy case (later use
  * will reinit it).
  */
-static inline void fpu_reset_state(struct task_struct *tsk)
+static inline void fpu_reset_state(struct fpu *fpu)
 {
-	struct fpu *fpu = &tsk->thread.fpu;
-
 	if (!use_eager_fpu())
 		drop_fpu(fpu);
 	else
@@ -460,7 +458,7 @@ static inline void switch_fpu_finish(struct task_struct *new, fpu_switch_t fpu)
 
 	if (fpu.preload) {
 		if (unlikely(restore_fpu_checking(new_fpu)))
-			fpu_reset_state(new);
+			fpu_reset_state(new_fpu);
 	}
 }
 

arch/x86/kernel/fpu/core.c

@@ -112,12 +112,11 @@ EXPORT_SYMBOL(__kernel_fpu_begin);
 
 void __kernel_fpu_end(void)
 {
-	struct task_struct *me = current;
-	struct fpu *fpu = &me->thread.fpu;
+	struct fpu *fpu = &current->thread.fpu;
 
 	if (fpu->has_fpu) {
 		if (WARN_ON(restore_fpu_checking(fpu)))
-			fpu_reset_state(me);
+			fpu_reset_state(fpu);
 	} else if (!use_eager_fpu()) {
 		stts();
 	}
@@ -371,7 +370,7 @@ void fpu__restore(void)
 	kernel_fpu_disable();
 	__thread_fpu_begin(fpu);
 	if (unlikely(restore_fpu_checking(fpu))) {
-		fpu_reset_state(tsk);
+		fpu_reset_state(fpu);
 		force_sig_info(SIGSEGV, SEND_SIG_PRIV, tsk);
 	} else {
 		tsk->thread.fpu.counter++;

arch/x86/kernel/fpu/xsave.c

@@ -343,7 +343,7 @@ int __restore_xstate_sig(void __user *buf, void __user *buf_fx, int size)
 			 config_enabled(CONFIG_IA32_EMULATION));
 
 	if (!buf) {
-		fpu_reset_state(tsk);
+		fpu_reset_state(fpu);
 		return 0;
 	}
 
@@ -417,7 +417,7 @@ int __restore_xstate_sig(void __user *buf, void __user *buf_fx, int size)
 		 */
 		user_fpu_begin();
 		if (restore_user_xstate(buf_fx, xstate_bv, fx_only)) {
-			fpu_reset_state(tsk);
+			fpu_reset_state(fpu);
 			return -1;
 		}
 	}

arch/x86/kernel/signal.c

@@ -667,7 +667,7 @@ handle_signal(struct ksignal *ksig, struct pt_regs *regs)
 		 * Ensure the signal handler starts with the new fpu state.
 		 */
 		if (fpu->fpstate_active)
-			fpu_reset_state(current);
+			fpu_reset_state(fpu);
 	}
 	signal_setup_done(failed, ksig, stepping);
 }