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Commit fbce7782 authored by Ingo Molnar's avatar Ingo Molnar
Browse files

x86/fpu: Merge fpu__reset() and fpu__clear() 



With recent cleanups and fixes the fpu__reset() and fpu__clear()
functions have become almost identical in functionality: the only
difference is that fpu__reset() assumed that the fpstate
was already active in the eagerfpu case, while fpu__clear()
activated it if it was inactive.

This distinction almost never matters, the only case where such
fpstate activation happens if if the init thread (PID 1) gets exec()-ed
for the first time.

So keep fpu__clear() and change all fpu__reset() uses to
fpu__clear() to simpify the logic.

( In a later patch we'll further simplify fpu__clear() by making
  sure that all contexts it is called on are already active. )

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: default avatarIngo Molnar <mingo@kernel.org>
parent 82c0e45e

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

+1 −2
Original line number Diff line number Diff line
@@ -56,7 +56,6 @@ extern void fpu__restore(void); 
extern int  fpu__restore_sig(void __user *buf, int ia32_frame);

extern void fpu__drop(struct fpu *fpu);

extern int  fpu__copy(struct fpu *dst_fpu, struct fpu *src_fpu);

extern void fpu__reset(struct fpu *fpu);

extern void fpu__clear(struct fpu *fpu);



extern void fpu__init_check_bugs(void);
@@ -490,7 +489,7 @@ static inline void switch_fpu_finish(struct fpu *new_fpu, fpu_switch_t fpu_switc 
{

	if (fpu_switch.preload) {

		if (unlikely(copy_fpstate_to_fpregs(new_fpu)))

			fpu__reset(new_fpu);

			fpu__clear(new_fpu);

	}

}

arch/x86/kernel/fpu/core.c

+6 −15
Original line number Diff line number Diff line
@@ -116,7 +116,7 @@ void __kernel_fpu_end(void) 


	if (fpu->fpregs_active) {

		if (WARN_ON(copy_fpstate_to_fpregs(fpu)))

			fpu__reset(fpu);

			fpu__clear(fpu);

	} else {

		__fpregs_deactivate_hw();

	}
@@ -339,7 +339,7 @@ void fpu__restore(void) 
	kernel_fpu_disable();

	fpregs_activate(fpu);

	if (unlikely(copy_fpstate_to_fpregs(fpu))) {

		fpu__reset(fpu);

		fpu__clear(fpu);

		force_sig_info(SIGSEGV, SEND_SIG_PRIV, tsk);

	} else {

		tsk->thread.fpu.counter++;
@@ -376,19 +376,10 @@ void fpu__drop(struct fpu *fpu) 
}



/*

 * Reset the FPU state back to init state:

 */

void fpu__reset(struct fpu *fpu)

{

	if (!use_eager_fpu())

		fpu__drop(fpu);

	else

		restore_init_xstate();

}



/*

 * Called by sys_execve() to clear the FPU fpregs, so that FPU state

 * of the previous binary does not leak over into the exec()ed binary:

 * Clear the FPU state back to init state.

 *

 * Called by sys_execve(), by the signal handler code and by various

 * error paths.

 */

void fpu__clear(struct fpu *fpu)

{

arch/x86/kernel/fpu/xstate.c

+2 −2
Original line number Diff line number Diff line
@@ -401,7 +401,7 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size) 
			 config_enabled(CONFIG_IA32_EMULATION));



	if (!buf) {

		fpu__reset(fpu);

		fpu__clear(fpu);

		return 0;

	}
@@ -474,7 +474,7 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size) 
		 */

		user_fpu_begin();

		if (restore_user_xstate(buf_fx, xfeatures, fx_only)) {

			fpu__reset(fpu);

			fpu__clear(fpu);

			return -1;

		}

	}

arch/x86/kernel/signal.c

+1 −1
Original line number Diff line number Diff line
@@ -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(fpu);

			fpu__clear(fpu);

	}

	signal_setup_done(failed, ksig, stepping);

}