Commit 93b90712 authored by Ingo Molnar's avatar Ingo Molnar
Browse files

x86/fpu: Move math_state_restore() to fpu/core.c 



It's another piece of FPU internals that is better off close to
the other FPU internals.

Reviewed-by: default avatarBorislav 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: default avatarIngo Molnar <mingo@kernel.org>
parent 81683cc8

arch/x86/kernel/fpu/core.c

+42 −0
Original line number Diff line number Diff line
@@ -227,6 +227,48 @@ static int fpu__unlazy_stopped(struct task_struct *child) 
	return 0;

}



/*

 * 'math_state_restore()' saves the current math information in the

 * old math state array, and gets the new ones from the current task

 *

 * Careful.. There are problems with IBM-designed IRQ13 behaviour.

 * Don't touch unless you *really* know how it works.

 *

 * Must be called with kernel preemption disabled (eg with local

 * local interrupts as in the case of do_device_not_available).

 */

void math_state_restore(void)

{

	struct task_struct *tsk = current;



	if (!tsk_used_math(tsk)) {

		local_irq_enable();

		/*

		 * does a slab alloc which can sleep

		 */

		if (fpstate_alloc_init(tsk)) {

			/*

			 * ran out of memory!

			 */

			do_group_exit(SIGKILL);

			return;

		}

		local_irq_disable();

	}



	/* Avoid __kernel_fpu_begin() right after __thread_fpu_begin() */

	kernel_fpu_disable();

	__thread_fpu_begin(tsk);

	if (unlikely(restore_fpu_checking(tsk))) {

		fpu_reset_state(tsk);

		force_sig_info(SIGSEGV, SEND_SIG_PRIV, tsk);

	} else {

		tsk->thread.fpu.counter++;

	}

	kernel_fpu_enable();

}

EXPORT_SYMBOL_GPL(math_state_restore);



void fpu__flush_thread(struct task_struct *tsk)

{

	if (!use_eager_fpu()) {

arch/x86/kernel/traps.c

+0 −42
Original line number Diff line number Diff line
@@ -826,48 +826,6 @@ asmlinkage __visible void __attribute__((weak)) smp_threshold_interrupt(void) 
{

}



/*

 * 'math_state_restore()' saves the current math information in the

 * old math state array, and gets the new ones from the current task

 *

 * Careful.. There are problems with IBM-designed IRQ13 behaviour.

 * Don't touch unless you *really* know how it works.

 *

 * Must be called with kernel preemption disabled (eg with local

 * local interrupts as in the case of do_device_not_available).

 */

void math_state_restore(void)

{

	struct task_struct *tsk = current;



	if (!tsk_used_math(tsk)) {

		local_irq_enable();

		/*

		 * does a slab alloc which can sleep

		 */

		if (fpstate_alloc_init(tsk)) {

			/*

			 * ran out of memory!

			 */

			do_group_exit(SIGKILL);

			return;

		}

		local_irq_disable();

	}



	/* Avoid __kernel_fpu_begin() right after __thread_fpu_begin() */

	kernel_fpu_disable();

	__thread_fpu_begin(tsk);

	if (unlikely(restore_fpu_checking(tsk))) {

		fpu_reset_state(tsk);

		force_sig_info(SIGSEGV, SEND_SIG_PRIV, tsk);

	} else {

		tsk->thread.fpu.counter++;

	}

	kernel_fpu_enable();

}

EXPORT_SYMBOL_GPL(math_state_restore);



dotraplinkage void

do_device_not_available(struct pt_regs *regs, long error_code)

{

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