Commit c7b228ad authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge branch 'x86-fpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 

Pull x86 FPU updates from Ingo Molnar:
 "x86 FPU handling fixes, cleanups and enhancements from Oleg.

  The signal handling race fix and the __restore_xstate_sig() preemption
  fix for eager-mode is marked for -stable as well"

* 'x86-fpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86: copy_thread: Don't nullify ->ptrace_bps twice
  x86, fpu: Shift "fpu_counter = 0" from copy_thread() to arch_dup_task_struct()
  x86, fpu: copy_process: Sanitize fpu->last_cpu initialization
  x86, fpu: copy_process: Avoid fpu_alloc/copy if !used_math()
  x86, fpu: Change __thread_fpu_begin() to use use_eager_fpu()
  x86, fpu: __restore_xstate_sig()->math_state_restore() needs preempt_disable()
  x86, fpu: shift drop_init_fpu() from save_xstate_sig() to handle_signal()
parents 708d0b41 6f46b3ae

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

+1 −1
Original line number Diff line number Diff line
@@ -344,7 +344,7 @@ static inline void __thread_fpu_end(struct task_struct *tsk) 


static inline void __thread_fpu_begin(struct task_struct *tsk)

{

	if (!static_cpu_has_safe(X86_FEATURE_EAGER_FPU))

	if (!use_eager_fpu())

		clts();

	__thread_set_has_fpu(tsk);

}

arch/x86/kernel/process.c

+9 −7
Original line number Diff line number Diff line
@@ -64,14 +64,16 @@ EXPORT_SYMBOL_GPL(task_xstate_cachep); 
 */

int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)

{

	int ret;



	*dst = *src;

	if (fpu_allocated(&src->thread.fpu)) {

		memset(&dst->thread.fpu, 0, sizeof(dst->thread.fpu));

		ret = fpu_alloc(&dst->thread.fpu);

		if (ret)

			return ret;



	dst->thread.fpu_counter = 0;

	dst->thread.fpu.has_fpu = 0;

	dst->thread.fpu.last_cpu = ~0;

	dst->thread.fpu.state = NULL;

	if (tsk_used_math(src)) {

		int err = fpu_alloc(&dst->thread.fpu);

		if (err)

			return err;

		fpu_copy(dst, src);

	}

	return 0;

arch/x86/kernel/process_32.c

+1 −5
Original line number Diff line number Diff line
@@ -138,6 +138,7 @@ int copy_thread(unsigned long clone_flags, unsigned long sp, 


	p->thread.sp = (unsigned long) childregs;

	p->thread.sp0 = (unsigned long) (childregs+1);

	memset(p->thread.ptrace_bps, 0, sizeof(p->thread.ptrace_bps));



	if (unlikely(p->flags & PF_KTHREAD)) {

		/* kernel thread */
@@ -152,9 +153,7 @@ int copy_thread(unsigned long clone_flags, unsigned long sp, 
		childregs->orig_ax = -1;

		childregs->cs = __KERNEL_CS | get_kernel_rpl();

		childregs->flags = X86_EFLAGS_IF | X86_EFLAGS_FIXED;

		p->thread.fpu_counter = 0;

		p->thread.io_bitmap_ptr = NULL;

		memset(p->thread.ptrace_bps, 0, sizeof(p->thread.ptrace_bps));

		return 0;

	}

	*childregs = *current_pt_regs();
@@ -165,13 +164,10 @@ int copy_thread(unsigned long clone_flags, unsigned long sp, 
	p->thread.ip = (unsigned long) ret_from_fork;

	task_user_gs(p) = get_user_gs(current_pt_regs());



	p->thread.fpu_counter = 0;

	p->thread.io_bitmap_ptr = NULL;

	tsk = current;

	err = -ENOMEM;



	memset(p->thread.ptrace_bps, 0, sizeof(p->thread.ptrace_bps));



	if (unlikely(test_tsk_thread_flag(tsk, TIF_IO_BITMAP))) {

		p->thread.io_bitmap_ptr = kmemdup(tsk->thread.io_bitmap_ptr,

						IO_BITMAP_BYTES, GFP_KERNEL);

arch/x86/kernel/process_64.c

+0 −3
Original line number Diff line number Diff line
@@ -163,7 +163,6 @@ int copy_thread(unsigned long clone_flags, unsigned long sp, 
	p->thread.sp = (unsigned long) childregs;

	p->thread.usersp = me->thread.usersp;

	set_tsk_thread_flag(p, TIF_FORK);

	p->thread.fpu_counter = 0;

	p->thread.io_bitmap_ptr = NULL;



	savesegment(gs, p->thread.gsindex);
@@ -193,8 +192,6 @@ int copy_thread(unsigned long clone_flags, unsigned long sp, 
		childregs->sp = sp;



	err = -ENOMEM;

	memset(p->thread.ptrace_bps, 0, sizeof(p->thread.ptrace_bps));



	if (unlikely(test_tsk_thread_flag(me, TIF_IO_BITMAP))) {

		p->thread.io_bitmap_ptr = kmemdup(me->thread.io_bitmap_ptr,

						  IO_BITMAP_BYTES, GFP_KERNEL);

arch/x86/kernel/signal.c

+5 −0
Original line number Diff line number Diff line
@@ -675,6 +675,11 @@ handle_signal(struct ksignal *ksig, struct pt_regs *regs) 
		 * handler too.

		 */

		regs->flags &= ~(X86_EFLAGS_DF|X86_EFLAGS_RF|X86_EFLAGS_TF);

		/*

		 * Ensure the signal handler starts with the new fpu state.

		 */

		if (used_math())

			drop_init_fpu(current);

	}

	signal_setup_done(failed, ksig, test_thread_flag(TIF_SINGLESTEP));

}

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