Commit 81683cc8 authored by Ingo Molnar's avatar Ingo Molnar
Browse files

x86/fpu: Factor out fpu__flush_thread() from flush_thread() 



flush_thread() open codes a lot of FPU internals - create a separate
function for it in fpu/core.c.

Turns out that this does not hurt performance:

   text    data     bss     dec     hex filename
   11843039        1884440 1130496 14857975         e2b6f7 vmlinux.before
   11843039        1884440 1130496 14857975         e2b6f7 vmlinux.after

and since this is a slowpath clarity comes first anyway.

We can reconsider inlining decisions after the FPU code has been cleaned up.

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 11ad1927

arch/x86/include/asm/i387.h

+1 −0
Original line number Diff line number Diff line
@@ -20,6 +20,7 @@ struct user_i387_struct; 


extern int fpstate_alloc_init(struct task_struct *curr);

extern void fpstate_init(struct fpu *fpu);

extern void fpu__flush_thread(struct task_struct *tsk);



extern int dump_fpu(struct pt_regs *, struct user_i387_struct *);

extern void math_state_restore(void);

arch/x86/kernel/fpu/core.c

+17 −0
Original line number Diff line number Diff line
@@ -227,6 +227,23 @@ static int fpu__unlazy_stopped(struct task_struct *child) 
	return 0;

}



void fpu__flush_thread(struct task_struct *tsk)

{

	if (!use_eager_fpu()) {

		/* FPU state will be reallocated lazily at the first use. */

		drop_fpu(tsk);

		fpstate_free(&tsk->thread.fpu);

	} else {

		if (!tsk_used_math(tsk)) {

			/* kthread execs. TODO: cleanup this horror. */

		if (WARN_ON(fpstate_alloc_init(tsk)))

				force_sig(SIGKILL, tsk);

			user_fpu_begin();

		}

		restore_init_xstate();

	}

}



/*

 * The xstateregs_active() routine is the same as the fpregs_active() routine,

 * as the "regset->n" for the xstate regset will be updated based on the feature

arch/x86/kernel/process.c

+1 −13
Original line number Diff line number Diff line
@@ -146,19 +146,7 @@ void flush_thread(void) 
	flush_ptrace_hw_breakpoint(tsk);

	memset(tsk->thread.tls_array, 0, sizeof(tsk->thread.tls_array));



	if (!use_eager_fpu()) {

		/* FPU state will be reallocated lazily at the first use. */

		drop_fpu(tsk);

		fpstate_free(&tsk->thread.fpu);

	} else {

		if (!tsk_used_math(tsk)) {

			/* kthread execs. TODO: cleanup this horror. */

		if (WARN_ON(fpstate_alloc_init(tsk)))

				force_sig(SIGKILL, tsk);

			user_fpu_begin();

		}

		restore_init_xstate();

	}

	fpu__flush_thread(tsk);

}



static void hard_disable_TSC(void)

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