Commit 0c867537 authored by Ingo Molnar's avatar Ingo Molnar
Browse files

x86/fpu: Split out the boot time FPU init code into fpu/init.c 



Move boot time FPU initialization code into init.c, to better
isolate it into its own domain.

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 f89e32e0

arch/x86/kernel/fpu/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -2,4 +2,4 @@ 
# Build rules for the FPU support code:

#



obj-y				+= core.o xsave.o
 
obj-y				+= init.o core.o xsave.o

arch/x86/kernel/fpu/core.c

+0 −88
Original line number Diff line number Diff line
@@ -139,94 +139,6 @@ void fpu__save(struct task_struct *tsk) 
}

EXPORT_SYMBOL_GPL(fpu__save);



unsigned int mxcsr_feature_mask __read_mostly = 0xffffffffu;

unsigned int xstate_size;

EXPORT_SYMBOL_GPL(xstate_size);

static struct i387_fxsave_struct fx_scratch;



static void mxcsr_feature_mask_init(void)

{

	unsigned long mask = 0;



	if (cpu_has_fxsr) {

		memset(&fx_scratch, 0, sizeof(struct i387_fxsave_struct));

		asm volatile("fxsave %0" : "+m" (fx_scratch));

		mask = fx_scratch.mxcsr_mask;

		if (mask == 0)

			mask = 0x0000ffbf;

	}

	mxcsr_feature_mask &= mask;

}



static void fpstate_xstate_init_size(void)

{

	/*

	 * Note that xstate_size might be overwriten later during

	 * xsave_init().

	 */



	if (!cpu_has_fpu) {

		/*

		 * Disable xsave as we do not support it if i387

		 * emulation is enabled.

		 */

		setup_clear_cpu_cap(X86_FEATURE_XSAVE);

		setup_clear_cpu_cap(X86_FEATURE_XSAVEOPT);

		xstate_size = sizeof(struct i387_soft_struct);

		return;

	}



	if (cpu_has_fxsr)

		xstate_size = sizeof(struct i387_fxsave_struct);

	else

		xstate_size = sizeof(struct i387_fsave_struct);

}



/*

 * Called on the boot CPU at bootup to set up the initial FPU state that

 * is later cloned into all processes.

 *

 * Also called on secondary CPUs to set up the FPU state of their

 * idle threads.

 */

void fpu__cpu_init(void)

{

	unsigned long cr0;

	unsigned long cr4_mask = 0;



#ifndef CONFIG_MATH_EMULATION

	if (!cpu_has_fpu) {

		pr_emerg("No FPU found and no math emulation present\n");

		pr_emerg("Giving up\n");

		for (;;)

			asm volatile("hlt");

	}

#endif

	if (cpu_has_fxsr)

		cr4_mask |= X86_CR4_OSFXSR;

	if (cpu_has_xmm)

		cr4_mask |= X86_CR4_OSXMMEXCPT;

	if (cr4_mask)

		cr4_set_bits(cr4_mask);



	cr0 = read_cr0();

	cr0 &= ~(X86_CR0_TS|X86_CR0_EM); /* clear TS and EM */

	if (!cpu_has_fpu)

		cr0 |= X86_CR0_EM;

	write_cr0(cr0);



	/*

	 * fpstate_xstate_init_size() is only called once, to avoid overriding

	 * 'xstate_size' during (secondary CPU) bootup or during CPU hotplug.

	 */

	if (xstate_size == 0)

		fpstate_xstate_init_size();



	mxcsr_feature_mask_init();

	xsave_init();

	eager_fpu_init();

}



void fpstate_init(struct fpu *fpu)

{

	if (!cpu_has_fpu) {

arch/x86/kernel/fpu/init.c

0 → 100644
+93 −0
Original line number Diff line number Diff line 
/*

 * x86 FPU boot time init code

 */

#include <asm/fpu-internal.h>

#include <asm/tlbflush.h>



unsigned int mxcsr_feature_mask __read_mostly = 0xffffffffu;

unsigned int xstate_size;

EXPORT_SYMBOL_GPL(xstate_size);

static struct i387_fxsave_struct fx_scratch;



static void mxcsr_feature_mask_init(void)

{

	unsigned long mask = 0;



	if (cpu_has_fxsr) {

		memset(&fx_scratch, 0, sizeof(struct i387_fxsave_struct));

		asm volatile("fxsave %0" : "+m" (fx_scratch));

		mask = fx_scratch.mxcsr_mask;

		if (mask == 0)

			mask = 0x0000ffbf;

	}

	mxcsr_feature_mask &= mask;

}



static void fpstate_xstate_init_size(void)

{

	/*

	 * Note that xstate_size might be overwriten later during

	 * xsave_init().

	 */



	if (!cpu_has_fpu) {

		/*

		 * Disable xsave as we do not support it if i387

		 * emulation is enabled.

		 */

		setup_clear_cpu_cap(X86_FEATURE_XSAVE);

		setup_clear_cpu_cap(X86_FEATURE_XSAVEOPT);

		xstate_size = sizeof(struct i387_soft_struct);

		return;

	}



	if (cpu_has_fxsr)

		xstate_size = sizeof(struct i387_fxsave_struct);

	else

		xstate_size = sizeof(struct i387_fsave_struct);

}



/*

 * Called on the boot CPU at bootup to set up the initial FPU state that

 * is later cloned into all processes.

 *

 * Also called on secondary CPUs to set up the FPU state of their

 * idle threads.

 */

void fpu__cpu_init(void)

{

	unsigned long cr0;

	unsigned long cr4_mask = 0;



#ifndef CONFIG_MATH_EMULATION

	if (!cpu_has_fpu) {

		pr_emerg("No FPU found and no math emulation present\n");

		pr_emerg("Giving up\n");

		for (;;)

			asm volatile("hlt");

	}

#endif

	if (cpu_has_fxsr)

		cr4_mask |= X86_CR4_OSFXSR;

	if (cpu_has_xmm)

		cr4_mask |= X86_CR4_OSXMMEXCPT;

	if (cr4_mask)

		cr4_set_bits(cr4_mask);



	cr0 = read_cr0();

	cr0 &= ~(X86_CR0_TS|X86_CR0_EM); /* clear TS and EM */

	if (!cpu_has_fpu)

		cr0 |= X86_CR0_EM;

	write_cr0(cr0);



	/*

	 * fpstate_xstate_init_size() is only called once, to avoid overriding

	 * 'xstate_size' during (secondary CPU) bootup or during CPU hotplug.

	 */

	if (xstate_size == 0)

		fpstate_xstate_init_size();



	mxcsr_feature_mask_init();

	xsave_init();

	eager_fpu_init();

}

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