Commit ab2486a9 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 Thomas Gleixner:
 "A small set of updates for the FPU code:

   - Make the no387/nofxsr command line options useful by restricting
     them to 32bit and actually clearing all dependencies to prevent
     random crashes and malfunction.

   - Simplify and cleanup the kernel_fpu_*() helpers"

* 'x86-fpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/fpu: Inline fpu__xstate_clear_all_cpu_caps()
  x86/fpu: Make 'no387' and 'nofxsr' command line options useful
  x86/fpu: Remove the fpu__save() export
  x86/fpu: Simplify kernel_fpu_begin()
  x86/fpu: Simplify kernel_fpu_end()
parents 0d37dde7 7891bc0a

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

+0 −1
Original line number Diff line number Diff line
@@ -47,7 +47,6 @@ extern u64 xstate_fx_sw_bytes[USER_XSTATE_FX_SW_WORDS]; 
extern void __init update_regset_xstate_info(unsigned int size,

					     u64 xstate_mask);



void fpu__xstate_clear_all_cpu_caps(void);

void *get_xsave_addr(struct xregs_state *xsave, int xfeature_nr);

const void *get_xsave_field_ptr(int xfeature_nr);

int using_compacted_format(void);

arch/x86/kernel/cpu/cpuid-deps.c

+5 −0
Original line number Diff line number Diff line
@@ -20,6 +20,7 @@ struct cpuid_dep { 
 * but it's difficult to tell that to the init reference checker.

 */

static const struct cpuid_dep cpuid_deps[] = {

	{ X86_FEATURE_FXSR,		X86_FEATURE_FPU	      },

	{ X86_FEATURE_XSAVEOPT,		X86_FEATURE_XSAVE     },

	{ X86_FEATURE_XSAVEC,		X86_FEATURE_XSAVE     },

	{ X86_FEATURE_XSAVES,		X86_FEATURE_XSAVE     },
@@ -27,7 +28,11 @@ static const struct cpuid_dep cpuid_deps[] = { 
	{ X86_FEATURE_PKU,		X86_FEATURE_XSAVE     },

	{ X86_FEATURE_MPX,		X86_FEATURE_XSAVE     },

	{ X86_FEATURE_XGETBV1,		X86_FEATURE_XSAVE     },

	{ X86_FEATURE_CMOV,		X86_FEATURE_FXSR      },

	{ X86_FEATURE_MMX,		X86_FEATURE_FXSR      },

	{ X86_FEATURE_MMXEXT,		X86_FEATURE_MMX       },

	{ X86_FEATURE_FXSR_OPT,		X86_FEATURE_FXSR      },

	{ X86_FEATURE_XSAVE,		X86_FEATURE_FXSR      },

	{ X86_FEATURE_XMM,		X86_FEATURE_FXSR      },

	{ X86_FEATURE_XMM2,		X86_FEATURE_XMM       },

	{ X86_FEATURE_XMM3,		X86_FEATURE_XMM2      },

arch/x86/kernel/fpu/core.c

+15 −37
Original line number Diff line number Diff line
@@ -43,18 +43,6 @@ static DEFINE_PER_CPU(bool, in_kernel_fpu); 
 */

DEFINE_PER_CPU(struct fpu *, fpu_fpregs_owner_ctx);



static void kernel_fpu_disable(void)

{

	WARN_ON_FPU(this_cpu_read(in_kernel_fpu));

	this_cpu_write(in_kernel_fpu, true);

}



static void kernel_fpu_enable(void)

{

	WARN_ON_FPU(!this_cpu_read(in_kernel_fpu));

	this_cpu_write(in_kernel_fpu, false);

}



static bool kernel_fpu_disabled(void)

{

	return this_cpu_read(in_kernel_fpu);
@@ -94,42 +82,33 @@ bool irq_fpu_usable(void) 
}

EXPORT_SYMBOL(irq_fpu_usable);



static void __kernel_fpu_begin(void)

void kernel_fpu_begin(void)

{

	struct fpu *fpu = &current->thread.fpu;

	preempt_disable();



	WARN_ON_FPU(!irq_fpu_usable());

	WARN_ON_FPU(this_cpu_read(in_kernel_fpu));



	kernel_fpu_disable();

	this_cpu_write(in_kernel_fpu, true);



	if (!(current->flags & PF_KTHREAD)) {

		if (!test_thread_flag(TIF_NEED_FPU_LOAD)) {

	if (!(current->flags & PF_KTHREAD) &&

	    !test_thread_flag(TIF_NEED_FPU_LOAD)) {

		set_thread_flag(TIF_NEED_FPU_LOAD);

		/*

		 * Ignore return value -- we don't care if reg state

		 * is clobbered.

		 */

			copy_fpregs_to_fpstate(fpu);

		}

		copy_fpregs_to_fpstate(&current->thread.fpu);

	}

	__cpu_invalidate_fpregs_state();

}



static void __kernel_fpu_end(void)

{

	kernel_fpu_enable();

}



void kernel_fpu_begin(void)

{

	preempt_disable();

	__kernel_fpu_begin();

}

EXPORT_SYMBOL_GPL(kernel_fpu_begin);



void kernel_fpu_end(void)

{

	__kernel_fpu_end();

	WARN_ON_FPU(!this_cpu_read(in_kernel_fpu));



	this_cpu_write(in_kernel_fpu, false);

	preempt_enable();

}

EXPORT_SYMBOL_GPL(kernel_fpu_end);
@@ -155,7 +134,6 @@ void fpu__save(struct fpu *fpu) 
	trace_x86_fpu_after_save(fpu);

	fpregs_unlock();

}

EXPORT_SYMBOL_GPL(fpu__save);



/*

 * Legacy x87 fpstate state init:

arch/x86/kernel/fpu/init.c

+8 −11
Original line number Diff line number Diff line
@@ -204,12 +204,6 @@ static void __init fpu__init_system_xstate_size_legacy(void) 
	 */



	if (!boot_cpu_has(X86_FEATURE_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);

		fpu_kernel_xstate_size = sizeof(struct swregs_state);

	} else {

		if (boot_cpu_has(X86_FEATURE_FXSR))
@@ -252,17 +246,20 @@ static void __init fpu__init_parse_early_param(void) 
	char *argptr = arg;

	int bit;



#ifdef CONFIG_X86_32

	if (cmdline_find_option_bool(boot_command_line, "no387"))

#ifdef CONFIG_MATH_EMULATION

		setup_clear_cpu_cap(X86_FEATURE_FPU);

#else

		pr_err("Option 'no387' required CONFIG_MATH_EMULATION enabled.\n");

#endif



	if (cmdline_find_option_bool(boot_command_line, "nofxsr")) {

	if (cmdline_find_option_bool(boot_command_line, "nofxsr"))

		setup_clear_cpu_cap(X86_FEATURE_FXSR);

		setup_clear_cpu_cap(X86_FEATURE_FXSR_OPT);

		setup_clear_cpu_cap(X86_FEATURE_XMM);

	}

#endif



	if (cmdline_find_option_bool(boot_command_line, "noxsave"))

		fpu__xstate_clear_all_cpu_caps();

		setup_clear_cpu_cap(X86_FEATURE_XSAVE);



	if (cmdline_find_option_bool(boot_command_line, "noxsaveopt"))

		setup_clear_cpu_cap(X86_FEATURE_XSAVEOPT);

arch/x86/kernel/fpu/xstate.c

+1 −10
Original line number Diff line number Diff line
@@ -67,15 +67,6 @@ static unsigned int xstate_comp_offsets[sizeof(xfeatures_mask)*8]; 
 */

unsigned int fpu_user_xstate_size;



/*

 * Clear all of the X86_FEATURE_* bits that are unavailable

 * when the CPU has no XSAVE support.

 */

void fpu__xstate_clear_all_cpu_caps(void)

{

	setup_clear_cpu_cap(X86_FEATURE_XSAVE);

}



/*

 * Return whether the system supports a given xfeature.

 *
@@ -709,7 +700,7 @@ static void fpu__init_disable_system_xstate(void) 
{

	xfeatures_mask = 0;

	cr4_clear_bits(X86_CR4_OSXSAVE);

	fpu__xstate_clear_all_cpu_caps();

	setup_clear_cpu_cap(X86_FEATURE_XSAVE);

}



/*

CRA Git | Maintained and supported by SUSTech CRA and CCSE