Commit 60e019eb authored by H. Peter Anvin's avatar H. Peter Anvin Committed by H. Peter Anvin
Browse files

x86: Get rid of ->hard_math and all the FPU asm fu 



Reimplement FPU detection code in C and drop old, not-so-recommended
detection method in asm. Move all the relevant stuff into i387.c where
it conceptually belongs. Finally drop cpuinfo_x86.hard_math.

[ hpa: huge thanks to Borislav for taking my original concept patch
  and productizing it ]

[ Boris, note to self: do not use static_cpu_has before alternatives! ]

Signed-off-by: default avatarH. Peter Anvin <hpa@zytor.com>
Link: http://lkml.kernel.org/r/1367244262-29511-2-git-send-email-bp@alien8.de
Link: http://lkml.kernel.org/r/1365436666-9837-2-git-send-email-bp@alien8.de


Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
Signed-off-by: default avatarH. Peter Anvin <hpa@linux.intel.com>
parent d683b96b

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

+0 −2
Original line number Diff line number Diff line
@@ -62,10 +62,8 @@ extern user_regset_set_fn fpregs_set, xfpregs_set, fpregs_soft_set, 
#define xstateregs_active	fpregs_active



#ifdef CONFIG_MATH_EMULATION

# define HAVE_HWFP		(boot_cpu_data.hard_math)

extern void finit_soft_fpu(struct i387_soft_struct *soft);

#else

# define HAVE_HWFP		1

static inline void finit_soft_fpu(struct i387_soft_struct *soft) {}

#endif

arch/x86/include/asm/processor.h

+2 −1
Original line number Diff line number Diff line
@@ -89,9 +89,9 @@ struct cpuinfo_x86 { 
	char			wp_works_ok;	/* It doesn't on 386's */



	/* Problems on some 486Dx4's and old 386's: */

	char			hard_math;

	char			rfu;

	char			pad0;

	char			pad1;

#else

	/* Number of 4K pages in DTLB/ITLB combined(in pages): */

	int			x86_tlbsize;
@@ -164,6 +164,7 @@ extern const struct seq_operations cpuinfo_op; 
#define cache_line_size()	(boot_cpu_data.x86_cache_alignment)



extern void cpu_detect(struct cpuinfo_x86 *c);

extern void __cpuinit fpu_detect(struct cpuinfo_x86 *c);



extern void early_cpu_init(void);

extern void identify_boot_cpu(void);

arch/x86/kernel/asm-offsets_32.c

+0 −1
Original line number Diff line number Diff line
@@ -28,7 +28,6 @@ void foo(void) 
	OFFSET(CPUINFO_x86_vendor, cpuinfo_x86, x86_vendor);

	OFFSET(CPUINFO_x86_model, cpuinfo_x86, x86_model);

	OFFSET(CPUINFO_x86_mask, cpuinfo_x86, x86_mask);

	OFFSET(CPUINFO_hard_math, cpuinfo_x86, hard_math);

	OFFSET(CPUINFO_cpuid_level, cpuinfo_x86, cpuid_level);

	OFFSET(CPUINFO_x86_capability, cpuinfo_x86, x86_capability);

	OFFSET(CPUINFO_x86_vendor_id, cpuinfo_x86, x86_vendor_id);

arch/x86/kernel/cpu/bugs.c

+2 −19
Original line number Diff line number Diff line
@@ -17,15 +17,6 @@ 
#include <asm/paravirt.h>

#include <asm/alternative.h>



static int __init no_387(char *s)

{

	boot_cpu_data.hard_math = 0;

	write_cr0(X86_CR0_TS | X86_CR0_EM | X86_CR0_MP | read_cr0());

	return 1;

}



__setup("no387", no_387);



static double __initdata x = 4195835.0;

static double __initdata y = 3145727.0;
@@ -44,15 +35,6 @@ static void __init check_fpu(void) 
{

	s32 fdiv_bug;



	if (!boot_cpu_data.hard_math) {

#ifndef CONFIG_MATH_EMULATION

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

		pr_emerg("Giving up\n");

		for (;;) ;

#endif

		return;

	}



	kernel_fpu_begin();



	/*
@@ -107,5 +89,6 @@ void __init check_bugs(void) 
	 * kernel_fpu_begin/end() in check_fpu() relies on the patched

	 * alternative instructions.

	 */

	if (cpu_has_fpu)

		check_fpu();

}

arch/x86/kernel/cpu/common.c

+1 −2
Original line number Diff line number Diff line
@@ -711,10 +711,9 @@ static void __init early_identify_cpu(struct cpuinfo_x86 *c) 
		return;



	cpu_detect(c);



	get_cpu_vendor(c);



	get_cpu_cap(c);

	fpu_detect(c);



	if (this_cpu->c_early_init)

		this_cpu->c_early_init(c);

CRA Git | Maintained and supported by SUSTech CRA and CCSE