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Commit 93a829e8 authored by Borislav Petkov's avatar Borislav Petkov Committed by H. Peter Anvin
Browse files

x86, cpu: Convert FDIV bug detection 



... to the new facility. Add a reference to the wikipedia article
explaining the FDIV test we're doing here.

Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
Link: http://lkml.kernel.org/r/1363788448-31325-4-git-send-email-bp@alien8.de


Signed-off-by: default avatarH. Peter Anvin <hpa@zytor.com>
parent e2604b49

arch/x86/include/asm/cpufeature.h

+1 −0
Original line number Diff line number Diff line
@@ -223,6 +223,7 @@ 
#define X86_BUG(x)		(NCAPINTS*32 + (x))



#define X86_BUG_F00F		X86_BUG(0) /* Intel F00F */

#define X86_BUG_FDIV		X86_BUG(1) /* FPU FDIV */



#if defined(__KERNEL__) && !defined(__ASSEMBLY__)

arch/x86/include/asm/processor.h

+0 −1
Original line number Diff line number Diff line
@@ -91,7 +91,6 @@ struct cpuinfo_x86 { 
	/* Problems on some 486Dx4's and old 386's: */

	char			hard_math;

	char			rfu;

	char			fdiv_bug;

	char			coma_bug;

	char			pad0;

#else

arch/x86/kernel/cpu/bugs.c

+4 −3
Original line number Diff line number Diff line
@@ -59,7 +59,7 @@ static void __init check_fpu(void) 
	 * trap_init() enabled FXSR and company _before_ testing for FP

	 * problems here.

	 *

	 * Test for the divl bug..

	 * Test for the divl bug: http://en.wikipedia.org/wiki/Fdiv_bug

	 */

	__asm__("fninit\n\t"

		"fldl %1\n\t"
@@ -75,10 +75,11 @@ static void __init check_fpu(void) 


	kernel_fpu_end();



	boot_cpu_data.fdiv_bug = fdiv_bug;

	if (boot_cpu_data.fdiv_bug)

	if (fdiv_bug) {

		set_cpu_bug(&boot_cpu_data, X86_BUG_FDIV);

		pr_warn("Hmm, FPU with FDIV bug\n");

	}

}



/*

 * Check whether we are able to run this kernel safely on SMP.

arch/x86/kernel/cpu/proc.c

+1 −1
Original line number Diff line number Diff line
@@ -34,7 +34,7 @@ static void show_cpuinfo_misc(struct seq_file *m, struct cpuinfo_x86 *c) 
		   "fpu_exception\t: %s\n"

		   "cpuid level\t: %d\n"

		   "wp\t\t: %s\n",

		   c->fdiv_bug ? "yes" : "no",

		   static_cpu_has_bug(X86_BUG_FDIV) ? "yes" : "no",

		   static_cpu_has_bug(X86_BUG_F00F) ? "yes" : "no",

		   c->coma_bug ? "yes" : "no",

		   c->hard_math ? "yes" : "no",

arch/x86/kernel/setup.c

+0 −2
Original line number Diff line number Diff line
@@ -173,12 +173,10 @@ static struct resource bss_resource = { 
/* cpu data as detected by the assembly code in head.S */

struct cpuinfo_x86 new_cpu_data __cpuinitdata = {

	.wp_works_ok = -1,

	.fdiv_bug = -1,

};

/* common cpu data for all cpus */

struct cpuinfo_x86 boot_cpu_data __read_mostly = {

	.wp_works_ok = -1,

	.fdiv_bug = -1,

};

EXPORT_SYMBOL(boot_cpu_data);