x86-32, fpu: Fix DNA exception during check_fpu() (3e7cf5b0) · Commits · e / devices / android_kernel_xiaomi_markw

Before check_fpu() is called, we have cr0.TS bit set and hence the floating point code to check the FDIV bug was generating a DNA exception. Use kernel_fpu_begin()/kernel_fpu_end() around the floating point code to avoid this unnecessary device not available exception during boot. Signed-off-by:

Suresh Siddha <suresh.b.siddha@intel.com> Link: http://lkml.kernel.org/r/1309479572.2665.1372.camel@sbsiddha-MOBL3.sc.intel.com Signed-off-by:

H. Peter Anvin <hpa@linux.intel.com>

arch/x86/kernel/cpu/bugs.c

+4 −0

Original line number	Original line	Diff line number	Diff line
	@@ -62,6 +62,8 @@ static void __init check_fpu(void)
	return;		return;
	}		}

			kernel_fpu_begin();

	/*		/*
	* trap_init() enabled FXSR and company _before_ testing for FP		* trap_init() enabled FXSR and company _before_ testing for FP
	* problems here.		* problems here.
	@@ -80,6 +82,8 @@ static void __init check_fpu(void)
	: "=m" (*&fdiv_bug)		: "=m" (*&fdiv_bug)
	: "m" (&x), "m" (&y));		: "m" (&x), "m" (&y));

			kernel_fpu_end();

	boot_cpu_data.fdiv_bug = fdiv_bug;		boot_cpu_data.fdiv_bug = fdiv_bug;
	if (boot_cpu_data.fdiv_bug)		if (boot_cpu_data.fdiv_bug)
	printk(KERN_WARNING "Hmm, FPU with FDIV bug.\n");		printk(KERN_WARNING "Hmm, FPU with FDIV bug.\n");