Commit 3e0c3737 authored by Yinghai Lu's avatar Yinghai Lu Committed by Ingo Molnar
Browse files

x86: clean up and fix setup_clear/force_cpu_cap handling 



setup_force_cpu_cap() only have one user (Xen guest code),
but it should not reuse cleared_cpu_cpus, otherwise it
will have problems on SMP.

Need to have a separate cpu_cpus_set array too, for forced-on
flags, beyond the forced-off flags.

Also need to setup handling before all cpus caps are combined.

[ Impact: fix the forced-set CPU feature flag logic ]

Cc: H. Peter Anvin <hpa@linux.intel.com>
Cc: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: default avatarYinghai Lu <yinghai.lu@kernel.org>
LKML-Reference: <new-submission>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 3969c52d

arch/x86/include/asm/cpufeature.h

+2 −2
Original line number Diff line number Diff line
@@ -192,11 +192,11 @@ extern const char * const x86_power_flags[32]; 
#define clear_cpu_cap(c, bit)	clear_bit(bit, (unsigned long *)((c)->x86_capability))

#define setup_clear_cpu_cap(bit) do { \

	clear_cpu_cap(&boot_cpu_data, bit);	\

	set_bit(bit, (unsigned long *)cleared_cpu_caps); \

	set_bit(bit, (unsigned long *)cpu_caps_cleared); \

} while (0)

#define setup_force_cpu_cap(bit) do { \

	set_cpu_cap(&boot_cpu_data, bit);	\

	clear_bit(bit, (unsigned long *)cleared_cpu_caps);	\

	set_bit(bit, (unsigned long *)cpu_caps_set);	\

} while (0)



#define cpu_has_fpu		boot_cpu_has(X86_FEATURE_FPU)

arch/x86/include/asm/processor.h

+2 −1
Original line number Diff line number Diff line
@@ -135,7 +135,8 @@ extern struct cpuinfo_x86 boot_cpu_data; 
extern struct cpuinfo_x86	new_cpu_data;



extern struct tss_struct	doublefault_tss;

extern __u32			cleared_cpu_caps[NCAPINTS];

extern __u32			cpu_caps_cleared[NCAPINTS];

extern __u32			cpu_caps_set[NCAPINTS];



#ifdef CONFIG_SMP

DECLARE_PER_CPU_SHARED_ALIGNED(struct cpuinfo_x86, cpu_info);

arch/x86/kernel/cpu/common.c

+12 −5
Original line number Diff line number Diff line
@@ -292,7 +292,8 @@ static const char *__cpuinit table_lookup_model(struct cpuinfo_x86 *c) 
	return NULL;		/* Not found */

}



__u32 cleared_cpu_caps[NCAPINTS] __cpuinitdata;

__u32 cpu_caps_cleared[NCAPINTS] __cpuinitdata;

__u32 cpu_caps_set[NCAPINTS] __cpuinitdata;



void load_percpu_segment(int cpu)

{
@@ -806,6 +807,16 @@ static void __cpuinit identify_cpu(struct cpuinfo_x86 *c) 
#endif



	init_hypervisor(c);



	/*

	 * Clear/Set all flags overriden by options, need do it

	 * before following smp all cpus cap AND.

	 */

	for (i = 0; i < NCAPINTS; i++) {

		c->x86_capability[i] &= ~cpu_caps_cleared[i];

		c->x86_capability[i] |= cpu_caps_set[i];

	}



	/*

	 * On SMP, boot_cpu_data holds the common feature set between

	 * all CPUs; so make sure that we indicate which features are
@@ -818,10 +829,6 @@ static void __cpuinit identify_cpu(struct cpuinfo_x86 *c) 
			boot_cpu_data.x86_capability[i] &= c->x86_capability[i];

	}



	/* Clear all flags overriden by options */

	for (i = 0; i < NCAPINTS; i++)

		c->x86_capability[i] &= ~cleared_cpu_caps[i];



#ifdef CONFIG_X86_MCE

	/* Init Machine Check Exception if available. */

	mcheck_init(c);

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