Re: [PATCH] x86: clean up setup_clear/force_cpu_cap handling - resend

From: Yinghai Lu
Date: Sat Apr 18 2009 - 23:49:49 EST


ping.

Ingo, can you pick it up?

YH

Yinghai Lu wrote:
> it looks get lost somehow,... resend again.
>
> Impact: fix and cleanup
>
> setup_force_cpu_cap() only have one user xen
> but it should not reuse cleared_cpu_cpus. it will have problem
> for smp.
>
> need to have cpu_cpus_set array too.
> also need to setup handling before all cpus cap AND
>
> Signed-off-by: Yinghai Lu <yinghai.lu@xxxxxxxxxx>
>
> ---
> arch/x86/include/asm/cpufeature.h | 4 ++--
> arch/x86/include/asm/processor.h | 3 ++-
> arch/x86/kernel/cpu/common.c | 17 ++++++++++++-----
> 3 files changed, 16 insertions(+), 8 deletions(-)
>
> Index: linux-2.6/arch/x86/include/asm/cpufeature.h
> ===================================================================
> --- linux-2.6.orig/arch/x86/include/asm/cpufeature.h
> +++ linux-2.6/arch/x86/include/asm/cpufeature.h
> @@ -192,11 +192,11 @@ extern const char * const x86_power_flag
> #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)
> Index: linux-2.6/arch/x86/include/asm/processor.h
> ===================================================================
> --- linux-2.6.orig/arch/x86/include/asm/processor.h
> +++ linux-2.6/arch/x86/include/asm/processor.h
> @@ -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(struct cpuinfo_x86, cpu_info);
> Index: linux-2.6/arch/x86/kernel/cpu/common.c
> ===================================================================
> --- linux-2.6.orig/arch/x86/kernel/cpu/common.c
> +++ linux-2.6/arch/x86/kernel/cpu/common.c
> @@ -293,7 +293,8 @@ static const char *__cpuinit table_looku
> 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)
> {
> @@ -807,6 +808,16 @@ static void __cpuinit identify_cpu(struc
> #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
> @@ -819,10 +830,6 @@ static void __cpuinit identify_cpu(struc
> 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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