[PATCH] x86: clean up setup_clear/force_cpu_cap handling

From: Yinghai Lu
Date: Tue Dec 23 2008 - 02:34:09 EST



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
@@ -190,11 +190,11 @@ 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
@@ -134,7 +134,8 @@ 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
@@ -221,7 +221,8 @@ static char __cpuinit *table_lookup_mode
return NULL; /* Not found */
}

-__u32 cleared_cpu_caps[NCAPINTS] __cpuinitdata;
+__u32 cpu_caps_cleared[NCAPINTS] __cpuinitdata;
+__u32 cpu_caps_set[NCAPINTS] __cpuinitdata;

/* Current gdt points %fs at the "master" per-cpu area: after this,
* it's on the real one. */
@@ -706,6 +707,16 @@ 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
@@ -718,10 +729,6 @@ 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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