[PATCH] x86: clean up setup_clear/force_cpu_cap handling

[PATCH] x86: clean up setup_clear/force_cpu_cap handling

[Yinghai Lu]

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@kernel.org>

---
 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);

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

[Ingo Molnar]

* Yinghai Lu <yinghai@kernel.org> wrote:

> 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@kernel.org>
> 
> ---
>  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(-)

Rusty, you'll carry this patch in your linux-2.6-boot-params.git tree, 
right? Merging this in the x86 tree would just needlessly complicate your 
logistics, right?

	Ingo

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

[Yinghai Lu]

Ingo Molnar wrote:
> * Yinghai Lu <yinghai@kernel.org> wrote:
> 
>> 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@kernel.org>
>>
>> ---
>>  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(-)
> 
> Rusty, you'll carry this patch in your linux-2.6-boot-params.git tree, 
> right? Merging this in the x86 tree would just needlessly complicate your 
> logistics, right?

Rusty polished this patch a little bit and put the updated one in his tree.
so you may need to pick up the updated one.

YH

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

[Rusty Russell]

On Saturday 27 December 2008 20:52:34 Ingo Molnar wrote:
> 
> * Yinghai Lu <yinghai@kernel.org> wrote:
> 
> > 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@kernel.org>
> > 
> > ---
> >  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(-)
> 
> Rusty, you'll carry this patch in your linux-2.6-boot-params.git tree, 
> right? Merging this in the x86 tree would just needlessly complicate your 
> logistics, right?

Yep, if you're happy to ack, I'm happy to carry.

Cheers,
Rusty.

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

[Ingo Molnar]

* Rusty Russell <rusty@rustcorp.com.au> wrote:

> On Saturday 27 December 2008 20:52:34 Ingo Molnar wrote:
> > 
> > * Yinghai Lu <yinghai@kernel.org> wrote:
> > 
> > > 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@kernel.org>
> > > 
> > > ---
> > >  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(-)
> > 
> > Rusty, you'll carry this patch in your linux-2.6-boot-params.git tree, 
> > right? Merging this in the x86 tree would just needlessly complicate your 
> > logistics, right?
> 
> Yep, if you're happy to ack, I'm happy to carry.

yeah. And if it breaks, that's your fault ;-)

Acked-by: Ingo Molnar <mingo@elte.hu>

	Ingo