Re: [PATCH 2/2] x86, apic: Disable BSP if boot cpu is AP

2013-09-09 Thread HATAYAMA Daisuke
(2013/09/04 15:12), Borislav Petkov wrote: On Mon, Sep 02, 2013 at 06:42:44PM +0900, HATAYAMA Daisuke wrote: The reason why I don't lookup BSP flag in MSR is that it's impossible. To read MSR of some CPU, we need to use rdmsr instruction on the CPU. However, in case of this issue, the BSP is

Re: [PATCH 2/2] x86, apic: Disable BSP if boot cpu is AP

2013-09-09 Thread HATAYAMA Daisuke
(2013/09/04 15:12), Borislav Petkov wrote: On Mon, Sep 02, 2013 at 06:42:44PM +0900, HATAYAMA Daisuke wrote: The reason why I don't lookup BSP flag in MSR is that it's impossible. To read MSR of some CPU, we need to use rdmsr instruction on the CPU. However, in case of this issue, the BSP is

Re: [PATCH 2/2] x86, apic: Disable BSP if boot cpu is AP

2013-09-04 Thread Borislav Petkov
On Mon, Sep 02, 2013 at 06:42:44PM +0900, HATAYAMA Daisuke wrote: > The reason why I don't lookup BSP flag in MSR is that it's impossible. > To read MSR of some CPU, we need to use rdmsr instruction on the CPU. > However, in case of this issue, the BSP is halting or running in > the kdump 1st

Re: [PATCH 2/2] x86, apic: Disable BSP if boot cpu is AP

2013-09-04 Thread Borislav Petkov
On Mon, Sep 02, 2013 at 06:42:44PM +0900, HATAYAMA Daisuke wrote: The reason why I don't lookup BSP flag in MSR is that it's impossible. To read MSR of some CPU, we need to use rdmsr instruction on the CPU. However, in case of this issue, the BSP is halting or running in the kdump 1st kernel.

Re: [PATCH 2/2] x86, apic: Disable BSP if boot cpu is AP

2013-09-02 Thread HATAYAMA Daisuke
(2013/09/02 16:13), Borislav Petkov wrote: On Mon, Sep 02, 2013 at 11:32:59AM +0900, HATAYAMA Daisuke wrote: As you suggest, boot_cpu seems more understandable also to me. BTW, please notice that it doesn't denote that the CPU we're booting on currently, but that the CPU with BSP flag set.

Re: [PATCH 2/2] x86, apic: Disable BSP if boot cpu is AP

2013-09-02 Thread Borislav Petkov
On Mon, Sep 02, 2013 at 11:32:59AM +0900, HATAYAMA Daisuke wrote: > As you suggest, boot_cpu seems more understandable also to me. BTW, > please notice that it doesn't denote that the CPU we're booting on > currently, but that the CPU with BSP flag set. Hmm, by "BSP flag set" you mean it is the

Re: [PATCH 2/2] x86, apic: Disable BSP if boot cpu is AP

2013-09-02 Thread Borislav Petkov
On Mon, Sep 02, 2013 at 11:32:59AM +0900, HATAYAMA Daisuke wrote: As you suggest, boot_cpu seems more understandable also to me. BTW, please notice that it doesn't denote that the CPU we're booting on currently, but that the CPU with BSP flag set. Hmm, by BSP flag set you mean it is the first

Re: [PATCH 2/2] x86, apic: Disable BSP if boot cpu is AP

2013-09-02 Thread HATAYAMA Daisuke
(2013/09/02 16:13), Borislav Petkov wrote: On Mon, Sep 02, 2013 at 11:32:59AM +0900, HATAYAMA Daisuke wrote: As you suggest, boot_cpu seems more understandable also to me. BTW, please notice that it doesn't denote that the CPU we're booting on currently, but that the CPU with BSP flag set.

Re: [PATCH 2/2] x86, apic: Disable BSP if boot cpu is AP

2013-09-01 Thread HATAYAMA Daisuke
(2013/08/31 14:22), Borislav Petkov wrote: On Thu, Aug 29, 2013 at 06:28:04PM +0900, HATAYAMA Daisuke wrote: diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c index 66cab35..fd969d1 100644 --- a/arch/x86/kernel/apic/apic.c +++ b/arch/x86/kernel/apic/apic.c @@ -2113,13

Re: [PATCH 2/2] x86, apic: Disable BSP if boot cpu is AP

2013-09-01 Thread HATAYAMA Daisuke
(2013/08/31 14:22), Borislav Petkov wrote: On Thu, Aug 29, 2013 at 06:28:04PM +0900, HATAYAMA Daisuke wrote: diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c index 66cab35..fd969d1 100644 --- a/arch/x86/kernel/apic/apic.c +++ b/arch/x86/kernel/apic/apic.c @@ -2113,13

Re: [PATCH 2/2] x86, apic: Disable BSP if boot cpu is AP

2013-08-30 Thread Borislav Petkov
On Thu, Aug 29, 2013 at 06:28:04PM +0900, HATAYAMA Daisuke wrote: > diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c > index 66cab35..fd969d1 100644 > --- a/arch/x86/kernel/apic/apic.c > +++ b/arch/x86/kernel/apic/apic.c > @@ -2113,13 +2113,29 @@ void disconnect_bsp_APIC(int

Re: [PATCH 2/2] x86, apic: Disable BSP if boot cpu is AP

2013-08-30 Thread Borislav Petkov
On Thu, Aug 29, 2013 at 06:28:04PM +0900, HATAYAMA Daisuke wrote: diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c index 66cab35..fd969d1 100644 --- a/arch/x86/kernel/apic/apic.c +++ b/arch/x86/kernel/apic/apic.c @@ -2113,13 +2113,29 @@ void disconnect_bsp_APIC(int

[PATCH 2/2] x86, apic: Disable BSP if boot cpu is AP

2013-08-29 Thread HATAYAMA Daisuke
Currently, on x86 architecture, if crash happens on AP in the kdump 1st kernel, the 2nd kernel fails to wake up multiple CPUs. The typical behaviour we actually see is immediate system reset or hang. This comes from the hardware specification that the processor with BSP flag is jumped at BIOS

[PATCH 2/2] x86, apic: Disable BSP if boot cpu is AP

2013-08-29 Thread HATAYAMA Daisuke
Currently, on x86 architecture, if crash happens on AP in the kdump 1st kernel, the 2nd kernel fails to wake up multiple CPUs. The typical behaviour we actually see is immediate system reset or hang. This comes from the hardware specification that the processor with BSP flag is jumped at BIOS