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SubjectRe: [PATCH v2] kexec: Fix kdump failure with notsc
Date
On Tue, 2016-07-12 at 16:21 +0800, Baoquan He wrote:
> On 07/12/16 at 02:52pm, Xunlei Pang wrote:
> > On 2016/07/07 at 18:17, Wei Jiangang wrote:
> > > Signed-off-by: Wei Jiangang <weijg.fnst@cn.fujitsu.com>
> > > ---
> > > +/* Local APIC is disabled by the kernel for crash or reboot path */
> > > +static int disabled_local_apic;
> > > +
> > > /*
> > > * Knob to control our willingness to enable the local APIC.
> > > *
> > > @@ -1097,10 +1100,16 @@ void lapic_shutdown(void)
> > > #endif
> > > disable_local_APIC();
> > >
> > > + disabled_local_apic = 1;
> > >
> > > local_irq_restore(flags);
> > > }
> > >
> > > +int lapic_disabled(void)
> > > +{
> > > + return disabled_local_apic;
> > > +}
> > > +
> > > /**
> > > * sync_Arb_IDs - synchronize APIC bus arbitration IDs
> > > */
> > > diff --git a/arch/x86/kernel/machine_kexec_32.c b/arch/x86/kernel/machine_kexec_32.c
> > > index 469b23d6acc2..c934a7868e6b 100644
> > > --- a/arch/x86/kernel/machine_kexec_32.c
> > > +++ b/arch/x86/kernel/machine_kexec_32.c
> > > @@ -202,14 +202,13 @@ void machine_kexec(struct kimage *image)
> > > local_irq_disable();
> > > hw_breakpoint_disable();
> > >
> > > - if (image->preserve_context) {
> > > + if (image->preserve_context || lapic_disabled()) {
> > > #ifdef CONFIG_X86_IO_APIC
> > > /*
> > > * We need to put APICs in legacy mode so that we can
> > > * get timer interrupts in second kernel. kexec/kdump
> > > * paths already have calls to disable_IO_APIC() in
> > > - * one form or other. kexec jump path also need
> > > - * one.
> > > + * one form or other. kexec jump path also need one.
> > > */
> > > disable_IO_APIC();
> >
> > Hi Wei,
> >
> > As the comment says, kexec/kdump paths already have disable_IO_APIC(), why again here?
>
> I also have this question. I guess Jiangang didn't post his modification
> correctly. He should remove calling of disable_IO_APIC in
> native_machine_crash_shutdown(). Assume his test was done on correct
> code change.
Hi he,
Thanks for your suggestion firstly.

In fact, Eric had suggested me to do that last week
(https://lkml.org/lkml/2016/7/8/14).
And i had a try to remove the calling of disable_IO_APIC in
native_machine_crash_shutdown().
But it doesn't work for kdump with notsc.

Thanks,
wei
>
> >
> > Regards,
> > Xunlei
> >
> > > #endif
> > > diff --git a/arch/x86/kernel/machine_kexec_64.c b/arch/x86/kernel/machine_kexec_64.c
> > > index 5a294e48b185..d3598cdd6437 100644
> > > --- a/arch/x86/kernel/machine_kexec_64.c
> > > +++ b/arch/x86/kernel/machine_kexec_64.c
> > > @@ -23,6 +23,7 @@
> > > #include <asm/pgtable.h>
> > > #include <asm/tlbflush.h>
> > > #include <asm/mmu_context.h>
> > > +#include <asm/apic.h>
> > > #include <asm/io_apic.h>
> > > #include <asm/debugreg.h>
> > > #include <asm/kexec-bzimage64.h>
> > > @@ -269,14 +270,13 @@ void machine_kexec(struct kimage *image)
> > > local_irq_disable();
> > > hw_breakpoint_disable();
> > >
> > > - if (image->preserve_context) {
> > > + if (image->preserve_context || lapic_disabled()) {
> > > #ifdef CONFIG_X86_IO_APIC
> > > /*
> > > * We need to put APICs in legacy mode so that we can
> > > * get timer interrupts in second kernel. kexec/kdump
> > > * paths already have calls to disable_IO_APIC() in
> > > - * one form or other. kexec jump path also need
> > > - * one.
> > > + * one form or other. kexec jump path also need one.
> > > */
> > > disable_IO_APIC();
> > > #endif
> >
> >
> > _______________________________________________
> > kexec mailing list
> > kexec@lists.infradead.org
> > http://lists.infradead.org/mailman/listinfo/kexec
>
>



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