[RFC] Save/restore MISC_ENABLE register
in [Kernel]
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From: H. Peter Anvin on 7 Jun 2010 13:40 On 06/07/2010 09:14 AM, Ondrej Zary wrote: > Save/restore MISC_ENABLE register on suspend/resume. > This fixes OOPS (invalid opcode) on resume from STR on Asus P4P800-VM, which > wakes up with MWAIT disabled. > > Is this a correct thing to do? Is it OK on x86_64? This MSR isn't available on all processors, and thus cannot be saved and restored unconditionally like this. On the save path, one can use rdmsr_safe(); on the wakeup path it's not clear to me it is safe to do so, so it would be better to save a presence flag on the save path and conditionalize the write. -hpa -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Ondrej Zary on 7 Jun 2010 15:00 On Monday 07 June 2010 19:27:23 H. Peter Anvin wrote: > On 06/07/2010 09:14 AM, Ondrej Zary wrote: > > Save/restore MISC_ENABLE register on suspend/resume. > > This fixes OOPS (invalid opcode) on resume from STR on Asus P4P800-VM, > > which wakes up with MWAIT disabled. > > > > Is this a correct thing to do? Is it OK on x86_64? > > This MSR isn't available on all processors, and thus cannot be saved and > restored unconditionally like this. On the save path, one can use > rdmsr_safe(); on the wakeup path it's not clear to me it is safe to do > so, so it would be better to save a presence flag on the save path and > conditionalize the write. Something like this? Save/restore MISC_ENABLE register on suspend/resume. This fixes OOPS (invalid opcode) on resume from STR on Asus P4P800-VM, which wakes up with MWAIT disabled. Signed-off-by: Ondrej Zary <linux(a)rainbow-software.org> diff -urp linux-2.6.35-rc1-git2-orig/arch/x86//include/asm/suspend_32.h linux-2.6.35-rc1-git2/arch/x86//include/asm/suspend_32.h --- linux-2.6.35-rc1-git2-orig/arch/x86//include/asm/suspend_32.h 2010-05-30 22:21:02.000000000 +0200 +++ linux-2.6.35-rc1-git2/arch/x86//include/asm/suspend_32.h 2010-06-07 20:41:44.000000000 +0200 @@ -15,6 +15,8 @@ static inline int arch_prepare_suspend(v struct saved_context { u16 es, fs, gs, ss; unsigned long cr0, cr2, cr3, cr4; + u64 misc_enable; + bool misc_enable_saved; struct desc_ptr gdt; struct desc_ptr idt; u16 ldt; diff -urp linux-2.6.35-rc1-git2-orig/arch/x86//include/asm/suspend_64.h linux-2.6.35-rc1-git2/arch/x86//include/asm/suspend_64.h --- linux-2.6.35-rc1-git2-orig/arch/x86//include/asm/suspend_64.h 2010-05-30 22:21:02.000000000 +0200 +++ linux-2.6.35-rc1-git2/arch/x86//include/asm/suspend_64.h 2010-06-07 20:38:42.000000000 +0200 @@ -27,6 +27,8 @@ struct saved_context { u16 ds, es, fs, gs, ss; unsigned long gs_base, gs_kernel_base, fs_base; unsigned long cr0, cr2, cr3, cr4, cr8; + u64 misc_enable; + bool misc_enable_saved; unsigned long efer; u16 gdt_pad; u16 gdt_limit; diff -urp linux-2.6.35-rc1-git2-orig/arch/x86//power/cpu.c linux-2.6.35-rc1-git2/arch/x86//power/cpu.c --- linux-2.6.35-rc1-git2-orig/arch/x86//power/cpu.c 2010-05-30 22:21:02.000000000 +0200 +++ linux-2.6.35-rc1-git2/arch/x86//power/cpu.c 2010-06-07 20:41:13.000000000 +0200 @@ -105,6 +105,8 @@ static void __save_processor_state(struc ctxt->cr4 = read_cr4(); ctxt->cr8 = read_cr8(); #endif + ctxt->misc_enable_saved = !rdmsrl_safe(MSR_IA32_MISC_ENABLE, + &ctxt->misc_enable); } /* Needed by apm.c */ @@ -152,6 +154,8 @@ static void fix_processor_context(void) */ static void __restore_processor_state(struct saved_context *ctxt) { + if (ctxt->misc_enable_saved) + wrmsrl(MSR_IA32_MISC_ENABLE, ctxt->misc_enable); /* * control registers */ -- Ondrej Zary -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: H. Peter Anvin on 7 Jun 2010 15:00 On 06/07/2010 11:51 AM, Ondrej Zary wrote: > > Something like this? > > Save/restore MISC_ENABLE register on suspend/resume. > This fixes OOPS (invalid opcode) on resume from STR on Asus P4P800-VM, which > wakes up with MWAIT disabled. > > Signed-off-by: Ondrej Zary <linux(a)rainbow-software.org> > Yes, that's a lot better. I presume you have tested it. Rafael, do you want to take this or should I? -hpa -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Ondrej Zary on 7 Jun 2010 15:10 On Monday 07 June 2010 20:53:38 H. Peter Anvin wrote: > On 06/07/2010 11:51 AM, Ondrej Zary wrote: > > Something like this? > > > > Save/restore MISC_ENABLE register on suspend/resume. > > This fixes OOPS (invalid opcode) on resume from STR on Asus P4P800-VM, > > which wakes up with MWAIT disabled. > > > > Signed-off-by: Ondrej Zary <linux(a)rainbow-software.org> > > Yes, that's a lot better. > > I presume you have tested it. Rafael, do you want to take this or should > I? Yes, it works on the P4P800-VM. Don't have any x86_64 machine to test. -- Ondrej Zary -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: H. Peter Anvin on 7 Jun 2010 17:10
On 06/07/2010 02:05 PM, Rafael J. Wysocki wrote: > On Monday 07 June 2010, H. Peter Anvin wrote: >> On 06/07/2010 11:51 AM, Ondrej Zary wrote: >>> >>> Something like this? >>> >>> Save/restore MISC_ENABLE register on suspend/resume. >>> This fixes OOPS (invalid opcode) on resume from STR on Asus P4P800-VM, which >>> wakes up with MWAIT disabled. >>> >>> Signed-off-by: Ondrej Zary <linux(a)rainbow-software.org> >>> >> >> Yes, that's a lot better. >> >> I presume you have tested it. Rafael, do you want to take this or should I? > > I can take it. Is it OK to add your ACK? > Yes. Acked-by: H. Peter Anvin <hpa(a)linux.intel.com> -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |