Messages in this thread Patch in this message | | | Date | Fri, 01 Apr 2011 16:04:40 -0700 | From | Yinghai Lu <> | Subject | Re: 2.6.38.2 breaks suspend to disk |
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On 04/01/2011 02:42 PM, H. Peter Anvin wrote: > > And why on Earth is it worth saving a couple of instructions (and > introducing code ugliness and a more complex testing matrix) in the case > when it is not?
Please check this one, it moves storing mmu_cr4 to arch_prepare_suspend.
Thanks
Yinghai
From: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
[PATCH -v5] x86: Save cr4 to mmu_cr4_features at boot time
Save cr4 to mmu_cr4_features at boot time
Michael reported 2.6.38.2 hibernation is broken by one backported patch. it cause a freeze when resuming from hibernation
| "x86: Cleanup highmap after brk is concluded" | commit id e5f15b45ddf3afa2bbbb10c7ea34fb32b6de0a0e.
it turns out the mmu_cr4 save it lost somehow.
-v3: read back cr4 for 32bit too according to HPA -v4: use cpuid_level to check if we can read cr4 according to HPA don't touch mmu_cr4_features if CONFIG_HIBERNATION is defined from Yinghai -v5: reduce the using of CONFIG_HIBERNATION
Bisected-and-tested-by: Michael Leun <lkml20101129@newton.leun.net> Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Signed-off-by: Yinghai Lu <yinghai@kernel.org>
--- arch/x86/include/asm/processor.h | 2 -- arch/x86/include/asm/suspend_32.h | 2 +- arch/x86/include/asm/suspend_64.h | 5 +---- arch/x86/kernel/setup.c | 16 +++++++++++++++- 4 files changed, 17 insertions(+), 8 deletions(-)
Index: linux-2.6/arch/x86/kernel/setup.c =================================================================== --- linux-2.6.orig/arch/x86/kernel/setup.c +++ linux-2.6/arch/x86/kernel/setup.c @@ -212,12 +212,26 @@ struct cpuinfo_x86 boot_cpu_data __read_ EXPORT_SYMBOL(boot_cpu_data); #endif - +/* + * mmu_cr4_features has two purposes: + * a. head_32.S will access cr4 according if X86_CR4_PAE is set in it. + * b. store read back cr4 for hibernation + */ #if !defined(CONFIG_X86_PAE) || defined(CONFIG_X86_64) unsigned long mmu_cr4_features; #else unsigned long mmu_cr4_features = X86_CR4_PAE; #endif +#ifdef CONFIG_HIBERNATION +int arch_prepare_suspend(void) +{ + /* a CPU has CR4 iff it has CPUID --- hpa */ + if (boot_cpu_data.cpuid_level >= 0) + mmu_cr4_features = read_cr4(); + + return 0; +} +#endif /* Boot loader ID and version as integers, for the benefit of proc_dointvec */ int bootloader_type, bootloader_version; 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 @@ -601,7 +601,6 @@ static inline void set_in_cr4(unsigned l { unsigned long cr4; - mmu_cr4_features |= mask; cr4 = read_cr4(); cr4 |= mask; write_cr4(cr4); @@ -611,7 +610,6 @@ static inline void clear_in_cr4(unsigned { unsigned long cr4; - mmu_cr4_features &= ~mask; cr4 = read_cr4(); cr4 &= ~mask; write_cr4(cr4); Index: linux-2.6/arch/x86/include/asm/suspend_32.h =================================================================== --- linux-2.6.orig/arch/x86/include/asm/suspend_32.h +++ linux-2.6/arch/x86/include/asm/suspend_32.h @@ -9,7 +9,7 @@ #include <asm/desc.h> #include <asm/i387.h> -static inline int arch_prepare_suspend(void) { return 0; } +int arch_prepare_suspend(void); /* image of the saved processor state */ struct saved_context { Index: linux-2.6/arch/x86/include/asm/suspend_64.h =================================================================== --- linux-2.6.orig/arch/x86/include/asm/suspend_64.h +++ linux-2.6/arch/x86/include/asm/suspend_64.h @@ -9,10 +9,7 @@ #include <asm/desc.h> #include <asm/i387.h> -static inline int arch_prepare_suspend(void) -{ - return 0; -} +int arch_prepare_suspend(void); /* * Image of the saved processor state, used by the low level ACPI suspend to
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