Messages in this thread Patch in this message | | | Date | Fri, 01 Apr 2011 12:54:26 -0700 | From | Yinghai Lu <> | Subject | Re: 2.6.38.2 breaks suspend to disk |
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On 04/01/2011 12:36 PM, H. Peter Anvin wrote: > On 04/01/2011 12:32 PM, Yinghai Lu wrote: >> >> So for 32 bit, PAE support is not compiled in for old 486 cpus. >> mmu_cr4_feautres will be used to make sure head_32.S will not access cr4. >> >> that could be the reason why 32 bit does not do read back at beginning. >> > > Yes, but that doesn't explain why we shouldn't set new bits like NX and > PSE in this register.
ok, please check if you are happy with this one.
From: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
[PATCH -v3] 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
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/kernel/setup.c | 12 ++++++++++++ 1 file changed, 12 insertions(+)
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 @@ -219,6 +219,17 @@ unsigned long mmu_cr4_features; unsigned long mmu_cr4_features = X86_CR4_PAE; #endif +#if defined(CONFIG_X86_PAE) || defined(CONFIG_X86_64) +static void __init read_back_mmu_cr4(void) +{ + mmu_cr4_features = read_cr4(); +} +#else +static void __init read_back_mmu_cr4(void) +{ +} +#endif + /* Boot loader ID and version as integers, for the benefit of proc_dointvec */ int bootloader_type, bootloader_version; @@ -892,6 +903,7 @@ void __init setup_arch(char **cmdline_p) high_memory = (void *)__va(max_pfn * PAGE_SIZE - 1) + 1; #endif + read_back_mmu_cr4(); /* * Find and reserve possible boot-time SMP configuration:
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