lkml.org 
[lkml]   [2011]   [Apr]   [1]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
SubjectRe: 2.6.38.2 breaks suspend to disk
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:

\
 
 \ /
  Last update: 2011-04-01 21:57    [W:0.098 / U:0.504 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site