[PATCH] UBUNTU: SAUCE: dove: avoid page table overwrite when resuming from hibernation

[Eric Miao]

On Thu, May 27, 2010 at 11:35 PM, Tim Gardner <tim.gardner at canonical.com> wrote:
> On 05/27/2010 09:03 AM, Eric Miao wrote:
>>
>>  From 1ae0436f8c2159936ca42d9ef938055b68af64f7 Mon Sep 17 00:00:00 2001
>> From: Eric Miao<eric.miao at canonical.com>
>> Date: Fri, 23 Apr 2010 14:16:17 +0800
>> Subject: [PATCH] UBUNTU: SAUCE: dove: avoid page table overwrite when
>> resuming from hibernation
>>
>> BugLink: http://bugs.launchpad.net/bugs/509006
>>
>> Resuming from hibernation is OK if 'resume=/dev/sdaX' is explicitly
>> specified on the kernel command line, but it fails if scripts in
>> initramfs are used to trigger the resume. It turned out to be page
>> table being overwritten when restoring the memory content because
>> it's using a normal user process's page table in the latter case,
>> which is not safe and could be overwritten. Fix this by using the
>> safe swapper_pg_dir during restoring.
>>
>> Signed-off-by: Eric Miao<eric.miao at canonical.com>
>> ---
>>
>> It was posted weeks ago, thought it was merged but not. This is an updated
>> version addressing the previous comments to make it cleaner.
>>
>>  arch/arm/mach-dove/Makefile |    2 ++
>>  arch/arm/mach-dove/swsusp.S |    8 ++++++++
>>  2 files changed, 10 insertions(+), 0 deletions(-)
>>
>> diff --git a/arch/arm/mach-dove/Makefile b/arch/arm/mach-dove/Makefile
>> index 0be1e1c..c5c028f 100755
>> --- a/arch/arm/mach-dove/Makefile
>> +++ b/arch/arm/mach-dove/Makefile
>> @@ -1,3 +1,5 @@
>> +AFLAGS_swsusp.o                        := -DTEXT_OFFSET=$(TEXT_OFFSET)
>> +
>>  obj-y                         += clock.o common.o addr-map.o irq.o pcie.o
>> mpp.o \
>>                                sdhci_cam_mbus.o
>>  obj-$(CONFIG_MACH_DOVE_RD_AVNG)       += dove-rd-avng-setup.o
>> diff --git a/arch/arm/mach-dove/swsusp.S b/arch/arm/mach-dove/swsusp.S
>> index 4f4a884..9b752a0 100644
>> --- a/arch/arm/mach-dove/swsusp.S
>> +++ b/arch/arm/mach-dove/swsusp.S
>> @@ -28,6 +28,7 @@
>>   */
>>
>>  #include<linux/linkage.h>
>> +#include<asm/memory.h>
>>  #include<asm/segment.h>
>>  #include<asm/page.h>
>>  #include<asm/asm-offsets.h>
>> @@ -209,8 +210,15 @@ FUNC(swsusp_arch_suspend)
>>
>>  FUNC_END(swsusp_arch_suspend)
>>
>> +#define KERNEL_RAM_PADDR       (PHYS_OFFSET + TEXT_OFFSET)
>> +#define SWAPPER_PG_DIR         (KERNEL_RAM_PADDR - 0x4000)
>> +
>>  FUNC(swsusp_arch_resume)
>>        /* set page table if needed */
>> +       ldr     r0, =SWAPPER_PG_DIR
>> +       mcr     p15, 0, r0, c2, c0, 0           @ load page table pointer
>> +       mcr     p15, 0, r0, c8, c7, 0           @ invalidate I,D TLBs
>> +       mcr     p15, 0, r0, c7, c5, 4           @ ISB
>>
>>        /*
>>         * retore "nr_copy_pages" pages which are saved and specified
>
> Test results in the LP report look good. Has this patch been upstreamed? I
> cannot remember from the original discussions a few weeks ago.
>
> Acked-by: Tim Gardner <tim.gardner at canonical.com>
>

Andy,

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