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

[Eric Miao]

On Wed, Apr 28, 2010 at 1:56 PM, Bryan Wu <bryan.wu at canonical.com> wrote:
> On 04/28/2010 11:00 AM, Eric Miao wrote:
>>>
>>> Hm, wouldn't it then be possible to make the patch actually use the macro
>>> name
>>> instead of the hard coded values?
>>>
>>
>> How about the patch below, making thing a little bit clearer?
>>
>> commit ee5c472440e089eba863689c446adb5f1c0ae05e
>> Author: Eric Miao<eric.miao at canonical.com>
>> Date:   Fri Apr 23 14:16:17 2010 +0800
>>
>>     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>
>>
>> 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..8e308d8 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 +210,14 @@ FUNC(swsusp_arch_suspend)
>>
>>  FUNC_END(swsusp_arch_suspend)
>>
>> +#define KERNEL_RAM_PADDR       (PHYS_OFFSET + TEXT_OFFSET)
>> +
>>  FUNC(swsusp_arch_resume)
>>        /* set page table if needed */
>> +       ldr     r0, =(KERNEL_RAM_PADDR - 0x4000)
>
> How about using the pgtbl marco as you posted in previous email?
>
>  +     pgtbl   r0                      @ page table address
>
> I think Stephan was asking for this. But if 'pgtbl' is not available in this
> ASM file, I am OK with this patch.
>

Yeah, that's a better approach and I was originally thinking of that, but it
needs this macro to be declared somewhere in a assembly header.