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

[Bryan Wu]

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.

> +	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
>

Thanks,
-- 
Bryan Wu <bryan.wu at canonical.com>
Kernel Developer    +86.138-1617-6545 Mobile
Ubuntu Kernel Team | Hardware Enablement Team
Canonical Ltd.      www.canonical.com
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