| Message ID | i2wf17812d71004230014wfd919c34i5d73c0b909c63b9@mail.gmail.com |
|---|---|
| State | Superseded |
| Delegated to: | Stefan Bader |
| Headers | show |
Eric Miao wrote: > BTW, this may apply to other ARM variants as well, but the hibernation > feature should really be made common first of all in that sense. > > commit 1f3ebd28c0e8adf7f7a1fc85377a57d8dbc56267 > Author: Eric Miao <eric.miao@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@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) > + 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 > The patch probably is correct, but from the reviewing point of view I do not know how I make the connection between swapper_pg_dir in the comment and the patch itself. Is that only me? Stefan
On 04/23/2010 07:18 AM, Stefan Bader wrote: > Eric Miao wrote: >> BTW, this may apply to other ARM variants as well, but the hibernation >> feature should really be made common first of all in that sense. >> >> commit 1f3ebd28c0e8adf7f7a1fc85377a57d8dbc56267 >> Author: Eric Miao <eric.miao@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@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) >> + 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 >> > The patch probably is correct, but from the reviewing point of view I do not > know how I make the connection between swapper_pg_dir in the comment and the > patch itself. Is that only me? > No, I also would like to see a little more information.
On Sat, Apr 24, 2010 at 12:40 AM, John Johansen <john.johansen@canonical.com> wrote: > On 04/23/2010 07:18 AM, Stefan Bader wrote: >> Eric Miao wrote: >>> BTW, this may apply to other ARM variants as well, but the hibernation >>> feature should really be made common first of all in that sense. >>> >>> commit 1f3ebd28c0e8adf7f7a1fc85377a57d8dbc56267 >>> Author: Eric Miao <eric.miao@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@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) >>> + 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 >>> >> The patch probably is correct, but from the reviewing point of view I do not >> know how I make the connection between swapper_pg_dir in the comment and the >> patch itself. Is that only me? >> > No, I also would like to see a little more information. > Ah, sorry for the confusion. swapper_pg_dir is the initial page table for ARM kernel, which is physically located at KERNEL_RAM_PADDR - 0x4000. I should have made it clear by a macro or something. The following code is excerpted from arch/arm/kernel/head.S: /* * swapper_pg_dir is the virtual address of the initial page table. * We place the page tables 16K below KERNEL_RAM_VADDR. Therefore, we must * make sure that KERNEL_RAM_VADDR is correctly set. Currently, we expect * the least significant 16 bits to be 0x8000, but we could probably * relax this restriction to KERNEL_RAM_VADDR >= PAGE_OFFSET + 0x4000. */ #if (KERNEL_RAM_VADDR & 0xffff) != 0x8000 #error KERNEL_RAM_VADDR must start at 0xXXXX8000 #endif .globl swapper_pg_dir .equ swapper_pg_dir, KERNEL_RAM_VADDR - 0x4000 .macro pgtbl, rd ldr \rd, =(KERNEL_RAM_PADDR - 0x4000) .endm
Eric Miao wrote: > On Sat, Apr 24, 2010 at 12:40 AM, John Johansen > <john.johansen@canonical.com> wrote: >> On 04/23/2010 07:18 AM, Stefan Bader wrote: >>> Eric Miao wrote: >>>> BTW, this may apply to other ARM variants as well, but the hibernation >>>> feature should really be made common first of all in that sense. >>>> >>>> commit 1f3ebd28c0e8adf7f7a1fc85377a57d8dbc56267 >>>> Author: Eric Miao <eric.miao@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@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) >>>> + 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 >>>> >>> The patch probably is correct, but from the reviewing point of view I do not >>> know how I make the connection between swapper_pg_dir in the comment and the >>> patch itself. Is that only me? >>> >> No, I also would like to see a little more information. >> > > Ah, sorry for the confusion. swapper_pg_dir is the initial page table for > ARM kernel, which is physically located at KERNEL_RAM_PADDR - 0x4000. > I should have made it clear by a macro or something. The following code is > excerpted from arch/arm/kernel/head.S: > > /* > * swapper_pg_dir is the virtual address of the initial page table. > * We place the page tables 16K below KERNEL_RAM_VADDR. Therefore, we must > * make sure that KERNEL_RAM_VADDR is correctly set. Currently, we expect > * the least significant 16 bits to be 0x8000, but we could probably > * relax this restriction to KERNEL_RAM_VADDR >= PAGE_OFFSET + 0x4000. > */ > #if (KERNEL_RAM_VADDR & 0xffff) != 0x8000 > #error KERNEL_RAM_VADDR must start at 0xXXXX8000 > #endif > > .globl swapper_pg_dir > .equ swapper_pg_dir, KERNEL_RAM_VADDR - 0x4000 > > .macro pgtbl, rd > ldr \rd, =(KERNEL_RAM_PADDR - 0x4000) > .endm Hm, wouldn't it then be possible to make the patch actually use the macro name instead of the hard coded values? Stefan
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) + 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
BTW, this may apply to other ARM variants as well, but the hibernation feature should really be made common first of all in that sense. commit 1f3ebd28c0e8adf7f7a1fc85377a57d8dbc56267 Author: Eric Miao <eric.miao@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@canonical.com>