Hi, all
Current -tip tree(92c883a) fail to resume after suspend to mem.
Bisect to commit 5bd5a45(x86: Add NX protection for kernel data).
commit 5bd5a452662bc37c54fb6828db1a3faf87e6511c
Author: Matthieu Castet <[email protected]>
Date: Tue Nov 16 22:31:26 2010 +0100
x86: Add NX protection for kernel data
I did some debug and found the regression is caused by below line.
- set_memory_nx(rodata_start, (end - rodata_start) >> PAGE_SHIFT);
+ set_memory_nx(rodata_start, (kernel_end - rodata_start) >> PAGE_SHIFT);
In my machine,
rodata_start=0xffffffff81a00000, end=0xffffffff81e00000, kernel_end=0xffffffff82200000
Without this commit, kernel page table dumps
---[ High Kernel Mapping ]---
....
0xffffffff81a00000-0xffffffff81c00000 2M ro PSE GLB NX pmd
0xffffffff81c00000-0xffffffff81d91000 1604K ro GLB NX pte
0xffffffff81d91000-0xffffffff81e00000 444K ro GLB NX pte
0xffffffff81e00000-0xffffffff82000000 2M RW PSE GLB x pmd
0xffffffff82000000-0xffffffff8200c000 48K RW GLB x pte
0xffffffff8200c000-0xffffffff82100000 976K RW GLB x pte
0xffffffff82100000-0xffffffff82200000 1M RW GLB x pte
.....
With this commit, kernel page table dumps
---[ High Kernel Mapping ]---
....
0xffffffff81a00000-0xffffffff81c00000 2M ro PSE GLB NX pmd
0xffffffff81c00000-0xffffffff81d91000 1604K ro GLB NX pte
0xffffffff81d91000-0xffffffff81e00000 444K ro GLB NX pte
0xffffffff81e00000-0xffffffff82000000 2M RW PSE GLB NX pmd
0xffffffff82000000-0xffffffff8200c000 48K RW GLB NX pte
0xffffffff8200c000-0xffffffff82100000 976K RW GLB NX pte
0xffffffff82100000-0xffffffff82200000 1M RW GLB NX pte
.....
The only difference is 0xffffffff81e00000(end) to 0xffffffff82200000(kernel_end) is set to NX.
I guess this range code is used by resume wakeup code. So setting it to NX causes problem.
Any idea?
Thanks,
Lin Ming
* Lin Ming <[email protected]> wrote:
> Hi, all
>
> Current -tip tree(92c883a) fail to resume after suspend to mem.
> Bisect to commit 5bd5a45(x86: Add NX protection for kernel data).
>
> commit 5bd5a452662bc37c54fb6828db1a3faf87e6511c
> Author: Matthieu Castet <[email protected]>
> Date: Tue Nov 16 22:31:26 2010 +0100
>
> x86: Add NX protection for kernel data
>
>
> I did some debug and found the regression is caused by below line.
>
> - set_memory_nx(rodata_start, (end - rodata_start) >> PAGE_SHIFT);
> + set_memory_nx(rodata_start, (kernel_end - rodata_start) >> PAGE_SHIFT);
>
> In my machine,
> rodata_start=0xffffffff81a00000, end=0xffffffff81e00000, kernel_end=0xffffffff82200000
>
> Without this commit, kernel page table dumps
>
> ---[ High Kernel Mapping ]---
> ....
> 0xffffffff81a00000-0xffffffff81c00000 2M ro PSE GLB NX pmd
> 0xffffffff81c00000-0xffffffff81d91000 1604K ro GLB NX pte
> 0xffffffff81d91000-0xffffffff81e00000 444K ro GLB NX pte
> 0xffffffff81e00000-0xffffffff82000000 2M RW PSE GLB x pmd
> 0xffffffff82000000-0xffffffff8200c000 48K RW GLB x pte
> 0xffffffff8200c000-0xffffffff82100000 976K RW GLB x pte
> 0xffffffff82100000-0xffffffff82200000 1M RW GLB x pte
> .....
>
> With this commit, kernel page table dumps
>
> ---[ High Kernel Mapping ]---
> ....
> 0xffffffff81a00000-0xffffffff81c00000 2M ro PSE GLB NX pmd
> 0xffffffff81c00000-0xffffffff81d91000 1604K ro GLB NX pte
> 0xffffffff81d91000-0xffffffff81e00000 444K ro GLB NX pte
> 0xffffffff81e00000-0xffffffff82000000 2M RW PSE GLB NX pmd
> 0xffffffff82000000-0xffffffff8200c000 48K RW GLB NX pte
> 0xffffffff8200c000-0xffffffff82100000 976K RW GLB NX pte
> 0xffffffff82100000-0xffffffff82200000 1M RW GLB NX pte
> .....
>
> The only difference is 0xffffffff81e00000(end) to 0xffffffff82200000(kernel_end) is set to NX.
>
> I guess this range code is used by resume wakeup code. So setting it to NX causes problem.
>
> Any idea?
Yeah, the resume area is a trampoline, it needs to be executable.
Thanks,
Ingo
On Mon, Nov 22, 2010 at 09:07:10AM +0100, Ingo Molnar wrote:
> > ---[ High Kernel Mapping ]---
> > ....
> > 0xffffffff81a00000-0xffffffff81c00000 2M ro PSE GLB NX pmd
> > 0xffffffff81c00000-0xffffffff81d91000 1604K ro GLB NX pte
> > 0xffffffff81d91000-0xffffffff81e00000 444K ro GLB NX pte
> > 0xffffffff81e00000-0xffffffff82000000 2M RW PSE GLB NX pmd
> > 0xffffffff82000000-0xffffffff8200c000 48K RW GLB NX pte
> > 0xffffffff8200c000-0xffffffff82100000 976K RW GLB NX pte
> > 0xffffffff82100000-0xffffffff82200000 1M RW GLB NX pte
> > .....
> >
> > The only difference is 0xffffffff81e00000(end) to 0xffffffff82200000(kernel_end) is set to NX.
> >
> > I guess this range code is used by resume wakeup code. So setting it to NX causes problem.
> >
> > Any idea?
>
> Yeah, the resume area is a trampoline, it needs to be executable.
Also it looks like most of the kernel linker supplied data is now not
2MB mapped anymore? That will surely cost TLB entries.
-Andi
--
[email protected] -- Speaking for myself only.
Hi Andi,
Quoting Andi Kleen <[email protected]>:
> On Mon, Nov 22, 2010 at 09:07:10AM +0100, Ingo Molnar wrote:
> > > ---[ High Kernel Mapping ]---
> > > ....
> > > 0xffffffff81a00000-0xffffffff81c00000 2M ro PSE GLB
> NX pmd
> > > 0xffffffff81c00000-0xffffffff81d91000 1604K ro GLB
> NX pte
> > > 0xffffffff81d91000-0xffffffff81e00000 444K ro GLB
> NX pte
> > > 0xffffffff81e00000-0xffffffff82000000 2M RW PSE GLB
> NX pmd
> > > 0xffffffff82000000-0xffffffff8200c000 48K RW GLB
> NX pte
> > > 0xffffffff8200c000-0xffffffff82100000 976K RW GLB
> NX pte
> > > 0xffffffff82100000-0xffffffff82200000 1M RW GLB
> NX pte
> > > .....
> > >
> > > The only difference is 0xffffffff81e00000(end) to
> 0xffffffff82200000(kernel_end) is set to NX.
> > >
> > > I guess this range code is used by resume wakeup code. So setting it to
> NX causes problem.
> > >
> > > Any idea?
> >
> > Yeah, the resume area is a trampoline, it needs to be executable.
>
> Also it looks like most of the kernel linker supplied data is now not
> 2MB mapped anymore? That will surely cost TLB entries.
>
Any idea where it comes from ?
The mapping is still not 2MB mapped without the commit.
The patch only add
+#if defined(CONFIG_DEBUG_RODATA)
+ /* .text should occupy whole number of pages */
+ . = ALIGN(PAGE_SIZE);
+#endif
X64_ALIGN_DEBUG_RODATA_BEGIN
RO_DATA(PAGE_SIZE)
X64_ALIGN_DEBUG_RODATA_END
But X64_ALIGN_DEBUG_RODATA_BEGIN is aligned on 2M, so it shouldn't change
nothing on x64 ?
Matthieu
>
> But X64_ALIGN_DEBUG_RODATA_BEGIN is aligned on 2M, so it shouldn't change
> nothing on x64 ?
Yes sorry for the confusion. That's unrelated to your patch and already
happened earlier. I just noticed it while looking at the page table dumps
in the report.
-Andi
--
[email protected] -- Speaking for myself only.
On Mon, 2010-11-22 at 15:23 +0800, Lin Ming wrote:
> Hi, all
>
> Current -tip tree(92c883a) fail to resume after suspend to mem.
> Bisect to commit 5bd5a45(x86: Add NX protection for kernel data).
Drad, if only I'd looked at LKML before I did the bisection myself..
> commit 5bd5a452662bc37c54fb6828db1a3faf87e6511c
> Author: Matthieu Castet <[email protected]>
> Date: Tue Nov 16 22:31:26 2010 +0100
>
> x86: Add NX protection for kernel data
>
>
> I did some debug and found the regression is caused by below line.
>
> - set_memory_nx(rodata_start, (end - rodata_start) >> PAGE_SHIFT);
> + set_memory_nx(rodata_start, (kernel_end - rodata_start) >> PAGE_SHIFT);
Confirmed, with that hunk reverted my machine works again..
---
arch/x86/mm/init_64.c | 3 +--
1 files changed, 1 insertions(+), 2 deletions(-)
diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index ce59c05..71a5929 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -788,7 +788,6 @@ void mark_rodata_ro(void)
unsigned long rodata_start =
((unsigned long)__start_rodata + PAGE_SIZE - 1) & PAGE_MASK;
unsigned long end = (unsigned long) &__end_rodata_hpage_align;
- unsigned long kernel_end = (((unsigned long)&__init_end + HPAGE_SIZE) & HPAGE_MASK);
unsigned long text_end = PAGE_ALIGN((unsigned long) &__stop___ex_table);
unsigned long rodata_end = PAGE_ALIGN((unsigned long) &__end_rodata);
unsigned long data_start = (unsigned long) &_sdata;
@@ -803,7 +802,7 @@ void mark_rodata_ro(void)
* The rodata section (but not the kernel text!) should also be
* not-executable.
*/
- set_memory_nx(rodata_start, (kernel_end - rodata_start) >> PAGE_SHIFT);
+ set_memory_nx(rodata_start, (end - rodata_start) >> PAGE_SHIFT);
rodata_test();
Commit-ID: 691513f70d3957939a318da970987b876c720861
Gitweb: http://git.kernel.org/tip/691513f70d3957939a318da970987b876c720861
Author: Lin Ming <[email protected]>
AuthorDate: Mon, 22 Nov 2010 14:03:28 +0100
Committer: Thomas Gleixner <[email protected]>
CommitDate: Mon, 22 Nov 2010 14:38:52 +0100
x86: Resume trampoline must be executable
commit 5bd5a452(x86: Add NX protection for kernel data) marked the
trampoline area NX - which unsurprisingly breaks resume and cpu
hotplug.
Revert the portion of that commit, which touches the trampoline.
Originally-from: Lin Ming <[email protected]>
LKML-Reference: <[email protected]>
Cc: Matthieu Castet <[email protected]>
Cc: Siarhei Liakh <[email protected]>
Cc: Xuxian Jiang <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Arjan van de Ven <[email protected]>
Cc: Andi Kleen <[email protected]>
Tested-by: Peter Zijlstra <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
---
arch/x86/mm/init_64.c | 3 +--
1 files changed, 1 insertions(+), 2 deletions(-)
diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index ce59c05..71a5929 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -788,7 +788,6 @@ void mark_rodata_ro(void)
unsigned long rodata_start =
((unsigned long)__start_rodata + PAGE_SIZE - 1) & PAGE_MASK;
unsigned long end = (unsigned long) &__end_rodata_hpage_align;
- unsigned long kernel_end = (((unsigned long)&__init_end + HPAGE_SIZE) & HPAGE_MASK);
unsigned long text_end = PAGE_ALIGN((unsigned long) &__stop___ex_table);
unsigned long rodata_end = PAGE_ALIGN((unsigned long) &__end_rodata);
unsigned long data_start = (unsigned long) &_sdata;
@@ -803,7 +802,7 @@ void mark_rodata_ro(void)
* The rodata section (but not the kernel text!) should also be
* not-executable.
*/
- set_memory_nx(rodata_start, (kernel_end - rodata_start) >> PAGE_SHIFT);
+ set_memory_nx(rodata_start, (end - rodata_start) >> PAGE_SHIFT);
rodata_test();
Hi,
Quoting Peter Zijlstra <[email protected]>:
> On Mon, 2010-11-22 at 15:23 +0800, Lin Ming wrote:
> > Hi, all
> >
> > Current -tip tree(92c883a) fail to resume after suspend to mem.
> > Bisect to commit 5bd5a45(x86: Add NX protection for kernel data).
>
> Drad, if only I'd looked at LKML before I did the bisection myself..
>
> > commit 5bd5a452662bc37c54fb6828db1a3faf87e6511c
> > Author: Matthieu Castet <[email protected]>
> > Date: Tue Nov 16 22:31:26 2010 +0100
> >
> > x86: Add NX protection for kernel data
> >
> >
> > I did some debug and found the regression is caused by below line.
> >
> > - set_memory_nx(rodata_start, (end - rodata_start) >> PAGE_SHIFT);
> > + set_memory_nx(rodata_start, (kernel_end - rodata_start) >>
> PAGE_SHIFT);
>
>
> Confirmed, with that hunk reverted my machine works again..
>
Ok,
I will submit a proper fix :
in acpi_save_state_mem/acpi_restore_state_mem make the trampoline X or NX.
Matthieu
On Mon, 2010-11-22 at 17:29 +0100, [email protected] wrote:
> Hi,
>
> Quoting Peter Zijlstra <[email protected]>:
>
> > On Mon, 2010-11-22 at 15:23 +0800, Lin Ming wrote:
> > > Hi, all
> > >
> > > Current -tip tree(92c883a) fail to resume after suspend to mem.
> > > Bisect to commit 5bd5a45(x86: Add NX protection for kernel data).
> >
> > Drad, if only I'd looked at LKML before I did the bisection myself..
> >
> > > commit 5bd5a452662bc37c54fb6828db1a3faf87e6511c
> > > Author: Matthieu Castet <[email protected]>
> > > Date: Tue Nov 16 22:31:26 2010 +0100
> > >
> > > x86: Add NX protection for kernel data
> > >
> > >
> > > I did some debug and found the regression is caused by below line.
> > >
> > > - set_memory_nx(rodata_start, (end - rodata_start) >> PAGE_SHIFT);
> > > + set_memory_nx(rodata_start, (kernel_end - rodata_start) >>
> > PAGE_SHIFT);
> >
> >
> > Confirmed, with that hunk reverted my machine works again..
> >
> Ok,
> I will submit a proper fix :
> in acpi_save_state_mem/acpi_restore_state_mem make the trampoline X or NX.
That seems to be a S3 specific code path, that won't fix anything.
Simply do:
echo 0 > /sys/devices/system/cpu/cpu1/online;
echo 1 > /sys/devices/system/cpu/cpu1/online;
and your machine will explode..
> That seems to be a S3 specific code path, that won't fix anything.
> Simply do:
>
> echo 0 > /sys/devices/system/cpu/cpu1/online;
> echo 1 > /sys/devices/system/cpu/cpu1/online;
>
> and your machine will explode..
The SMP startup trampoline is copied I believe
and only executed in real mode without page tables.
So it's perhaps not the trampoline, but the early startup
code that ends up being broken.
-Andi
--
[email protected] -- Speaking for myself only.
Le Mon, 22 Nov 2010 17:42:47 +0100,
Andi Kleen <[email protected]> a ?crit :
> > That seems to be a S3 specific code path, that won't fix anything.
> > Simply do:
> >
> > echo 0 > /sys/devices/system/cpu/cpu1/online;
> > echo 1 > /sys/devices/system/cpu/cpu1/online;
> >
> > and your machine will explode..
>
> The SMP startup trampoline is copied I believe
> and only executed in real mode without page tables.
>
> So it's perhaps not the trampoline, but the early startup
> code that ends up being broken.
yes :
acpi wakeup code and smp trampoline are copied in low memory (first
1MB).
So they can't end up int the kernel data mapping ?
So it should something else.
I will try to investigate on this.
Matthieu
Le Tue, 23 Nov 2010 23:55:27 +0100,
mat <[email protected]> a ?crit :
> Le Mon, 22 Nov 2010 17:42:47 +0100,
> Andi Kleen <[email protected]> a ?crit :
>
> > > That seems to be a S3 specific code path, that won't fix anything.
> > > Simply do:
> > >
> > > echo 0 > /sys/devices/system/cpu/cpu1/online;
> > > echo 1 > /sys/devices/system/cpu/cpu1/online;
> > >
> > > and your machine will explode..
> >
> > The SMP startup trampoline is copied I believe
> > and only executed in real mode without page tables.
> >
> > So it's perhaps not the trampoline, but the early startup
> > code that ends up being broken.
> yes :
> acpi wakeup code and smp trampoline are copied in low memory (first
> 1MB).
>
> So they can't end up int the kernel data mapping ?
>
> So it should something else.
>
> I will try to investigate on this.
>
Unfortunately on my laptop supporting NX, suspend to ram seems broken
(even without this patch) and I got only one core, so I am unable to
test it.
Does cpu suspend/resume is broken ? Or it is only S3 ?
If yes, are there any interesting trace if we suspend only one core with
sysfs.
Thanks,
Matthieu
On Sat, Nov 27, 2010 at 1:31 AM, mat <[email protected]> wrote:
> Le Tue, 23 Nov 2010 23:55:27 +0100,
> mat <[email protected]> a ?crit :
>
>> Le Mon, 22 Nov 2010 17:42:47 +0100,
>> Andi Kleen <[email protected]> a ?crit :
>>
>> > > That seems to be a S3 specific code path, that won't fix anything.
>> > > Simply do:
>> > >
>> > > echo 0 > /sys/devices/system/cpu/cpu1/online;
>> > > echo 1 > /sys/devices/system/cpu/cpu1/online;
>> > >
>> > > and your machine will explode..
>> >
>> > The SMP startup trampoline is copied I believe
>> > and only executed in real mode without page tables.
>> >
>> > So it's perhaps not the trampoline, but the early startup
>> > code that ends up being broken.
>> yes :
>> acpi wakeup code and smp trampoline are copied in low memory (first
>> 1MB).
>>
>> So they can't end up int the kernel data mapping ?
>>
>> So it should something else.
>>
>> I will try to investigate on this.
>>
> Unfortunately on my laptop supporting NX, suspend to ram seems broken
> (even without this patch) and I got only one core, so I am unable to
> test it.
>
> Does cpu suspend/resume is broken ? Or it is only S3 ?
>
> If yes, are there any interesting trace if we suspend only one core with
> sysfs.
Hi,
I am on travel now, will test it when I'm back next week.
Thanks,
Lin Ming
>
> Thanks,
>
> Matthieu
On Sat, 2010-11-27 at 01:31 +0800, mat wrote:
> Le Tue, 23 Nov 2010 23:55:27 +0100,
> mat <[email protected]> a écrit :
>
> > Le Mon, 22 Nov 2010 17:42:47 +0100,
> > Andi Kleen <[email protected]> a écrit :
> >
> > > > That seems to be a S3 specific code path, that won't fix anything.
> > > > Simply do:
> > > >
> > > > echo 0 > /sys/devices/system/cpu/cpu1/online;
> > > > echo 1 > /sys/devices/system/cpu/cpu1/online;
> > > >
> > > > and your machine will explode..
> > >
> > > The SMP startup trampoline is copied I believe
> > > and only executed in real mode without page tables.
> > >
> > > So it's perhaps not the trampoline, but the early startup
> > > code that ends up being broken.
> > yes :
> > acpi wakeup code and smp trampoline are copied in low memory (first
> > 1MB).
> >
> > So they can't end up int the kernel data mapping ?
> >
> > So it should something else.
> >
> > I will try to investigate on this.
> >
> Unfortunately on my laptop supporting NX, suspend to ram seems broken
> (even without this patch) and I got only one core, so I am unable to
> test it.
>
> Does cpu suspend/resume is broken ? Or it is only S3 ?
>
> If yes, are there any interesting trace if we suspend only one core with
> sysfs.
echo 0 > /sys/devices/system/cpu/cpu1/online;
echo 1 > /sys/devices/system/cpu/cpu1/online;
then machine just reboots...
>
> Thanks,
>
> Matthieu
On Tue, 2010-11-30 at 13:00 +0800, Lin Ming wrote:
> echo 0 > /sys/devices/system/cpu/cpu1/online;
> echo 1 > /sys/devices/system/cpu/cpu1/online;
>
> then machine just reboots...
>
That should work on current -tip (and my test machine confirms with a
-tip of yesterday) due to:
---
commit 691513f70d3957939a318da970987b876c720861
Author: Lin Ming <[email protected]>
Date: Mon Nov 22 14:03:28 2010 +0100
x86: Resume trampoline must be executable
commit 5bd5a452(x86: Add NX protection for kernel data) marked the
trampoline area NX - which unsurprisingly breaks resume and cpu
hotplug.
Revert the portion of that commit, which touches the trampoline.
Originally-from: Lin Ming <[email protected]>
LKML-Reference: <[email protected]>
Cc: Matthieu Castet <[email protected]>
Cc: Siarhei Liakh <[email protected]>
Cc: Xuxian Jiang <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Arjan van de Ven <[email protected]>
Cc: Andi Kleen <[email protected]>
Tested-by: Peter Zijlstra <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index ce59c05..71a5929 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -788,7 +788,6 @@ void mark_rodata_ro(void)
unsigned long rodata_start =
((unsigned long)__start_rodata + PAGE_SIZE - 1) & PAGE_MASK;
unsigned long end = (unsigned long) &__end_rodata_hpage_align;
- unsigned long kernel_end = (((unsigned long)&__init_end + HPAGE_SIZE) & HPAGE_MASK);
unsigned long text_end = PAGE_ALIGN((unsigned long) &__stop___ex_table);
unsigned long rodata_end = PAGE_ALIGN((unsigned long) &__end_rodata);
unsigned long data_start = (unsigned long) &_sdata;
@@ -803,7 +802,7 @@ void mark_rodata_ro(void)
* The rodata section (but not the kernel text!) should also be
* not-executable.
*/
- set_memory_nx(rodata_start, (kernel_end - rodata_start) >> PAGE_SHIFT);
+ set_memory_nx(rodata_start, (end - rodata_start) >> PAGE_SHIFT);
rodata_test();
On Tue, 2010-11-30 at 19:27 +0800, Peter Zijlstra wrote:
> On Tue, 2010-11-30 at 13:00 +0800, Lin Ming wrote:
> > echo 0 > /sys/devices/system/cpu/cpu1/online;
> > echo 1 > /sys/devices/system/cpu/cpu1/online;
> >
> > then machine just reboots...
> >
>
> That should work on current -tip (and my test machine confirms with a
> -tip of yesterday) due to:
Yes, I know.
I tested for Mat's request to confirm that CPU suspend/resume also
broken, not only S3.
And no interesting trace I can get because machine just reboots
immediately when CPU suspend/resume.
Thanks.
>
> ---
> commit 691513f70d3957939a318da970987b876c720861
> Author: Lin Ming <[email protected]>
> Date: Mon Nov 22 14:03:28 2010 +0100
>
> x86: Resume trampoline must be executable
>
> commit 5bd5a452(x86: Add NX protection for kernel data) marked the
> trampoline area NX - which unsurprisingly breaks resume and cpu
> hotplug.
>
> Revert the portion of that commit, which touches the trampoline.
>
> Originally-from: Lin Ming <[email protected]>
> LKML-Reference: <[email protected]>
> Cc: Matthieu Castet <[email protected]>
> Cc: Siarhei Liakh <[email protected]>
> Cc: Xuxian Jiang <[email protected]>
> Cc: Ingo Molnar <[email protected]>
> Cc: Arjan van de Ven <[email protected]>
> Cc: Andi Kleen <[email protected]>
> Tested-by: Peter Zijlstra <[email protected]>
> Signed-off-by: Thomas Gleixner <[email protected]>
>
> diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
> index ce59c05..71a5929 100644
> --- a/arch/x86/mm/init_64.c
> +++ b/arch/x86/mm/init_64.c
> @@ -788,7 +788,6 @@ void mark_rodata_ro(void)
> unsigned long rodata_start =
> ((unsigned long)__start_rodata + PAGE_SIZE - 1) & PAGE_MASK;
> unsigned long end = (unsigned long) &__end_rodata_hpage_align;
> - unsigned long kernel_end = (((unsigned long)&__init_end + HPAGE_SIZE) & HPAGE_MASK);
> unsigned long text_end = PAGE_ALIGN((unsigned long) &__stop___ex_table);
> unsigned long rodata_end = PAGE_ALIGN((unsigned long) &__end_rodata);
> unsigned long data_start = (unsigned long) &_sdata;
> @@ -803,7 +802,7 @@ void mark_rodata_ro(void)
> * The rodata section (but not the kernel text!) should also be
> * not-executable.
> */
> - set_memory_nx(rodata_start, (kernel_end - rodata_start) >> PAGE_SHIFT);
> + set_memory_nx(rodata_start, (end - rodata_start) >> PAGE_SHIFT);
>
> rodata_test();
>
>
Hi,
Le Tue, 30 Nov 2010 13:00:30 +0800,
Lin Ming <[email protected]> a ?crit :
> On Sat, 2010-11-27 at 01:31 +0800, mat wrote:
> > Le Tue, 23 Nov 2010 23:55:27 +0100,
> > mat <[email protected]> a ?crit :
> >
> > > Le Mon, 22 Nov 2010 17:42:47 +0100,
> > > Andi Kleen <[email protected]> a ?crit :
> > >
> > > > > That seems to be a S3 specific code path, that won't fix
> > > > > anything. Simply do:
> > > > >
> > > > > echo 0 > /sys/devices/system/cpu/cpu1/online;
> > > > > echo 1 > /sys/devices/system/cpu/cpu1/online;
> > > > >
> > > > > and your machine will explode..
> > > >
> > > > The SMP startup trampoline is copied I believe
> > > > and only executed in real mode without page tables.
> > > >
> > > > So it's perhaps not the trampoline, but the early startup
> > > > code that ends up being broken.
> > > yes :
> > > acpi wakeup code and smp trampoline are copied in low memory
> > > (first 1MB).
> > >
> > > So they can't end up int the kernel data mapping ?
> > >
> > > So it should something else.
> > >
> > > I will try to investigate on this.
> > >
> > Unfortunately on my laptop supporting NX, suspend to ram seems
> > broken (even without this patch) and I got only one core, so I am
> > unable to test it.
> >
> > Does cpu suspend/resume is broken ? Or it is only S3 ?
> >
> > If yes, are there any interesting trace if we suspend only one core
> > with sysfs.
>
> echo 0 > /sys/devices/system/cpu/cpu1/online;
> echo 1 > /sys/devices/system/cpu/cpu1/online;
>
> then machine just reboots...
>
Ok,
could you try the attached patch ?
Thanks
Matthieu
On Sat, 2010-12-25 at 01:26 +0800, matthieu castet wrote:
> Hi,
>
> Le Tue, 30 Nov 2010 13:00:30 +0800,
> Lin Ming <[email protected]> a écrit :
>
> > On Sat, 2010-11-27 at 01:31 +0800, mat wrote:
> > > Le Tue, 23 Nov 2010 23:55:27 +0100,
> > > mat <[email protected]> a écrit :
> > >
> > > > Le Mon, 22 Nov 2010 17:42:47 +0100,
> > > > Andi Kleen <[email protected]> a écrit :
> > > >
> > > > > > That seems to be a S3 specific code path, that won't fix
> > > > > > anything. Simply do:
> > > > > >
> > > > > > echo 0 > /sys/devices/system/cpu/cpu1/online;
> > > > > > echo 1 > /sys/devices/system/cpu/cpu1/online;
> > > > > >
> > > > > > and your machine will explode..
> > > > >
> > > > > The SMP startup trampoline is copied I believe
> > > > > and only executed in real mode without page tables.
> > > > >
> > > > > So it's perhaps not the trampoline, but the early startup
> > > > > code that ends up being broken.
> > > > yes :
> > > > acpi wakeup code and smp trampoline are copied in low memory
> > > > (first 1MB).
> > > >
> > > > So they can't end up int the kernel data mapping ?
> > > >
> > > > So it should something else.
> > > >
> > > > I will try to investigate on this.
> > > >
> > > Unfortunately on my laptop supporting NX, suspend to ram seems
> > > broken (even without this patch) and I got only one core, so I am
> > > unable to test it.
> > >
> > > Does cpu suspend/resume is broken ? Or it is only S3 ?
> > >
> > > If yes, are there any interesting trace if we suspend only one core
> > > with sysfs.
> >
> > echo 0 > /sys/devices/system/cpu/cpu1/online;
> > echo 1 > /sys/devices/system/cpu/cpu1/online;
> >
> > then machine just reboots...
> >
> Ok,
>
> could you try the attached patch ?
Unfortunately, it does not work against current tip/master(1f7107c8).
Lin Ming
>
> Thanks
>
> Matthieu
Hi,
matthieu castet a écrit :
> matthieu castet a écrit :
>> Lin Ming a écrit :
>>> On Tue, 2010-11-30 at 19:27 +0800, Peter Zijlstra wrote:
>>>> On Tue, 2010-11-30 at 13:00 +0800, Lin Ming wrote:
>>>>> echo 0 > /sys/devices/system/cpu/cpu1/online;
>>>>> echo 1 > /sys/devices/system/cpu/cpu1/online;
>>>>>
>>>>> then machine just reboots...
>>>>>
>> I tried to do the same thing on qemu, and the same behavior happened
>> (ie reboot when resuming cpu1).
>>
>> After enabling qemu log, I found that a triple fault was happening at
>> the beginning of secondary_startup_64
>> when doing "addq phys_base(%rip), %rax".
>>
>> Why ?
>> I suppose because we access data set to NX, but we don't have enabled
>> yet NX in the msr. So the cpu crash due to "reserved bit check".
>>
>> If we enable NX before reading data, there is no more crash (patch
>> attached).
>>
>> Now I am not sure this is the correct fix. I think the problem is that
>> trampoline using kernel page table
>> is very dangerous. The kernel can have modified them atfer booting !
>> May be all the paging stuff should have been done in head_64.S. A
>> first one with identity mapping, and the second one for
>> the real kernel stuff.
>>
> Lin, could you try this patch on your x64 machine.
>
>
I updated the patch to last tip. I tested on a 64 bits config and everything works.
Any comment on it ?
Thanks
Matthieu
From: Matthieu CASTET <[email protected]>
Date: Thu, 10 Mar 2011 00:10:01 +0100
Subject: [PATCH] x86 : Add NX protection for kernel data on 64 bit
This fix the cpu hotplug support, by allocating dedicated page table
for ident mapping in trampoline.
This is need because kernel set NX flag in level3_ident_pgt and
level3_kernel_pgt, and made it unusable from trampoline.
We also set the Low kernel Mapping to NX.
Finaly we apply nx in free_init_pages only when we switch to NX mode in order
to preserve large page mapping.
mapping now look like :
---[ Low Kernel Mapping ]---
0xffff880000000000-0xffff880000200000 2M RW GLB NX pte
0xffff880000200000-0xffff880001000000 14M RW PSE GLB NX pmd
0xffff880001000000-0xffff880001200000 2M ro PSE GLB NX pmd
0xffff880001200000-0xffff8800012ae000 696K ro GLB NX pte
0xffff8800012ae000-0xffff880001400000 1352K RW GLB NX pte
0xffff880001400000-0xffff880001503000 1036K ro GLB NX pte
0xffff880001503000-0xffff880001600000 1012K RW GLB NX pte
0xffff880001600000-0xffff880007e00000 104M RW PSE GLB NX pmd
0xffff880007e00000-0xffff880007ffd000 2036K RW GLB NX pte
0xffff880007ffd000-0xffff880008000000 12K pte
0xffff880008000000-0xffff880040000000 896M pmd
0xffff880040000000-0xffff888000000000 511G pud
0xffff888000000000-0xffffc90000000000 66048G pgd
---[ vmalloc() Area ]---
[...]
---[ High Kernel Mapping ]---
0xffffffff80000000-0xffffffff81000000 16M pmd
0xffffffff81000000-0xffffffff81400000 4M ro PSE GLB x pmd
0xffffffff81400000-0xffffffff81600000 2M ro PSE GLB NX pmd
0xffffffff81600000-0xffffffff81800000 2M RW PSE GLB NX pmd
0xffffffff81800000-0xffffffffa0000000 488M pmd
---[ Modules ]---
Signed-off-by: Matthieu CASTET <[email protected]>
Conflicts:
arch/x86/kernel/head_64.S
---
arch/x86/kernel/head_64.S | 15 +++++++++++++++
arch/x86/kernel/trampoline_64.S | 4 ++--
arch/x86/mm/init.c | 6 ++++--
arch/x86/mm/init_64.c | 6 +++++-
4 files changed, 26 insertions(+), 5 deletions(-)
diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S
index e11e394..e261354 100644
--- a/arch/x86/kernel/head_64.S
+++ b/arch/x86/kernel/head_64.S
@@ -140,6 +140,9 @@ ident_complete:
addq %rbp, trampoline_level4_pgt + 0(%rip)
addq %rbp, trampoline_level4_pgt + (511*8)(%rip)
+ addq %rbp, trampoline_level3_ident_pgt + 0(%rip)
+ addq %rbp, trampoline_level3_ident_pgt + (L3_START_KERNEL*8)(%rip)
+
/* Due to ENTRY(), sometimes the empty space gets filled with
* zeros. Better take a jmp than relying on empty space being
* filled with 0x90 (nop)
@@ -395,6 +398,18 @@ NEXT_PAGE(level2_kernel_pgt)
NEXT_PAGE(level2_spare_pgt)
.fill 512, 8, 0
+NEXT_PAGE(trampoline_level3_ident_pgt)
+ .quad trampoline_level2_ident_pgt - __START_KERNEL_map + _KERNPG_TABLE
+ .fill L3_START_KERNEL-1,8,0
+ .quad trampoline_level2_ident_pgt - __START_KERNEL_map + _KERNPG_TABLE
+ .fill 511-L3_START_KERNEL,8,0
+
+
+NEXT_PAGE(trampoline_level2_ident_pgt)
+ /* Since I easily can, map the first 1G.
+ * Don't set NX because code runs from these pages.
+ */
+ PMDS(0, __PAGE_KERNEL_IDENT_LARGE_EXEC, PTRS_PER_PMD)
#undef PMDS
#undef NEXT_PAGE
diff --git a/arch/x86/kernel/trampoline_64.S b/arch/x86/kernel/trampoline_64.S
index 09ff517..8723e47 100644
--- a/arch/x86/kernel/trampoline_64.S
+++ b/arch/x86/kernel/trampoline_64.S
@@ -164,8 +164,8 @@ trampoline_stack:
.org 0x1000
trampoline_stack_end:
ENTRY(trampoline_level4_pgt)
- .quad level3_ident_pgt - __START_KERNEL_map + _KERNPG_TABLE
+ .quad trampoline_level3_ident_pgt - __START_KERNEL_map + _KERNPG_TABLE
.fill 510,8,0
- .quad level3_kernel_pgt - __START_KERNEL_map + _KERNPG_TABLE
+ .quad trampoline_level3_ident_pgt - __START_KERNEL_map + _KERNPG_TABLE
ENTRY(trampoline_end)
diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
index 286d289..98dd5fa 100644
--- a/arch/x86/mm/init.c
+++ b/arch/x86/mm/init.c
@@ -338,8 +338,10 @@ void free_init_pages(char *what, unsigned long begin, unsigned long end)
* we are going to free part of that, we need to make that
* writeable and non-executable first.
*/
- set_memory_nx(begin, (end - begin) >> PAGE_SHIFT);
- set_memory_rw(begin, (end - begin) >> PAGE_SHIFT);
+ if (kernel_set_to_readonly) {
+ set_memory_nx(begin, (end - begin) >> PAGE_SHIFT);
+ set_memory_rw(begin, (end - begin) >> PAGE_SHIFT);
+ }
printk(KERN_INFO "Freeing %s: %luk freed\n", what, (end - begin) >> 10);
diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index 470cc47..e9bb29d 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -832,6 +832,7 @@ void mark_rodata_ro(void)
unsigned long rodata_start =
((unsigned long)__start_rodata + PAGE_SIZE - 1) & PAGE_MASK;
unsigned long end = (unsigned long) &__end_rodata_hpage_align;
+ unsigned long kernel_end = (((unsigned long)&__init_end + HPAGE_SIZE) & HPAGE_MASK);
unsigned long text_end = PAGE_ALIGN((unsigned long) &__stop___ex_table);
unsigned long rodata_end = PAGE_ALIGN((unsigned long) &__end_rodata);
unsigned long data_start = (unsigned long) &_sdata;
@@ -842,11 +843,14 @@ void mark_rodata_ro(void)
kernel_set_to_readonly = 1;
+ /* make low level mapping NX */
+ set_memory_nx(PAGE_OFFSET, (PMD_PAGE_SIZE*PTRS_PER_PMD) >> PAGE_SHIFT);
+
/*
* The rodata section (but not the kernel text!) should also be
* not-executable.
*/
- set_memory_nx(rodata_start, (end - rodata_start) >> PAGE_SHIFT);
+ set_memory_nx(rodata_start, (kernel_end - rodata_start) >> PAGE_SHIFT);
rodata_test();
--
1.7.4.1
On Thu, 2011-03-10 at 07:16 +0800, matthieu castet wrote:
> Hi,
>
> matthieu castet a écrit :
> > matthieu castet a écrit :
> >> Lin Ming a écrit :
> >>> On Tue, 2010-11-30 at 19:27 +0800, Peter Zijlstra wrote:
> >>>> On Tue, 2010-11-30 at 13:00 +0800, Lin Ming wrote:
> >>>>> echo 0 > /sys/devices/system/cpu/cpu1/online;
> >>>>> echo 1 > /sys/devices/system/cpu/cpu1/online;
> >>>>>
> >>>>> then machine just reboots...
> >>>>>
> >> I tried to do the same thing on qemu, and the same behavior happened
> >> (ie reboot when resuming cpu1).
> >>
> >> After enabling qemu log, I found that a triple fault was happening at
> >> the beginning of secondary_startup_64
> >> when doing "addq phys_base(%rip), %rax".
> >>
> >> Why ?
> >> I suppose because we access data set to NX, but we don't have enabled
> >> yet NX in the msr. So the cpu crash due to "reserved bit check".
> >>
> >> If we enable NX before reading data, there is no more crash (patch
> >> attached).
> >>
> >> Now I am not sure this is the correct fix. I think the problem is that
> >> trampoline using kernel page table
> >> is very dangerous. The kernel can have modified them atfer booting !
> >> May be all the paging stuff should have been done in head_64.S. A
> >> first one with identity mapping, and the second one for
> >> the real kernel stuff.
> >>
> > Lin, could you try this patch on your x64 machine.
> >
> >
> I updated the patch to last tip. I tested on a 64 bits config and everything works.
I tested suspend/resume/hotplug and it works on my 64 bit notebook too.
Thanks,
Lin Ming
>
> Any comment on it ?
>
>
> Thanks
>
>
> Matthieu
>
>
> From: Matthieu CASTET <[email protected]>
> Date: Thu, 10 Mar 2011 00:10:01 +0100
> Subject: [PATCH] x86 : Add NX protection for kernel data on 64 bit
>
> This fix the cpu hotplug support, by allocating dedicated page table
> for ident mapping in trampoline.
> This is need because kernel set NX flag in level3_ident_pgt and
> level3_kernel_pgt, and made it unusable from trampoline.
>
> We also set the Low kernel Mapping to NX.
>
> Finaly we apply nx in free_init_pages only when we switch to NX mode in order
> to preserve large page mapping.
>
> mapping now look like :
> ---[ Low Kernel Mapping ]---
> 0xffff880000000000-0xffff880000200000 2M RW GLB NX pte
> 0xffff880000200000-0xffff880001000000 14M RW PSE GLB NX pmd
> 0xffff880001000000-0xffff880001200000 2M ro PSE GLB NX pmd
> 0xffff880001200000-0xffff8800012ae000 696K ro GLB NX pte
> 0xffff8800012ae000-0xffff880001400000 1352K RW GLB NX pte
> 0xffff880001400000-0xffff880001503000 1036K ro GLB NX pte
> 0xffff880001503000-0xffff880001600000 1012K RW GLB NX pte
> 0xffff880001600000-0xffff880007e00000 104M RW PSE GLB NX pmd
> 0xffff880007e00000-0xffff880007ffd000 2036K RW GLB NX pte
> 0xffff880007ffd000-0xffff880008000000 12K pte
> 0xffff880008000000-0xffff880040000000 896M pmd
> 0xffff880040000000-0xffff888000000000 511G pud
> 0xffff888000000000-0xffffc90000000000 66048G pgd
> ---[ vmalloc() Area ]---
> [...]
> ---[ High Kernel Mapping ]---
> 0xffffffff80000000-0xffffffff81000000 16M pmd
> 0xffffffff81000000-0xffffffff81400000 4M ro PSE GLB x pmd
> 0xffffffff81400000-0xffffffff81600000 2M ro PSE GLB NX pmd
> 0xffffffff81600000-0xffffffff81800000 2M RW PSE GLB NX pmd
> 0xffffffff81800000-0xffffffffa0000000 488M pmd
> ---[ Modules ]---
>
> Signed-off-by: Matthieu CASTET <[email protected]>
>
> Conflicts:
>
> arch/x86/kernel/head_64.S
> ---
> arch/x86/kernel/head_64.S | 15 +++++++++++++++
> arch/x86/kernel/trampoline_64.S | 4 ++--
> arch/x86/mm/init.c | 6 ++++--
> arch/x86/mm/init_64.c | 6 +++++-
> 4 files changed, 26 insertions(+), 5 deletions(-)
>
> diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S
> index e11e394..e261354 100644
> --- a/arch/x86/kernel/head_64.S
> +++ b/arch/x86/kernel/head_64.S
> @@ -140,6 +140,9 @@ ident_complete:
> addq %rbp, trampoline_level4_pgt + 0(%rip)
> addq %rbp, trampoline_level4_pgt + (511*8)(%rip)
>
> + addq %rbp, trampoline_level3_ident_pgt + 0(%rip)
> + addq %rbp, trampoline_level3_ident_pgt + (L3_START_KERNEL*8)(%rip)
> +
> /* Due to ENTRY(), sometimes the empty space gets filled with
> * zeros. Better take a jmp than relying on empty space being
> * filled with 0x90 (nop)
> @@ -395,6 +398,18 @@ NEXT_PAGE(level2_kernel_pgt)
> NEXT_PAGE(level2_spare_pgt)
> .fill 512, 8, 0
>
> +NEXT_PAGE(trampoline_level3_ident_pgt)
> + .quad trampoline_level2_ident_pgt - __START_KERNEL_map + _KERNPG_TABLE
> + .fill L3_START_KERNEL-1,8,0
> + .quad trampoline_level2_ident_pgt - __START_KERNEL_map + _KERNPG_TABLE
> + .fill 511-L3_START_KERNEL,8,0
> +
> +
> +NEXT_PAGE(trampoline_level2_ident_pgt)
> + /* Since I easily can, map the first 1G.
> + * Don't set NX because code runs from these pages.
> + */
> + PMDS(0, __PAGE_KERNEL_IDENT_LARGE_EXEC, PTRS_PER_PMD)
> #undef PMDS
> #undef NEXT_PAGE
>
> diff --git a/arch/x86/kernel/trampoline_64.S b/arch/x86/kernel/trampoline_64.S
> index 09ff517..8723e47 100644
> --- a/arch/x86/kernel/trampoline_64.S
> +++ b/arch/x86/kernel/trampoline_64.S
> @@ -164,8 +164,8 @@ trampoline_stack:
> .org 0x1000
> trampoline_stack_end:
> ENTRY(trampoline_level4_pgt)
> - .quad level3_ident_pgt - __START_KERNEL_map + _KERNPG_TABLE
> + .quad trampoline_level3_ident_pgt - __START_KERNEL_map + _KERNPG_TABLE
> .fill 510,8,0
> - .quad level3_kernel_pgt - __START_KERNEL_map + _KERNPG_TABLE
> + .quad trampoline_level3_ident_pgt - __START_KERNEL_map + _KERNPG_TABLE
>
> ENTRY(trampoline_end)
> diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
> index 286d289..98dd5fa 100644
> --- a/arch/x86/mm/init.c
> +++ b/arch/x86/mm/init.c
> @@ -338,8 +338,10 @@ void free_init_pages(char *what, unsigned long begin, unsigned long end)
> * we are going to free part of that, we need to make that
> * writeable and non-executable first.
> */
> - set_memory_nx(begin, (end - begin) >> PAGE_SHIFT);
> - set_memory_rw(begin, (end - begin) >> PAGE_SHIFT);
> + if (kernel_set_to_readonly) {
> + set_memory_nx(begin, (end - begin) >> PAGE_SHIFT);
> + set_memory_rw(begin, (end - begin) >> PAGE_SHIFT);
> + }
>
> printk(KERN_INFO "Freeing %s: %luk freed\n", what, (end - begin) >> 10);
>
> diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
> index 470cc47..e9bb29d 100644
> --- a/arch/x86/mm/init_64.c
> +++ b/arch/x86/mm/init_64.c
> @@ -832,6 +832,7 @@ void mark_rodata_ro(void)
> unsigned long rodata_start =
> ((unsigned long)__start_rodata + PAGE_SIZE - 1) & PAGE_MASK;
> unsigned long end = (unsigned long) &__end_rodata_hpage_align;
> + unsigned long kernel_end = (((unsigned long)&__init_end + HPAGE_SIZE) & HPAGE_MASK);
> unsigned long text_end = PAGE_ALIGN((unsigned long) &__stop___ex_table);
> unsigned long rodata_end = PAGE_ALIGN((unsigned long) &__end_rodata);
> unsigned long data_start = (unsigned long) &_sdata;
> @@ -842,11 +843,14 @@ void mark_rodata_ro(void)
>
> kernel_set_to_readonly = 1;
>
> + /* make low level mapping NX */
> + set_memory_nx(PAGE_OFFSET, (PMD_PAGE_SIZE*PTRS_PER_PMD) >> PAGE_SHIFT);
> +
> /*
> * The rodata section (but not the kernel text!) should also be
> * not-executable.
> */
> - set_memory_nx(rodata_start, (end - rodata_start) >> PAGE_SHIFT);
> + set_memory_nx(rodata_start, (kernel_end - rodata_start) >> PAGE_SHIFT);
>
> rodata_test();
>