When enable LPAE and big-endian in a hisilicon board, while specify
mem=384M mem=512M@7680M, will get bad page state:
Freeing unused kernel memory: 180K (c0466000 - c0493000)
BUG: Bad page state in process init pfn:fa442
page:c7749840 count:0 mapcount:-1 mapping: (null) index:0x0
page flags: 0x40000400(reserved)
Modules linked in:
CPU: 0 PID: 1 Comm: init Not tainted 3.10.27+ #66
[<c000f5f0>] (unwind_backtrace+0x0/0x11c) from [<c000cbc4>] (show_stack+0x10/0x14)
[<c000cbc4>] (show_stack+0x10/0x14) from [<c009e448>] (bad_page+0xd4/0x104)
[<c009e448>] (bad_page+0xd4/0x104) from [<c009e520>] (free_pages_prepare+0xa8/0x14c)
[<c009e520>] (free_pages_prepare+0xa8/0x14c) from [<c009f8ec>] (free_hot_cold_page+0x18/0xf0)
[<c009f8ec>] (free_hot_cold_page+0x18/0xf0) from [<c00b5444>] (handle_pte_fault+0xcf4/0xdc8)
[<c00b5444>] (handle_pte_fault+0xcf4/0xdc8) from [<c00b6458>] (handle_mm_fault+0xf4/0x120)
[<c00b6458>] (handle_mm_fault+0xf4/0x120) from [<c0013754>] (do_page_fault+0xfc/0x354)
[<c0013754>] (do_page_fault+0xfc/0x354) from [<c0008400>] (do_DataAbort+0x2c/0x90)
[<c0008400>] (do_DataAbort+0x2c/0x90) from [<c0008fb4>] (__dabt_usr+0x34/0x40)
The bad pfn:fa442 is not system memory(mem=384M mem=512M@7680M), after debugging,
I find in page fault handler, will get wrong pfn from pte just after set pte,
as follow:
do_anonymous_page()
{
...
set_pte_at(mm, address, page_table, entry);
//debug code
pfn = pte_pfn(entry);
pr_info("pfn:0x%lx, pte:0x%llx\n", pfn, pte_val(entry));
//read out the pte just set
new_pte = pte_offset_map(pmd, address);
new_pfn = pte_pfn(*new_pte);
pr_info("new pfn:0x%lx, new pte:0x%llx\n", pfn, pte_val(entry));
...
}
pfn: 0x1fa4f5, pte:0xc00001fa4f575f
new_pfn:0xfa4f5, new_pte:0xc00000fa4f5f5f //new pfn/pte is wrong.
The bug is happened in cpu_v7_set_pte_ext(ptep, pte):
An LPAE PTE is a 64bit quantity, passed to cpu_v7_set_pte_ext in the r2 and r3 registers.
On an LE kernel, r2 contains the LSB of the PTE, and r3 the MSB.
On a BE kernel, the assignment is reversed.
Unfortunately, the current code always assumes the LE case,
leading to corruption of the PTE when clearing/setting bits.
This patch fixes this issue much like it has been done already in the
cpu_v7_switch_mm case.
Signed-off-by: Jianguo Wu <[email protected]>
Cc: [email protected]
---
-v2: Refactoring code suggested by Ben Dooks.
-v3: Rewrite commit message suggested by Marc Zyngier.
---
arch/arm/mm/proc-v7-3level.S | 18 +++++++++++++-----
1 files changed, 13 insertions(+), 5 deletions(-)
diff --git a/arch/arm/mm/proc-v7-3level.S b/arch/arm/mm/proc-v7-3level.S
index 01a719e..22e3ad6 100644
--- a/arch/arm/mm/proc-v7-3level.S
+++ b/arch/arm/mm/proc-v7-3level.S
@@ -64,6 +64,14 @@ ENTRY(cpu_v7_switch_mm)
mov pc, lr
ENDPROC(cpu_v7_switch_mm)
+#ifdef __ARMEB__
+#define rl r3
+#define rh r2
+#else
+#define rl r2
+#define rh r3
+#endif
+
/*
* cpu_v7_set_pte_ext(ptep, pte)
*
@@ -73,13 +81,13 @@ ENDPROC(cpu_v7_switch_mm)
*/
ENTRY(cpu_v7_set_pte_ext)
#ifdef CONFIG_MMU
- tst r2, #L_PTE_VALID
+ tst rl, #L_PTE_VALID
beq 1f
- tst r3, #1 << (57 - 32) @ L_PTE_NONE
- bicne r2, #L_PTE_VALID
+ tst rh, #1 << (57 - 32) @ L_PTE_NONE
+ bicne rl, #L_PTE_VALID
bne 1f
- tst r3, #1 << (55 - 32) @ L_PTE_DIRTY
- orreq r2, #L_PTE_RDONLY
+ tst rh, #1 << (55 - 32) @ L_PTE_DIRTY
+ orreq rl, #L_PTE_RDONLY
1: strd r2, r3, [r0]
ALT_SMP(W(nop))
ALT_UP (mcr p15, 0, r0, c7, c10, 1) @ flush_pte
--
1.7.1
On Thu, Apr 17 2014 at 10:31:37 am BST, Jianguo Wu <[email protected]> wrote:
> When enable LPAE and big-endian in a hisilicon board, while specify
> mem=384M mem=512M@7680M, will get bad page state:
>
> Freeing unused kernel memory: 180K (c0466000 - c0493000)
> BUG: Bad page state in process init pfn:fa442
> page:c7749840 count:0 mapcount:-1 mapping: (null) index:0x0
> page flags: 0x40000400(reserved)
> Modules linked in:
> CPU: 0 PID: 1 Comm: init Not tainted 3.10.27+ #66
> [<c000f5f0>] (unwind_backtrace+0x0/0x11c) from [<c000cbc4>] (show_stack+0x10/0x14)
> [<c000cbc4>] (show_stack+0x10/0x14) from [<c009e448>] (bad_page+0xd4/0x104)
> [<c009e448>] (bad_page+0xd4/0x104) from [<c009e520>] (free_pages_prepare+0xa8/0x14c)
> [<c009e520>] (free_pages_prepare+0xa8/0x14c) from [<c009f8ec>] (free_hot_cold_page+0x18/0xf0)
> [<c009f8ec>] (free_hot_cold_page+0x18/0xf0) from [<c00b5444>] (handle_pte_fault+0xcf4/0xdc8)
> [<c00b5444>] (handle_pte_fault+0xcf4/0xdc8) from [<c00b6458>] (handle_mm_fault+0xf4/0x120)
> [<c00b6458>] (handle_mm_fault+0xf4/0x120) from [<c0013754>] (do_page_fault+0xfc/0x354)
> [<c0013754>] (do_page_fault+0xfc/0x354) from [<c0008400>] (do_DataAbort+0x2c/0x90)
> [<c0008400>] (do_DataAbort+0x2c/0x90) from [<c0008fb4>] (__dabt_usr+0x34/0x40)
>
> The bad pfn:fa442 is not system memory(mem=384M mem=512M@7680M), after debugging,
> I find in page fault handler, will get wrong pfn from pte just after set pte,
> as follow:
> do_anonymous_page()
> {
> ...
> set_pte_at(mm, address, page_table, entry);
>
> //debug code
> pfn = pte_pfn(entry);
> pr_info("pfn:0x%lx, pte:0x%llx\n", pfn, pte_val(entry));
>
> //read out the pte just set
> new_pte = pte_offset_map(pmd, address);
> new_pfn = pte_pfn(*new_pte);
> pr_info("new pfn:0x%lx, new pte:0x%llx\n", pfn, pte_val(entry));
> ...
> }
>
> pfn: 0x1fa4f5, pte:0xc00001fa4f575f
> new_pfn:0xfa4f5, new_pte:0xc00000fa4f5f5f //new pfn/pte is wrong.
>
> The bug is happened in cpu_v7_set_pte_ext(ptep, pte):
> An LPAE PTE is a 64bit quantity, passed to cpu_v7_set_pte_ext in the r2 and r3 registers.
> On an LE kernel, r2 contains the LSB of the PTE, and r3 the MSB.
> On a BE kernel, the assignment is reversed.
>
> Unfortunately, the current code always assumes the LE case,
> leading to corruption of the PTE when clearing/setting bits.
>
> This patch fixes this issue much like it has been done already in the
> cpu_v7_switch_mm case.
>
> Signed-off-by: Jianguo Wu <[email protected]>
> Cc: [email protected]
Acked-by: Marc Zyngier <[email protected]>
> ---
> -v2: Refactoring code suggested by Ben Dooks.
> -v3: Rewrite commit message suggested by Marc Zyngier.
> ---
> arch/arm/mm/proc-v7-3level.S | 18 +++++++++++++-----
> 1 files changed, 13 insertions(+), 5 deletions(-)
>
> diff --git a/arch/arm/mm/proc-v7-3level.S b/arch/arm/mm/proc-v7-3level.S
> index 01a719e..22e3ad6 100644
> --- a/arch/arm/mm/proc-v7-3level.S
> +++ b/arch/arm/mm/proc-v7-3level.S
> @@ -64,6 +64,14 @@ ENTRY(cpu_v7_switch_mm)
> mov pc, lr
> ENDPROC(cpu_v7_switch_mm)
>
> +#ifdef __ARMEB__
> +#define rl r3
> +#define rh r2
> +#else
> +#define rl r2
> +#define rh r3
> +#endif
> +
> /*
> * cpu_v7_set_pte_ext(ptep, pte)
> *
> @@ -73,13 +81,13 @@ ENDPROC(cpu_v7_switch_mm)
> */
> ENTRY(cpu_v7_set_pte_ext)
> #ifdef CONFIG_MMU
> - tst r2, #L_PTE_VALID
> + tst rl, #L_PTE_VALID
> beq 1f
> - tst r3, #1 << (57 - 32) @ L_PTE_NONE
> - bicne r2, #L_PTE_VALID
> + tst rh, #1 << (57 - 32) @ L_PTE_NONE
> + bicne rl, #L_PTE_VALID
> bne 1f
> - tst r3, #1 << (55 - 32) @ L_PTE_DIRTY
> - orreq r2, #L_PTE_RDONLY
> + tst rh, #1 << (55 - 32) @ L_PTE_DIRTY
> + orreq rl, #L_PTE_RDONLY
> 1: strd r2, r3, [r0]
> ALT_SMP(W(nop))
> ALT_UP (mcr p15, 0, r0, c7, c10, 1) @ flush_pte
--
Jazz is not dead. It just smells funny.
Hi Jianguo,
On Thu, Apr 17, 2014 at 10:43:01AM +0100, Marc Zyngier wrote:
> On Thu, Apr 17 2014 at 10:31:37 am BST, Jianguo Wu <[email protected]> wrote:
> > When enable LPAE and big-endian in a hisilicon board, while specify
> > mem=384M mem=512M@7680M, will get bad page state:
> >
> > Freeing unused kernel memory: 180K (c0466000 - c0493000)
> > BUG: Bad page state in process init pfn:fa442
> > page:c7749840 count:0 mapcount:-1 mapping: (null) index:0x0
> > page flags: 0x40000400(reserved)
> > Modules linked in:
> > CPU: 0 PID: 1 Comm: init Not tainted 3.10.27+ #66
> > [<c000f5f0>] (unwind_backtrace+0x0/0x11c) from [<c000cbc4>] (show_stack+0x10/0x14)
> > [<c000cbc4>] (show_stack+0x10/0x14) from [<c009e448>] (bad_page+0xd4/0x104)
> > [<c009e448>] (bad_page+0xd4/0x104) from [<c009e520>] (free_pages_prepare+0xa8/0x14c)
> > [<c009e520>] (free_pages_prepare+0xa8/0x14c) from [<c009f8ec>] (free_hot_cold_page+0x18/0xf0)
> > [<c009f8ec>] (free_hot_cold_page+0x18/0xf0) from [<c00b5444>] (handle_pte_fault+0xcf4/0xdc8)
> > [<c00b5444>] (handle_pte_fault+0xcf4/0xdc8) from [<c00b6458>] (handle_mm_fault+0xf4/0x120)
> > [<c00b6458>] (handle_mm_fault+0xf4/0x120) from [<c0013754>] (do_page_fault+0xfc/0x354)
> > [<c0013754>] (do_page_fault+0xfc/0x354) from [<c0008400>] (do_DataAbort+0x2c/0x90)
> > [<c0008400>] (do_DataAbort+0x2c/0x90) from [<c0008fb4>] (__dabt_usr+0x34/0x40)
[...]
Please can you put this into Russell's patch system? You can also add my
ack:
Acked-by: Will Deacon <[email protected]>
You should also CC stable <[email protected]> in the commit log.
Cheers,
Will
On 2014/4/23 21:20, Will Deacon wrote:
> Hi Jianguo,
>
> On Thu, Apr 17, 2014 at 10:43:01AM +0100, Marc Zyngier wrote:
>> On Thu, Apr 17 2014 at 10:31:37 am BST, Jianguo Wu <[email protected]> wrote:
>>> When enable LPAE and big-endian in a hisilicon board, while specify
>>> mem=384M mem=512M@7680M, will get bad page state:
>>>
>>> Freeing unused kernel memory: 180K (c0466000 - c0493000)
>>> BUG: Bad page state in process init pfn:fa442
>>> page:c7749840 count:0 mapcount:-1 mapping: (null) index:0x0
>>> page flags: 0x40000400(reserved)
>>> Modules linked in:
>>> CPU: 0 PID: 1 Comm: init Not tainted 3.10.27+ #66
>>> [<c000f5f0>] (unwind_backtrace+0x0/0x11c) from [<c000cbc4>] (show_stack+0x10/0x14)
>>> [<c000cbc4>] (show_stack+0x10/0x14) from [<c009e448>] (bad_page+0xd4/0x104)
>>> [<c009e448>] (bad_page+0xd4/0x104) from [<c009e520>] (free_pages_prepare+0xa8/0x14c)
>>> [<c009e520>] (free_pages_prepare+0xa8/0x14c) from [<c009f8ec>] (free_hot_cold_page+0x18/0xf0)
>>> [<c009f8ec>] (free_hot_cold_page+0x18/0xf0) from [<c00b5444>] (handle_pte_fault+0xcf4/0xdc8)
>>> [<c00b5444>] (handle_pte_fault+0xcf4/0xdc8) from [<c00b6458>] (handle_mm_fault+0xf4/0x120)
>>> [<c00b6458>] (handle_mm_fault+0xf4/0x120) from [<c0013754>] (do_page_fault+0xfc/0x354)
>>> [<c0013754>] (do_page_fault+0xfc/0x354) from [<c0008400>] (do_DataAbort+0x2c/0x90)
>>> [<c0008400>] (do_DataAbort+0x2c/0x90) from [<c0008fb4>] (__dabt_usr+0x34/0x40)
>
>
> [...]
>
> Please can you put this into Russell's patch system? You can also add my
> ack:
>
> Acked-by: Will Deacon <[email protected]>
>
> You should also CC stable <[email protected]> in the commit log.
>
Hi Will,
I have submit to http://www.arm.linux.org.uk/developer/patches/viewpatch.php?id=8037/1.
Thanks,
Jianguo Wu.
> Cheers,
>
> Will
>
> .
>