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From: koct9i@gmail.com (Konstantin Khlebnikov)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 1/2] ARM: LPAE: load upper bits of early TTBR0/TTBR1
Date: Wed, 27 Aug 2014 19:31:29 +0400	[thread overview]
Message-ID: <CALYGNiN-SHr6YJ53_deizb1VoXTBzD7dn8hcwqd4zLjx6utCDw@mail.gmail.com> (raw)
In-Reply-To: <CABb+yY17Y18oAivi_VxPJqDEGLTbEy_PfsdeK9jXWZ0iV3vZ=w@mail.gmail.com>

On Wed, Aug 27, 2014 at 7:26 PM, Jassi Brar <jassisinghbrar@gmail.com> wrote:
> On Tue, Jul 29, 2014 at 5:59 PM, Konstantin Khlebnikov <koct9i@gmail.com> wrote:
>> On Mon, Jul 28, 2014 at 10:47 PM, Will Deacon <will.deacon@arm.com> wrote:
>>> On Mon, Jul 28, 2014 at 07:40:58PM +0100, Konstantin Khlebnikov wrote:
>>>> On Mon, Jul 28, 2014 at 10:12 PM, Will Deacon <will.deacon@arm.com> wrote:
>>>> > On Tue, Jul 22, 2014 at 04:36:23PM +0100, Konstantin Khlebnikov wrote:
>>>> >> This patch fixes booting when idmap pgd lays above 4gb. Commit
>>>> >> 4756dcbfd37 mostly had fixed this, but it'd failed to load upper bits.
>>>> >>
>>>> >> Also this fixes adding TTBR1_OFFSET to TTRR1: if lower part overflows
>>>> >> carry flag must be added to the upper part.
>>>> >>
>>>> >> Signed-off-by: Konstantin Khlebnikov <k.khlebnikov@samsung.com>
>>>> >> Cc: Cyril Chemparathy <cyril@ti.com>
>>>> >> Cc: Vitaly Andrianov <vitalya@ti.com>
>>>> >> ---
>>>> >>  arch/arm/mm/proc-v7-3level.S |    7 +++----
>>>> >>  1 file changed, 3 insertions(+), 4 deletions(-)
>>>> >>
>>>> >> diff --git a/arch/arm/mm/proc-v7-3level.S b/arch/arm/mm/proc-v7-3level.S
>>>> >> index 22e3ad6..f0481dd 100644
>>>> >> --- a/arch/arm/mm/proc-v7-3level.S
>>>> >> +++ b/arch/arm/mm/proc-v7-3level.S
>>>> >> @@ -140,12 +140,11 @@ ENDPROC(cpu_v7_set_pte_ext)
>>>> >>       mov     \tmp, \ttbr1, lsr #(32 - ARCH_PGD_SHIFT)        @ upper bits
>>>> >>       mov     \ttbr1, \ttbr1, lsl #ARCH_PGD_SHIFT             @ lower bits
>>>> >>       addls   \ttbr1, \ttbr1, #TTBR1_OFFSET
>>>> >> -     mcrr    p15, 1, \ttbr1, \zero, c2                       @ load TTBR1
>>>> >> +     adcls   \tmp, \tmp, #0
>>>> >> +     mcrr    p15, 1, \ttbr1, \tmp, c2                        @ load TTBR1
>>>> >>       mov     \tmp, \ttbr0, lsr #(32 - ARCH_PGD_SHIFT)        @ upper bits
>>>> >>       mov     \ttbr0, \ttbr0, lsl #ARCH_PGD_SHIFT             @ lower bits
>>>> >> -     mcrr    p15, 0, \ttbr0, \zero, c2                       @ load TTBR0
>>>> >> -     mcrr    p15, 1, \ttbr1, \zero, c2                       @ load TTBR1
>>>> >> -     mcrr    p15, 0, \ttbr0, \zero, c2                       @ load TTBR0
>>>> >> +     mcrr    p15, 0, \ttbr0, \tmp, c2                        @ load TTBR0
>>>> >
>>>> > I must admit, the code you are removing here looks really strange. Was there
>>>> > a badly resolved conflict somewhere along the way? It would be nice to see
>>>> > if your fix (which seems ok to me) was actually present in the mailing list
>>>> > posting of the patch that ended in the above mess.
>>>>
>>>> Nope, no merge conflicts, source in original patch
>>>> https://lkml.org/lkml/2012/9/11/346
>>>>
>>>> That mess completely harmless, this code is used only once on boot.
>>>> I don't have that email, so replying isn't trivial for me.
>>>
>>> How bizarre. Also, Cyril doesn't work for TI anymore (his email is
>>> bouncing), so it's tricky to know what he meant here.
>>>
>>> Your patch looks better than what we currently have though. Have you managed
>>> to test it on a keystone platform (I don't have one)?
>>
>> No, I don't have it too. As well as I don't have direct access to the
>> platform where
>> problem was found. I've debugged this in patched qemu.
>>
> It seems the patch wasn't tested on any real platform, I did on my
> CA15 based platform - it breaks boot. Simply reverting the patch gets
> it going again. I am happy to try any fix.
>

Please try to remove adcls line.
Seems like this affects only systems where PHYS_OFFSET == PAGE_OFFSET.

--- a/arch/arm/mm/proc-v7-3level.S
+++ b/arch/arm/mm/proc-v7-3level.S
@@ -146,7 +146,6 @@ ENDPROC(cpu_v7_set_pte_ext)
        mov     \tmp, \ttbr1, lsr #(32 - ARCH_PGD_SHIFT)        @ upper bits
        mov     \ttbr1, \ttbr1, lsl #ARCH_PGD_SHIFT             @ lower bits
        addls   \ttbr1, \ttbr1, #TTBR1_OFFSET
-       adcls   \tmp, \tmp, #0
        mcrr    p15, 1, \ttbr1, \tmp, c2                        @ load TTBR1
        mov     \tmp, \ttbr0, lsr #(32 - ARCH_PGD_SHIFT)        @ upper bits
        mov     \ttbr0, \ttbr0, lsl #ARCH_PGD_SHIFT             @ lower bits


> Thanks
> Jassi

  reply	other threads:[~2014-08-27 15:31 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-07-22 15:36 [PATCH 1/2] ARM: LPAE: load upper bits of early TTBR0/TTBR1 Konstantin Khlebnikov
2014-07-22 15:36 ` [PATCH 2/2] ARM: LPAE: reduce damage caused by idmap to virtual memory layout Konstantin Khlebnikov
2014-07-28 18:14   ` Will Deacon
2014-07-28 18:25     ` Konstantin Khlebnikov
2014-07-28 18:41       ` Will Deacon
2014-07-28 18:57         ` Konstantin Khlebnikov
2014-07-28 19:06           ` Will Deacon
2014-07-28 19:13           ` Russell King - ARM Linux
2014-07-28 19:29             ` Konstantin Khlebnikov
2014-07-28 19:34               ` Konstantin Khlebnikov
2014-07-28 19:42               ` Russell King - ARM Linux
2014-07-28 19:57                 ` Konstantin Khlebnikov
2014-07-29 10:57                   ` Russell King - ARM Linux
2014-07-29 12:37                     ` Konstantin Khlebnikov
2014-07-28 18:12 ` [PATCH 1/2] ARM: LPAE: load upper bits of early TTBR0/TTBR1 Will Deacon
2014-07-28 18:40   ` Konstantin Khlebnikov
2014-07-28 18:47     ` Will Deacon
2014-07-29 11:15       ` Will Deacon
2014-07-29 12:29       ` Konstantin Khlebnikov
2014-08-27 15:26         ` Jassi Brar
2014-08-27 15:31           ` Konstantin Khlebnikov [this message]
2014-08-27 15:33             ` Konstantin Khlebnikov
2014-08-27 15:45             ` Jassi Brar
2014-08-28 11:03               ` Will Deacon
2014-08-28 11:50                 ` Konstantin Khlebnikov
2014-08-05 15:42 ` Konstantin Khlebnikov

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