From: Victor Hassan <victor@allwinnertech.com>
To: Linus Walleij <linus.walleij@linaro.org>
Cc: linux@armlinux.org.uk, rmk+kernel@armlinux.org.uk,
yanfei.xu@windriver.com, ardb@kernel.org, tglx@linutronix.de,
mirq-linux@rere.qmqm.pl, arnd@arndb.de,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] ARM: mmu: fix access to illegal address when using earlycon & memblock=debug
Date: Fri, 17 Jun 2022 21:30:57 +0800 [thread overview]
Message-ID: <ecabcfa6-7408-d10b-7d88-b1a202b2a90d@allwinnertech.com> (raw)
In-Reply-To: <0fa192d1-b6cc-4a8a-c319-36471cba79e8@allwinnertech.com>
On 4/18/2022 11:08 PM, Victor Hassan wrote:
> On 18/04/2022 07:21, Linus Walleij wrote:
>> On Wed, Mar 16, 2022 at 3:33 AM Victor Hassan
>> <victor@allwinnertech.com> wrote:
>>
>>> earlycon uses fixmap to create a memory map,
>>> So we need to close earlycon before closing fixmap,
>>> otherwise printk will access illegal addresses.
>>> After creating a new memory map, we open earlycon again.
>>>
>>> Signed-off-by: Victor Hassan <victor@allwinnertech.com>
>>
>> I think noone really noticed this because everyone on Arm systems
>> use CONFIG_DEBUG_LL, and that makes printascii hammer out
>> stuff on the console very early, it even accounts for whether we have
>> MMU on or not.
>>
> Hi Linus,
> Thank you for the reply. I used earlycon, in early_fixmap_shutdown, the
> base address of earlycon is in the critical stage of release and
> reassignment, so early_fixmap_shutdown -> create_mapping should not call
> earlycon in this process, and create_mapping has a lot of conditions
> that trigger print, memblock=debug just makes it easier to expose problems.
>
>> How are you using this on Arm even? What system and what serial
>> driver?
> I'm using serial driver 8250 on arm32, with cmdline: memblock=debug.
> CONFIG_SERIAL_8250=y
> CONFIG_SERIAL_8520_CONSOLE=y
>>
>> That said, it looks correct.
>> Acked-by: Linus Walleij <linus.walleij@linaro.org>
Hi Linus,
Sorry to disturb. Is there any question about this issue? Thank you :)
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next prev parent reply other threads:[~2022-06-17 13:32 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-16 2:33 [PATCH] ARM: mmu: fix access to illegal address when using earlycon & memblock=debug Victor Hassan
2022-04-17 23:21 ` Linus Walleij
2022-04-18 15:08 ` Victor Hassan
2022-06-17 13:30 ` Victor Hassan [this message]
2022-06-28 8:34 ` Linus Walleij
[not found] ` <CGME20220831115257eucas1p20d37a01c51e42767860920a936255bd7@eucas1p2.samsung.com>
2022-08-31 11:52 ` Marek Szyprowski
2022-08-31 12:37 ` Victor Hassan
2022-09-01 12:53 ` Victor Hassan
2022-09-01 13:21 ` Rob Herring
2022-09-01 13:49 ` Rob Herring
2022-09-03 8:54 ` Victor Hassan
2022-08-31 13:51 ` Russell King (Oracle)
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