Messages in this thread | | | From | Linus Walleij <> | Date | Tue, 28 Jun 2022 10:34:49 +0200 | Subject | Re: [PATCH] ARM: mmu: fix access to illegal address when using earlycon & memblock=debug |
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On Fri, Jun 17, 2022 at 3:31 PM Victor Hassan <victor@allwinnertech.com> wrote: > 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 :)
No, I understand the problem, I provided my ACK.
Maybe you wanna add the patch to Russell's patch tracker so he can apply it? https://www.arm.linux.org.uk/developer/patches/
Yours, Linus Walleij
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