linux-kernel - Re: [PATCH] ARM: kexec: Fix panic after TLB are invalidated

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Date:   Mon, 1 Feb 2021 10:10:43 +0000
From:   Giancarlo Ferrari <giancarlo.ferrari89@...il.com>
To:     linux@...linux.org.uk
Cc:     giancarlo.ferrari@...ia.com, michal.simek@...inx.com,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] ARM: kexec: Fix panic after TLB are invalidated

Hi all,

On Tue, Jan 12, 2021 at 04:49:06PM +0000, Giancarlo Ferrari wrote:
> machine_kexec() need to set rw permission in text and rodata sections
> to assign some variables (e.g. kexec_start_address). To do that at
> the end (after flushing pdm in memory, inv D-Cache, etc.) it needs to
> invalidate TLB [section] entries.
> 
> If during the TLB invalidation an interrupt occours, which might cause
> a context switch, there is the risk to inject invalid TLBs, with ro
> permissions.
> 
> When trying to assign .text labels, this lead to the following issue:
> 
> "Unable to handle kernel paging request at virtual address <valid_addr>"
> 
> with FSR 0x80d.
> 
> Signed-off-by: Giancarlo Ferrari <giancarlo.ferrari89@...il.com>
> ---
>  arch/arm/kernel/machine_kexec.c | 10 ++++++++++
>  1 file changed, 10 insertions(+)

has been re-submitted here:

https://lore.kernel.org/lkml/1612140296-12546-1-git-send-email-giancarlo.ferrari89@gmail.com/


GF