linux-kernel - Re: [PATCH] riscv: Disallow to build XIP_KERNEL with SOC_SIFIVE

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Message-ID: <CAM4kBBK=yQ=jXYw85Ti7Y3EyGd11aOYt7QnD4+fFFkDhvrwcxA@mail.gmail.com>
Date:   Thu, 29 Apr 2021 11:11:55 +0200
From:   Vitaly Wool <vitaly.wool@...sulko.com>
To:     Alexandre Ghiti <alex@...ti.fr>
Cc:     Paul Walmsley <paul.walmsley@...ive.com>,
        Palmer Dabbelt <palmer@...belt.com>,
        Albert Ou <aou@...s.berkeley.edu>,
        linux-riscv <linux-riscv@...ts.infradead.org>,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] riscv: Disallow to build XIP_KERNEL with SOC_SIFIVE

On Thu, Apr 29, 2021 at 10:47 AM Alexandre Ghiti <alex@...ti.fr> wrote:
>
> RISCV_ERRATA_ALTERNATIVE patches text at runtime which is not possible when
> the kernel is executed from the flash in XIP mode, and as the SIFIVE
> errata must be fixed somehow, disallow to build a XIP kernel that
> supports SIFIVE socs.

Could you please hold off this patch for a bit? I will try to come up
with an alternative solution. It should be possible to define a
special section within the RW area and place the functions that need
such patching there.
Not that I like that much but at least we'll keep the ability to use
XIP on SiFive.

Best regards,
   Vitaly

> Signed-off-by: Alexandre Ghiti <alex@...ti.fr>
> ---
>  arch/riscv/Kconfig.erratas | 2 +-
>  arch/riscv/Kconfig.socs    | 1 +
>  2 files changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/arch/riscv/Kconfig.erratas b/arch/riscv/Kconfig.erratas
> index d5d03ae8d685..9537dbd67357 100644
> --- a/arch/riscv/Kconfig.erratas
> +++ b/arch/riscv/Kconfig.erratas
> @@ -2,7 +2,7 @@ menu "CPU errata selection"
>
>  config RISCV_ERRATA_ALTERNATIVE
>         bool "RISC-V alternative scheme"
> -       default y
> +       default y if !XIP_KERNEL
>         help
>           This Kconfig allows the kernel to automatically patch the
>           errata required by the execution platform at run time. The
> diff --git a/arch/riscv/Kconfig.socs b/arch/riscv/Kconfig.socs
> index 00c2b205654c..9cb38bc9d7cd 100644
> --- a/arch/riscv/Kconfig.socs
> +++ b/arch/riscv/Kconfig.socs
> @@ -9,6 +9,7 @@ config SOC_MICROCHIP_POLARFIRE
>
>  config SOC_SIFIVE
>         bool "SiFive SoCs"
> +       depends on !XIP_KERNEL
>         select SERIAL_SIFIVE if TTY
>         select SERIAL_SIFIVE_CONSOLE if TTY
>         select CLK_SIFIVE
> --
> 2.20.1
>
>
> _______________________________________________
> linux-riscv mailing list
> linux-riscv@...ts.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-riscv

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