Re: [PATCH V2 1/3] riscv: Fixup static_obj() fail

From: Atish Patra <atishp@atishpatra.org>
To: Guo Ren <guoren@kernel.org>
Cc: Tycho Andersen <tycho@tycho.ws>,
	Albert Ou <aou@eecs.berkeley.edu>, Nick Hu <nickhu@andestech.com>,
	Anup Patel <anup@brainfault.org>,
	Palmer Dabbelt <palmerdabbelt@google.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	linux-csky@vger.kernel.org, Guo Ren <guoren@linux.alibaba.com>,
	Andreas Schwab <schwab@linux-m68k.org>,
	Zong Li <zong.li@sifive.com>,
	Paul Walmsley <paul.walmsley@sifive.com>,
	Greentime Hu <greentime.hu@sifive.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	linux-riscv <linux-riscv@lists.infradead.org>
Subject: Re: [PATCH V2 1/3] riscv: Fixup static_obj() fail
Date: Mon, 5 Oct 2020 12:14:01 -0700	[thread overview]
Message-ID: <CAOnJCUJhb2K89pRETbfTJ=5jHQhWfyfrOUu8zOE77j+id6OpSA@mail.gmail.com> (raw)
In-Reply-To: <CAJF2gTQ8ONde3GRhQgx2Nqvb5X20nTmW8jZEemZKhezRDzP3aQ@mail.gmail.com>

On Thu, Sep 24, 2020 at 9:19 AM Guo Ren <guoren@kernel.org> wrote:
>
> How about this, revert the commit and don't free INIT_DATA_SECTION. I
> think the solution is safe enough, but wast a little memory.
>
> diff --git a/arch/riscv/kernel/vmlinux.lds.S b/arch/riscv/kernel/vmlinux.lds.S
> index f3586e3..34d00d9 100644
> --- a/arch/riscv/kernel/vmlinux.lds.S
> +++ b/arch/riscv/kernel/vmlinux.lds.S
> @@ -22,13 +22,11 @@ SECTIONS
>         /* Beginning of code and text segment */
>         . = LOAD_OFFSET;
>         _start = .;
> -       _stext = .;
>         HEAD_TEXT_SECTION
>         . = ALIGN(PAGE_SIZE);
>
>         __init_begin = .;
>         INIT_TEXT_SECTION(PAGE_SIZE)
> -       INIT_DATA_SECTION(16)
>         . = ALIGN(8);
>         __soc_early_init_table : {
>                 __soc_early_init_table_start = .;
> @@ -55,6 +53,7 @@ SECTIONS
>         . = ALIGN(SECTION_ALIGN);
>         .text : {
>                 _text = .;
> +               _stext = .;
>                 TEXT_TEXT
>                 SCHED_TEXT
>                 CPUIDLE_TEXT
> @@ -67,6 +66,8 @@ SECTIONS
>                 _etext = .;
>         }
>
> +       INIT_DATA_SECTION(16)
> +

I think you need to move EXIT_DATA as well. Currently, we have init
data & text in one section.
In general it is better idea to separate those similar to ARM64.
Additionally, ARM64 applies different mapping for init data & text
as the init data section is marked as non-executable[1]

However, we don't modify any permission for any init sections. Should
we do that as well ?

[1] https://patchwork.kernel.org/patch/9572869/

>         /* Start of data section */
>         _sdata = .;
>         RO_DATA(SECTION_ALIGN)
>
> On Thu, Sep 24, 2020 at 3:36 PM Andreas Schwab <schwab@linux-m68k.org> wrote:
> >
> > On Sep 14 2020, Aurelien Jarno wrote:
> >
> > > How should we proceed to get that fixed in time for 5.9? For the older
> > > branches where it has been backported (so far 5.7 and 5.8), should we
> > > just get that commit reverted instead?
> >
> > Can this please be resolved ASAP?
> >
> > Andreas.
> >
> > --
> > Andreas Schwab, schwab@linux-m68k.org
> > GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510  2552 DF73 E780 A9DA AEC1
> > "And now for something completely different."
>
>
>
> --
> Best Regards
>  Guo Ren
>
> ML: https://lore.kernel.org/linux-csky/
>
> _______________________________________________
> linux-riscv mailing list
> linux-riscv@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-riscv

-- 
Regards,
Atish

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