linux-kernel - Re: [PATCH] RISC-V: mm: Fix set_satp_mode() for platform not having Sv57

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Date:   Thu, 21 Apr 2022 15:00:05 +0530
From:   Anup Patel <apatel@...tanamicro.com>
To:     Palmer Dabbelt <palmer@...belt.com>,
        Paul Walmsley <paul.walmsley@...ive.com>
Cc:     Alexandre Ghiti <alexandre.ghiti@...onical.com>,
        Atish Patra <atishp@...shpatra.org>,
        Alistair Francis <Alistair.Francis@....com>,
        Anup Patel <anup@...infault.org>,
        linux-riscv <linux-riscv@...ts.infradead.org>,
        "linux-kernel@...r.kernel.org List" <linux-kernel@...r.kernel.org>,
        Mayuresh Chitale <mchitale@...tanamicro.com>
Subject: Re: [PATCH] RISC-V: mm: Fix set_satp_mode() for platform not having Sv57

Hi Palmer,

On Tue, Apr 12, 2022 at 9:04 AM Anup Patel <apatel@...tanamicro.com> wrote:
>
> When Sv57 is not available the satp.MODE test in set_satp_mode() will
> fail and lead to pgdir re-programming for Sv48. The pgdir re-programming
> will fail as well due to pre-existing pgdir entry used for Sv57 and as
> a result kernel fails to boot on RISC-V platform not having Sv57.
>
> To fix above issue, we should clear the pgdir memory in set_satp_mode()
> before re-programming.
>
> Fixes: 011f09d12052 ("riscv: mm: Set sv57 on defaultly")
> Reported-by: Mayuresh Chitale <mchitale@...tanamicro.com>
> Signed-off-by: Anup Patel <apatel@...tanamicro.com>

Can this be considered for 5.18-rcX ?

Regards,
Anup

> ---
>  arch/riscv/mm/init.c | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
> index 9535bea8688c..b0793dc0c291 100644
> --- a/arch/riscv/mm/init.c
> +++ b/arch/riscv/mm/init.c
> @@ -718,6 +718,7 @@ static __init void set_satp_mode(void)
>                 if (!check_l4) {
>                         disable_pgtable_l5();
>                         check_l4 = true;
> +                       memset(early_pg_dir, 0, PAGE_SIZE);
>                         goto retry;
>                 }
>                 disable_pgtable_l4();
> --
> 2.25.1
>