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From:   Anup Patel <anup@brainfault.org>
Date:   Mon, 28 Feb 2022 15:36:59 +0530
Message-ID: <CAAhSdy0Vzdx0y5Kt7JWq6QFRR4OO5Ea5PNF=pN3Nu0Q28r+CNA@mail.gmail.com>
Subject: Re: [PATCH v5 5/6] RISC-V: Do no continue isa string parsing without
 correct XLEN
To:     Atish Patra <atishp@rivosinc.com>
Cc:     "linux-kernel@vger.kernel.org List" <linux-kernel@vger.kernel.org>,
        Heiko Stuebner <heiko@sntech.de>,
        Albert Ou <aou@eecs.berkeley.edu>,
        Atish Patra <atishp@atishpatra.org>,
        Damien Le Moal <damien.lemoal@wdc.com>,
        DTML <devicetree@vger.kernel.org>,
        Jisheng Zhang <jszhang@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>,
        linux-riscv <linux-riscv@lists.infradead.org>,
        Palmer Dabbelt <palmer@dabbelt.com>,
        Paul Walmsley <paul.walmsley@sifive.com>,
        Rob Herring <robh+dt@kernel.org>
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On Wed, Feb 23, 2022 at 2:18 AM Atish Patra <atishp@rivosinc.com> wrote:
>
> The isa string should begin with either rv64 or rv32. Otherwise, it is
> an incorrect isa string. Currently, the string parsing continues even if
> it doesnot begin with current XLEN.
>
> Fix this by checking if it found "rv64" or "rv32" in the beginning.
>
> Tested-by: Heiko Stuebner <heiko@sntech.de>
> Signed-off-by: Atish Patra <atishp@rivosinc.com>

Looks good to me.

Reviewed-by: Anup Patel <anup@brainfault.org>

Regards,
Anup

> ---
>  arch/riscv/kernel/cpufeature.c | 5 +++++
>  1 file changed, 5 insertions(+)
>
> diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
> index c6693873e95c..f3a4b0619aa0 100644
> --- a/arch/riscv/kernel/cpufeature.c
> +++ b/arch/riscv/kernel/cpufeature.c
> @@ -84,6 +84,7 @@ void __init riscv_fill_hwcap(void)
>         for_each_of_cpu_node(node) {
>                 unsigned long this_hwcap = 0;
>                 DECLARE_BITMAP(this_isa, RISCV_ISA_EXT_MAX);
> +               const char *temp;
>
>                 if (riscv_of_processor_hartid(node) < 0)
>                         continue;
> @@ -93,6 +94,7 @@ void __init riscv_fill_hwcap(void)
>                         continue;
>                 }
>
> +               temp = isa;
>  #if IS_ENABLED(CONFIG_32BIT)
>                 if (!strncmp(isa, "rv32", 4))
>                         isa += 4;
> @@ -100,6 +102,9 @@ void __init riscv_fill_hwcap(void)
>                 if (!strncmp(isa, "rv64", 4))
>                         isa += 4;
>  #endif
> +               /* The riscv,isa DT property must start with rv64 or rv32 */
> +               if (temp == isa)
> +                       continue;
>                 bitmap_zero(this_isa, RISCV_ISA_EXT_MAX);
>                 for (; *isa; ++isa) {
>                         const char *ext = isa++;
> --
> 2.30.2
>