linux-kernel - Re: [PATCH] riscv: alternative: proceed one more instruction for auipc/jalr pair

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Message-ID: <20230119084534.v3asjioao2zyvpje@orel>
Date:   Thu, 19 Jan 2023 09:45:34 +0100
From:   Andrew Jones <ajones@...tanamicro.com>
To:     Jisheng Zhang <jszhang@...nel.org>
Cc:     Paul Walmsley <paul.walmsley@...ive.com>,
        Palmer Dabbelt <palmer@...belt.com>,
        Albert Ou <aou@...s.berkeley.edu>,
        Heiko Stuebner <heiko.stuebner@...ll.eu>,
        linux-riscv@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] riscv: alternative: proceed one more instruction for
 auipc/jalr pair

On Mon, Jan 16, 2023 at 12:28:11AM +0800, Jisheng Zhang wrote:
> If we patched auipc + jalr pair, we'd better proceed one more
> instruction. Andrew pointed out "There's not a problem now, since
> we're only adding a fixup for jal, not jalr, but we should
> future-proof this and there's no reason to revisit an already fixed-up
> instruction anyway."
> 
> Signed-off-by: Jisheng Zhang <jszhang@...nel.org>
> Suggested-by: Andrew Jones <ajones@...tanamicro.com>
> ---
>  arch/riscv/kernel/alternative.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/arch/riscv/kernel/alternative.c b/arch/riscv/kernel/alternative.c
> index fc341b69bf62..2354c69dc7d1 100644
> --- a/arch/riscv/kernel/alternative.c
> +++ b/arch/riscv/kernel/alternative.c
> @@ -122,6 +122,7 @@ void riscv_alternative_fix_offsets(void *alt_ptr, unsigned int len,
>  
>  			riscv_alternative_fix_auipc_jalr(alt_ptr + i * sizeof(u32),
>  							 insn, insn2, patch_offset);
> +			i++;
>  		}
>  
>  		if (riscv_insn_is_jal(insn)) {
> -- 
> 2.38.1
>

Reviewed-by: Andrew Jones <ajones@...tanamicro.com>