linux-kernel - Re: [PATCH 2/8] riscv: cpufeature: detect RISCV_ALTERNATIVES_EARLY

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Message-ID: <2057655.bB369e8A3T@diego>
Date:   Fri, 07 Oct 2022 11:38:08 +0200
From:   Heiko Stübner <heiko@...ech.de>
To:     Paul Walmsley <paul.walmsley@...ive.com>,
        Palmer Dabbelt <palmer@...belt.com>,
        Albert Ou <aou@...s.berkeley.edu>,
        linux-riscv@...ts.infradead.org
Cc:     linux-riscv@...ts.infradead.org, linux-kernel@...r.kernel.org,
        Jisheng Zhang <jszhang@...nel.org>
Subject: Re: [PATCH 2/8] riscv: cpufeature: detect RISCV_ALTERNATIVES_EARLY_BOOT earlier

Am Donnerstag, 6. Oktober 2022, 09:08:12 CEST schrieb Jisheng Zhang:
> Now, the riscv_cpufeature_patch_func() do nothing in the stage of
> RISCV_ALTERNATIVES_EARLY_BOOT. We can move the detection of "early
> boot" stage earlier.
> 
> In following patch, we will make riscv_cpufeature_patch_func() scans
> all ISA extensions.
> 
> Signed-off-by: Jisheng Zhang <jszhang@...nel.org>
> ---
>  arch/riscv/kernel/cpufeature.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
> index 03611b3ef45e..afa54635c180 100644
> --- a/arch/riscv/kernel/cpufeature.c
> +++ b/arch/riscv/kernel/cpufeature.c
> @@ -307,6 +307,9 @@ void __init_or_module riscv_cpufeature_patch_func(struct alt_entry *begin,
>  	struct alt_entry *alt;
>  	u32 tmp;
>  
> +	if (stage == RISCV_ALTERNATIVES_EARLY_BOOT)
> +		return;
> +

This will work as long as no extension needs early patching,
but we can cross that bridge when this happens :-)

Reviewed-by: Heiko Stuebner <heiko@...ech.de>

>  	for (alt = begin; alt < end; alt++) {
>  		if (alt->vendor_id != 0)
>  			continue;
>