linux-kernel - Re: [PATCH V2] arm64/cpufeature: Add get_arm64_ftr_reg

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Message-ID: <20200526150135.GI17051@gaia>
Date:   Tue, 26 May 2020 16:01:35 +0100
From:   Catalin Marinas <catalin.marinas@....com>
To:     Anshuman Khandual <anshuman.khandual@....com>
Cc:     linux-arm-kernel@...ts.infradead.org, mark.rutland@....com,
        Will Deacon <will@...nel.org>,
        Suzuki K Poulose <suzuki.poulose@....com>,
        Mark Brown <broonie@...nel.org>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH V2] arm64/cpufeature: Add get_arm64_ftr_reg_nowarn()

On Tue, May 26, 2020 at 07:09:13PM +0530, Anshuman Khandual wrote:
> @@ -632,8 +654,6 @@ static void __init init_cpu_ftr_reg(u32 sys_reg, u64 new)
>  	const struct arm64_ftr_bits *ftrp;
>  	struct arm64_ftr_reg *reg = get_arm64_ftr_reg(sys_reg);
>  
> -	BUG_ON(!reg);
> -
>  	for (ftrp = reg->ftr_bits; ftrp->width; ftrp++) {
>  		u64 ftr_mask = arm64_ftr_mask(ftrp);
>  		s64 ftr_new = arm64_ftr_value(ftrp, new);
> @@ -762,7 +782,6 @@ static int check_update_ftr_reg(u32 sys_id, int cpu, u64 val, u64 boot)
>  {
>  	struct arm64_ftr_reg *regp = get_arm64_ftr_reg(sys_id);
>  
> -	BUG_ON(!regp);
>  	update_cpu_ftr_reg(regp, val);
>  	if ((boot & regp->strict_mask) == (val & regp->strict_mask))
>  		return 0;
> @@ -776,9 +795,6 @@ static void relax_cpu_ftr_reg(u32 sys_id, int field)
>  	const struct arm64_ftr_bits *ftrp;
>  	struct arm64_ftr_reg *regp = get_arm64_ftr_reg(sys_id);
>  
> -	if (WARN_ON(!regp))
> -		return;

I think Will wanted an early return in all these functions not just
removing the BUG_ON(). I'll let him clarify.

-- 
Catalin