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Date:   Wed, 28 Oct 2020 11:18:10 +0000
From:   Catalin Marinas <catalin.marinas@arm.com>
To:     Will Deacon <will@kernel.org>
Cc:     linux-arm-kernel@lists.infradead.org, linux-arch@vger.kernel.org,
        Marc Zyngier <maz@kernel.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Morten Rasmussen <morten.rasmussen@arm.com>,
        Qais Yousef <qais.yousef@arm.com>,
        Suren Baghdasaryan <surenb@google.com>, kernel-team@android.com
Subject: Re: [PATCH 2/6] arm64: Allow mismatched 32-bit EL0 support
Message-ID: <20201028111810.GC13345@gaia>
References: <20201027215118.27003-1-will@kernel.org>
 <20201027215118.27003-3-will@kernel.org>
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On Tue, Oct 27, 2020 at 09:51:14PM +0000, Will Deacon wrote:
> +bool system_has_mismatched_32bit_el0(void)
> +{
> +	u64 reg;
> +	unsigned int fld;
> +
> +	if (!__allow_mismatched_32bit_el0)
> +		return false;
> +
> +	reg = read_sanitised_ftr_reg(SYS_ID_AA64PFR0_EL1);
> +	fld = cpuid_feature_extract_unsigned_field(reg, ID_AA64PFR0_EL0_SHIFT);
> +	return fld == ID_AA64PFR0_EL0_64BIT_ONLY;
> +}

Same here, this reports true even if no 32-bit is available (I have yet
to go through the other patches to see how this function is used).

-- 
Catalin