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Subject: Re: [PATCH v3 4/5] ARM: perf: Allow the use of the PMUv3 driver on
 32bit ARM
To:     Marc Zyngier <marc.zyngier@arm.com>,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org
Cc:     Will Deacon <will.deacon@arm.com>,
        Mark Rutland <mark.rutland@arm.com>,
        Russell King <linux@arm.linux.org.uk>,
        Vince Weaver <vincent.weaver@maine.edu>,
        Peter Zijlstra <peterz@infradead.org>,
        Stefan Wahren <stefan.wahren@i2se.com>,
        Eric Anholt <eric@anholt.net>,
        Florian Fainelli <f.fainelli@gmail.com>
References: <20180518143913.26306-1-marc.zyngier@arm.com>
 <20180518143913.26306-5-marc.zyngier@arm.com>
From:   Vladimir Murzin <vladimir.murzin@arm.com>
Message-ID: <f40d8620-eb57-37be-a2f0-b7bf7a74c087@arm.com>
Date:   Mon, 21 May 2018 10:34:19 +0100
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On 18/05/18 15:39, Marc Zyngier wrote:
> +static inline int read_pmuver(void)
> +{
> +	/* PMUVers is not a signed field */
> +	u32 dfr0 = read_cpuid_ext(CPUID_EXT_DFR0);
> +	return (dfr0 >> 24) & 0xf;
> +}

Should we rule out versions prior v3 here or in __armv8pmu_probe_pmu()?

Thanks
Vladimir