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Date:   Tue, 27 Sep 2022 14:52:24 +0200
From:   Peter Zijlstra <peterz@infradead.org>
To:     Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
Cc:     Juri Lelli <juri.lelli@redhat.com>,
        Vincent Guittot <vincent.guittot@linaro.org>,
        Ricardo Neri <ricardo.neri@intel.com>,
        "Ravi V. Shankar" <ravi.v.shankar@intel.com>,
        Ben Segall <bsegall@google.com>,
        Daniel Bristot de Oliveira <bristot@redhat.com>,
        Dietmar Eggemann <dietmar.eggemann@arm.com>,
        Len Brown <len.brown@intel.com>, Mel Gorman <mgorman@suse.de>,
        "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>,
        Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        Tim Chen <tim.c.chen@linux.intel.com>,
        Valentin Schneider <vschneid@redhat.com>, x86@kernel.org,
        linux-kernel@vger.kernel.org, "Tim C . Chen" <tim.c.chen@intel.com>
Subject: Re: [RFC PATCH 23/23] x86/process: Reset hardware history in context
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Message-ID: <YzLyCD0P7MATFiVM@hirez.programming.kicks-ass.net>
References: <20220909231205.14009-1-ricardo.neri-calderon@linux.intel.com>
 <20220909231205.14009-24-ricardo.neri-calderon@linux.intel.com>
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In-Reply-To: <20220909231205.14009-24-ricardo.neri-calderon@linux.intel.com>
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On Fri, Sep 09, 2022 at 04:12:05PM -0700, Ricardo Neri wrote:

> +void reset_hardware_history(void)
> +{
> +	if (!static_cpu_has(X86_FEATURE_HRESET))
> +		return;
> +
> +	asm volatile("mov %0, %%eax;" __ASM_HRESET "\n" : :
> +		     "r" (hardware_history_features) : "%rax");
> +}

	asm_inline volatile (ALTERNATIVE("", __ASM_HRESET, X86_FEATURE_HRESET)
			     : : "a" (hardware_history_features) : "memory");