linux-kernel - Re: [PATCH v3 16/20] arm64: entry: Add fake CPU feature for unmapping the kernel at EL0

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Message-ID: <20171206141138.33mw3tmhwfuh6x3y@lakrids.cambridge.arm.com>
Date:   Wed, 6 Dec 2017 14:11:39 +0000
From:   Mark Rutland <mark.rutland@....com>
To:     Will Deacon <will.deacon@....com>
Cc:     linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        catalin.marinas@....com, ard.biesheuvel@...aro.org,
        sboyd@...eaurora.org, dave.hansen@...ux.intel.com,
        keescook@...omium.org, msalter@...hat.com, labbott@...hat.com,
        tglx@...utronix.de
Subject: Re: [PATCH v3 16/20] arm64: entry: Add fake CPU feature for
 unmapping the kernel at EL0

On Wed, Dec 06, 2017 at 12:35:35PM +0000, Will Deacon wrote:
> +static bool unmap_kernel_at_el0(const struct arm64_cpu_capabilities *entry,
> +				int __unused)
> +{
> +	/* Forced on command line? */
> +	if (__kpti_forced) {
> +		pr_info("kernel page table isolation forced %s by command line option\n",
> +			__kpti_forced > 0 ? "ON" : "OFF");
> +		return __kpti_forced > 0;
> +	}

I think we want this to be a pr_info_once() so that we don't print this
for late-onlined secondaries due to verify_local_cpu_features().

With that changed:

Reviewed-by: Mark Rutland <mark.rutland@....com>

Thanks,
Mark.