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From: Suzuki K Poulose <suzuki.poulose@arm.com>
To: jeremy.linton@arm.com, linux-arm-kernel@lists.infradead.org
Cc: stefan.wahren@i2se.com, mlangsdo@redhat.com,
	julien.thierry@arm.com, marc.zyngier@arm.com,
	catalin.marinas@arm.com, will.deacon@arm.com,
	linux-kernel@vger.kernel.org, Steven.Price@arm.com,
	ykaukab@suse.de, dave.martin@arm.com, shankerd@codeaurora.org
Subject: Re: [PATCH v3 3/7] arm64: kpti: move check for non-vulnerable CPUs to a function
Date: Mon, 14 Jan 2019 11:32:03 +0000
Message-ID: <553c4f17-b504-a7a2-51cf-9c0d6c5d7797@arm.com> (raw)
In-Reply-To: <20190109235544.2992426-4-jeremy.linton@arm.com>

Hi Jeremy,

On 09/01/2019 23:55, Jeremy Linton wrote:
> From: Mian Yousaf Kaukab <ykaukab@suse.de>
> 
> Add is_meltdown_safe() which is a whitelist of known safe cores.
> 
> Signed-off-by: Mian Yousaf Kaukab <ykaukab@suse.de>
> [Moved location of function]
> Signed-off-by: Jeremy Linton <jeremy.linton@arm.com>
> ---
>   arch/arm64/kernel/cpufeature.c | 15 +++++++++++----
>   1 file changed, 11 insertions(+), 4 deletions(-)
> 
> diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
> index 4f272399de89..ab784d7a0083 100644
> --- a/arch/arm64/kernel/cpufeature.c
> +++ b/arch/arm64/kernel/cpufeature.c
> @@ -947,8 +947,7 @@ has_useable_cnp(const struct arm64_cpu_capabilities *entry, int scope)
>   #ifdef CONFIG_UNMAP_KERNEL_AT_EL0
>   static int __kpti_forced; /* 0: not forced, >0: forced on, <0: forced off */
>   
> -static bool unmap_kernel_at_el0(const struct arm64_cpu_capabilities *entry,
> -				int scope)
> +static bool is_cpu_meltdown_safe(void)
>   {
>   	/* List of CPUs that are not vulnerable and don't need KPTI */
>   	static const struct midr_range kpti_safe_list[] = {
> @@ -962,6 +961,15 @@ static bool unmap_kernel_at_el0(const struct arm64_cpu_capabilities *entry,
>   		MIDR_ALL_VERSIONS(MIDR_CORTEX_A73),
>   		{ /* sentinel */ }
>   	};
> +	if (is_midr_in_range_list(read_cpuid_id(), kpti_safe_list))

nit: Does it make sense to rename the list to "meltdown_safe_list", to match the
function name ?

Also also, you may do :

	return is_midr_in_range_list(read_cpuid_id(), kpti_safe_list);

Either way

Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>

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  parent reply index

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-01-09 23:55 [PATCH v3 0/7] arm64: add system vulnerability sysfs entries Jeremy Linton
2019-01-09 23:55 ` [PATCH v3 1/7] sysfs/cpu: Allow individual architectures to select vulnerabilities Jeremy Linton
2019-01-14 10:02   ` Suzuki K Poulose
2019-01-18 15:46     ` Greg KH
2019-01-18 16:31       ` Jeremy Linton
2019-01-09 23:55 ` [PATCH v3 2/7] arm64: add sysfs vulnerability show for spectre v1 Jeremy Linton
2019-01-09 23:55 ` [PATCH v3 3/7] arm64: kpti: move check for non-vulnerable CPUs to a function Jeremy Linton
2019-01-12 10:41   ` Stefan Wahren
2019-01-14 11:32   ` Suzuki K Poulose [this message]
2019-01-18 16:35     ` Jeremy Linton
2019-01-09 23:55 ` [PATCH v3 4/7] arm64: add sysfs vulnerability show for meltdown Jeremy Linton
2019-01-10  9:23   ` Julien Thierry
2019-01-10 14:10     ` Jeremy Linton
2019-01-10 14:16       ` Julien Thierry
2019-01-09 23:55 ` [PATCH v3 5/7] arm64: add sysfs vulnerability show for spectre v2 Jeremy Linton
2019-01-09 23:55 ` [PATCH v3 6/7] arm64: add sysfs vulnerability show for speculative store bypass Jeremy Linton
2019-01-14 10:15   ` Marc Zyngier
2019-01-14 16:37     ` Jeremy Linton
2019-01-14 17:05       ` Marc Zyngier
2019-01-09 23:55 ` [PATCH v3 7/7] arm64: enable generic CPU vulnerabilites support Jeremy Linton
2019-01-15 19:50 ` [PATCH v3 0/7] arm64: add system vulnerability sysfs entries Stefan Wahren
2019-01-15 21:21   ` Jeremy Linton
2019-01-18 18:05     ` Stefan Wahren
2019-01-18 22:22       ` Jeremy Linton
2019-01-19 11:52         ` Stefan Wahren

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