From: Steven Price <steven.price@arm.com>
To: Jeremy Linton <jeremy.linton@arm.com>,
linux-arm-kernel@lists.infradead.org
Cc: mark.rutland@arm.com, suzuki.poulose@arm.com,
marc.zyngier@arm.com, catalin.marinas@arm.com,
will.deacon@arm.com, linux-kernel@vger.kernel.org,
ykaukab@suse.de, dave.martin@arm.com, shankerd@codeaurora.org
Subject: Re: [PATCH 5/6] arm64: add sysfs vulnerability show for speculative store bypass
Date: Fri, 14 Dec 2018 10:34:31 +0000 [thread overview]
Message-ID: <901bdfff-df83-846f-1695-a89e8bbfa787@arm.com> (raw)
In-Reply-To: <20181206234408.1287689-6-jeremy.linton@arm.com>
On 06/12/2018 23:44, Jeremy Linton wrote:
> From: Mian Yousaf Kaukab <ykaukab@suse.de>
>
> Return status based no ssbd_state and the arm64 SSBS feature.
^^ on
> Return string "Unknown" in case CONFIG_ARM64_SSBD is
> disabled or arch workaround2 is not available
> in the firmware.
>
> Signed-off-by: Mian Yousaf Kaukab <ykaukab@suse.de>
> [Added SSBS logic]
> Signed-off-by: Jeremy Linton <jeremy.linton@arm.com>
> ---
> arch/arm64/kernel/cpu_errata.c | 28 ++++++++++++++++++++++++++++
> 1 file changed, 28 insertions(+)
>
> diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c
> index 6505c93d507e..8aeb5ca38db8 100644
> --- a/arch/arm64/kernel/cpu_errata.c
> +++ b/arch/arm64/kernel/cpu_errata.c
> @@ -423,6 +423,7 @@ static bool has_ssbd_mitigation(const struct arm64_cpu_capabilities *entry,
> ssbd_state = ARM64_SSBD_UNKNOWN;
> return false;
>
> + /* machines with mixed mitigation requirements must not return this */
> case SMCCC_RET_NOT_REQUIRED:
> pr_info_once("%s mitigation not required\n", entry->desc);
> ssbd_state = ARM64_SSBD_MITIGATED;
> @@ -828,4 +829,31 @@ ssize_t cpu_show_spectre_v2(struct device *dev, struct device_attribute *attr,
> }
> }
>
> +ssize_t cpu_show_spec_store_bypass(struct device *dev,
> + struct device_attribute *attr, char *buf)
> +{
> + /*
> + * Two assumptions: First, get_ssbd_state() reflects the worse case
> + * for hetrogenous machines, and that if SSBS is supported its
^^^^ SSBD
> + * supported by all cores.
> + */
> + switch (arm64_get_ssbd_state()) {
> + case ARM64_SSBD_MITIGATED:
> + return sprintf(buf, "Not affected\n");
> +
> + case ARM64_SSBD_KERNEL:
> + case ARM64_SSBD_FORCE_ENABLE:
> + if (cpus_have_cap(ARM64_SSBS))
> + return sprintf(buf, "Not affected\n");
> + return sprintf(buf,
> + "Mitigation: Speculative Store Bypass disabled\n");
NIT: To me this reads as the mitigation is disabled. Can we call it
"Speculative Store Bypass Disable" (with a capital 'D' and without the
'd at the end)?
Steve
> +
> + case ARM64_SSBD_FORCE_DISABLE:
> + return sprintf(buf, "Vulnerable\n");
> +
> + default: /* ARM64_SSBD_UNKNOWN*/
> + return sprintf(buf, "Unknown\n");
> + }
> +}
> +
> #endif
>
next prev parent reply other threads:[~2018-12-14 10:34 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-06 23:44 [PATCH 0/6] add system vulnerability sysfs entries Jeremy Linton
2018-12-06 23:44 ` [PATCH 1/6] arm64: kpti: move check for non-vulnerable CPUs to a function Jeremy Linton
2018-12-13 9:13 ` Julien Thierry
2018-12-12 14:36 ` Jeremy Linton
2018-12-06 23:44 ` [PATCH 2/6] arm64: add sysfs vulnerability show for meltdown Jeremy Linton
2018-12-13 9:23 ` Julien Thierry
2018-12-13 10:46 ` Julien Thierry
2018-12-12 14:49 ` Jeremy Linton
2018-12-14 8:55 ` Julien Thierry
2018-12-06 23:44 ` [PATCH 3/6] arm64: add sysfs vulnerability show for spectre v1 Jeremy Linton
2018-12-06 23:44 ` [PATCH 4/6] arm64: add sysfs vulnerability show for spectre v2 Jeremy Linton
2018-12-13 11:09 ` Julien Thierry
2019-01-02 22:19 ` Jeremy Linton
2018-12-06 23:44 ` [PATCH 5/6] arm64: add sysfs vulnerability show for speculative store bypass Jeremy Linton
2018-12-14 10:34 ` Steven Price [this message]
2018-12-14 10:36 ` Will Deacon
2018-12-14 10:41 ` Steven Price
2018-12-14 11:28 ` Dave Martin
2018-12-14 11:33 ` Will Deacon
2018-12-06 23:44 ` [PATCH 6/6] arm64: enable generic CPU vulnerabilites support Jeremy Linton
2018-12-13 12:07 ` [PATCH 0/6] add system vulnerability sysfs entries Dave Martin
2018-12-12 15:48 ` Jeremy Linton
2018-12-13 19:26 ` Dave Martin
-- strict thread matches above, loose matches on Subject: below --
2018-08-07 18:14 [PATCH 0/6] arm64: add support for generic cpu vulnerabilities Mian Yousaf Kaukab
2018-08-07 18:14 ` [PATCH 5/6] arm64: add sysfs vulnerability show for speculative store bypass Mian Yousaf Kaukab
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