lkml.org 
[lkml]   [2018]   [Dec]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH 4/6] arm64: add sysfs vulnerability show for spectre v2
From
Date


On 06/12/2018 23:44, Jeremy Linton wrote:
> Add code to track whether all the cores in the machine are
> vulnerable, and whether all the vulnerable cores have been
> mitigated.
>
> Once we have that information we can add the sysfs stub and
> provide an accurate view of what is known about the machine.
>
> Signed-off-by: Jeremy Linton <jeremy.linton@arm.com>
> ---
> arch/arm64/kernel/cpu_errata.c | 72 +++++++++++++++++++++++++++++++---
> 1 file changed, 67 insertions(+), 5 deletions(-)
>
> diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c
> index 559ecdee6fd2..6505c93d507e 100644
> --- a/arch/arm64/kernel/cpu_errata.c
> +++ b/arch/arm64/kernel/cpu_errata.c

[...]

> @@ -766,4 +812,20 @@ ssize_t cpu_show_spectre_v1(struct device *dev, struct device_attribute *attr,
> return sprintf(buf, "Mitigation: __user pointer sanitization\n");
> }
>
> +ssize_t cpu_show_spectre_v2(struct device *dev, struct device_attribute *attr,
> + char *buf)
> +{
> + switch (__spectrev2_safe) {
> + case A64_SV2_SAFE:
> + return sprintf(buf, "Not affected\n");
> + case A64_SV2_UNSAFE:
> + if (__hardenbp_enab == A64_HBP_MIT)
> + return sprintf(buf,
> + "Mitigation: Branch predictor hardening\n");
> + return sprintf(buf, "Vulnerable\n");
> + default:
> + return sprintf(buf, "Unknown\n");
> + }

Again I see that we are going to display "Unknown" when the mitigation
is not built in.

Couldn't we make that CONFIG_GENERIC_CPU_VULNERABILITIES check whether a
CPU is vulnerable or not even if the mitigation is not implemented? It's
just checking the list of MIDRs.

Thanks,

--
Julien Thierry

\
 
 \ /
  Last update: 2018-12-13 12:11    [W:0.241 / U:15.004 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site