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s390: add sysfs attributes for spectre 

Set CONFIG_GENERIC_CPU_VULNERABILITIES and provide the two functions
cpu_show_spectre_v1 and cpu_show_spectre_v2 to report the spectre
mitigations.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
hifive-unleashed-5.1
Martin Schwidefsky 2018-03-21 09:38:21 +01:00
parent bc03559971
commit d424986f1d
2 changed files with 20 additions and 0 deletions
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1
arch/s390/Kconfig
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@ -120,6 +120,7 @@ config S390
select GENERIC_CLOCKEVENTS
select GENERIC_CPU_AUTOPROBE
select GENERIC_CPU_DEVICES if !SMP
select GENERIC_CPU_VULNERABILITIES
select GENERIC_FIND_FIRST_BIT
select GENERIC_SMP_IDLE_THREAD
select GENERIC_TIME_VSYSCALL

19
arch/s390/kernel/nospec-branch.c
View File

@ -1,5 +1,6 @@
// SPDX-License-Identifier: GPL-2.0
#include <linux/module.h>
#include <linux/device.h>
#include <asm/nospec-branch.h>
static int __init nobp_setup_early(char *str)
@ -42,6 +43,24 @@ static int __init nospec_report(void)
}
arch_initcall(nospec_report);
#ifdef CONFIG_SYSFS
ssize_t cpu_show_spectre_v1(struct device *dev,
struct device_attribute *attr, char *buf)
{
return sprintf(buf, "Mitigation: __user pointer sanitization\n");
}
ssize_t cpu_show_spectre_v2(struct device *dev,
struct device_attribute *attr, char *buf)
{
if (IS_ENABLED(CC_USING_EXPOLINE) && !nospec_disable)
return sprintf(buf, "Mitigation: execute trampolines\n");
if (__test_facility(82, S390_lowcore.alt_stfle_fac_list))
return sprintf(buf, "Mitigation: limited branch prediction.\n");
return sprintf(buf, "Vulnerable\n");
}
#endif
#ifdef CONFIG_EXPOLINE
int nospec_disable = IS_ENABLED(CONFIG_EXPOLINE_OFF);