[ Upstream commit d424986f1d6b16079b3231db0314923f4f8deed1 ]
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 --- arch/s390/Kconfig | 1 + arch/s390/kernel/nospec-branch.c | 19 +++++++++++++++++++ 2 files changed, 20 insertions(+)
diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig index fbb8fca6f9c2..1c4a595e8224 100644 --- a/arch/s390/Kconfig +++ b/arch/s390/Kconfig @@ -118,6 +118,7 @@ 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 diff --git a/arch/s390/kernel/nospec-branch.c b/arch/s390/kernel/nospec-branch.c index 7387ebace891..73c06d42792d 100644 --- a/arch/s390/kernel/nospec-branch.c +++ b/arch/s390/kernel/nospec-branch.c @@ -1,5 +1,6 @@ // SPDX-License-Identifier: GPL-2.0 #include <linux/module.h> +#include <linux/device.h> #include <asm/facility.h> #include <asm/nospec-branch.h>
@@ -43,6 +44,24 @@ 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);