From 6fd16ce5590e30d0ed8b21e977102361ff9f92ef Mon Sep 17 00:00:00 2001 From: Michael Cree Date: Mon, 26 Feb 2018 22:02:12 +1300 Subject: [PATCH] alpha: Implement CPU vulnerabilities sysfs functions. Implement the CPU vulnerabilty show functions for meltdown, spectre_v1 and spectre_v2 on Alpha. Tests on XP1000 (EV67/667MHz) and ES45 (EV68CB/1.25GHz) show them to be vulnerable to Meltdown and Spectre V1. In the case of Meltdown I saw a 1 to 2% success rate in reading bytes on the XP1000 and 50 to 60% success rate on the ES45. (This compares to 99.97% success reported for Intel CPUs.) Report EV6 and later CPUs as vulnerable. Tests on PWS600au (EV56/600MHz) for Spectre V1 attack were unsuccessful (though I did not try particularly hard) so mark EV4 through to EV56 as not vulnerable. Signed-off-by: Michael Cree Signed-off-by: Matt Turner --- arch/alpha/Kconfig | 1 + arch/alpha/kernel/Makefile | 2 +- arch/alpha/kernel/bugs.c | 45 ++++++++++++++++++++++++++++++++++++++ 3 files changed, 47 insertions(+), 1 deletion(-) create mode 100644 arch/alpha/kernel/bugs.c diff --git a/arch/alpha/Kconfig b/arch/alpha/Kconfig index e96adcbcab41..b2022885ced8 100644 --- a/arch/alpha/Kconfig +++ b/arch/alpha/Kconfig @@ -18,6 +18,7 @@ config ALPHA select ARCH_HAVE_NMI_SAFE_CMPXCHG select AUDIT_ARCH select GENERIC_CLOCKEVENTS + select GENERIC_CPU_VULNERABILITIES select GENERIC_SMP_IDLE_THREAD select GENERIC_STRNCPY_FROM_USER select GENERIC_STRNLEN_USER diff --git a/arch/alpha/kernel/Makefile b/arch/alpha/kernel/Makefile index bf7b41fa7b01..5a74581bf0ee 100644 --- a/arch/alpha/kernel/Makefile +++ b/arch/alpha/kernel/Makefile @@ -9,7 +9,7 @@ ccflags-y := -Wno-sign-compare obj-y := entry.o traps.o process.o osf_sys.o irq.o \ irq_alpha.o signal.o setup.o ptrace.o time.o \ - systbls.o err_common.o io.o + systbls.o err_common.o io.o bugs.o obj-$(CONFIG_VGA_HOSE) += console.o obj-$(CONFIG_SMP) += smp.o diff --git a/arch/alpha/kernel/bugs.c b/arch/alpha/kernel/bugs.c new file mode 100644 index 000000000000..08cc10d7fa17 --- /dev/null +++ b/arch/alpha/kernel/bugs.c @@ -0,0 +1,45 @@ + +#include +#include + + +#ifdef CONFIG_SYSFS + +static int cpu_is_ev6_or_later(void) +{ + struct percpu_struct *cpu; + unsigned long cputype; + + cpu = (struct percpu_struct *)((char *)hwrpb + hwrpb->processor_offset); + cputype = cpu->type & 0xffffffff; + /* Include all of EV6, EV67, EV68, EV7, EV79 and EV69. */ + return (cputype == EV6_CPU) || ((cputype >= EV67_CPU) && (cputype <= EV69_CPU)); +} + +ssize_t cpu_show_meltdown(struct device *dev, + struct device_attribute *attr, char *buf) +{ + if (cpu_is_ev6_or_later()) + return sprintf(buf, "Vulnerable\n"); + else + return sprintf(buf, "Not affected\n"); +} + +ssize_t cpu_show_spectre_v1(struct device *dev, + struct device_attribute *attr, char *buf) +{ + if (cpu_is_ev6_or_later()) + return sprintf(buf, "Vulnerable\n"); + else + return sprintf(buf, "Not affected\n"); +} + +ssize_t cpu_show_spectre_v2(struct device *dev, + struct device_attribute *attr, char *buf) +{ + if (cpu_is_ev6_or_later()) + return sprintf(buf, "Vulnerable\n"); + else + return sprintf(buf, "Not affected\n"); +} +#endif