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 <mcree@orcon.net.nz>
Signed-off-by: Matt Turner <mattst88@gmail.com>
This commit is contained in:
Michael Cree 2018-02-26 22:02:12 +13:00 committed by Matt Turner
parent 54f16b1967
commit 6fd16ce559
3 changed files with 47 additions and 1 deletions

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@ -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

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@ -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

45
arch/alpha/kernel/bugs.c Normal file
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@ -0,0 +1,45 @@
#include <asm/hwrpb.h>
#include <linux/device.h>
#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