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authorLinus Torvalds <torvalds@linux-foundation.org>2018-06-24 19:48:30 +0800
committerLinus Torvalds <torvalds@linux-foundation.org>2018-06-24 19:48:30 +0800
commit177d363e720c9a940282a295acbd36c2657cc279 (patch)
tree69141a102f050cc2c3cdd621e6fc0a83b318bd19
parent2da2ca24a38f0200111e3b8823c08d02cb59d362 (diff)
parenteab6870fee877258122a042bfd99ee7908c40280 (diff)
downloadlinux-stericsson-177d363e720c9a940282a295acbd36c2657cc279.tar.gz
Merge branch 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 pti fixes from Thomas Gleixner: "Two small updates for the speculative distractions: - Make it more clear to the compiler that array_index_mask_nospec() is not subject for optimizations. It's not perfect, but ... - Don't report XEN PV guests as vulnerable because their mitigation state depends on the hypervisor. Report unknown and refer to the hypervisor requirement" * 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/spectre_v1: Disable compiler optimizations over array_index_mask_nospec() x86/pti: Don't report XenPV as vulnerable
-rw-r--r--arch/x86/include/asm/barrier.h2
-rw-r--r--arch/x86/kernel/cpu/bugs.c4
2 files changed, 5 insertions, 1 deletions
diff --git a/arch/x86/include/asm/barrier.h b/arch/x86/include/asm/barrier.h
index 042b5e892ed1..14de0432d288 100644
--- a/arch/x86/include/asm/barrier.h
+++ b/arch/x86/include/asm/barrier.h
@@ -38,7 +38,7 @@ static inline unsigned long array_index_mask_nospec(unsigned long index,
{
unsigned long mask;
- asm ("cmp %1,%2; sbb %0,%0;"
+ asm volatile ("cmp %1,%2; sbb %0,%0;"
:"=r" (mask)
:"g"(size),"r" (index)
:"cc");
diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index cd0fda1fff6d..404df26b7de8 100644
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -27,6 +27,7 @@
#include <asm/pgtable.h>
#include <asm/set_memory.h>
#include <asm/intel-family.h>
+#include <asm/hypervisor.h>
static void __init spectre_v2_select_mitigation(void);
static void __init ssb_select_mitigation(void);
@@ -664,6 +665,9 @@ static ssize_t cpu_show_common(struct device *dev, struct device_attribute *attr
if (boot_cpu_has(X86_FEATURE_PTI))
return sprintf(buf, "Mitigation: PTI\n");
+ if (hypervisor_is_type(X86_HYPER_XEN_PV))
+ return sprintf(buf, "Unknown (XEN PV detected, hypervisor mitigation required)\n");
+
break;
case X86_BUG_SPECTRE_V1: