summaryrefslogtreecommitdiff
path: root/arch/x86/include/asm/thread_info.h
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2020-03-31 05:35:52 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2020-03-31 05:35:52 +0300
commit2853d5fafb1e21707e89aa2e227c90bb2c1ea4a9 (patch)
treefc8243bcf4a75902ef843ec65fc06a9d65b187e1 /arch/x86/include/asm/thread_info.h
parentd5f744f9a2ac9ca6d5baf72e97ce6dc4c2f19fe4 (diff)
parenta6a60741035bb48ca8d9f92a138958818148064c (diff)
downloadlinux-2853d5fafb1e21707e89aa2e227c90bb2c1ea4a9.tar.xz
Merge tag 'x86-splitlock-2020-03-30' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 splitlock updates from Thomas Gleixner: "Support for 'split lock' detection: Atomic operations (lock prefixed instructions) which span two cache lines have to acquire the global bus lock. This is at least 1k cycles slower than an atomic operation within a cache line and disrupts performance on other cores. Aside of performance disruption this is a unpriviledged form of DoS. Some newer CPUs have the capability to raise an #AC trap when such an operation is attempted. The detection is by default enabled in warning mode which will warn once when a user space application is caught. A command line option allows to disable the detection or to select fatal mode which will terminate offending applications with SIGBUS" * tag 'x86-splitlock-2020-03-30' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/split_lock: Avoid runtime reads of the TEST_CTRL MSR x86/split_lock: Rework the initialization flow of split lock detection x86/split_lock: Enable split lock detection by kernel
Diffstat (limited to 'arch/x86/include/asm/thread_info.h')
-rw-r--r--arch/x86/include/asm/thread_info.h4
1 files changed, 3 insertions, 1 deletions
diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h
index 384cdde10680..8de8ceccb8bc 100644
--- a/arch/x86/include/asm/thread_info.h
+++ b/arch/x86/include/asm/thread_info.h
@@ -92,6 +92,7 @@ struct thread_info {
#define TIF_NOCPUID 15 /* CPUID is not accessible in userland */
#define TIF_NOTSC 16 /* TSC is not accessible in userland */
#define TIF_IA32 17 /* IA32 compatibility process */
+#define TIF_SLD 18 /* Restore split lock detection on context switch */
#define TIF_MEMDIE 20 /* is terminating due to OOM killer */
#define TIF_POLLING_NRFLAG 21 /* idle is polling for TIF_NEED_RESCHED */
#define TIF_IO_BITMAP 22 /* uses I/O bitmap */
@@ -121,6 +122,7 @@ struct thread_info {
#define _TIF_NOCPUID (1 << TIF_NOCPUID)
#define _TIF_NOTSC (1 << TIF_NOTSC)
#define _TIF_IA32 (1 << TIF_IA32)
+#define _TIF_SLD (1 << TIF_SLD)
#define _TIF_POLLING_NRFLAG (1 << TIF_POLLING_NRFLAG)
#define _TIF_IO_BITMAP (1 << TIF_IO_BITMAP)
#define _TIF_FORCED_TF (1 << TIF_FORCED_TF)
@@ -139,7 +141,7 @@ struct thread_info {
/* flags to check in __switch_to() */
#define _TIF_WORK_CTXSW_BASE \
(_TIF_NOCPUID | _TIF_NOTSC | _TIF_BLOCKSTEP | \
- _TIF_SSBD | _TIF_SPEC_FORCE_UPDATE)
+ _TIF_SSBD | _TIF_SPEC_FORCE_UPDATE | _TIF_SLD)
/*
* Avoid calls to __switch_to_xtra() on UP as STIBP is not evaluated.