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| author |   Linus Torvalds <torvalds@linux-foundation.org> | 2020-03-30 19:35:52 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-03-30 19:35:52 -0700 |
| commit | 2853d5fafb1e21707e89aa2e227c90bb2c1ea4a9 (patch) | |
| tree | fc8243bcf4a75902ef843ec65fc06a9d65b187e1 /arch/x86/include/asm/thread_info.h | |
| parent | Merge tag 'x86-entry-2020-03-30' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip (diff) | |
| parent | x86/split_lock: Avoid runtime reads of the TEST_CTRL MSR (diff) | |
| download | linux-dev-2853d5fafb1e21707e89aa2e227c90bb2c1ea4a9.tar.xz linux-dev-2853d5fafb1e21707e89aa2e227c90bb2c1ea4a9.zip | |
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.h | 4 |
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. |