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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/msr-index.h | |
| parent | d5f744f9a2ac9ca6d5baf72e97ce6dc4c2f19fe4 (diff) | |
| parent | a6a60741035bb48ca8d9f92a138958818148064c (diff) | |
| download | linux-2853d5fafb1e21707e89aa2e227c90bb2c1ea4a9.tar.bz2 | |
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/msr-index.h')
| -rw-r--r-- | arch/x86/include/asm/msr-index.h | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h index d5e517d1c3dd..12c9684d59ba 100644 --- a/arch/x86/include/asm/msr-index.h +++ b/arch/x86/include/asm/msr-index.h @@ -41,6 +41,10 @@ /* Intel MSRs. Some also available on other CPUs */ +#define MSR_TEST_CTRL 0x00000033 +#define MSR_TEST_CTRL_SPLIT_LOCK_DETECT_BIT 29 +#define MSR_TEST_CTRL_SPLIT_LOCK_DETECT BIT(MSR_TEST_CTRL_SPLIT_LOCK_DETECT_BIT) + #define MSR_IA32_SPEC_CTRL 0x00000048 /* Speculation Control */ #define SPEC_CTRL_IBRS BIT(0) /* Indirect Branch Restricted Speculation */ #define SPEC_CTRL_STIBP_SHIFT 1 /* Single Thread Indirect Branch Predictor (STIBP) bit */ @@ -70,6 +74,11 @@ */ #define MSR_IA32_UMWAIT_CONTROL_TIME_MASK (~0x03U) +/* Abbreviated from Intel SDM name IA32_CORE_CAPABILITIES */ +#define MSR_IA32_CORE_CAPS 0x000000cf +#define MSR_IA32_CORE_CAPS_SPLIT_LOCK_DETECT_BIT 5 +#define MSR_IA32_CORE_CAPS_SPLIT_LOCK_DETECT BIT(MSR_IA32_CORE_CAPS_SPLIT_LOCK_DETECT_BIT) + #define MSR_PKG_CST_CONFIG_CONTROL 0x000000e2 #define NHM_C3_AUTO_DEMOTE (1UL << 25) #define NHM_C1_AUTO_DEMOTE (1UL << 26) |