diff options
| author | Linus Torvalds <torvalds@linux-foundation.org> | 2021-04-26 10:09:38 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2021-04-26 10:09:38 -0700 |
| commit | 64f8e73de08d11cbe01347340db95b4011872ec5 (patch) | |
| tree | f1a3574482457a91d4eea2af9bc3aeb7b8c26bae /arch/x86/include/asm | |
| parent | eea2647e74cd7bd5d04861ce55fa502de165de14 (diff) | |
| parent | ebca17707e38f2050b188d837bd4646b29a1b0c2 (diff) | |
Merge tag 'x86-splitlock-2021-04-26' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 bus lock detection updates from Thomas Gleixner:
"Support for enhanced split lock detection:
Newer CPUs provide a second mechanism to detect operations with lock
prefix which go accross a cache line boundary. Such operations have to
take bus lock which causes a system wide performance degradation when
these operations happen frequently.
The new mechanism is not using the #AC exception. It triggers #DB and
is restricted to operations in user space. Kernel side split lock
access can only be detected by the #AC based variant.
Contrary to the #AC based mechanism the #DB based variant triggers
_after_ the instruction was executed. The mechanism is CPUID
enumerated and contrary to the #AC version which is based on the magic
TEST_CTRL_MSR and model/family based enumeration on the way to become
architectural"
* tag 'x86-splitlock-2021-04-26' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
Documentation/admin-guide: Change doc for split_lock_detect parameter
x86/traps: Handle #DB for bus lock
x86/cpufeatures: Enumerate #DB for bus lock detection
Diffstat (limited to 'arch/x86/include/asm')
| -rw-r--r-- | arch/x86/include/asm/cpu.h | 7 | ||||
| -rw-r--r-- | arch/x86/include/asm/cpufeatures.h | 1 | ||||
| -rw-r--r-- | arch/x86/include/asm/msr-index.h | 1 |
3 files changed, 7 insertions, 2 deletions
diff --git a/arch/x86/include/asm/cpu.h b/arch/x86/include/asm/cpu.h index da78ccbd493b..0d7fc0e2bfc9 100644 --- a/arch/x86/include/asm/cpu.h +++ b/arch/x86/include/asm/cpu.h @@ -41,12 +41,13 @@ unsigned int x86_family(unsigned int sig); unsigned int x86_model(unsigned int sig); unsigned int x86_stepping(unsigned int sig); #ifdef CONFIG_CPU_SUP_INTEL -extern void __init cpu_set_core_cap_bits(struct cpuinfo_x86 *c); +extern void __init sld_setup(struct cpuinfo_x86 *c); extern void switch_to_sld(unsigned long tifn); extern bool handle_user_split_lock(struct pt_regs *regs, long error_code); extern bool handle_guest_split_lock(unsigned long ip); +extern void handle_bus_lock(struct pt_regs *regs); #else -static inline void __init cpu_set_core_cap_bits(struct cpuinfo_x86 *c) {} +static inline void __init sld_setup(struct cpuinfo_x86 *c) {} static inline void switch_to_sld(unsigned long tifn) {} static inline bool handle_user_split_lock(struct pt_regs *regs, long error_code) { @@ -57,6 +58,8 @@ static inline bool handle_guest_split_lock(unsigned long ip) { return false; } + +static inline void handle_bus_lock(struct pt_regs *regs) {} #endif #ifdef CONFIG_IA32_FEAT_CTL void init_ia32_feat_ctl(struct cpuinfo_x86 *c); diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h index 5e2624a9d890..624116562086 100644 --- a/arch/x86/include/asm/cpufeatures.h +++ b/arch/x86/include/asm/cpufeatures.h @@ -358,6 +358,7 @@ #define X86_FEATURE_AVX512_VPOPCNTDQ (16*32+14) /* POPCNT for vectors of DW/QW */ #define X86_FEATURE_LA57 (16*32+16) /* 5-level page tables */ #define X86_FEATURE_RDPID (16*32+22) /* RDPID instruction */ +#define X86_FEATURE_BUS_LOCK_DETECT (16*32+24) /* Bus Lock detect */ #define X86_FEATURE_CLDEMOTE (16*32+25) /* CLDEMOTE instruction */ #define X86_FEATURE_MOVDIRI (16*32+27) /* MOVDIRI instruction */ #define X86_FEATURE_MOVDIR64B (16*32+28) /* MOVDIR64B instruction */ diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h index 45029354e0a8..fe335d8c1676 100644 --- a/arch/x86/include/asm/msr-index.h +++ b/arch/x86/include/asm/msr-index.h @@ -265,6 +265,7 @@ #define DEBUGCTLMSR_LBR (1UL << 0) /* last branch recording */ #define DEBUGCTLMSR_BTF_SHIFT 1 #define DEBUGCTLMSR_BTF (1UL << 1) /* single-step on branches */ +#define DEBUGCTLMSR_BUS_LOCK_DETECT (1UL << 2) #define DEBUGCTLMSR_TR (1UL << 6) #define DEBUGCTLMSR_BTS (1UL << 7) #define DEBUGCTLMSR_BTINT (1UL << 8) |