diff options
| author | David Woodhouse <dwmw@amazon.co.uk> | 2018-01-25 16:14:15 +0000 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2018-01-26 15:53:18 +0100 |
| commit | 20ffa1caecca4db8f79fe665acdeaa5af815a24d (patch) | |
| tree | 7c96c70a366d24e44e6b85d84921cd837c3fad76 /arch/x86/include | |
| parent | a5b2966364538a0e68c9fa29bc0a3a1651799035 (diff) | |
x86/speculation: Add basic IBPB (Indirect Branch Prediction Barrier) support
Expose indirect_branch_prediction_barrier() for use in subsequent patches.
[ tglx: Add IBPB status to spectre_v2 sysfs file ]
Co-developed-by: KarimAllah Ahmed <karahmed@amazon.de>
Signed-off-by: KarimAllah Ahmed <karahmed@amazon.de>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Cc: gnomes@lxorguk.ukuu.org.uk
Cc: ak@linux.intel.com
Cc: ashok.raj@intel.com
Cc: dave.hansen@intel.com
Cc: arjan@linux.intel.com
Cc: torvalds@linux-foundation.org
Cc: peterz@infradead.org
Cc: bp@alien8.de
Cc: pbonzini@redhat.com
Cc: tim.c.chen@linux.intel.com
Cc: gregkh@linux-foundation.org
Link: https://lkml.kernel.org/r/1516896855-7642-8-git-send-email-dwmw@amazon.co.uk
Diffstat (limited to 'arch/x86/include')
| -rw-r--r-- | arch/x86/include/asm/cpufeatures.h | 2 | ||||
| -rw-r--r-- | arch/x86/include/asm/nospec-branch.h | 13 |
2 files changed, 15 insertions, 0 deletions
diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h index ae3212f14dec..07934b2f8df2 100644 --- a/arch/x86/include/asm/cpufeatures.h +++ b/arch/x86/include/asm/cpufeatures.h @@ -210,6 +210,8 @@ #define X86_FEATURE_MBA ( 7*32+18) /* Memory Bandwidth Allocation */ #define X86_FEATURE_RSB_CTXSW ( 7*32+19) /* Fill RSB on context switches */ +#define X86_FEATURE_IBPB ( 7*32+21) /* Indirect Branch Prediction Barrier enabled*/ + /* Virtualization flags: Linux defined, word 8 */ #define X86_FEATURE_TPR_SHADOW ( 8*32+ 0) /* Intel TPR Shadow */ #define X86_FEATURE_VNMI ( 8*32+ 1) /* Intel Virtual NMI */ diff --git a/arch/x86/include/asm/nospec-branch.h b/arch/x86/include/asm/nospec-branch.h index 4ad41087ce0e..34e384c7208f 100644 --- a/arch/x86/include/asm/nospec-branch.h +++ b/arch/x86/include/asm/nospec-branch.h @@ -218,5 +218,18 @@ static inline void vmexit_fill_RSB(void) #endif } +static inline void indirect_branch_prediction_barrier(void) +{ + asm volatile(ALTERNATIVE("", + "movl %[msr], %%ecx\n\t" + "movl %[val], %%eax\n\t" + "movl $0, %%edx\n\t" + "wrmsr", + X86_FEATURE_IBPB) + : : [msr] "i" (MSR_IA32_PRED_CMD), + [val] "i" (PRED_CMD_IBPB) + : "eax", "ecx", "edx", "memory"); +} + #endif /* __ASSEMBLY__ */ #endif /* __NOSPEC_BRANCH_H__ */ |