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authorLinus Torvalds <torvalds@linux-foundation.org>2022-08-09 09:29:07 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2022-08-09 09:29:07 -0700
commit5318b987fe9f3430adb0f5d81d07052fd996835b (patch)
tree35b0c7287c7ca98d3a5302aa72e948e3fbec2000 /tools/arch/x86
parenteb555cb5b794f4e12a9897f3d46d5a72104cd4a7 (diff)
parentba6e31af2be96c4d0536f2152ed6f7b6c11bca47 (diff)
downloadlinux-5318b987fe9f3430adb0f5d81d07052fd996835b.tar.gz
Merge tag 'x86_bugs_pbrsb' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 eIBRS fixes from Borislav Petkov:
 "More from the CPU vulnerability nightmares front:

  Intel eIBRS machines do not sufficiently mitigate against RET
  mispredictions when doing a VM Exit therefore an additional RSB,
  one-entry stuffing is needed"

* tag 'x86_bugs_pbrsb' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/speculation: Add LFENCE to RSB fill sequence
  x86/speculation: Add RSB VM Exit protections
Diffstat (limited to 'tools/arch/x86')
-rw-r--r--tools/arch/x86/include/asm/cpufeatures.h1
-rw-r--r--tools/arch/x86/include/asm/msr-index.h4
2 files changed, 5 insertions, 0 deletions
diff --git a/tools/arch/x86/include/asm/cpufeatures.h b/tools/arch/x86/include/asm/cpufeatures.h
index a77b915d36a8..8323ac5b7eee 100644
--- a/tools/arch/x86/include/asm/cpufeatures.h
+++ b/tools/arch/x86/include/asm/cpufeatures.h
@@ -303,6 +303,7 @@
 #define X86_FEATURE_RETHUNK		(11*32+14) /* "" Use REturn THUNK */
 #define X86_FEATURE_UNRET		(11*32+15) /* "" AMD BTB untrain return */
 #define X86_FEATURE_USE_IBPB_FW		(11*32+16) /* "" Use IBPB during runtime firmware calls */
+#define X86_FEATURE_RSB_VMEXIT_LITE	(11*32+17) /* "" Fill RSB on VM-Exit when EIBRS is enabled */
 
 /* Intel-defined CPU features, CPUID level 0x00000007:1 (EAX), word 12 */
 #define X86_FEATURE_AVX_VNNI		(12*32+ 4) /* AVX VNNI instructions */
diff --git a/tools/arch/x86/include/asm/msr-index.h b/tools/arch/x86/include/asm/msr-index.h
index cc615be27a54..e057e039173c 100644
--- a/tools/arch/x86/include/asm/msr-index.h
+++ b/tools/arch/x86/include/asm/msr-index.h
@@ -150,6 +150,10 @@
 						 * are restricted to targets in
 						 * kernel.
 						 */
+#define ARCH_CAP_PBRSB_NO		BIT(24)	/*
+						 * Not susceptible to Post-Barrier
+						 * Return Stack Buffer Predictions.
+						 */
 
 #define MSR_IA32_FLUSH_CMD		0x0000010b
 #define L1D_FLUSH			BIT(0)	/*