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-rw-r--r--arch/x86/include/asm/cpufeatures.h14
-rw-r--r--arch/x86/include/asm/msr-index.h12
-rw-r--r--arch/x86/include/asm/nospec-branch.h23
-rw-r--r--arch/x86/include/asm/processor.h4
4 files changed, 47 insertions, 6 deletions
diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
index cb8ca46213be..b69b0d7756aa 100644
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -14,7 +14,7 @@
* Defines x86 CPU feature bits
*/
#define NCAPINTS 21 /* N 32-bit words worth of info */
-#define NBUGINTS 1 /* N 32-bit bug flags */
+#define NBUGINTS 2 /* N 32-bit bug flags */
/*
* Note: If the comment begins with a quoted string, that string is used
@@ -309,6 +309,10 @@
#define X86_FEATURE_SMBA (11*32+21) /* "" Slow Memory Bandwidth Allocation */
#define X86_FEATURE_BMEC (11*32+22) /* "" Bandwidth Monitoring Event Configuration */
+#define X86_FEATURE_SRSO (11*32+24) /* "" AMD BTB untrain RETs */
+#define X86_FEATURE_SRSO_ALIAS (11*32+25) /* "" AMD BTB untrain RETs through aliasing */
+#define X86_FEATURE_IBPB_ON_VMEXIT (11*32+26) /* "" Issue an IBPB only on VMEXIT */
+
/* Intel-defined CPU features, CPUID level 0x00000007:1 (EAX), word 12 */
#define X86_FEATURE_AVX_VNNI (12*32+ 4) /* AVX VNNI instructions */
#define X86_FEATURE_AVX512_BF16 (12*32+ 5) /* AVX512 BFLOAT16 instructions */
@@ -442,6 +446,10 @@
#define X86_FEATURE_AUTOIBRS (20*32+ 8) /* "" Automatic IBRS */
#define X86_FEATURE_NO_SMM_CTL_MSR (20*32+ 9) /* "" SMM_CTL MSR is not present */
+#define X86_FEATURE_SBPB (20*32+27) /* "" Selective Branch Prediction Barrier */
+#define X86_FEATURE_IBPB_BRTYPE (20*32+28) /* "" MSR_PRED_CMD[IBPB] flushes all branch type predictions */
+#define X86_FEATURE_SRSO_NO (20*32+29) /* "" CPU is not affected by SRSO */
+
/*
* BUG word(s)
*/
@@ -483,5 +491,9 @@
#define X86_BUG_RETBLEED X86_BUG(27) /* CPU is affected by RETBleed */
#define X86_BUG_EIBRS_PBRSB X86_BUG(28) /* EIBRS is vulnerable to Post Barrier RSB Predictions */
#define X86_BUG_SMT_RSB X86_BUG(29) /* CPU is vulnerable to Cross-Thread Return Address Predictions */
+#define X86_BUG_GDS X86_BUG(30) /* CPU is affected by Gather Data Sampling */
+/* BUG word 2 */
+#define X86_BUG_SRSO X86_BUG(1*32 + 0) /* AMD SRSO bug */
+#define X86_BUG_DIV0 X86_BUG(1*32 + 1) /* AMD DIV0 speculation bug */
#endif /* _ASM_X86_CPUFEATURES_H */
diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h
index a00a53e15ab7..1d111350197f 100644
--- a/arch/x86/include/asm/msr-index.h
+++ b/arch/x86/include/asm/msr-index.h
@@ -57,6 +57,7 @@
#define MSR_IA32_PRED_CMD 0x00000049 /* Prediction Command */
#define PRED_CMD_IBPB BIT(0) /* Indirect Branch Prediction Barrier */
+#define PRED_CMD_SBPB BIT(7) /* Selective Branch Prediction Barrier */
#define MSR_PPIN_CTL 0x0000004e
#define MSR_PPIN 0x0000004f
@@ -155,6 +156,15 @@
* Not susceptible to Post-Barrier
* Return Stack Buffer Predictions.
*/
+#define ARCH_CAP_GDS_CTRL BIT(25) /*
+ * CPU is vulnerable to Gather
+ * Data Sampling (GDS) and
+ * has controls for mitigation.
+ */
+#define ARCH_CAP_GDS_NO BIT(26) /*
+ * CPU is not vulnerable to Gather
+ * Data Sampling (GDS).
+ */
#define ARCH_CAP_XAPIC_DISABLE BIT(21) /*
* IA32_XAPIC_DISABLE_STATUS MSR
@@ -178,6 +188,8 @@
#define RNGDS_MITG_DIS BIT(0) /* SRBDS support */
#define RTM_ALLOW BIT(1) /* TSX development mode */
#define FB_CLEAR_DIS BIT(3) /* CPU Fill buffer clear disable */
+#define GDS_MITG_DIS BIT(4) /* Disable GDS mitigation */
+#define GDS_MITG_LOCKED BIT(5) /* GDS mitigation locked */
#define MSR_IA32_SYSENTER_CS 0x00000174
#define MSR_IA32_SYSENTER_ESP 0x00000175
diff --git a/arch/x86/include/asm/nospec-branch.h b/arch/x86/include/asm/nospec-branch.h
index 1a65cf4acb2b..3faf044569a5 100644
--- a/arch/x86/include/asm/nospec-branch.h
+++ b/arch/x86/include/asm/nospec-branch.h
@@ -211,7 +211,8 @@
* eventually turn into it's own annotation.
*/
.macro VALIDATE_UNRET_END
-#if defined(CONFIG_NOINSTR_VALIDATION) && defined(CONFIG_CPU_UNRET_ENTRY)
+#if defined(CONFIG_NOINSTR_VALIDATION) && \
+ (defined(CONFIG_CPU_UNRET_ENTRY) || defined(CONFIG_CPU_SRSO))
ANNOTATE_RETPOLINE_SAFE
nop
#endif
@@ -289,13 +290,18 @@
*/
.macro UNTRAIN_RET
#if defined(CONFIG_CPU_UNRET_ENTRY) || defined(CONFIG_CPU_IBPB_ENTRY) || \
- defined(CONFIG_CALL_DEPTH_TRACKING)
+ defined(CONFIG_CALL_DEPTH_TRACKING) || defined(CONFIG_CPU_SRSO)
VALIDATE_UNRET_END
ALTERNATIVE_3 "", \
CALL_ZEN_UNTRAIN_RET, X86_FEATURE_UNRET, \
"call entry_ibpb", X86_FEATURE_ENTRY_IBPB, \
__stringify(RESET_CALL_DEPTH), X86_FEATURE_CALL_DEPTH
#endif
+
+#ifdef CONFIG_CPU_SRSO
+ ALTERNATIVE_2 "", "call srso_untrain_ret", X86_FEATURE_SRSO, \
+ "call srso_untrain_ret_alias", X86_FEATURE_SRSO_ALIAS
+#endif
.endm
.macro UNTRAIN_RET_FROM_CALL
@@ -307,6 +313,11 @@
"call entry_ibpb", X86_FEATURE_ENTRY_IBPB, \
__stringify(RESET_CALL_DEPTH_FROM_CALL), X86_FEATURE_CALL_DEPTH
#endif
+
+#ifdef CONFIG_CPU_SRSO
+ ALTERNATIVE_2 "", "call srso_untrain_ret", X86_FEATURE_SRSO, \
+ "call srso_untrain_ret_alias", X86_FEATURE_SRSO_ALIAS
+#endif
.endm
@@ -332,6 +343,8 @@ extern retpoline_thunk_t __x86_indirect_jump_thunk_array[];
extern void __x86_return_thunk(void);
extern void zen_untrain_ret(void);
+extern void srso_untrain_ret(void);
+extern void srso_untrain_ret_alias(void);
extern void entry_ibpb(void);
#ifdef CONFIG_CALL_THUNKS
@@ -479,11 +492,11 @@ void alternative_msr_write(unsigned int msr, u64 val, unsigned int feature)
: "memory");
}
+extern u64 x86_pred_cmd;
+
static inline void indirect_branch_prediction_barrier(void)
{
- u64 val = PRED_CMD_IBPB;
-
- alternative_msr_write(MSR_IA32_PRED_CMD, val, X86_FEATURE_USE_IBPB);
+ alternative_msr_write(MSR_IA32_PRED_CMD, x86_pred_cmd, X86_FEATURE_USE_IBPB);
}
/* The Intel SPEC CTRL MSR base value cache */
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index d46300e94f85..973db0406528 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -682,9 +682,13 @@ extern u16 get_llc_id(unsigned int cpu);
#ifdef CONFIG_CPU_SUP_AMD
extern u32 amd_get_nodes_per_socket(void);
extern u32 amd_get_highest_perf(void);
+extern bool cpu_has_ibpb_brtype_microcode(void);
+extern void amd_clear_divider(void);
#else
static inline u32 amd_get_nodes_per_socket(void) { return 0; }
static inline u32 amd_get_highest_perf(void) { return 0; }
+static inline bool cpu_has_ibpb_brtype_microcode(void) { return false; }
+static inline void amd_clear_divider(void) { }
#endif
extern unsigned long arch_align_stack(unsigned long sp);