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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-18 17:35:05 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-18 17:39:31 +0000
commit85c675d0d09a45a135bddd15d7b385f8758c32fb (patch)
tree76267dbc9b9a130337be3640948fe397b04ac629 /arch/x86/include/asm/nospec-branch.h
parentAdding upstream version 6.6.15. (diff)
downloadlinux-85c675d0d09a45a135bddd15d7b385f8758c32fb.tar.xz
linux-85c675d0d09a45a135bddd15d7b385f8758c32fb.zip
Adding upstream version 6.7.7.upstream/6.7.7
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'arch/x86/include/asm/nospec-branch.h')
-rw-r--r--arch/x86/include/asm/nospec-branch.h78
1 files changed, 41 insertions, 37 deletions
diff --git a/arch/x86/include/asm/nospec-branch.h b/arch/x86/include/asm/nospec-branch.h
index 0396458c20..2519615936 100644
--- a/arch/x86/include/asm/nospec-branch.h
+++ b/arch/x86/include/asm/nospec-branch.h
@@ -288,38 +288,24 @@
* As such, this must be placed after every *SWITCH_TO_KERNEL_CR3 at a point
* where we have a stack but before any RET instruction.
*/
-.macro UNTRAIN_RET
-#if defined(CONFIG_CPU_UNRET_ENTRY) || defined(CONFIG_CPU_IBPB_ENTRY) || \
- defined(CONFIG_CALL_DEPTH_TRACKING) || defined(CONFIG_CPU_SRSO)
+.macro __UNTRAIN_RET ibpb_feature, call_depth_insns
+#if defined(CONFIG_RETHUNK) || defined(CONFIG_CPU_IBPB_ENTRY)
VALIDATE_UNRET_END
ALTERNATIVE_3 "", \
CALL_UNTRAIN_RET, X86_FEATURE_UNRET, \
- "call entry_ibpb", X86_FEATURE_ENTRY_IBPB, \
- __stringify(RESET_CALL_DEPTH), X86_FEATURE_CALL_DEPTH
+ "call entry_ibpb", \ibpb_feature, \
+ __stringify(\call_depth_insns), X86_FEATURE_CALL_DEPTH
#endif
.endm
-.macro UNTRAIN_RET_VM
-#if defined(CONFIG_CPU_UNRET_ENTRY) || defined(CONFIG_CPU_IBPB_ENTRY) || \
- defined(CONFIG_CALL_DEPTH_TRACKING) || defined(CONFIG_CPU_SRSO)
- VALIDATE_UNRET_END
- ALTERNATIVE_3 "", \
- CALL_UNTRAIN_RET, X86_FEATURE_UNRET, \
- "call entry_ibpb", X86_FEATURE_IBPB_ON_VMEXIT, \
- __stringify(RESET_CALL_DEPTH), X86_FEATURE_CALL_DEPTH
-#endif
-.endm
+#define UNTRAIN_RET \
+ __UNTRAIN_RET X86_FEATURE_ENTRY_IBPB, __stringify(RESET_CALL_DEPTH)
-.macro UNTRAIN_RET_FROM_CALL
-#if defined(CONFIG_CPU_UNRET_ENTRY) || defined(CONFIG_CPU_IBPB_ENTRY) || \
- defined(CONFIG_CALL_DEPTH_TRACKING) || defined(CONFIG_CPU_SRSO)
- VALIDATE_UNRET_END
- ALTERNATIVE_3 "", \
- CALL_UNTRAIN_RET, X86_FEATURE_UNRET, \
- "call entry_ibpb", X86_FEATURE_ENTRY_IBPB, \
- __stringify(RESET_CALL_DEPTH_FROM_CALL), X86_FEATURE_CALL_DEPTH
-#endif
-.endm
+#define UNTRAIN_RET_VM \
+ __UNTRAIN_RET X86_FEATURE_IBPB_ON_VMEXIT, __stringify(RESET_CALL_DEPTH)
+
+#define UNTRAIN_RET_FROM_CALL \
+ __UNTRAIN_RET X86_FEATURE_ENTRY_IBPB, __stringify(RESET_CALL_DEPTH_FROM_CALL)
.macro CALL_DEPTH_ACCOUNT
@@ -329,6 +315,17 @@
#endif
.endm
+/*
+ * Macro to execute VERW instruction that mitigate transient data sampling
+ * attacks such as MDS. On affected systems a microcode update overloaded VERW
+ * instruction to also clear the CPU buffers. VERW clobbers CFLAGS.ZF.
+ *
+ * Note: Only the memory operand variant of VERW clears the CPU buffers.
+ */
+.macro CLEAR_CPU_BUFFERS
+ ALTERNATIVE "", __stringify(verw _ASM_RIP(mds_verw_sel)), X86_FEATURE_CLEAR_CPU_BUF
+.endm
+
#else /* __ASSEMBLY__ */
#define ANNOTATE_RETPOLINE_SAFE \
@@ -348,13 +345,23 @@ extern void __x86_return_thunk(void);
static inline void __x86_return_thunk(void) {}
#endif
+#ifdef CONFIG_CPU_UNRET_ENTRY
extern void retbleed_return_thunk(void);
+#else
+static inline void retbleed_return_thunk(void) {}
+#endif
+
+#ifdef CONFIG_CPU_SRSO
extern void srso_return_thunk(void);
extern void srso_alias_return_thunk(void);
+#else
+static inline void srso_return_thunk(void) {}
+static inline void srso_alias_return_thunk(void) {}
+#endif
-extern void retbleed_untrain_ret(void);
-extern void srso_untrain_ret(void);
-extern void srso_alias_untrain_ret(void);
+extern void retbleed_return_thunk(void);
+extern void srso_return_thunk(void);
+extern void srso_alias_return_thunk(void);
extern void entry_untrain_ret(void);
extern void entry_ibpb(void);
@@ -362,12 +369,7 @@ extern void entry_ibpb(void);
extern void (*x86_return_thunk)(void);
#ifdef CONFIG_CALL_DEPTH_TRACKING
-extern void __x86_return_skl(void);
-
-static inline void x86_set_skl_return_thunk(void)
-{
- x86_return_thunk = &__x86_return_skl;
-}
+extern void call_depth_return_thunk(void);
#define CALL_DEPTH_ACCOUNT \
ALTERNATIVE("", \
@@ -380,12 +382,12 @@ DECLARE_PER_CPU(u64, __x86_ret_count);
DECLARE_PER_CPU(u64, __x86_stuffs_count);
DECLARE_PER_CPU(u64, __x86_ctxsw_count);
#endif
-#else
-static inline void x86_set_skl_return_thunk(void) {}
+#else /* !CONFIG_CALL_DEPTH_TRACKING */
+static inline void call_depth_return_thunk(void) {}
#define CALL_DEPTH_ACCOUNT ""
-#endif
+#endif /* CONFIG_CALL_DEPTH_TRACKING */
#ifdef CONFIG_RETPOLINE
@@ -545,6 +547,8 @@ DECLARE_STATIC_KEY_FALSE(switch_mm_cond_l1d_flush);
DECLARE_STATIC_KEY_FALSE(mmio_stale_data_clear);
+extern u16 mds_verw_sel;
+
#include <asm/segment.h>
/**