Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
---
arch/x86/include/asm/nospec-branch.h | 24 ++++++++++++++++++++++++
1 file changed, 24 insertions(+)
--- a/arch/x86/include/asm/nospec-branch.h
+++ b/arch/x86/include/asm/nospec-branch.h
@@ -438,6 +438,9 @@ static inline void call_depth_return_thu
#define CALL_NOSPEC __CS_PREFIX("%V[thunk_target]") \
"call __x86_indirect_thunk_%V[thunk_target]\n"
+#define JMP_NOSPEC __CS_PREFIX("%V[thunk_target]") \
+ "jmp __x86_indirect_thunk_%V[thunk_target]\n"
+
# define THUNK_TARGET(addr) [thunk_target] "r" (addr)
#else /* CONFIG_X86_32 */
@@ -468,10 +471,31 @@ static inline void call_depth_return_thu
"call *%[thunk_target]\n", \
X86_FEATURE_RETPOLINE_LFENCE)
+# define JMP_NOSPEC \
+ ALTERNATIVE_2( \
+ ANNOTATE_RETPOLINE_SAFE \
+ "jmp *%[thunk_target]\n", \
+ " jmp 901f;\n" \
+ " .align 16\n" \
+ "901: call 903f;\n" \
+ "902: pause;\n" \
+ " lfence;\n" \
+ " jmp 902b;\n" \
+ " .align 16\n" \
+ "903: lea 4(%%esp), %%esp;\n" \
+ " pushl %[thunk_target];\n" \
+ " ret;\n", \
+ X86_FEATURE_RETPOLINE, \
+ "lfence;\n" \
+ ANNOTATE_RETPOLINE_SAFE \
+ "jmp *%[thunk_target]\n", \
+ X86_FEATURE_RETPOLINE_LFENCE)
+
# define THUNK_TARGET(addr) [thunk_target] "rm" (addr)
#endif
#else /* No retpoline for C / inline asm */
# define CALL_NOSPEC "call *%[thunk_target]\n"
+# define JMP_NOSPEC "jmp *%[thunk_target]\n"
# define THUNK_TARGET(addr) [thunk_target] "rm" (addr)
#endif
