* the optimal version — two calls, each with their own speculation
* trap should their return address end up getting used, in a loop.
*/
+#ifdef CONFIG_X86_64
#define __FILL_RETURN_BUFFER(reg, nr, sp) \
mov $(nr/2), reg; \
771: \
add $(BITS_PER_LONG/8) * nr, sp; \
/* barrier for jnz misprediction */ \
lfence;
+#else
+/*
+ * i386 doesn't unconditionally have LFENCE, as such it can't
+ * do a loop.
+ */
+#define __FILL_RETURN_BUFFER(reg, nr, sp) \
+ .rept nr; \
+ call 772f; \
+ int3; \
+772:; \
+ .endr; \
+ add $(BITS_PER_LONG/8) * nr, sp;
+#endif
/* Sequence to mitigate PBRSB on eIBRS CPUs */
#define __ISSUE_UNBALANCED_RET_GUARD(sp) \