1 files changed, 31 insertions, 11 deletions

diff --git a/tools/objtool/arch/x86/decode.c b/tools/objtool/arch/x86/decode.c
index e327cd827135..fe1362c34564 100644
--- a/tools/objtool/arch/x86/decode.c
+++ b/tools/objtool/arch/x86/decode.c
@@ -125,8 +125,14 @@ bool arch_pc_relative_reloc(struct reloc *reloc)
 #define is_RIP()   ((modrm_rm & 7) == CFI_BP && modrm_mod == 0)
 #define have_SIB() ((modrm_rm & 7) == CFI_SP && mod_is_mem())
 
+/*
+ * Check the ModRM register. If there is a SIB byte then check with
+ * the SIB base register. But if the SIB base is 5 (i.e. CFI_BP) and
+ * ModRM mod is 0 then there is no base register.
+ */
 #define rm_is(reg) (have_SIB() ? \
-		    sib_base == (reg) && sib_index == CFI_SP : \
+		    sib_base == (reg) && sib_index == CFI_SP && \
+		    (sib_base != CFI_BP || modrm_mod != 0) :	\
 		    modrm_rm == (reg))
 
 #define rm_is_mem(reg)	(mod_is_mem() && !is_RIP() && rm_is(reg))
@@ -450,10 +456,6 @@ int arch_decode_instruction(struct objtool_file *file, const struct section *sec
 		if (!rex_w)
 			break;
 
-		/* skip RIP relative displacement */
-		if (is_RIP())
-			break;
-
 		/* skip nontrivial SIB */
 		if (have_SIB()) {
 			modrm_rm = sib_base;
@@ -461,6 +463,12 @@ int arch_decode_instruction(struct objtool_file *file, const struct section *sec
 				break;
 		}
 
+		/* lea disp(%rip), %dst */
+		if (is_RIP()) {
+			insn->type = INSN_LEA_RIP;
+			break;
+		}
+
 		/* lea disp(%src), %dst */
 		ADD_OP(op) {
 			op->src.offset = ins.displacement.value;
@@ -509,11 +517,20 @@ int arch_decode_instruction(struct objtool_file *file, const struct section *sec
 
 		if (op2 == 0x01) {
 
-			if (modrm == 0xca)
-				insn->type = INSN_CLAC;
-			else if (modrm == 0xcb)
-				insn->type = INSN_STAC;
-
+			switch (insn_last_prefix_id(&ins)) {
+			case INAT_PFX_REPE:
+			case INAT_PFX_REPNE:
+				if (modrm == 0xca)
+					/* eretu/erets */
+					insn->type = INSN_CONTEXT_SWITCH;
+				break;
+			default:
+				if (modrm == 0xca)
+					insn->type = INSN_CLAC;
+				else if (modrm == 0xcb)
+					insn->type = INSN_STAC;
+				break;
+			}
 		} else if (op2 >= 0x80 && op2 <= 0x8f) {
 
 			insn->type = INSN_JUMP_CONDITIONAL;
@@ -722,7 +739,10 @@ int arch_decode_instruction(struct objtool_file *file, const struct section *sec
 		break;
 	}
 
-	insn->immediate = ins.immediate.nbytes ? ins.immediate.value : 0;
+	if (ins.immediate.nbytes)
+		insn->immediate = ins.immediate.value;
+	else if (ins.displacement.nbytes)
+		insn->immediate = ins.displacement.value;
 
 	return 0;
 }