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[v9,06/36] x86/objtool: Teach objtool about ERETU and ERETS

Message ID 20230731063317.3720-7-xin3.li@intel.com (mailing list archive)
State New, archived
Headers show
Series x86: enable FRED for x86-64 | expand

Commit Message

Li, Xin3 July 31, 2023, 6:32 a.m. UTC 
From: "H. Peter Anvin (Intel)" <hpa@zytor.com>

Update the objtool decoder to know about the ERETU and ERETS
instructions (type INSN_CONTEXT_SWITCH).

Signed-off-by: H. Peter Anvin (Intel) <hpa@zytor.com>
Tested-by: Shan Kang <shan.kang@intel.com>
Signed-off-by: Xin Li <xin3.li@intel.com>
---
 tools/objtool/arch/x86/decode.c | 19 ++++++++++++++-----
 1 file changed, 14 insertions(+), 5 deletions(-)
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Patch

diff --git a/tools/objtool/arch/x86/decode.c b/tools/objtool/arch/x86/decode.c
index 2e1caabecb18..a486485cff20 100644
--- a/tools/objtool/arch/x86/decode.c
+++ b/tools/objtool/arch/x86/decode.c
@@ -509,11 +509,20 @@  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;