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-rw-r--r--tools/objtool/arch.h4
-rw-r--r--tools/objtool/arch/x86/decode.c8
-rw-r--r--tools/objtool/check.c25
-rw-r--r--tools/objtool/check.h2
4 files changed, 37 insertions, 2 deletions
diff --git a/tools/objtool/arch.h b/tools/objtool/arch.h
index 467c2fe798a9..7a111a77b7aa 100644
--- a/tools/objtool/arch.h
+++ b/tools/objtool/arch.h
@@ -35,7 +35,9 @@
#define INSN_NOP 10
#define INSN_STAC 11
#define INSN_CLAC 12
-#define INSN_OTHER 13
+#define INSN_STD 13
+#define INSN_CLD 14
+#define INSN_OTHER 15
#define INSN_LAST INSN_OTHER
enum op_dest_type {
diff --git a/tools/objtool/arch/x86/decode.c b/tools/objtool/arch/x86/decode.c
index ab20a96fee50..472e991f6512 100644
--- a/tools/objtool/arch/x86/decode.c
+++ b/tools/objtool/arch/x86/decode.c
@@ -451,6 +451,14 @@ int arch_decode_instruction(struct elf *elf, struct section *sec,
*type = INSN_CALL;
break;
+ case 0xfc:
+ *type = INSN_CLD;
+ break;
+
+ case 0xfd:
+ *type = INSN_STD;
+ break;
+
case 0xff:
if (modrm_reg == 2 || modrm_reg == 3)
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 965e954e07f4..38b0517dc49e 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -1903,6 +1903,12 @@ static int validate_call(struct instruction *insn, struct insn_state *state)
return 1;
}
+ if (state->df) {
+ WARN_FUNC("call to %s() with DF set",
+ insn->sec, insn->offset, insn_dest_name(insn));
+ return 1;
+ }
+
return 0;
}
@@ -2044,6 +2050,11 @@ static int validate_branch(struct objtool_file *file, struct instruction *first,
return 1;
}
+ if (state.df) {
+ WARN_FUNC("return with DF set", sec, insn->offset);
+ return 1;
+ }
+
if (func && has_modified_stack_frame(&state)) {
WARN_FUNC("return with modified stack frame",
sec, insn->offset);
@@ -2172,6 +2183,20 @@ static int validate_branch(struct objtool_file *file, struct instruction *first,
state.uaccess = false;
break;
+ case INSN_STD:
+ if (state.df)
+ WARN_FUNC("recursive STD", sec, insn->offset);
+
+ state.df = true;
+ break;
+
+ case INSN_CLD:
+ if (!state.df && insn->func)
+ WARN_FUNC("redundant CLD", sec, insn->offset);
+
+ state.df = false;
+ break;
+
default:
break;
}
diff --git a/tools/objtool/check.h b/tools/objtool/check.h
index 78a95d06c165..71e54f97dbcd 100644
--- a/tools/objtool/check.h
+++ b/tools/objtool/check.h
@@ -31,7 +31,7 @@ struct insn_state {
int stack_size;
unsigned char type;
bool bp_scratch;
- bool drap, end, uaccess;
+ bool drap, end, uaccess, df;
unsigned int uaccess_stack;
int drap_reg, drap_offset;
struct cfi_reg vals[CFI_NUM_REGS];