objtool: Convert insn type to enum

This makes it easier to add new instruction types.  Also it's hopefully
more robust since the compiler should warn about out-of-range enums.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/0740e96af0d40e54cfd6a07bf09db0fbd10793cd.1563413318.git.jpoimboe@redhat.com

tools/objtool/arch.h

@@ -11,22 +11,23 @@
 #include "elf.h"
 #include "cfi.h"
 
-#define INSN_JUMP_CONDITIONAL	1
-#define INSN_JUMP_UNCONDITIONAL	2
-#define INSN_JUMP_DYNAMIC	3
-#define INSN_CALL		4
-#define INSN_CALL_DYNAMIC	5
-#define INSN_RETURN		6
-#define INSN_CONTEXT_SWITCH	7
-#define INSN_STACK		8
-#define INSN_BUG		9
-#define INSN_NOP		10
-#define INSN_STAC		11
-#define INSN_CLAC		12
-#define INSN_STD		13
-#define INSN_CLD		14
-#define INSN_OTHER		15
-#define INSN_LAST		INSN_OTHER
+enum insn_type {
+	INSN_JUMP_CONDITIONAL,
+	INSN_JUMP_UNCONDITIONAL,
+	INSN_JUMP_DYNAMIC,
+	INSN_CALL,
+	INSN_CALL_DYNAMIC,
+	INSN_RETURN,
+	INSN_CONTEXT_SWITCH,
+	INSN_STACK,
+	INSN_BUG,
+	INSN_NOP,
+	INSN_STAC,
+	INSN_CLAC,
+	INSN_STD,
+	INSN_CLD,
+	INSN_OTHER,
+};
 
 enum op_dest_type {
 	OP_DEST_REG,
@@ -68,7 +69,7 @@ void arch_initial_func_cfi_state(struct cfi_state *state);
 
 int arch_decode_instruction(struct elf *elf, struct section *sec,
 			    unsigned long offset, unsigned int maxlen,
-			    unsigned int *len, unsigned char *type,
+			    unsigned int *len, enum insn_type *type,
 			    unsigned long *immediate, struct stack_op *op);
 
 bool arch_callee_saved_reg(unsigned char reg);

tools/objtool/arch/x86/decode.c

@@ -68,7 +68,7 @@ bool arch_callee_saved_reg(unsigned char reg)
 
 int arch_decode_instruction(struct elf *elf, struct section *sec,
 			    unsigned long offset, unsigned int maxlen,
-			    unsigned int *len, unsigned char *type,
+			    unsigned int *len, enum insn_type *type,
 			    unsigned long *immediate, struct stack_op *op)
 {
 	struct insn insn;

tools/objtool/check.c

@@ -267,13 +267,6 @@ static int decode_instructions(struct objtool_file *file)
 			if (ret)
 				goto err;
 
-			if (!insn->type || insn->type > INSN_LAST) {
-				WARN_FUNC("invalid instruction type %d",
-					  insn->sec, insn->offset, insn->type);
-				ret = -1;
-				goto err;
-			}
-
 			hash_add(file->insn_hash, &insn->hash, insn->offset);
 			list_add_tail(&insn->list, &file->insn_list);
 		}

tools/objtool/check.h

@@ -31,7 +31,7 @@ struct instruction {
 	struct section *sec;
 	unsigned long offset;
 	unsigned int len;
-	unsigned char type;
+	enum insn_type type;
 	unsigned long immediate;
 	bool alt_group, visited, dead_end, ignore, hint, save, restore, ignore_alts;
 	bool retpoline_safe;