objtool: Implement stack validation 2.0

This is a major rewrite of objtool.  Instead of only tracking frame
pointer changes, it now tracks all stack-related operations, including
all register saves/restores.

In addition to making stack validation more robust, this also paves the
way for undwarf generation.

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: live-patching@vger.kernel.org
Link: http://lkml.kernel.org/r/678bd94c0566c6129bcc376cddb259c4c5633004.1498659915.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

tools/objtool/check.h

@@ -20,22 +20,34 @@
 
 #include <stdbool.h>
 #include "elf.h"
+#include "cfi.h"
 #include "arch.h"
 #include <linux/hashtable.h>
 
+struct insn_state {
+	struct cfi_reg cfa;
+	struct cfi_reg regs[CFI_NUM_REGS];
+	int stack_size;
+	bool bp_scratch;
+	bool drap;
+	int drap_reg;
+};
+
 struct instruction {
 	struct list_head list;
 	struct hlist_node hash;
 	struct section *sec;
 	unsigned long offset;
-	unsigned int len, state;
+	unsigned int len;
 	unsigned char type;
 	unsigned long immediate;
-	bool alt_group, visited, dead_end;
+	bool alt_group, visited, dead_end, ignore;
 	struct symbol *call_dest;
 	struct instruction *jump_dest;
 	struct list_head alts;
 	struct symbol *func;
+	struct stack_op stack_op;
+	struct insn_state state;
 };
 
 struct objtool_file {
@@ -48,4 +60,7 @@ struct objtool_file {
 
 int check(const char *objname, bool nofp);
 
+#define for_each_insn(file, insn)					\
+	list_for_each_entry(insn, &file->insn_list, list)
+
 #endif /* _CHECK_H */