objtool: Add ORC unwind table generation

Now that objtool knows the states of all registers on the stack for each
instruction, it's straightforward to generate debuginfo for an unwinder
to use.

Instead of generating DWARF, generate a new format called ORC, which is
more suitable for an in-kernel unwinder.  See
Documentation/x86/orc-unwinder.txt for a more detailed description of
this new debuginfo format and why it's preferable to DWARF.

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: live-patching@vger.kernel.org
Link: http://lkml.kernel.org/r/c9b9f01ba6c5ed2bdc9bb0957b78167fdbf9632e.1499786555.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 14 insertions, 1 deletions

diff --git a/tools/objtool/check.h b/tools/objtool/check.h
index da85f5b00ec6..046874bbe226 100644
--- a/tools/objtool/check.h
+++ b/tools/objtool/check.h
@@ -22,12 +22,14 @@
 #include "elf.h"
 #include "cfi.h"
 #include "arch.h"
+#include "orc.h"
 #include <linux/hashtable.h>
 
 struct insn_state {
         struct cfi_reg cfa;
         struct cfi_reg regs[CFI_NUM_REGS];
         int stack_size;
+        unsigned char type;
         bool bp_scratch;
         bool drap;
         int drap_reg;
@@ -48,6 +50,7 @@ struct instruction {
         struct symbol *func;
         struct stack_op stack_op;
         struct insn_state state;
+        struct orc_entry orc;
 };
 
 struct objtool_file {
@@ -58,9 +61,19 @@ struct objtool_file {
         bool ignore_unreachables, c_file;
 };
 
-int check(const char *objname, bool nofp);
+int check(const char *objname, bool nofp, bool orc);
+
+struct instruction *find_insn(struct objtool_file *file,
+                              struct section *sec, unsigned long offset);
 
 #define for_each_insn(file, insn)                                       \
         list_for_each_entry(insn, &file->insn_list, list)
 
+#define sec_for_each_insn(file, sec, insn)                              \
+        for (insn = find_insn(file, sec, 0);                            \
+             insn && &insn->list != &file->insn_list &&                 \
+                        insn->sec == sec;                               \
+             insn = list_next_entry(insn, list))
+
+
 #endif /* _CHECK_H */