[tip: objtool/core] objtool: Uniquely identify alternative instruction groups

From: tip-bot2 for Alexandre Chartre
Date: Fri May 01 2020 - 14:23:09 EST


The following commit has been merged into the objtool/core branch of tip:

Commit-ID: 13fab06d9a3ad3afdfd51c7f8f87f2ae28444648
Gitweb: https://git.kernel.org/tip/13fab06d9a3ad3afdfd51c7f8f87f2ae28444648
Author: Alexandre Chartre <alexandre.chartre@xxxxxxxxxx>
AuthorDate: Tue, 14 Apr 2020 12:36:11 +02:00
Committer: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
CommitterDate: Thu, 30 Apr 2020 20:14:31 +02:00

objtool: Uniquely identify alternative instruction groups

Assign a unique identifier to every alternative instruction group in
order to be able to tell which instructions belong to what
alternative.

[peterz: extracted from a larger patch]
Signed-off-by: Alexandre Chartre <alexandre.chartre@xxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Reviewed-by: Miroslav Benes <mbenes@xxxxxxx>
---
tools/objtool/check.c | 6 +++++-
tools/objtool/check.h | 3 ++-
2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index cc52da6..4da6bfb 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -752,7 +752,9 @@ static int handle_group_alt(struct objtool_file *file,
struct instruction *orig_insn,
struct instruction **new_insn)
{
+ static unsigned int alt_group_next_index = 1;
struct instruction *last_orig_insn, *last_new_insn, *insn, *fake_jump = NULL;
+ unsigned int alt_group = alt_group_next_index++;
unsigned long dest_off;

last_orig_insn = NULL;
@@ -761,7 +763,7 @@ static int handle_group_alt(struct objtool_file *file,
if (insn->offset >= special_alt->orig_off + special_alt->orig_len)
break;

- insn->alt_group = true;
+ insn->alt_group = alt_group;
last_orig_insn = insn;
}

@@ -795,6 +797,7 @@ static int handle_group_alt(struct objtool_file *file,
}

last_new_insn = NULL;
+ alt_group = alt_group_next_index++;
insn = *new_insn;
sec_for_each_insn_from(file, insn) {
if (insn->offset >= special_alt->new_off + special_alt->new_len)
@@ -804,6 +807,7 @@ static int handle_group_alt(struct objtool_file *file,

insn->ignore = orig_insn->ignore_alts;
insn->func = orig_insn->func;
+ insn->alt_group = alt_group;

/*
* Since alternative replacement code is copy/pasted by the
diff --git a/tools/objtool/check.h b/tools/objtool/check.h
index 12a9660..2428022 100644
--- a/tools/objtool/check.h
+++ b/tools/objtool/check.h
@@ -30,12 +30,13 @@ struct instruction {
unsigned int len;
enum insn_type type;
unsigned long immediate;
- bool alt_group, dead_end, ignore, ignore_alts;
+ bool dead_end, ignore, ignore_alts;
bool hint;
bool retpoline_safe;
s8 instr;
u8 visited;
u8 ret_offset;
+ int alt_group;
struct symbol *call_dest;
struct instruction *jump_dest;
struct instruction *first_jump_src;