linux_dsm_epyc7002/tools/objtool/builtin-orc.c
Josh Poimboeuf 867ac9d737 objtool: Fix gcov check for older versions of GCC
Objtool tries to silence 'unreachable instruction' warnings when it
detects gcov is enabled, because gcov produces a lot of unreachable
instructions and they don't really matter.

However, the 0-day bot is still reporting some unreachable instruction
warnings with CONFIG_GCOV_KERNEL=y on GCC 4.6.4.

As it turns out, objtool's gcov detection doesn't work with older
versions of GCC because they don't create a bunch of symbols with the
'gcov.' prefix like newer versions of GCC do.

Move the gcov check out of objtool and instead just create a new
'--no-unreachable' flag which can be passed in by the kernel Makefile
when CONFIG_GCOV_KERNEL is defined.

Also rename the 'nofp' variable to 'no_fp' for consistency with the new
'no_unreachable' variable.

Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: 9cfffb1168 ("objtool: Skip all "unreachable instruction" warnings for gcov kernels")
Link: http://lkml.kernel.org/r/c243dc78eb2ffdabb6e927844dea39b6033cd395.1500939244.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-07-25 11:12:45 +02:00

71 lines
1.7 KiB
C

/*
* Copyright (C) 2017 Josh Poimboeuf <jpoimboe@redhat.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <http://www.gnu.org/licenses/>.
*/
/*
* objtool orc:
*
* This command analyzes a .o file and adds .orc_unwind and .orc_unwind_ip
* sections to it, which is used by the in-kernel ORC unwinder.
*
* This command is a superset of "objtool check".
*/
#include <string.h>
#include <subcmd/parse-options.h>
#include "builtin.h"
#include "check.h"
static const char *orc_usage[] = {
"objtool orc generate [<options>] file.o",
"objtool orc dump file.o",
NULL,
};
extern const struct option check_options[];
extern bool no_fp, no_unreachable;
int cmd_orc(int argc, const char **argv)
{
const char *objname;
argc--; argv++;
if (!strncmp(argv[0], "gen", 3)) {
argc = parse_options(argc, argv, check_options, orc_usage, 0);
if (argc != 1)
usage_with_options(orc_usage, check_options);
objname = argv[0];
return check(objname, no_fp, no_unreachable, true);
}
if (!strcmp(argv[0], "dump")) {
if (argc != 2)
usage_with_options(orc_usage, check_options);
objname = argv[1];
return orc_dump(objname);
}
usage_with_options(orc_usage, check_options);
return 0;
}