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867ac9d737
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>
70 lines
1.7 KiB
C
70 lines
1.7 KiB
C
/*
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* Copyright (C) 2017 Josh Poimboeuf <jpoimboe@redhat.com>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, see <http://www.gnu.org/licenses/>.
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*/
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/*
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* objtool orc:
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*
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* This command analyzes a .o file and adds .orc_unwind and .orc_unwind_ip
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* sections to it, which is used by the in-kernel ORC unwinder.
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*
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* This command is a superset of "objtool check".
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*/
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#include <string.h>
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#include <subcmd/parse-options.h>
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#include "builtin.h"
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#include "check.h"
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static const char *orc_usage[] = {
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"objtool orc generate [<options>] file.o",
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"objtool orc dump file.o",
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NULL,
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};
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extern const struct option check_options[];
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extern bool no_fp, no_unreachable;
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int cmd_orc(int argc, const char **argv)
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{
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const char *objname;
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argc--; argv++;
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if (!strncmp(argv[0], "gen", 3)) {
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argc = parse_options(argc, argv, check_options, orc_usage, 0);
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if (argc != 1)
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usage_with_options(orc_usage, check_options);
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objname = argv[0];
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return check(objname, no_fp, no_unreachable, true);
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}
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if (!strcmp(argv[0], "dump")) {
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if (argc != 2)
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usage_with_options(orc_usage, check_options);
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objname = argv[1];
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return orc_dump(objname);
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}
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usage_with_options(orc_usage, check_options);
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return 0;
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}
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