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author | Josh Poimboeuf <jpoimboe@kernel.org> | 2023-04-18 23:27:48 +0200 |
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committer | Josh Poimboeuf <jpoimboe@kernel.org> | 2023-05-16 15:31:51 +0200 |
commit | ca653464dd097fe64e69f1735e9f348b2a0f8037 (patch) | |
tree | 0d1f42b5efb9e2f46957e590f79b2062cdb5619e /tools/objtool | |
parent | objtool: Limit unreachable warnings to once per function (diff) | |
download | linux-ca653464dd097fe64e69f1735e9f348b2a0f8037.tar.xz linux-ca653464dd097fe64e69f1735e9f348b2a0f8037.zip |
objtool: Add verbose option for disassembling affected functions
When a warning is associated with a function, add an option to
disassemble that function.
This makes it easier for reporters to submit the information needed to
diagnose objtool warnings.
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Link: https://lore.kernel.org/r/dd0fe13428ede186f09c74059a8001f4adcea5fc.1681853186.git.jpoimboe@kernel.org
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Diffstat (limited to 'tools/objtool')
-rw-r--r-- | tools/objtool/Documentation/objtool.txt | 5 | ||||
-rw-r--r-- | tools/objtool/builtin-check.c | 5 | ||||
-rw-r--r-- | tools/objtool/check.c | 77 | ||||
-rw-r--r-- | tools/objtool/include/objtool/builtin.h | 1 |
4 files changed, 88 insertions, 0 deletions
diff --git a/tools/objtool/Documentation/objtool.txt b/tools/objtool/Documentation/objtool.txt index 744db4218e7a..8db1f29bf432 100644 --- a/tools/objtool/Documentation/objtool.txt +++ b/tools/objtool/Documentation/objtool.txt @@ -244,6 +244,11 @@ To achieve the validation, objtool enforces the following rules: Objtool warnings ---------------- +NOTE: When requesting help with an objtool warning, please recreate with +OBJTOOL_VERBOSE=1 (e.g., "make OBJTOOL_VERBOSE=1") and send the full +output, including any disassembly below the warning, to the objtool +maintainers. + For asm files, if you're getting an error which doesn't make sense, first make sure that the affected code follows the above rules. diff --git a/tools/objtool/builtin-check.c b/tools/objtool/builtin-check.c index 7c175198d09f..5e21cfb7661d 100644 --- a/tools/objtool/builtin-check.c +++ b/tools/objtool/builtin-check.c @@ -93,6 +93,7 @@ static const struct option check_options[] = { OPT_BOOLEAN(0, "no-unreachable", &opts.no_unreachable, "skip 'unreachable instruction' warnings"), OPT_BOOLEAN(0, "sec-address", &opts.sec_address, "print section addresses in warnings"), OPT_BOOLEAN(0, "stats", &opts.stats, "print statistics"), + OPT_BOOLEAN('v', "verbose", &opts.verbose, "verbose warnings"), OPT_END(), }; @@ -118,6 +119,10 @@ int cmd_parse_options(int argc, const char **argv, const char * const usage[]) parse_options(envc, envv, check_options, env_usage, 0); } + env = getenv("OBJTOOL_VERBOSE"); + if (env && !strcmp(env, "1")) + opts.verbose = true; + argc = parse_options(argc, argv, check_options, usage, 0); if (argc != 1) usage_with_options(usage, check_options); diff --git a/tools/objtool/check.c b/tools/objtool/check.c index 98e6c3b5fefc..0bd0ca4c767c 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -4530,6 +4530,81 @@ static int validate_reachable_instructions(struct objtool_file *file) return warnings; } +/* 'funcs' is a space-separated list of function names */ +static int disas_funcs(const char *funcs) +{ + const char *objdump_str, *cross_compile; + int size, ret; + char *cmd; + + cross_compile = getenv("CROSS_COMPILE"); + + objdump_str = "%sobjdump -wdr %s | gawk -M -v _funcs='%s' '" + "BEGIN { split(_funcs, funcs); }" + "/^$/ { func_match = 0; }" + "/<.*>:/ { " + "f = gensub(/.*<(.*)>:/, \"\\\\1\", 1);" + "for (i in funcs) {" + "if (funcs[i] == f) {" + "func_match = 1;" + "base = strtonum(\"0x\" $1);" + "break;" + "}" + "}" + "}" + "{" + "if (func_match) {" + "addr = strtonum(\"0x\" $1);" + "printf(\"%%04x \", addr - base);" + "print;" + "}" + "}' 1>&2"; + + /* fake snprintf() to calculate the size */ + size = snprintf(NULL, 0, objdump_str, cross_compile, objname, funcs) + 1; + if (size <= 0) { + WARN("objdump string size calculation failed"); + return -1; + } + + cmd = malloc(size); + + /* real snprintf() */ + snprintf(cmd, size, objdump_str, cross_compile, objname, funcs); + ret = system(cmd); + if (ret) { + WARN("disassembly failed: %d", ret); + return -1; + } + + return 0; +} + +static int disas_warned_funcs(struct objtool_file *file) +{ + struct symbol *sym; + char *funcs = NULL, *tmp; + + for_each_sym(file, sym) { + if (sym->warned) { + if (!funcs) { + funcs = malloc(strlen(sym->name) + 1); + strcpy(funcs, sym->name); + } else { + tmp = malloc(strlen(funcs) + strlen(sym->name) + 2); + sprintf(tmp, "%s %s", funcs, sym->name); + free(funcs); + funcs = tmp; + } + } + } + + if (funcs) + disas_funcs(funcs); + + return 0; +} + int check(struct objtool_file *file) { int ret, warnings = 0; @@ -4674,6 +4749,8 @@ int check(struct objtool_file *file) warnings += ret; } + if (opts.verbose) + disas_warned_funcs(file); if (opts.stats) { printf("nr_insns_visited: %ld\n", nr_insns_visited); diff --git a/tools/objtool/include/objtool/builtin.h b/tools/objtool/include/objtool/builtin.h index 2a108e648b7a..fcca6662c8b4 100644 --- a/tools/objtool/include/objtool/builtin.h +++ b/tools/objtool/include/objtool/builtin.h @@ -37,6 +37,7 @@ struct opts { bool no_unreachable; bool sec_address; bool stats; + bool verbose; }; extern struct opts opts; |