From 5febf432df1cfa5b25d99b54c32103fafbdd0eb9 Mon Sep 17 00:00:00 2001 From: Miguel Ojeda Date: Sun, 16 Aug 2026 15:32:33 +0200 Subject: kbuild: rust: keep Rust objects out of Clang LTO with inline helpers Under `CONFIG_LTO_CLANG` + `CONFIG_RUST_INLINE_HELPERS`, one may hit `objtool` errors such as: vmlinux.o: error: objtool: _R..._3Gsp4boot+0xd6a: can't find jump dest instruction at .text._R..._3Gsp4boot+0x1dfd The reason is that in such builds, the Clang invocation that compiles the combined Rust plus helpers bitcode emits LLVM bitcode (again) -- the final code generation happens in the linker's LTO step, which the `-mllvm` trap options passed to Clang do not reach. This, in turn, means that unreachable traps are missing, and the impossible paths do not merely fallthrough to the next symbol, but past the end of their own section, since LTO builds place each function in its own section. Thus filter `CC_FLAGS_LTO` out of the Clang invocation, so that it always emits machine code directly, with the traps in place. Assisted-by: LLM Cc: Gary Guo Cc: Boqun Feng Cc: Alice Ryhl Cc: Matthew Maurer Cc: Josh Poimboeuf Cc: Peter Zijlstra Cc: stable@vger.kernel.org Fixes: 3a2486cc1da5 ("kbuild: rust: provide an option to inline C helpers into Rust") Acked-by: Gary Guo Link: https://patch.msgid.link/20260816133233.197500-2-ojeda@kernel.org Signed-off-by: Miguel Ojeda --- tools/perf/builtin-config.c | 298 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 298 insertions(+) create mode 100644 tools/perf/builtin-config.c (limited to 'tools/perf/builtin-config.c') diff --git a/tools/perf/builtin-config.c b/tools/perf/builtin-config.c new file mode 100644 index 000000000..237600643 --- /dev/null +++ b/tools/perf/builtin-config.c @@ -0,0 +1,298 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * builtin-config.c + * + * Copyright (C) 2015, Taeung Song + * + */ +#include "builtin.h" + +#include "util/cache.h" +#include +#include "util/debug.h" +#include "util/config.h" +#include +#include +#include +#include + +static bool use_system_config, use_user_config; + +static const char * const config_usage[] = { + "perf config [] [options] [section.name[=value] ...]", + NULL +}; + +static enum actions { + ACTION_LIST = 1 +} actions; + +static struct option config_options[] = { + OPT_SET_UINT('l', "list", &actions, + "show current config variables", ACTION_LIST), + OPT_BOOLEAN(0, "system", &use_system_config, "use system config file"), + OPT_BOOLEAN(0, "user", &use_user_config, "use user config file"), + OPT_END() +}; + +static int set_config(struct perf_config_set *set, const char *file_name) +{ + struct perf_config_section *section = NULL; + struct perf_config_item *item = NULL; + const char *first_line = "# this file is auto-generated."; + FILE *fp; + + if (set == NULL) + return -1; + + fp = fopen(file_name, "w"); + if (!fp) + return -1; + + fprintf(fp, "%s\n", first_line); + + /* overwrite configvariables */ + perf_config_items__for_each_entry(&set->sections, section) { + if (!use_system_config && section->from_system_config) + continue; + fprintf(fp, "[%s]\n", section->name); + + perf_config_items__for_each_entry(§ion->items, item) { + if (!use_system_config && item->from_system_config) + continue; + if (item->value) + fprintf(fp, "\t%s = %s\n", + item->name, item->value); + } + } + fclose(fp); + + return 0; +} + +static int show_spec_config(struct perf_config_set *set, const char *var) +{ + struct perf_config_section *section; + struct perf_config_item *item; + + if (set == NULL) + return -1; + + perf_config_items__for_each_entry(&set->sections, section) { + if (!strstarts(var, section->name)) + continue; + + perf_config_items__for_each_entry(§ion->items, item) { + const char *name = var + strlen(section->name) + 1; + + if (strcmp(name, item->name) == 0) { + char *value = item->value; + + if (value) { + printf("%s=%s\n", var, value); + return 0; + } + } + + } + } + + return 0; +} + +static int show_config(struct perf_config_set *set) +{ + struct perf_config_section *section; + struct perf_config_item *item; + + if (set == NULL) + return -1; + + perf_config_set__for_each_entry(set, section, item) { + char *value = item->value; + + if (value) + printf("%s.%s=%s\n", section->name, + item->name, value); + } + + return 0; +} + +static int parse_config_arg(char *arg, char **var, char **value) +{ + const char *last_dot = strchr(arg, '.'); + + /* + * Since "var" actually contains the section name and the real + * config variable name separated by a dot, we have to know where the dot is. + */ + if (last_dot == NULL || last_dot == arg) { + pr_err("The config variable does not contain a section name: %s\n", arg); + return -1; + } + if (!last_dot[1]) { + pr_err("The config variable does not contain a variable name: %s\n", arg); + return -1; + } + + *value = strchr(arg, '='); + if (*value == NULL) + *var = arg; + else if (!strcmp(*value, "=")) { + pr_err("The config variable does not contain a value: %s\n", arg); + return -1; + } else { + *value = *value + 1; /* excluding a first character '=' */ + *var = strsep(&arg, "="); + if (*var[0] == '\0') { + pr_err("invalid config variable: %s\n", arg); + return -1; + } + } + + return 0; +} + +int perf_config__set_variable(const char *var, const char *value) +{ + char path[PATH_MAX]; + char *user_config = mkpath(path, sizeof(path), "%s/.perfconfig", getenv("HOME")); + const char *config_filename; + struct perf_config_set *set; + int ret = -1; + + if (use_system_config) + config_exclusive_filename = perf_etc_perfconfig(); + else if (use_user_config) + config_exclusive_filename = user_config; + + if (!config_exclusive_filename) + config_filename = user_config; + else + config_filename = config_exclusive_filename; + + set = perf_config_set__new(); + if (!set) + goto out_err; + + if (perf_config_set__collect(set, config_filename, var, value) < 0) { + pr_err("Failed to add '%s=%s'\n", var, value); + goto out_err; + } + + if (set_config(set, config_filename) < 0) { + pr_err("Failed to set the configs on %s\n", config_filename); + goto out_err; + } + + ret = 0; +out_err: + perf_config_set__delete(set); + return ret; +} + +int cmd_config(int argc, const char **argv) +{ + int i, ret = -1; + struct perf_config_set *set; + char path[PATH_MAX]; + char *user_config = mkpath(path, sizeof(path), "%s/.perfconfig", getenv("HOME")); + const char *config_filename; + bool changed = false; + + argc = parse_options(argc, argv, config_options, config_usage, + PARSE_OPT_STOP_AT_NON_OPTION); + + if (use_system_config && use_user_config) { + pr_err("Error: only one config file at a time\n"); + parse_options_usage(config_usage, config_options, "user", 0); + parse_options_usage(NULL, config_options, "system", 0); + return -1; + } + + if (use_system_config) + config_exclusive_filename = perf_etc_perfconfig(); + else if (use_user_config) + config_exclusive_filename = user_config; + + if (!config_exclusive_filename) + config_filename = user_config; + else + config_filename = config_exclusive_filename; + + /* + * At only 'config' sub-command, individually use the config set + * because of reinitializing with options config file location. + */ + set = perf_config_set__new(); + if (!set) + goto out_err; + + switch (actions) { + case ACTION_LIST: + if (argc) { + pr_err("Error: takes no arguments\n"); + parse_options_usage(config_usage, config_options, "l", 1); + } else { +do_action_list: + if (show_config(set) < 0) { + pr_err("Nothing configured, " + "please check your %s \n", config_filename); + goto out_err; + } + } + break; + default: + if (!argc) + goto do_action_list; + + for (i = 0; argv[i]; i++) { + char *var, *value; + char *arg = strdup(argv[i]); + + if (!arg) { + pr_err("%s: strdup failed\n", __func__); + goto out_err; + } + + if (parse_config_arg(arg, &var, &value) < 0) { + free(arg); + goto out_err; + } + + if (value == NULL) { + if (show_spec_config(set, var) < 0) { + pr_err("%s is not configured: %s\n", + var, config_filename); + free(arg); + goto out_err; + } + } else { + if (perf_config_set__collect(set, config_filename, + var, value) < 0) { + pr_err("Failed to add '%s=%s'\n", + var, value); + free(arg); + goto out_err; + } + changed = true; + } + free(arg); + } + + if (!changed) + break; + + if (set_config(set, config_filename) < 0) { + pr_err("Failed to set the configs on %s\n", + config_filename); + goto out_err; + } + } + + ret = 0; +out_err: + perf_config_set__delete(set); + return ret; +} -- cgit v1.3.1