diff options
Diffstat (limited to 'kernel/tools/perf/util/llvm-utils.c')
| -rw-r--r-- | kernel/tools/perf/util/llvm-utils.c | 430 |
1 files changed, 430 insertions, 0 deletions
diff --git a/kernel/tools/perf/util/llvm-utils.c b/kernel/tools/perf/util/llvm-utils.c new file mode 100644 index 000000000..00724d496 --- /dev/null +++ b/kernel/tools/perf/util/llvm-utils.c @@ -0,0 +1,430 @@ +/* + * Copyright (C) 2015, Wang Nan <wangnan0@huawei.com> + * Copyright (C) 2015, Huawei Inc. + */ + +#include <stdio.h> +#include "util.h" +#include "debug.h" +#include "llvm-utils.h" +#include "cache.h" + +#define CLANG_BPF_CMD_DEFAULT_TEMPLATE \ + "$CLANG_EXEC -D__KERNEL__ -D__NR_CPUS__=$NR_CPUS "\ + "-DLINUX_VERSION_CODE=$LINUX_VERSION_CODE " \ + "$CLANG_OPTIONS $KERNEL_INC_OPTIONS " \ + "-Wno-unused-value -Wno-pointer-sign " \ + "-working-directory $WORKING_DIR " \ + "-c \"$CLANG_SOURCE\" -target bpf -O2 -o -" + +struct llvm_param llvm_param = { + .clang_path = "clang", + .clang_bpf_cmd_template = CLANG_BPF_CMD_DEFAULT_TEMPLATE, + .clang_opt = NULL, + .kbuild_dir = NULL, + .kbuild_opts = NULL, + .user_set_param = false, +}; + +int perf_llvm_config(const char *var, const char *value) +{ + if (prefixcmp(var, "llvm.")) + return 0; + var += sizeof("llvm.") - 1; + + if (!strcmp(var, "clang-path")) + llvm_param.clang_path = strdup(value); + else if (!strcmp(var, "clang-bpf-cmd-template")) + llvm_param.clang_bpf_cmd_template = strdup(value); + else if (!strcmp(var, "clang-opt")) + llvm_param.clang_opt = strdup(value); + else if (!strcmp(var, "kbuild-dir")) + llvm_param.kbuild_dir = strdup(value); + else if (!strcmp(var, "kbuild-opts")) + llvm_param.kbuild_opts = strdup(value); + else + return -1; + llvm_param.user_set_param = true; + return 0; +} + +static int +search_program(const char *def, const char *name, + char *output) +{ + char *env, *path, *tmp = NULL; + char buf[PATH_MAX]; + int ret; + + output[0] = '\0'; + if (def && def[0] != '\0') { + if (def[0] == '/') { + if (access(def, F_OK) == 0) { + strlcpy(output, def, PATH_MAX); + return 0; + } + } else if (def[0] != '\0') + name = def; + } + + env = getenv("PATH"); + if (!env) + return -1; + env = strdup(env); + if (!env) + return -1; + + ret = -ENOENT; + path = strtok_r(env, ":", &tmp); + while (path) { + scnprintf(buf, sizeof(buf), "%s/%s", path, name); + if (access(buf, F_OK) == 0) { + strlcpy(output, buf, PATH_MAX); + ret = 0; + break; + } + path = strtok_r(NULL, ":", &tmp); + } + + free(env); + return ret; +} + +#define READ_SIZE 4096 +static int +read_from_pipe(const char *cmd, void **p_buf, size_t *p_read_sz) +{ + int err = 0; + void *buf = NULL; + FILE *file = NULL; + size_t read_sz = 0, buf_sz = 0; + + file = popen(cmd, "r"); + if (!file) { + pr_err("ERROR: unable to popen cmd: %s\n", + strerror(errno)); + return -EINVAL; + } + + while (!feof(file) && !ferror(file)) { + /* + * Make buf_sz always have obe byte extra space so we + * can put '\0' there. + */ + if (buf_sz - read_sz < READ_SIZE + 1) { + void *new_buf; + + buf_sz = read_sz + READ_SIZE + 1; + new_buf = realloc(buf, buf_sz); + + if (!new_buf) { + pr_err("ERROR: failed to realloc memory\n"); + err = -ENOMEM; + goto errout; + } + + buf = new_buf; + } + read_sz += fread(buf + read_sz, 1, READ_SIZE, file); + } + + if (buf_sz - read_sz < 1) { + pr_err("ERROR: internal error\n"); + err = -EINVAL; + goto errout; + } + + if (ferror(file)) { + pr_err("ERROR: error occurred when reading from pipe: %s\n", + strerror(errno)); + err = -EIO; + goto errout; + } + + err = WEXITSTATUS(pclose(file)); + file = NULL; + if (err) { + err = -EINVAL; + goto errout; + } + + /* + * If buf is string, give it terminal '\0' to make our life + * easier. If buf is not string, that '\0' is out of space + * indicated by read_sz so caller won't even notice it. + */ + ((char *)buf)[read_sz] = '\0'; + + if (!p_buf) + free(buf); + else + *p_buf = buf; + + if (p_read_sz) + *p_read_sz = read_sz; + return 0; + +errout: + if (file) + pclose(file); + free(buf); + if (p_buf) + *p_buf = NULL; + if (p_read_sz) + *p_read_sz = 0; + return err; +} + +static inline void +force_set_env(const char *var, const char *value) +{ + if (value) { + setenv(var, value, 1); + pr_debug("set env: %s=%s\n", var, value); + } else { + unsetenv(var); + pr_debug("unset env: %s\n", var); + } +} + +static void +version_notice(void) +{ + pr_err( +" \tLLVM 3.7 or newer is required. Which can be found from http://llvm.org\n" +" \tYou may want to try git trunk:\n" +" \t\tgit clone http://llvm.org/git/llvm.git\n" +" \t\t and\n" +" \t\tgit clone http://llvm.org/git/clang.git\n\n" +" \tOr fetch the latest clang/llvm 3.7 from pre-built llvm packages for\n" +" \tdebian/ubuntu:\n" +" \t\thttp://llvm.org/apt\n\n" +" \tIf you are using old version of clang, change 'clang-bpf-cmd-template'\n" +" \toption in [llvm] section of ~/.perfconfig to:\n\n" +" \t \"$CLANG_EXEC $CLANG_OPTIONS $KERNEL_INC_OPTIONS \\\n" +" \t -working-directory $WORKING_DIR -c $CLANG_SOURCE \\\n" +" \t -emit-llvm -o - | /path/to/llc -march=bpf -filetype=obj -o -\"\n" +" \t(Replace /path/to/llc with path to your llc)\n\n" +); +} + +static int detect_kbuild_dir(char **kbuild_dir) +{ + const char *test_dir = llvm_param.kbuild_dir; + const char *prefix_dir = ""; + const char *suffix_dir = ""; + + char *autoconf_path; + + int err; + + if (!test_dir) { + /* _UTSNAME_LENGTH is 65 */ + char release[128]; + + err = fetch_kernel_version(NULL, release, + sizeof(release)); + if (err) + return -EINVAL; + + test_dir = release; + prefix_dir = "/lib/modules/"; + suffix_dir = "/build"; + } + + err = asprintf(&autoconf_path, "%s%s%s/include/generated/autoconf.h", + prefix_dir, test_dir, suffix_dir); + if (err < 0) + return -ENOMEM; + + if (access(autoconf_path, R_OK) == 0) { + free(autoconf_path); + + err = asprintf(kbuild_dir, "%s%s%s", prefix_dir, test_dir, + suffix_dir); + if (err < 0) + return -ENOMEM; + return 0; + } + free(autoconf_path); + return -ENOENT; +} + +static const char *kinc_fetch_script = +"#!/usr/bin/env sh\n" +"if ! test -d \"$KBUILD_DIR\"\n" +"then\n" +" exit -1\n" +"fi\n" +"if ! test -f \"$KBUILD_DIR/include/generated/autoconf.h\"\n" +"then\n" +" exit -1\n" +"fi\n" +"TMPDIR=`mktemp -d`\n" +"if test -z \"$TMPDIR\"\n" +"then\n" +" exit -1\n" +"fi\n" +"cat << EOF > $TMPDIR/Makefile\n" +"obj-y := dummy.o\n" +"\\$(obj)/%.o: \\$(src)/%.c\n" +"\t@echo -n \"\\$(NOSTDINC_FLAGS) \\$(LINUXINCLUDE) \\$(EXTRA_CFLAGS)\"\n" +"EOF\n" +"touch $TMPDIR/dummy.c\n" +"make -s -C $KBUILD_DIR M=$TMPDIR $KBUILD_OPTS dummy.o 2>/dev/null\n" +"RET=$?\n" +"rm -rf $TMPDIR\n" +"exit $RET\n"; + +static inline void +get_kbuild_opts(char **kbuild_dir, char **kbuild_include_opts) +{ + int err; + + if (!kbuild_dir || !kbuild_include_opts) + return; + + *kbuild_dir = NULL; + *kbuild_include_opts = NULL; + + if (llvm_param.kbuild_dir && !llvm_param.kbuild_dir[0]) { + pr_debug("[llvm.kbuild-dir] is set to \"\" deliberately.\n"); + pr_debug("Skip kbuild options detection.\n"); + return; + } + + err = detect_kbuild_dir(kbuild_dir); + if (err) { + pr_warning( +"WARNING:\tunable to get correct kernel building directory.\n" +"Hint:\tSet correct kbuild directory using 'kbuild-dir' option in [llvm]\n" +" \tsection of ~/.perfconfig or set it to \"\" to suppress kbuild\n" +" \tdetection.\n\n"); + return; + } + + pr_debug("Kernel build dir is set to %s\n", *kbuild_dir); + force_set_env("KBUILD_DIR", *kbuild_dir); + force_set_env("KBUILD_OPTS", llvm_param.kbuild_opts); + err = read_from_pipe(kinc_fetch_script, + (void **)kbuild_include_opts, + NULL); + if (err) { + pr_warning( +"WARNING:\tunable to get kernel include directories from '%s'\n" +"Hint:\tTry set clang include options using 'clang-bpf-cmd-template'\n" +" \toption in [llvm] section of ~/.perfconfig and set 'kbuild-dir'\n" +" \toption in [llvm] to \"\" to suppress this detection.\n\n", + *kbuild_dir); + + free(*kbuild_dir); + *kbuild_dir = NULL; + return; + } + + pr_debug("include option is set to %s\n", *kbuild_include_opts); +} + +int llvm__compile_bpf(const char *path, void **p_obj_buf, + size_t *p_obj_buf_sz) +{ + size_t obj_buf_sz; + void *obj_buf = NULL; + int err, nr_cpus_avail; + unsigned int kernel_version; + char linux_version_code_str[64]; + const char *clang_opt = llvm_param.clang_opt; + char clang_path[PATH_MAX], nr_cpus_avail_str[64]; + char *kbuild_dir = NULL, *kbuild_include_opts = NULL; + const char *template = llvm_param.clang_bpf_cmd_template; + + if (!template) + template = CLANG_BPF_CMD_DEFAULT_TEMPLATE; + + err = search_program(llvm_param.clang_path, + "clang", clang_path); + if (err) { + pr_err( +"ERROR:\tunable to find clang.\n" +"Hint:\tTry to install latest clang/llvm to support BPF. Check your $PATH\n" +" \tand 'clang-path' option in [llvm] section of ~/.perfconfig.\n"); + version_notice(); + return -ENOENT; + } + + /* + * This is an optional work. Even it fail we can continue our + * work. Needn't to check error return. + */ + get_kbuild_opts(&kbuild_dir, &kbuild_include_opts); + + nr_cpus_avail = sysconf(_SC_NPROCESSORS_CONF); + if (nr_cpus_avail <= 0) { + pr_err( +"WARNING:\tunable to get available CPUs in this system: %s\n" +" \tUse 128 instead.\n", strerror(errno)); + nr_cpus_avail = 128; + } + snprintf(nr_cpus_avail_str, sizeof(nr_cpus_avail_str), "%d", + nr_cpus_avail); + + if (fetch_kernel_version(&kernel_version, NULL, 0)) + kernel_version = 0; + + snprintf(linux_version_code_str, sizeof(linux_version_code_str), + "0x%x", kernel_version); + + force_set_env("NR_CPUS", nr_cpus_avail_str); + force_set_env("LINUX_VERSION_CODE", linux_version_code_str); + force_set_env("CLANG_EXEC", clang_path); + force_set_env("CLANG_OPTIONS", clang_opt); + force_set_env("KERNEL_INC_OPTIONS", kbuild_include_opts); + force_set_env("WORKING_DIR", kbuild_dir ? : "."); + + /* + * Since we may reset clang's working dir, path of source file + * should be transferred into absolute path, except we want + * stdin to be source file (testing). + */ + force_set_env("CLANG_SOURCE", + (path[0] == '-') ? path : + make_nonrelative_path(path)); + + pr_debug("llvm compiling command template: %s\n", template); + err = read_from_pipe(template, &obj_buf, &obj_buf_sz); + if (err) { + pr_err("ERROR:\tunable to compile %s\n", path); + pr_err("Hint:\tCheck error message shown above.\n"); + pr_err("Hint:\tYou can also pre-compile it into .o using:\n"); + pr_err(" \t\tclang -target bpf -O2 -c %s\n", path); + pr_err(" \twith proper -I and -D options.\n"); + goto errout; + } + + free(kbuild_dir); + free(kbuild_include_opts); + if (!p_obj_buf) + free(obj_buf); + else + *p_obj_buf = obj_buf; + + if (p_obj_buf_sz) + *p_obj_buf_sz = obj_buf_sz; + return 0; +errout: + free(kbuild_dir); + free(kbuild_include_opts); + free(obj_buf); + if (p_obj_buf) + *p_obj_buf = NULL; + if (p_obj_buf_sz) + *p_obj_buf_sz = 0; + return err; +} + +int llvm__search_clang(void) +{ + char clang_path[PATH_MAX]; + + return search_program(llvm_param.clang_path, "clang", clang_path); +} |