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![Arnaldo Carvalho de Melo](/assets/img/avatar_default.png)
In places where the equivalent was already being done, i.e.: free(a); a = NULL; And in placs where struct members are being freed so that if we have some erroneous reference to its struct, then accesses to freed members will result in segfaults, which we can detect faster than use after free to areas that may still have something seemingly valid. Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Namhyung Kim <namhyung@kernel.org> Link: https://lkml.kernel.org/n/tip-jatyoofo5boc1bsvoig6bb6i@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
577 lines
14 KiB
C
577 lines
14 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (C) 2015, Wang Nan <wangnan0@huawei.com>
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* Copyright (C) 2015, Huawei Inc.
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*/
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#include <errno.h>
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#include <limits.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <linux/err.h>
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#include <linux/zalloc.h>
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#include "debug.h"
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#include "llvm-utils.h"
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#include "config.h"
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#include "util.h"
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#include <sys/wait.h>
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#include <subcmd/exec-cmd.h>
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#define CLANG_BPF_CMD_DEFAULT_TEMPLATE \
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"$CLANG_EXEC -D__KERNEL__ -D__NR_CPUS__=$NR_CPUS "\
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"-DLINUX_VERSION_CODE=$LINUX_VERSION_CODE " \
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"$CLANG_OPTIONS $PERF_BPF_INC_OPTIONS $KERNEL_INC_OPTIONS " \
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"-Wno-unused-value -Wno-pointer-sign " \
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"-working-directory $WORKING_DIR " \
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"-c \"$CLANG_SOURCE\" -target bpf $CLANG_EMIT_LLVM -O2 -o - $LLVM_OPTIONS_PIPE"
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struct llvm_param llvm_param = {
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.clang_path = "clang",
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.llc_path = "llc",
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.clang_bpf_cmd_template = CLANG_BPF_CMD_DEFAULT_TEMPLATE,
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.clang_opt = NULL,
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.opts = NULL,
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.kbuild_dir = NULL,
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.kbuild_opts = NULL,
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.user_set_param = false,
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};
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int perf_llvm_config(const char *var, const char *value)
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{
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if (!strstarts(var, "llvm."))
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return 0;
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var += sizeof("llvm.") - 1;
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if (!strcmp(var, "clang-path"))
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llvm_param.clang_path = strdup(value);
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else if (!strcmp(var, "clang-bpf-cmd-template"))
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llvm_param.clang_bpf_cmd_template = strdup(value);
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else if (!strcmp(var, "clang-opt"))
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llvm_param.clang_opt = strdup(value);
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else if (!strcmp(var, "kbuild-dir"))
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llvm_param.kbuild_dir = strdup(value);
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else if (!strcmp(var, "kbuild-opts"))
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llvm_param.kbuild_opts = strdup(value);
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else if (!strcmp(var, "dump-obj"))
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llvm_param.dump_obj = !!perf_config_bool(var, value);
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else if (!strcmp(var, "opts"))
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llvm_param.opts = strdup(value);
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else {
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pr_debug("Invalid LLVM config option: %s\n", value);
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return -1;
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}
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llvm_param.user_set_param = true;
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return 0;
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}
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static int
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search_program(const char *def, const char *name,
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char *output)
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{
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char *env, *path, *tmp = NULL;
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char buf[PATH_MAX];
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int ret;
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output[0] = '\0';
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if (def && def[0] != '\0') {
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if (def[0] == '/') {
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if (access(def, F_OK) == 0) {
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strlcpy(output, def, PATH_MAX);
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return 0;
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}
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} else if (def[0] != '\0')
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name = def;
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}
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env = getenv("PATH");
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if (!env)
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return -1;
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env = strdup(env);
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if (!env)
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return -1;
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ret = -ENOENT;
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path = strtok_r(env, ":", &tmp);
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while (path) {
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scnprintf(buf, sizeof(buf), "%s/%s", path, name);
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if (access(buf, F_OK) == 0) {
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strlcpy(output, buf, PATH_MAX);
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ret = 0;
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break;
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}
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path = strtok_r(NULL, ":", &tmp);
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}
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free(env);
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return ret;
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}
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#define READ_SIZE 4096
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static int
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read_from_pipe(const char *cmd, void **p_buf, size_t *p_read_sz)
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{
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int err = 0;
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void *buf = NULL;
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FILE *file = NULL;
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size_t read_sz = 0, buf_sz = 0;
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char serr[STRERR_BUFSIZE];
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file = popen(cmd, "r");
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if (!file) {
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pr_err("ERROR: unable to popen cmd: %s\n",
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str_error_r(errno, serr, sizeof(serr)));
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return -EINVAL;
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}
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while (!feof(file) && !ferror(file)) {
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/*
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* Make buf_sz always have obe byte extra space so we
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* can put '\0' there.
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*/
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if (buf_sz - read_sz < READ_SIZE + 1) {
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void *new_buf;
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buf_sz = read_sz + READ_SIZE + 1;
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new_buf = realloc(buf, buf_sz);
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if (!new_buf) {
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pr_err("ERROR: failed to realloc memory\n");
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err = -ENOMEM;
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goto errout;
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}
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buf = new_buf;
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}
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read_sz += fread(buf + read_sz, 1, READ_SIZE, file);
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}
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if (buf_sz - read_sz < 1) {
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pr_err("ERROR: internal error\n");
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err = -EINVAL;
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goto errout;
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}
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if (ferror(file)) {
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pr_err("ERROR: error occurred when reading from pipe: %s\n",
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str_error_r(errno, serr, sizeof(serr)));
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err = -EIO;
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goto errout;
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}
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err = WEXITSTATUS(pclose(file));
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file = NULL;
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if (err) {
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err = -EINVAL;
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goto errout;
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}
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/*
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* If buf is string, give it terminal '\0' to make our life
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* easier. If buf is not string, that '\0' is out of space
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* indicated by read_sz so caller won't even notice it.
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*/
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((char *)buf)[read_sz] = '\0';
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if (!p_buf)
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free(buf);
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else
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*p_buf = buf;
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if (p_read_sz)
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*p_read_sz = read_sz;
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return 0;
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errout:
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if (file)
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pclose(file);
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free(buf);
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if (p_buf)
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*p_buf = NULL;
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if (p_read_sz)
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*p_read_sz = 0;
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return err;
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}
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static inline void
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force_set_env(const char *var, const char *value)
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{
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if (value) {
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setenv(var, value, 1);
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pr_debug("set env: %s=%s\n", var, value);
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} else {
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unsetenv(var);
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pr_debug("unset env: %s\n", var);
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}
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}
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static void
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version_notice(void)
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{
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pr_err(
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" \tLLVM 3.7 or newer is required. Which can be found from http://llvm.org\n"
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" \tYou may want to try git trunk:\n"
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" \t\tgit clone http://llvm.org/git/llvm.git\n"
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" \t\t and\n"
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" \t\tgit clone http://llvm.org/git/clang.git\n\n"
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" \tOr fetch the latest clang/llvm 3.7 from pre-built llvm packages for\n"
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" \tdebian/ubuntu:\n"
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" \t\thttp://llvm.org/apt\n\n"
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" \tIf you are using old version of clang, change 'clang-bpf-cmd-template'\n"
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" \toption in [llvm] section of ~/.perfconfig to:\n\n"
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" \t \"$CLANG_EXEC $CLANG_OPTIONS $KERNEL_INC_OPTIONS $PERF_BPF_INC_OPTIONS \\\n"
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" \t -working-directory $WORKING_DIR -c $CLANG_SOURCE \\\n"
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" \t -emit-llvm -o - | /path/to/llc -march=bpf -filetype=obj -o -\"\n"
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" \t(Replace /path/to/llc with path to your llc)\n\n"
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);
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}
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static int detect_kbuild_dir(char **kbuild_dir)
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{
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const char *test_dir = llvm_param.kbuild_dir;
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const char *prefix_dir = "";
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const char *suffix_dir = "";
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char *autoconf_path;
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int err;
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if (!test_dir) {
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/* _UTSNAME_LENGTH is 65 */
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char release[128];
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err = fetch_kernel_version(NULL, release,
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sizeof(release));
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if (err)
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return -EINVAL;
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test_dir = release;
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prefix_dir = "/lib/modules/";
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suffix_dir = "/build";
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}
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err = asprintf(&autoconf_path, "%s%s%s/include/generated/autoconf.h",
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prefix_dir, test_dir, suffix_dir);
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if (err < 0)
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return -ENOMEM;
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if (access(autoconf_path, R_OK) == 0) {
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free(autoconf_path);
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err = asprintf(kbuild_dir, "%s%s%s", prefix_dir, test_dir,
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suffix_dir);
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if (err < 0)
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return -ENOMEM;
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return 0;
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}
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free(autoconf_path);
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return -ENOENT;
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}
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static const char *kinc_fetch_script =
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"#!/usr/bin/env sh\n"
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"if ! test -d \"$KBUILD_DIR\"\n"
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"then\n"
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" exit 1\n"
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"fi\n"
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"if ! test -f \"$KBUILD_DIR/include/generated/autoconf.h\"\n"
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"then\n"
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" exit 1\n"
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"fi\n"
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"TMPDIR=`mktemp -d`\n"
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"if test -z \"$TMPDIR\"\n"
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"then\n"
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" exit 1\n"
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"fi\n"
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"cat << EOF > $TMPDIR/Makefile\n"
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"obj-y := dummy.o\n"
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"\\$(obj)/%.o: \\$(src)/%.c\n"
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"\t@echo -n \"\\$(NOSTDINC_FLAGS) \\$(LINUXINCLUDE) \\$(EXTRA_CFLAGS)\"\n"
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"EOF\n"
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"touch $TMPDIR/dummy.c\n"
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"make -s -C $KBUILD_DIR M=$TMPDIR $KBUILD_OPTS dummy.o 2>/dev/null\n"
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"RET=$?\n"
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"rm -rf $TMPDIR\n"
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"exit $RET\n";
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void llvm__get_kbuild_opts(char **kbuild_dir, char **kbuild_include_opts)
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{
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static char *saved_kbuild_dir;
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static char *saved_kbuild_include_opts;
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int err;
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if (!kbuild_dir || !kbuild_include_opts)
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return;
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*kbuild_dir = NULL;
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*kbuild_include_opts = NULL;
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if (saved_kbuild_dir && saved_kbuild_include_opts &&
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!IS_ERR(saved_kbuild_dir) && !IS_ERR(saved_kbuild_include_opts)) {
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*kbuild_dir = strdup(saved_kbuild_dir);
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*kbuild_include_opts = strdup(saved_kbuild_include_opts);
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if (*kbuild_dir && *kbuild_include_opts)
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return;
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zfree(kbuild_dir);
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zfree(kbuild_include_opts);
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/*
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* Don't fall through: it may breaks saved_kbuild_dir and
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* saved_kbuild_include_opts if detect them again when
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* memory is low.
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*/
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return;
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}
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if (llvm_param.kbuild_dir && !llvm_param.kbuild_dir[0]) {
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pr_debug("[llvm.kbuild-dir] is set to \"\" deliberately.\n");
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pr_debug("Skip kbuild options detection.\n");
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goto errout;
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}
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err = detect_kbuild_dir(kbuild_dir);
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if (err) {
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pr_warning(
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"WARNING:\tunable to get correct kernel building directory.\n"
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"Hint:\tSet correct kbuild directory using 'kbuild-dir' option in [llvm]\n"
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" \tsection of ~/.perfconfig or set it to \"\" to suppress kbuild\n"
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" \tdetection.\n\n");
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goto errout;
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}
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pr_debug("Kernel build dir is set to %s\n", *kbuild_dir);
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force_set_env("KBUILD_DIR", *kbuild_dir);
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force_set_env("KBUILD_OPTS", llvm_param.kbuild_opts);
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err = read_from_pipe(kinc_fetch_script,
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(void **)kbuild_include_opts,
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NULL);
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if (err) {
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pr_warning(
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"WARNING:\tunable to get kernel include directories from '%s'\n"
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"Hint:\tTry set clang include options using 'clang-bpf-cmd-template'\n"
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" \toption in [llvm] section of ~/.perfconfig and set 'kbuild-dir'\n"
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" \toption in [llvm] to \"\" to suppress this detection.\n\n",
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*kbuild_dir);
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zfree(kbuild_dir);
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goto errout;
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}
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pr_debug("include option is set to %s\n", *kbuild_include_opts);
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saved_kbuild_dir = strdup(*kbuild_dir);
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saved_kbuild_include_opts = strdup(*kbuild_include_opts);
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if (!saved_kbuild_dir || !saved_kbuild_include_opts) {
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zfree(&saved_kbuild_dir);
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zfree(&saved_kbuild_include_opts);
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}
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return;
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errout:
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saved_kbuild_dir = ERR_PTR(-EINVAL);
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saved_kbuild_include_opts = ERR_PTR(-EINVAL);
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}
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int llvm__get_nr_cpus(void)
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{
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static int nr_cpus_avail = 0;
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char serr[STRERR_BUFSIZE];
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if (nr_cpus_avail > 0)
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return nr_cpus_avail;
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nr_cpus_avail = sysconf(_SC_NPROCESSORS_CONF);
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if (nr_cpus_avail <= 0) {
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pr_err(
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"WARNING:\tunable to get available CPUs in this system: %s\n"
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" \tUse 128 instead.\n", str_error_r(errno, serr, sizeof(serr)));
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nr_cpus_avail = 128;
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}
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return nr_cpus_avail;
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}
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void llvm__dump_obj(const char *path, void *obj_buf, size_t size)
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{
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char *obj_path = strdup(path);
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FILE *fp;
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char *p;
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if (!obj_path) {
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pr_warning("WARNING: Not enough memory, skip object dumping\n");
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return;
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}
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p = strrchr(obj_path, '.');
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if (!p || (strcmp(p, ".c") != 0)) {
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pr_warning("WARNING: invalid llvm source path: '%s', skip object dumping\n",
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obj_path);
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goto out;
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}
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p[1] = 'o';
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fp = fopen(obj_path, "wb");
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if (!fp) {
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pr_warning("WARNING: failed to open '%s': %s, skip object dumping\n",
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obj_path, strerror(errno));
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goto out;
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}
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pr_info("LLVM: dumping %s\n", obj_path);
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if (fwrite(obj_buf, size, 1, fp) != 1)
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pr_warning("WARNING: failed to write to file '%s': %s, skip object dumping\n",
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obj_path, strerror(errno));
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fclose(fp);
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out:
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free(obj_path);
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}
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int llvm__compile_bpf(const char *path, void **p_obj_buf,
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size_t *p_obj_buf_sz)
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{
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size_t obj_buf_sz;
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void *obj_buf = NULL;
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int err, nr_cpus_avail;
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unsigned int kernel_version;
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char linux_version_code_str[64];
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const char *clang_opt = llvm_param.clang_opt;
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char clang_path[PATH_MAX], llc_path[PATH_MAX], abspath[PATH_MAX], nr_cpus_avail_str[64];
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char serr[STRERR_BUFSIZE];
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char *kbuild_dir = NULL, *kbuild_include_opts = NULL,
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*perf_bpf_include_opts = NULL;
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const char *template = llvm_param.clang_bpf_cmd_template;
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char *pipe_template = NULL;
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const char *opts = llvm_param.opts;
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char *command_echo = NULL, *command_out;
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char *perf_include_dir = system_path(PERF_INCLUDE_DIR);
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if (path[0] != '-' && realpath(path, abspath) == NULL) {
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err = errno;
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pr_err("ERROR: problems with path %s: %s\n",
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path, str_error_r(err, serr, sizeof(serr)));
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return -err;
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}
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if (!template)
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template = CLANG_BPF_CMD_DEFAULT_TEMPLATE;
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err = search_program(llvm_param.clang_path,
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"clang", clang_path);
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if (err) {
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pr_err(
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"ERROR:\tunable to find clang.\n"
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"Hint:\tTry to install latest clang/llvm to support BPF. Check your $PATH\n"
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" \tand 'clang-path' option in [llvm] section of ~/.perfconfig.\n");
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version_notice();
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return -ENOENT;
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}
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/*
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* This is an optional work. Even it fail we can continue our
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* work. Needn't to check error return.
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*/
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llvm__get_kbuild_opts(&kbuild_dir, &kbuild_include_opts);
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nr_cpus_avail = llvm__get_nr_cpus();
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snprintf(nr_cpus_avail_str, sizeof(nr_cpus_avail_str), "%d",
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nr_cpus_avail);
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if (fetch_kernel_version(&kernel_version, NULL, 0))
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kernel_version = 0;
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|
snprintf(linux_version_code_str, sizeof(linux_version_code_str),
|
|
"0x%x", kernel_version);
|
|
if (asprintf(&perf_bpf_include_opts, "-I%s/bpf", perf_include_dir) < 0)
|
|
goto errout;
|
|
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("PERF_BPF_INC_OPTIONS", perf_bpf_include_opts);
|
|
force_set_env("WORKING_DIR", kbuild_dir ? : ".");
|
|
|
|
if (opts) {
|
|
err = search_program(llvm_param.llc_path, "llc", llc_path);
|
|
if (err) {
|
|
pr_err("ERROR:\tunable to find llc.\n"
|
|
"Hint:\tTry to install latest clang/llvm to support BPF. Check your $PATH\n"
|
|
" \tand 'llc-path' option in [llvm] section of ~/.perfconfig.\n");
|
|
version_notice();
|
|
goto errout;
|
|
}
|
|
|
|
if (asprintf(&pipe_template, "%s -emit-llvm | %s -march=bpf %s -filetype=obj -o -",
|
|
template, llc_path, opts) < 0) {
|
|
pr_err("ERROR:\tnot enough memory to setup command line\n");
|
|
goto errout;
|
|
}
|
|
|
|
template = pipe_template;
|
|
|
|
}
|
|
|
|
/*
|
|
* 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 : abspath);
|
|
|
|
pr_debug("llvm compiling command template: %s\n", template);
|
|
|
|
if (asprintf(&command_echo, "echo -n \"%s\"", template) < 0)
|
|
goto errout;
|
|
|
|
err = read_from_pipe(command_echo, (void **) &command_out, NULL);
|
|
if (err)
|
|
goto errout;
|
|
|
|
pr_debug("llvm compiling command : %s\n", command_out);
|
|
|
|
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(command_echo);
|
|
free(command_out);
|
|
free(kbuild_dir);
|
|
free(kbuild_include_opts);
|
|
free(perf_bpf_include_opts);
|
|
free(perf_include_dir);
|
|
|
|
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(command_echo);
|
|
free(kbuild_dir);
|
|
free(kbuild_include_opts);
|
|
free(obj_buf);
|
|
free(perf_bpf_include_opts);
|
|
free(perf_include_dir);
|
|
free(pipe_template);
|
|
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);
|
|
}
|