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-rw-r--r--tools/lib/bpf/bpf_prog_linfo.c246
1 files changed, 246 insertions, 0 deletions
diff --git a/tools/lib/bpf/bpf_prog_linfo.c b/tools/lib/bpf/bpf_prog_linfo.c
new file mode 100644
index 000000000..3ed1a27b5
--- /dev/null
+++ b/tools/lib/bpf/bpf_prog_linfo.c
@@ -0,0 +1,246 @@
+// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
+/* Copyright (c) 2018 Facebook */
+
+#include <string.h>
+#include <stdlib.h>
+#include <linux/err.h>
+#include <linux/bpf.h>
+#include "libbpf.h"
+#include "libbpf_internal.h"
+
+struct bpf_prog_linfo {
+ void *raw_linfo;
+ void *raw_jited_linfo;
+ __u32 *nr_jited_linfo_per_func;
+ __u32 *jited_linfo_func_idx;
+ __u32 nr_linfo;
+ __u32 nr_jited_func;
+ __u32 rec_size;
+ __u32 jited_rec_size;
+};
+
+static int dissect_jited_func(struct bpf_prog_linfo *prog_linfo,
+ const __u64 *ksym_func, const __u32 *ksym_len)
+{
+ __u32 nr_jited_func, nr_linfo;
+ const void *raw_jited_linfo;
+ const __u64 *jited_linfo;
+ __u64 last_jited_linfo;
+ /*
+ * Index to raw_jited_linfo:
+ * i: Index for searching the next ksym_func
+ * prev_i: Index to the last found ksym_func
+ */
+ __u32 i, prev_i;
+ __u32 f; /* Index to ksym_func */
+
+ raw_jited_linfo = prog_linfo->raw_jited_linfo;
+ jited_linfo = raw_jited_linfo;
+ if (ksym_func[0] != *jited_linfo)
+ goto errout;
+
+ prog_linfo->jited_linfo_func_idx[0] = 0;
+ nr_jited_func = prog_linfo->nr_jited_func;
+ nr_linfo = prog_linfo->nr_linfo;
+
+ for (prev_i = 0, i = 1, f = 1;
+ i < nr_linfo && f < nr_jited_func;
+ i++) {
+ raw_jited_linfo += prog_linfo->jited_rec_size;
+ last_jited_linfo = *jited_linfo;
+ jited_linfo = raw_jited_linfo;
+
+ if (ksym_func[f] == *jited_linfo) {
+ prog_linfo->jited_linfo_func_idx[f] = i;
+
+ /* Sanity check */
+ if (last_jited_linfo - ksym_func[f - 1] + 1 >
+ ksym_len[f - 1])
+ goto errout;
+
+ prog_linfo->nr_jited_linfo_per_func[f - 1] =
+ i - prev_i;
+ prev_i = i;
+
+ /*
+ * The ksym_func[f] is found in jited_linfo.
+ * Look for the next one.
+ */
+ f++;
+ } else if (*jited_linfo <= last_jited_linfo) {
+ /* Ensure the addr is increasing _within_ a func */
+ goto errout;
+ }
+ }
+
+ if (f != nr_jited_func)
+ goto errout;
+
+ prog_linfo->nr_jited_linfo_per_func[nr_jited_func - 1] =
+ nr_linfo - prev_i;
+
+ return 0;
+
+errout:
+ return -EINVAL;
+}
+
+void bpf_prog_linfo__free(struct bpf_prog_linfo *prog_linfo)
+{
+ if (!prog_linfo)
+ return;
+
+ free(prog_linfo->raw_linfo);
+ free(prog_linfo->raw_jited_linfo);
+ free(prog_linfo->nr_jited_linfo_per_func);
+ free(prog_linfo->jited_linfo_func_idx);
+ free(prog_linfo);
+}
+
+struct bpf_prog_linfo *bpf_prog_linfo__new(const struct bpf_prog_info *info)
+{
+ struct bpf_prog_linfo *prog_linfo;
+ __u32 nr_linfo, nr_jited_func;
+ __u64 data_sz;
+
+ nr_linfo = info->nr_line_info;
+
+ if (!nr_linfo)
+ return NULL;
+
+ /*
+ * The min size that bpf_prog_linfo has to access for
+ * searching purpose.
+ */
+ if (info->line_info_rec_size <
+ offsetof(struct bpf_line_info, file_name_off))
+ return NULL;
+
+ prog_linfo = calloc(1, sizeof(*prog_linfo));
+ if (!prog_linfo)
+ return NULL;
+
+ /* Copy xlated line_info */
+ prog_linfo->nr_linfo = nr_linfo;
+ prog_linfo->rec_size = info->line_info_rec_size;
+ data_sz = (__u64)nr_linfo * prog_linfo->rec_size;
+ prog_linfo->raw_linfo = malloc(data_sz);
+ if (!prog_linfo->raw_linfo)
+ goto err_free;
+ memcpy(prog_linfo->raw_linfo, (void *)(long)info->line_info, data_sz);
+
+ nr_jited_func = info->nr_jited_ksyms;
+ if (!nr_jited_func ||
+ !info->jited_line_info ||
+ info->nr_jited_line_info != nr_linfo ||
+ info->jited_line_info_rec_size < sizeof(__u64) ||
+ info->nr_jited_func_lens != nr_jited_func ||
+ !info->jited_ksyms ||
+ !info->jited_func_lens)
+ /* Not enough info to provide jited_line_info */
+ return prog_linfo;
+
+ /* Copy jited_line_info */
+ prog_linfo->nr_jited_func = nr_jited_func;
+ prog_linfo->jited_rec_size = info->jited_line_info_rec_size;
+ data_sz = (__u64)nr_linfo * prog_linfo->jited_rec_size;
+ prog_linfo->raw_jited_linfo = malloc(data_sz);
+ if (!prog_linfo->raw_jited_linfo)
+ goto err_free;
+ memcpy(prog_linfo->raw_jited_linfo,
+ (void *)(long)info->jited_line_info, data_sz);
+
+ /* Number of jited_line_info per jited func */
+ prog_linfo->nr_jited_linfo_per_func = malloc(nr_jited_func *
+ sizeof(__u32));
+ if (!prog_linfo->nr_jited_linfo_per_func)
+ goto err_free;
+
+ /*
+ * For each jited func,
+ * the start idx to the "linfo" and "jited_linfo" array,
+ */
+ prog_linfo->jited_linfo_func_idx = malloc(nr_jited_func *
+ sizeof(__u32));
+ if (!prog_linfo->jited_linfo_func_idx)
+ goto err_free;
+
+ if (dissect_jited_func(prog_linfo,
+ (__u64 *)(long)info->jited_ksyms,
+ (__u32 *)(long)info->jited_func_lens))
+ goto err_free;
+
+ return prog_linfo;
+
+err_free:
+ bpf_prog_linfo__free(prog_linfo);
+ return NULL;
+}
+
+const struct bpf_line_info *
+bpf_prog_linfo__lfind_addr_func(const struct bpf_prog_linfo *prog_linfo,
+ __u64 addr, __u32 func_idx, __u32 nr_skip)
+{
+ __u32 jited_rec_size, rec_size, nr_linfo, start, i;
+ const void *raw_jited_linfo, *raw_linfo;
+ const __u64 *jited_linfo;
+
+ if (func_idx >= prog_linfo->nr_jited_func)
+ return NULL;
+
+ nr_linfo = prog_linfo->nr_jited_linfo_per_func[func_idx];
+ if (nr_skip >= nr_linfo)
+ return NULL;
+
+ start = prog_linfo->jited_linfo_func_idx[func_idx] + nr_skip;
+ jited_rec_size = prog_linfo->jited_rec_size;
+ raw_jited_linfo = prog_linfo->raw_jited_linfo +
+ (start * jited_rec_size);
+ jited_linfo = raw_jited_linfo;
+ if (addr < *jited_linfo)
+ return NULL;
+
+ nr_linfo -= nr_skip;
+ rec_size = prog_linfo->rec_size;
+ raw_linfo = prog_linfo->raw_linfo + (start * rec_size);
+ for (i = 0; i < nr_linfo; i++) {
+ if (addr < *jited_linfo)
+ break;
+
+ raw_linfo += rec_size;
+ raw_jited_linfo += jited_rec_size;
+ jited_linfo = raw_jited_linfo;
+ }
+
+ return raw_linfo - rec_size;
+}
+
+const struct bpf_line_info *
+bpf_prog_linfo__lfind(const struct bpf_prog_linfo *prog_linfo,
+ __u32 insn_off, __u32 nr_skip)
+{
+ const struct bpf_line_info *linfo;
+ __u32 rec_size, nr_linfo, i;
+ const void *raw_linfo;
+
+ nr_linfo = prog_linfo->nr_linfo;
+ if (nr_skip >= nr_linfo)
+ return NULL;
+
+ rec_size = prog_linfo->rec_size;
+ raw_linfo = prog_linfo->raw_linfo + (nr_skip * rec_size);
+ linfo = raw_linfo;
+ if (insn_off < linfo->insn_off)
+ return NULL;
+
+ nr_linfo -= nr_skip;
+ for (i = 0; i < nr_linfo; i++) {
+ if (insn_off < linfo->insn_off)
+ break;
+
+ raw_linfo += rec_size;
+ linfo = raw_linfo;
+ }
+
+ return raw_linfo - rec_size;
+}