261 lines · c
1// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)2 3#ifndef _GNU_SOURCE4#define _GNU_SOURCE5#endif6 7#include <errno.h>8#include <stdlib.h>9#include <linux/err.h>10#include <linux/kernel.h>11#include <bpf/bpf.h>12#include "bpf-utils.h"13#include "debug.h"14 15struct bpil_array_desc {16 int array_offset; /* e.g. offset of jited_prog_insns */17 int count_offset; /* e.g. offset of jited_prog_len */18 int size_offset; /* > 0: offset of rec size,19 * < 0: fix size of -size_offset20 */21};22 23static struct bpil_array_desc bpil_array_desc[] = {24 [PERF_BPIL_JITED_INSNS] = {25 offsetof(struct bpf_prog_info, jited_prog_insns),26 offsetof(struct bpf_prog_info, jited_prog_len),27 -1,28 },29 [PERF_BPIL_XLATED_INSNS] = {30 offsetof(struct bpf_prog_info, xlated_prog_insns),31 offsetof(struct bpf_prog_info, xlated_prog_len),32 -1,33 },34 [PERF_BPIL_MAP_IDS] = {35 offsetof(struct bpf_prog_info, map_ids),36 offsetof(struct bpf_prog_info, nr_map_ids),37 -(int)sizeof(__u32),38 },39 [PERF_BPIL_JITED_KSYMS] = {40 offsetof(struct bpf_prog_info, jited_ksyms),41 offsetof(struct bpf_prog_info, nr_jited_ksyms),42 -(int)sizeof(__u64),43 },44 [PERF_BPIL_JITED_FUNC_LENS] = {45 offsetof(struct bpf_prog_info, jited_func_lens),46 offsetof(struct bpf_prog_info, nr_jited_func_lens),47 -(int)sizeof(__u32),48 },49 [PERF_BPIL_FUNC_INFO] = {50 offsetof(struct bpf_prog_info, func_info),51 offsetof(struct bpf_prog_info, nr_func_info),52 offsetof(struct bpf_prog_info, func_info_rec_size),53 },54 [PERF_BPIL_LINE_INFO] = {55 offsetof(struct bpf_prog_info, line_info),56 offsetof(struct bpf_prog_info, nr_line_info),57 offsetof(struct bpf_prog_info, line_info_rec_size),58 },59 [PERF_BPIL_JITED_LINE_INFO] = {60 offsetof(struct bpf_prog_info, jited_line_info),61 offsetof(struct bpf_prog_info, nr_jited_line_info),62 offsetof(struct bpf_prog_info, jited_line_info_rec_size),63 },64 [PERF_BPIL_PROG_TAGS] = {65 offsetof(struct bpf_prog_info, prog_tags),66 offsetof(struct bpf_prog_info, nr_prog_tags),67 -(int)sizeof(__u8) * BPF_TAG_SIZE,68 },69 70};71 72static __u32 bpf_prog_info_read_offset_u32(struct bpf_prog_info *info,73 int offset)74{75 __u32 *array = (__u32 *)info;76 77 if (offset >= 0)78 return array[offset / sizeof(__u32)];79 return -(int)offset;80}81 82static __u64 bpf_prog_info_read_offset_u64(struct bpf_prog_info *info,83 int offset)84{85 __u64 *array = (__u64 *)info;86 87 if (offset >= 0)88 return array[offset / sizeof(__u64)];89 return -(int)offset;90}91 92static void bpf_prog_info_set_offset_u32(struct bpf_prog_info *info, int offset,93 __u32 val)94{95 __u32 *array = (__u32 *)info;96 97 if (offset >= 0)98 array[offset / sizeof(__u32)] = val;99}100 101static void bpf_prog_info_set_offset_u64(struct bpf_prog_info *info, int offset,102 __u64 val)103{104 __u64 *array = (__u64 *)info;105 106 if (offset >= 0)107 array[offset / sizeof(__u64)] = val;108}109 110struct perf_bpil *111get_bpf_prog_info_linear(int fd, __u64 arrays)112{113 struct bpf_prog_info info = {};114 struct perf_bpil *info_linear;115 __u32 info_len = sizeof(info);116 __u32 data_len = 0;117 int i, err;118 void *ptr;119 120 if (arrays >> PERF_BPIL_LAST_ARRAY)121 return ERR_PTR(-EINVAL);122 123 /* step 1: get array dimensions */124 err = bpf_obj_get_info_by_fd(fd, &info, &info_len);125 if (err) {126 pr_debug("can't get prog info: %s", strerror(errno));127 return ERR_PTR(-EFAULT);128 }129 130 /* step 2: calculate total size of all arrays */131 for (i = PERF_BPIL_FIRST_ARRAY; i < PERF_BPIL_LAST_ARRAY; ++i) {132 bool include_array = (arrays & (1UL << i)) > 0;133 struct bpil_array_desc *desc;134 __u32 count, size;135 136 desc = bpil_array_desc + i;137 138 /* kernel is too old to support this field */139 if (info_len < desc->array_offset + sizeof(__u32) ||140 info_len < desc->count_offset + sizeof(__u32) ||141 (desc->size_offset > 0 && info_len < (__u32)desc->size_offset))142 include_array = false;143 144 if (!include_array) {145 arrays &= ~(1UL << i); /* clear the bit */146 continue;147 }148 149 count = bpf_prog_info_read_offset_u32(&info, desc->count_offset);150 size = bpf_prog_info_read_offset_u32(&info, desc->size_offset);151 152 data_len += roundup(count * size, sizeof(__u64));153 }154 155 /* step 3: allocate continuous memory */156 info_linear = malloc(sizeof(struct perf_bpil) + data_len);157 if (!info_linear)158 return ERR_PTR(-ENOMEM);159 160 /* step 4: fill data to info_linear->info */161 info_linear->arrays = arrays;162 memset(&info_linear->info, 0, sizeof(info));163 ptr = info_linear->data;164 165 for (i = PERF_BPIL_FIRST_ARRAY; i < PERF_BPIL_LAST_ARRAY; ++i) {166 struct bpil_array_desc *desc;167 __u32 count, size;168 169 if ((arrays & (1UL << i)) == 0)170 continue;171 172 desc = bpil_array_desc + i;173 count = bpf_prog_info_read_offset_u32(&info, desc->count_offset);174 size = bpf_prog_info_read_offset_u32(&info, desc->size_offset);175 bpf_prog_info_set_offset_u32(&info_linear->info,176 desc->count_offset, count);177 bpf_prog_info_set_offset_u32(&info_linear->info,178 desc->size_offset, size);179 bpf_prog_info_set_offset_u64(&info_linear->info,180 desc->array_offset,181 ptr_to_u64(ptr));182 ptr += roundup(count * size, sizeof(__u64));183 }184 185 /* step 5: call syscall again to get required arrays */186 err = bpf_obj_get_info_by_fd(fd, &info_linear->info, &info_len);187 if (err) {188 pr_debug("can't get prog info: %s", strerror(errno));189 free(info_linear);190 return ERR_PTR(-EFAULT);191 }192 193 /* step 6: verify the data */194 for (i = PERF_BPIL_FIRST_ARRAY; i < PERF_BPIL_LAST_ARRAY; ++i) {195 struct bpil_array_desc *desc;196 __u32 v1, v2;197 198 if ((arrays & (1UL << i)) == 0)199 continue;200 201 desc = bpil_array_desc + i;202 v1 = bpf_prog_info_read_offset_u32(&info, desc->count_offset);203 v2 = bpf_prog_info_read_offset_u32(&info_linear->info,204 desc->count_offset);205 if (v1 != v2)206 pr_warning("%s: mismatch in element count\n", __func__);207 208 v1 = bpf_prog_info_read_offset_u32(&info, desc->size_offset);209 v2 = bpf_prog_info_read_offset_u32(&info_linear->info,210 desc->size_offset);211 if (v1 != v2)212 pr_warning("%s: mismatch in rec size\n", __func__);213 }214 215 /* step 7: update info_len and data_len */216 info_linear->info_len = sizeof(struct bpf_prog_info);217 info_linear->data_len = data_len;218 219 return info_linear;220}221 222void bpil_addr_to_offs(struct perf_bpil *info_linear)223{224 int i;225 226 for (i = PERF_BPIL_FIRST_ARRAY; i < PERF_BPIL_LAST_ARRAY; ++i) {227 struct bpil_array_desc *desc;228 __u64 addr, offs;229 230 if ((info_linear->arrays & (1UL << i)) == 0)231 continue;232 233 desc = bpil_array_desc + i;234 addr = bpf_prog_info_read_offset_u64(&info_linear->info,235 desc->array_offset);236 offs = addr - ptr_to_u64(info_linear->data);237 bpf_prog_info_set_offset_u64(&info_linear->info,238 desc->array_offset, offs);239 }240}241 242void bpil_offs_to_addr(struct perf_bpil *info_linear)243{244 int i;245 246 for (i = PERF_BPIL_FIRST_ARRAY; i < PERF_BPIL_LAST_ARRAY; ++i) {247 struct bpil_array_desc *desc;248 __u64 addr, offs;249 250 if ((info_linear->arrays & (1UL << i)) == 0)251 continue;252 253 desc = bpil_array_desc + i;254 offs = bpf_prog_info_read_offset_u64(&info_linear->info,255 desc->array_offset);256 addr = offs + ptr_to_u64(info_linear->data);257 bpf_prog_info_set_offset_u64(&info_linear->info,258 desc->array_offset, addr);259 }260}261