1// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
2/* Copyright (c) 2021 Facebook */
3#include <stdio.h>
4#include <stdlib.h>
5#include <string.h>
6#include <errno.h>
7#include <linux/filter.h>
8#include <sys/param.h>
9#include "btf.h"
10#include "bpf.h"
11#include "libbpf.h"
12#include "libbpf_internal.h"
13#include "hashmap.h"
14#include "bpf_gen_internal.h"
15#include "skel_internal.h"
16#include <asm/byteorder.h>
17
18#define MAX_USED_MAPS 64
19#define MAX_USED_PROGS 32
20#define MAX_KFUNC_DESCS 256
21#define MAX_FD_ARRAY_SZ (MAX_USED_MAPS + MAX_KFUNC_DESCS)
22
23/* The following structure describes the stack layout of the loader program.
24 * In addition R6 contains the pointer to context.
25 * R7 contains the result of the last sys_bpf command (typically error or FD).
26 * R9 contains the result of the last sys_close command.
27 *
28 * Naming convention:
29 * ctx - bpf program context
30 * stack - bpf program stack
31 * blob - bpf_attr-s, strings, insns, map data.
32 * All the bytes that loader prog will use for read/write.
33 */
34struct loader_stack {
35 __u32 btf_fd;
36 __u32 inner_map_fd;
37 __u32 prog_fd[MAX_USED_PROGS];
38};
39
40#define stack_off(field) \
41 (__s16)(-sizeof(struct loader_stack) + offsetof(struct loader_stack, field))
42
43#define attr_field(attr, field) (attr + offsetof(union bpf_attr, field))
44
45static int blob_fd_array_off(struct bpf_gen *gen, int index)
46{
47 return gen->fd_array + index * sizeof(int);
48}
49
50static int realloc_insn_buf(struct bpf_gen *gen, __u32 size)
51{
52 size_t off = gen->insn_cur - gen->insn_start;
53 void *insn_start;
54
55 if (gen->error)
56 return gen->error;
57 if (size > INT32_MAX || off + size > INT32_MAX) {
58 gen->error = -ERANGE;
59 return -ERANGE;
60 }
61 insn_start = realloc(gen->insn_start, off + size);
62 if (!insn_start) {
63 gen->error = -ENOMEM;
64 free(gen->insn_start);
65 gen->insn_start = NULL;
66 return -ENOMEM;
67 }
68 gen->insn_start = insn_start;
69 gen->insn_cur = insn_start + off;
70 return 0;
71}
72
73static int realloc_data_buf(struct bpf_gen *gen, __u32 size)
74{
75 size_t off = gen->data_cur - gen->data_start;
76 void *data_start;
77
78 if (gen->error)
79 return gen->error;
80 if (size > INT32_MAX || off + size > INT32_MAX) {
81 gen->error = -ERANGE;
82 return -ERANGE;
83 }
84 data_start = realloc(gen->data_start, off + size);
85 if (!data_start) {
86 gen->error = -ENOMEM;
87 free(gen->data_start);
88 gen->data_start = NULL;
89 return -ENOMEM;
90 }
91 gen->data_start = data_start;
92 gen->data_cur = data_start + off;
93 return 0;
94}
95
96static void emit(struct bpf_gen *gen, struct bpf_insn insn)
97{
98 if (realloc_insn_buf(gen, size: sizeof(insn)))
99 return;
100 memcpy(gen->insn_cur, &insn, sizeof(insn));
101 gen->insn_cur += sizeof(insn);
102}
103
104static void emit2(struct bpf_gen *gen, struct bpf_insn insn1, struct bpf_insn insn2)
105{
106 emit(gen, insn: insn1);
107 emit(gen, insn: insn2);
108}
109
110static int add_data(struct bpf_gen *gen, const void *data, __u32 size);
111static void emit_sys_close_blob(struct bpf_gen *gen, int blob_off);
112
113void bpf_gen__init(struct bpf_gen *gen, int log_level, int nr_progs, int nr_maps)
114{
115 size_t stack_sz = sizeof(struct loader_stack), nr_progs_sz;
116 int i;
117
118 gen->fd_array = add_data(gen, NULL, MAX_FD_ARRAY_SZ * sizeof(int));
119 gen->log_level = log_level;
120 /* save ctx pointer into R6 */
121 emit(gen, BPF_MOV64_REG(BPF_REG_6, BPF_REG_1));
122
123 /* bzero stack */
124 emit(gen, BPF_MOV64_REG(BPF_REG_1, BPF_REG_10));
125 emit(gen, BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -stack_sz));
126 emit(gen, BPF_MOV64_IMM(BPF_REG_2, stack_sz));
127 emit(gen, BPF_MOV64_IMM(BPF_REG_3, 0));
128 emit(gen, BPF_EMIT_CALL(BPF_FUNC_probe_read_kernel));
129
130 /* amount of stack actually used, only used to calculate iterations, not stack offset */
131 nr_progs_sz = offsetof(struct loader_stack, prog_fd[nr_progs]);
132 /* jump over cleanup code */
133 emit(gen, BPF_JMP_IMM(BPF_JA, 0, 0,
134 /* size of cleanup code below (including map fd cleanup) */
135 (nr_progs_sz / 4) * 3 + 2 +
136 /* 6 insns for emit_sys_close_blob,
137 * 6 insns for debug_regs in emit_sys_close_blob
138 */
139 nr_maps * (6 + (gen->log_level ? 6 : 0))));
140
141 /* remember the label where all error branches will jump to */
142 gen->cleanup_label = gen->insn_cur - gen->insn_start;
143 /* emit cleanup code: close all temp FDs */
144 for (i = 0; i < nr_progs_sz; i += 4) {
145 emit(gen, BPF_LDX_MEM(BPF_W, BPF_REG_1, BPF_REG_10, -stack_sz + i));
146 emit(gen, BPF_JMP_IMM(BPF_JSLE, BPF_REG_1, 0, 1));
147 emit(gen, BPF_EMIT_CALL(BPF_FUNC_sys_close));
148 }
149 for (i = 0; i < nr_maps; i++)
150 emit_sys_close_blob(gen, blob_off: blob_fd_array_off(gen, index: i));
151 /* R7 contains the error code from sys_bpf. Copy it into R0 and exit. */
152 emit(gen, BPF_MOV64_REG(BPF_REG_0, BPF_REG_7));
153 emit(gen, BPF_EXIT_INSN());
154}
155
156static int add_data(struct bpf_gen *gen, const void *data, __u32 size)
157{
158 __u32 size8 = roundup(size, 8);
159 __u64 zero = 0;
160 void *prev;
161
162 if (realloc_data_buf(gen, size: size8))
163 return 0;
164 prev = gen->data_cur;
165 if (data) {
166 memcpy(gen->data_cur, data, size);
167 memcpy(gen->data_cur + size, &zero, size8 - size);
168 } else {
169 memset(gen->data_cur, 0, size8);
170 }
171 gen->data_cur += size8;
172 return prev - gen->data_start;
173}
174
175/* Get index for map_fd/btf_fd slot in reserved fd_array, or in data relative
176 * to start of fd_array. Caller can decide if it is usable or not.
177 */
178static int add_map_fd(struct bpf_gen *gen)
179{
180 if (gen->nr_maps == MAX_USED_MAPS) {
181 pr_warn("Total maps exceeds %d\n", MAX_USED_MAPS);
182 gen->error = -E2BIG;
183 return 0;
184 }
185 return gen->nr_maps++;
186}
187
188static int add_kfunc_btf_fd(struct bpf_gen *gen)
189{
190 int cur;
191
192 if (gen->nr_fd_array == MAX_KFUNC_DESCS) {
193 cur = add_data(gen, NULL, size: sizeof(int));
194 return (cur - gen->fd_array) / sizeof(int);
195 }
196 return MAX_USED_MAPS + gen->nr_fd_array++;
197}
198
199static int insn_bytes_to_bpf_size(__u32 sz)
200{
201 switch (sz) {
202 case 8: return BPF_DW;
203 case 4: return BPF_W;
204 case 2: return BPF_H;
205 case 1: return BPF_B;
206 default: return -1;
207 }
208}
209
210/* *(u64 *)(blob + off) = (u64)(void *)(blob + data) */
211static void emit_rel_store(struct bpf_gen *gen, int off, int data)
212{
213 emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_0, BPF_PSEUDO_MAP_IDX_VALUE,
214 0, 0, 0, data));
215 emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_1, BPF_PSEUDO_MAP_IDX_VALUE,
216 0, 0, 0, off));
217 emit(gen, BPF_STX_MEM(BPF_DW, BPF_REG_1, BPF_REG_0, 0));
218}
219
220static void move_blob2blob(struct bpf_gen *gen, int off, int size, int blob_off)
221{
222 emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_2, BPF_PSEUDO_MAP_IDX_VALUE,
223 0, 0, 0, blob_off));
224 emit(gen, BPF_LDX_MEM(insn_bytes_to_bpf_size(size), BPF_REG_0, BPF_REG_2, 0));
225 emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_1, BPF_PSEUDO_MAP_IDX_VALUE,
226 0, 0, 0, off));
227 emit(gen, BPF_STX_MEM(insn_bytes_to_bpf_size(size), BPF_REG_1, BPF_REG_0, 0));
228}
229
230static void move_blob2ctx(struct bpf_gen *gen, int ctx_off, int size, int blob_off)
231{
232 emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_1, BPF_PSEUDO_MAP_IDX_VALUE,
233 0, 0, 0, blob_off));
234 emit(gen, BPF_LDX_MEM(insn_bytes_to_bpf_size(size), BPF_REG_0, BPF_REG_1, 0));
235 emit(gen, BPF_STX_MEM(insn_bytes_to_bpf_size(size), BPF_REG_6, BPF_REG_0, ctx_off));
236}
237
238static void move_ctx2blob(struct bpf_gen *gen, int off, int size, int ctx_off,
239 bool check_non_zero)
240{
241 emit(gen, BPF_LDX_MEM(insn_bytes_to_bpf_size(size), BPF_REG_0, BPF_REG_6, ctx_off));
242 if (check_non_zero)
243 /* If value in ctx is zero don't update the blob.
244 * For example: when ctx->map.max_entries == 0, keep default max_entries from bpf.c
245 */
246 emit(gen, BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 3));
247 emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_1, BPF_PSEUDO_MAP_IDX_VALUE,
248 0, 0, 0, off));
249 emit(gen, BPF_STX_MEM(insn_bytes_to_bpf_size(size), BPF_REG_1, BPF_REG_0, 0));
250}
251
252static void move_stack2blob(struct bpf_gen *gen, int off, int size, int stack_off)
253{
254 emit(gen, BPF_LDX_MEM(insn_bytes_to_bpf_size(size), BPF_REG_0, BPF_REG_10, stack_off));
255 emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_1, BPF_PSEUDO_MAP_IDX_VALUE,
256 0, 0, 0, off));
257 emit(gen, BPF_STX_MEM(insn_bytes_to_bpf_size(size), BPF_REG_1, BPF_REG_0, 0));
258}
259
260static void move_stack2ctx(struct bpf_gen *gen, int ctx_off, int size, int stack_off)
261{
262 emit(gen, BPF_LDX_MEM(insn_bytes_to_bpf_size(size), BPF_REG_0, BPF_REG_10, stack_off));
263 emit(gen, BPF_STX_MEM(insn_bytes_to_bpf_size(size), BPF_REG_6, BPF_REG_0, ctx_off));
264}
265
266static void emit_sys_bpf(struct bpf_gen *gen, int cmd, int attr, int attr_size)
267{
268 emit(gen, BPF_MOV64_IMM(BPF_REG_1, cmd));
269 emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_2, BPF_PSEUDO_MAP_IDX_VALUE,
270 0, 0, 0, attr));
271 emit(gen, BPF_MOV64_IMM(BPF_REG_3, attr_size));
272 emit(gen, BPF_EMIT_CALL(BPF_FUNC_sys_bpf));
273 /* remember the result in R7 */
274 emit(gen, BPF_MOV64_REG(BPF_REG_7, BPF_REG_0));
275}
276
277static bool is_simm16(__s64 value)
278{
279 return value == (__s64)(__s16)value;
280}
281
282static void emit_check_err(struct bpf_gen *gen)
283{
284 __s64 off = -(gen->insn_cur - gen->insn_start - gen->cleanup_label) / 8 - 1;
285
286 /* R7 contains result of last sys_bpf command.
287 * if (R7 < 0) goto cleanup;
288 */
289 if (is_simm16(value: off)) {
290 emit(gen, BPF_JMP_IMM(BPF_JSLT, BPF_REG_7, 0, off));
291 } else {
292 gen->error = -ERANGE;
293 emit(gen, BPF_JMP_IMM(BPF_JA, 0, 0, -1));
294 }
295}
296
297/* reg1 and reg2 should not be R1 - R5. They can be R0, R6 - R10 */
298static void emit_debug(struct bpf_gen *gen, int reg1, int reg2,
299 const char *fmt, va_list args)
300{
301 char buf[1024];
302 int addr, len, ret;
303
304 if (!gen->log_level)
305 return;
306 ret = vsnprintf(buf, size: sizeof(buf), fmt, args);
307 if (ret < 1024 - 7 && reg1 >= 0 && reg2 < 0)
308 /* The special case to accommodate common debug_ret():
309 * to avoid specifying BPF_REG_7 and adding " r=%%d" to
310 * prints explicitly.
311 */
312 strcat(p: buf, q: " r=%d");
313 len = strlen(buf) + 1;
314 addr = add_data(gen, data: buf, size: len);
315
316 emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_1, BPF_PSEUDO_MAP_IDX_VALUE,
317 0, 0, 0, addr));
318 emit(gen, BPF_MOV64_IMM(BPF_REG_2, len));
319 if (reg1 >= 0)
320 emit(gen, BPF_MOV64_REG(BPF_REG_3, reg1));
321 if (reg2 >= 0)
322 emit(gen, BPF_MOV64_REG(BPF_REG_4, reg2));
323 emit(gen, BPF_EMIT_CALL(BPF_FUNC_trace_printk));
324}
325
326static void debug_regs(struct bpf_gen *gen, int reg1, int reg2, const char *fmt, ...)
327{
328 va_list args;
329
330 va_start(args, fmt);
331 emit_debug(gen, reg1, reg2, fmt, args);
332 va_end(args);
333}
334
335static void debug_ret(struct bpf_gen *gen, const char *fmt, ...)
336{
337 va_list args;
338
339 va_start(args, fmt);
340 emit_debug(gen, reg1: BPF_REG_7, reg2: -1, fmt, args);
341 va_end(args);
342}
343
344static void __emit_sys_close(struct bpf_gen *gen)
345{
346 emit(gen, BPF_JMP_IMM(BPF_JSLE, BPF_REG_1, 0,
347 /* 2 is the number of the following insns
348 * * 6 is additional insns in debug_regs
349 */
350 2 + (gen->log_level ? 6 : 0)));
351 emit(gen, BPF_MOV64_REG(BPF_REG_9, BPF_REG_1));
352 emit(gen, BPF_EMIT_CALL(BPF_FUNC_sys_close));
353 debug_regs(gen, reg1: BPF_REG_9, reg2: BPF_REG_0, fmt: "close(%%d) = %%d");
354}
355
356static void emit_sys_close_stack(struct bpf_gen *gen, int stack_off)
357{
358 emit(gen, BPF_LDX_MEM(BPF_W, BPF_REG_1, BPF_REG_10, stack_off));
359 __emit_sys_close(gen);
360}
361
362static void emit_sys_close_blob(struct bpf_gen *gen, int blob_off)
363{
364 emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_0, BPF_PSEUDO_MAP_IDX_VALUE,
365 0, 0, 0, blob_off));
366 emit(gen, BPF_LDX_MEM(BPF_W, BPF_REG_1, BPF_REG_0, 0));
367 __emit_sys_close(gen);
368}
369
370int bpf_gen__finish(struct bpf_gen *gen, int nr_progs, int nr_maps)
371{
372 int i;
373
374 if (nr_progs < gen->nr_progs || nr_maps != gen->nr_maps) {
375 pr_warn("nr_progs %d/%d nr_maps %d/%d mismatch\n",
376 nr_progs, gen->nr_progs, nr_maps, gen->nr_maps);
377 gen->error = -EFAULT;
378 return gen->error;
379 }
380 emit_sys_close_stack(gen, stack_off(btf_fd));
381 for (i = 0; i < gen->nr_progs; i++)
382 move_stack2ctx(gen,
383 ctx_off: sizeof(struct bpf_loader_ctx) +
384 sizeof(struct bpf_map_desc) * gen->nr_maps +
385 sizeof(struct bpf_prog_desc) * i +
386 offsetof(struct bpf_prog_desc, prog_fd), size: 4,
387 stack_off(prog_fd[i]));
388 for (i = 0; i < gen->nr_maps; i++)
389 move_blob2ctx(gen,
390 ctx_off: sizeof(struct bpf_loader_ctx) +
391 sizeof(struct bpf_map_desc) * i +
392 offsetof(struct bpf_map_desc, map_fd), size: 4,
393 blob_off: blob_fd_array_off(gen, index: i));
394 emit(gen, BPF_MOV64_IMM(BPF_REG_0, 0));
395 emit(gen, BPF_EXIT_INSN());
396 pr_debug("gen: finish %d\n", gen->error);
397 if (!gen->error) {
398 struct gen_loader_opts *opts = gen->opts;
399
400 opts->insns = gen->insn_start;
401 opts->insns_sz = gen->insn_cur - gen->insn_start;
402 opts->data = gen->data_start;
403 opts->data_sz = gen->data_cur - gen->data_start;
404 }
405 return gen->error;
406}
407
408void bpf_gen__free(struct bpf_gen *gen)
409{
410 if (!gen)
411 return;
412 free(gen->data_start);
413 free(gen->insn_start);
414 free(gen);
415}
416
417void bpf_gen__load_btf(struct bpf_gen *gen, const void *btf_raw_data,
418 __u32 btf_raw_size)
419{
420 int attr_size = offsetofend(union bpf_attr, btf_log_level);
421 int btf_data, btf_load_attr;
422 union bpf_attr attr;
423
424 memset(&attr, 0, attr_size);
425 pr_debug("gen: load_btf: size %d\n", btf_raw_size);
426 btf_data = add_data(gen, data: btf_raw_data, size: btf_raw_size);
427
428 attr.btf_size = btf_raw_size;
429 btf_load_attr = add_data(gen, data: &attr, size: attr_size);
430
431 /* populate union bpf_attr with user provided log details */
432 move_ctx2blob(gen, attr_field(btf_load_attr, btf_log_level), size: 4,
433 offsetof(struct bpf_loader_ctx, log_level), check_non_zero: false);
434 move_ctx2blob(gen, attr_field(btf_load_attr, btf_log_size), size: 4,
435 offsetof(struct bpf_loader_ctx, log_size), check_non_zero: false);
436 move_ctx2blob(gen, attr_field(btf_load_attr, btf_log_buf), size: 8,
437 offsetof(struct bpf_loader_ctx, log_buf), check_non_zero: false);
438 /* populate union bpf_attr with a pointer to the BTF data */
439 emit_rel_store(gen, attr_field(btf_load_attr, btf), data: btf_data);
440 /* emit BTF_LOAD command */
441 emit_sys_bpf(gen, cmd: BPF_BTF_LOAD, attr: btf_load_attr, attr_size);
442 debug_ret(gen, fmt: "btf_load size %d", btf_raw_size);
443 emit_check_err(gen);
444 /* remember btf_fd in the stack, if successful */
445 emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_10, BPF_REG_7, stack_off(btf_fd)));
446}
447
448void bpf_gen__map_create(struct bpf_gen *gen,
449 enum bpf_map_type map_type,
450 const char *map_name,
451 __u32 key_size, __u32 value_size, __u32 max_entries,
452 struct bpf_map_create_opts *map_attr, int map_idx)
453{
454 int attr_size = offsetofend(union bpf_attr, map_extra);
455 bool close_inner_map_fd = false;
456 int map_create_attr, idx;
457 union bpf_attr attr;
458
459 memset(&attr, 0, attr_size);
460 attr.map_type = map_type;
461 attr.key_size = key_size;
462 attr.value_size = value_size;
463 attr.map_flags = map_attr->map_flags;
464 attr.map_extra = map_attr->map_extra;
465 if (map_name)
466 libbpf_strlcpy(dst: attr.map_name, src: map_name, sz: sizeof(attr.map_name));
467 attr.numa_node = map_attr->numa_node;
468 attr.map_ifindex = map_attr->map_ifindex;
469 attr.max_entries = max_entries;
470 attr.btf_key_type_id = map_attr->btf_key_type_id;
471 attr.btf_value_type_id = map_attr->btf_value_type_id;
472
473 pr_debug("gen: map_create: %s idx %d type %d value_type_id %d\n",
474 attr.map_name, map_idx, map_type, attr.btf_value_type_id);
475
476 map_create_attr = add_data(gen, data: &attr, size: attr_size);
477 if (attr.btf_value_type_id)
478 /* populate union bpf_attr with btf_fd saved in the stack earlier */
479 move_stack2blob(gen, attr_field(map_create_attr, btf_fd), size: 4,
480 stack_off(btf_fd));
481 switch (attr.map_type) {
482 case BPF_MAP_TYPE_ARRAY_OF_MAPS:
483 case BPF_MAP_TYPE_HASH_OF_MAPS:
484 move_stack2blob(gen, attr_field(map_create_attr, inner_map_fd), size: 4,
485 stack_off(inner_map_fd));
486 close_inner_map_fd = true;
487 break;
488 default:
489 break;
490 }
491 /* conditionally update max_entries */
492 if (map_idx >= 0)
493 move_ctx2blob(gen, attr_field(map_create_attr, max_entries), size: 4,
494 ctx_off: sizeof(struct bpf_loader_ctx) +
495 sizeof(struct bpf_map_desc) * map_idx +
496 offsetof(struct bpf_map_desc, max_entries),
497 check_non_zero: true /* check that max_entries != 0 */);
498 /* emit MAP_CREATE command */
499 emit_sys_bpf(gen, cmd: BPF_MAP_CREATE, attr: map_create_attr, attr_size);
500 debug_ret(gen, fmt: "map_create %s idx %d type %d value_size %d value_btf_id %d",
501 attr.map_name, map_idx, map_type, value_size,
502 attr.btf_value_type_id);
503 emit_check_err(gen);
504 /* remember map_fd in the stack, if successful */
505 if (map_idx < 0) {
506 /* This bpf_gen__map_create() function is called with map_idx >= 0
507 * for all maps that libbpf loading logic tracks.
508 * It's called with -1 to create an inner map.
509 */
510 emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_10, BPF_REG_7,
511 stack_off(inner_map_fd)));
512 } else if (map_idx != gen->nr_maps) {
513 gen->error = -EDOM; /* internal bug */
514 return;
515 } else {
516 /* add_map_fd does gen->nr_maps++ */
517 idx = add_map_fd(gen);
518 emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_1, BPF_PSEUDO_MAP_IDX_VALUE,
519 0, 0, 0, blob_fd_array_off(gen, index: idx)));
520 emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_1, BPF_REG_7, 0));
521 }
522 if (close_inner_map_fd)
523 emit_sys_close_stack(gen, stack_off(inner_map_fd));
524}
525
526void bpf_gen__record_attach_target(struct bpf_gen *gen, const char *attach_name,
527 enum bpf_attach_type type)
528{
529 const char *prefix;
530 int kind, ret;
531
532 btf_get_kernel_prefix_kind(attach_type: type, prefix: &prefix, kind: &kind);
533 gen->attach_kind = kind;
534 ret = snprintf(buf: gen->attach_target, size: sizeof(gen->attach_target), fmt: "%s%s",
535 prefix, attach_name);
536 if (ret >= sizeof(gen->attach_target))
537 gen->error = -ENOSPC;
538}
539
540static void emit_find_attach_target(struct bpf_gen *gen)
541{
542 int name, len = strlen(gen->attach_target) + 1;
543
544 pr_debug("gen: find_attach_tgt %s %d\n", gen->attach_target, gen->attach_kind);
545 name = add_data(gen, data: gen->attach_target, size: len);
546
547 emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_1, BPF_PSEUDO_MAP_IDX_VALUE,
548 0, 0, 0, name));
549 emit(gen, BPF_MOV64_IMM(BPF_REG_2, len));
550 emit(gen, BPF_MOV64_IMM(BPF_REG_3, gen->attach_kind));
551 emit(gen, BPF_MOV64_IMM(BPF_REG_4, 0));
552 emit(gen, BPF_EMIT_CALL(BPF_FUNC_btf_find_by_name_kind));
553 emit(gen, BPF_MOV64_REG(BPF_REG_7, BPF_REG_0));
554 debug_ret(gen, fmt: "find_by_name_kind(%s,%d)",
555 gen->attach_target, gen->attach_kind);
556 emit_check_err(gen);
557 /* if successful, btf_id is in lower 32-bit of R7 and
558 * btf_obj_fd is in upper 32-bit
559 */
560}
561
562void bpf_gen__record_extern(struct bpf_gen *gen, const char *name, bool is_weak,
563 bool is_typeless, bool is_ld64, int kind, int insn_idx)
564{
565 struct ksym_relo_desc *relo;
566
567 relo = libbpf_reallocarray(ptr: gen->relos, nmemb: gen->relo_cnt + 1, size: sizeof(*relo));
568 if (!relo) {
569 gen->error = -ENOMEM;
570 return;
571 }
572 gen->relos = relo;
573 relo += gen->relo_cnt;
574 relo->name = name;
575 relo->is_weak = is_weak;
576 relo->is_typeless = is_typeless;
577 relo->is_ld64 = is_ld64;
578 relo->kind = kind;
579 relo->insn_idx = insn_idx;
580 gen->relo_cnt++;
581}
582
583/* returns existing ksym_desc with ref incremented, or inserts a new one */
584static struct ksym_desc *get_ksym_desc(struct bpf_gen *gen, struct ksym_relo_desc *relo)
585{
586 struct ksym_desc *kdesc;
587 int i;
588
589 for (i = 0; i < gen->nr_ksyms; i++) {
590 kdesc = &gen->ksyms[i];
591 if (kdesc->kind == relo->kind && kdesc->is_ld64 == relo->is_ld64 &&
592 !strcmp(kdesc->name, relo->name)) {
593 kdesc->ref++;
594 return kdesc;
595 }
596 }
597 kdesc = libbpf_reallocarray(ptr: gen->ksyms, nmemb: gen->nr_ksyms + 1, size: sizeof(*kdesc));
598 if (!kdesc) {
599 gen->error = -ENOMEM;
600 return NULL;
601 }
602 gen->ksyms = kdesc;
603 kdesc = &gen->ksyms[gen->nr_ksyms++];
604 kdesc->name = relo->name;
605 kdesc->kind = relo->kind;
606 kdesc->ref = 1;
607 kdesc->off = 0;
608 kdesc->insn = 0;
609 kdesc->is_ld64 = relo->is_ld64;
610 return kdesc;
611}
612
613/* Overwrites BPF_REG_{0, 1, 2, 3, 4, 7}
614 * Returns result in BPF_REG_7
615 */
616static void emit_bpf_find_by_name_kind(struct bpf_gen *gen, struct ksym_relo_desc *relo)
617{
618 int name_off, len = strlen(relo->name) + 1;
619
620 name_off = add_data(gen, data: relo->name, size: len);
621 emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_1, BPF_PSEUDO_MAP_IDX_VALUE,
622 0, 0, 0, name_off));
623 emit(gen, BPF_MOV64_IMM(BPF_REG_2, len));
624 emit(gen, BPF_MOV64_IMM(BPF_REG_3, relo->kind));
625 emit(gen, BPF_MOV64_IMM(BPF_REG_4, 0));
626 emit(gen, BPF_EMIT_CALL(BPF_FUNC_btf_find_by_name_kind));
627 emit(gen, BPF_MOV64_REG(BPF_REG_7, BPF_REG_0));
628 debug_ret(gen, fmt: "find_by_name_kind(%s,%d)", relo->name, relo->kind);
629}
630
631/* Overwrites BPF_REG_{0, 1, 2, 3, 4, 7}
632 * Returns result in BPF_REG_7
633 * Returns u64 symbol addr in BPF_REG_9
634 */
635static void emit_bpf_kallsyms_lookup_name(struct bpf_gen *gen, struct ksym_relo_desc *relo)
636{
637 int name_off, len = strlen(relo->name) + 1, res_off;
638
639 name_off = add_data(gen, data: relo->name, size: len);
640 res_off = add_data(gen, NULL, size: 8); /* res is u64 */
641 emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_1, BPF_PSEUDO_MAP_IDX_VALUE,
642 0, 0, 0, name_off));
643 emit(gen, BPF_MOV64_IMM(BPF_REG_2, len));
644 emit(gen, BPF_MOV64_IMM(BPF_REG_3, 0));
645 emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_4, BPF_PSEUDO_MAP_IDX_VALUE,
646 0, 0, 0, res_off));
647 emit(gen, BPF_MOV64_REG(BPF_REG_7, BPF_REG_4));
648 emit(gen, BPF_EMIT_CALL(BPF_FUNC_kallsyms_lookup_name));
649 emit(gen, BPF_LDX_MEM(BPF_DW, BPF_REG_9, BPF_REG_7, 0));
650 emit(gen, BPF_MOV64_REG(BPF_REG_7, BPF_REG_0));
651 debug_ret(gen, fmt: "kallsyms_lookup_name(%s,%d)", relo->name, relo->kind);
652}
653
654/* Expects:
655 * BPF_REG_8 - pointer to instruction
656 *
657 * We need to reuse BTF fd for same symbol otherwise each relocation takes a new
658 * index, while kernel limits total kfunc BTFs to 256. For duplicate symbols,
659 * this would mean a new BTF fd index for each entry. By pairing symbol name
660 * with index, we get the insn->imm, insn->off pairing that kernel uses for
661 * kfunc_tab, which becomes the effective limit even though all of them may
662 * share same index in fd_array (such that kfunc_btf_tab has 1 element).
663 */
664static void emit_relo_kfunc_btf(struct bpf_gen *gen, struct ksym_relo_desc *relo, int insn)
665{
666 struct ksym_desc *kdesc;
667 int btf_fd_idx;
668
669 kdesc = get_ksym_desc(gen, relo);
670 if (!kdesc)
671 return;
672 /* try to copy from existing bpf_insn */
673 if (kdesc->ref > 1) {
674 move_blob2blob(gen, off: insn + offsetof(struct bpf_insn, imm), size: 4,
675 blob_off: kdesc->insn + offsetof(struct bpf_insn, imm));
676 move_blob2blob(gen, off: insn + offsetof(struct bpf_insn, off), size: 2,
677 blob_off: kdesc->insn + offsetof(struct bpf_insn, off));
678 goto log;
679 }
680 /* remember insn offset, so we can copy BTF ID and FD later */
681 kdesc->insn = insn;
682 emit_bpf_find_by_name_kind(gen, relo);
683 if (!relo->is_weak)
684 emit_check_err(gen);
685 /* get index in fd_array to store BTF FD at */
686 btf_fd_idx = add_kfunc_btf_fd(gen);
687 if (btf_fd_idx > INT16_MAX) {
688 pr_warn("BTF fd off %d for kfunc %s exceeds INT16_MAX, cannot process relocation\n",
689 btf_fd_idx, relo->name);
690 gen->error = -E2BIG;
691 return;
692 }
693 kdesc->off = btf_fd_idx;
694 /* jump to success case */
695 emit(gen, BPF_JMP_IMM(BPF_JSGE, BPF_REG_7, 0, 3));
696 /* set value for imm, off as 0 */
697 emit(gen, BPF_ST_MEM(BPF_W, BPF_REG_8, offsetof(struct bpf_insn, imm), 0));
698 emit(gen, BPF_ST_MEM(BPF_H, BPF_REG_8, offsetof(struct bpf_insn, off), 0));
699 /* skip success case for ret < 0 */
700 emit(gen, BPF_JMP_IMM(BPF_JA, 0, 0, 10));
701 /* store btf_id into insn[insn_idx].imm */
702 emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_8, BPF_REG_7, offsetof(struct bpf_insn, imm)));
703 /* obtain fd in BPF_REG_9 */
704 emit(gen, BPF_MOV64_REG(BPF_REG_9, BPF_REG_7));
705 emit(gen, BPF_ALU64_IMM(BPF_RSH, BPF_REG_9, 32));
706 /* load fd_array slot pointer */
707 emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_0, BPF_PSEUDO_MAP_IDX_VALUE,
708 0, 0, 0, blob_fd_array_off(gen, index: btf_fd_idx)));
709 /* store BTF fd in slot, 0 for vmlinux */
710 emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_0, BPF_REG_9, 0));
711 /* jump to insn[insn_idx].off store if fd denotes module BTF */
712 emit(gen, BPF_JMP_IMM(BPF_JNE, BPF_REG_9, 0, 2));
713 /* set the default value for off */
714 emit(gen, BPF_ST_MEM(BPF_H, BPF_REG_8, offsetof(struct bpf_insn, off), 0));
715 /* skip BTF fd store for vmlinux BTF */
716 emit(gen, BPF_JMP_IMM(BPF_JA, 0, 0, 1));
717 /* store index into insn[insn_idx].off */
718 emit(gen, BPF_ST_MEM(BPF_H, BPF_REG_8, offsetof(struct bpf_insn, off), btf_fd_idx));
719log:
720 if (!gen->log_level)
721 return;
722 emit(gen, BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_8,
723 offsetof(struct bpf_insn, imm)));
724 emit(gen, BPF_LDX_MEM(BPF_H, BPF_REG_9, BPF_REG_8,
725 offsetof(struct bpf_insn, off)));
726 debug_regs(gen, reg1: BPF_REG_7, reg2: BPF_REG_9, fmt: " func (%s:count=%d): imm: %%d, off: %%d",
727 relo->name, kdesc->ref);
728 emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_0, BPF_PSEUDO_MAP_IDX_VALUE,
729 0, 0, 0, blob_fd_array_off(gen, index: kdesc->off)));
730 emit(gen, BPF_LDX_MEM(BPF_W, BPF_REG_9, BPF_REG_0, 0));
731 debug_regs(gen, reg1: BPF_REG_9, reg2: -1, fmt: " func (%s:count=%d): btf_fd",
732 relo->name, kdesc->ref);
733}
734
735static void emit_ksym_relo_log(struct bpf_gen *gen, struct ksym_relo_desc *relo,
736 int ref)
737{
738 if (!gen->log_level)
739 return;
740 emit(gen, BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_8,
741 offsetof(struct bpf_insn, imm)));
742 emit(gen, BPF_LDX_MEM(BPF_H, BPF_REG_9, BPF_REG_8, sizeof(struct bpf_insn) +
743 offsetof(struct bpf_insn, imm)));
744 debug_regs(gen, reg1: BPF_REG_7, reg2: BPF_REG_9, fmt: " var t=%d w=%d (%s:count=%d): imm[0]: %%d, imm[1]: %%d",
745 relo->is_typeless, relo->is_weak, relo->name, ref);
746 emit(gen, BPF_LDX_MEM(BPF_B, BPF_REG_9, BPF_REG_8, offsetofend(struct bpf_insn, code)));
747 debug_regs(gen, reg1: BPF_REG_9, reg2: -1, fmt: " var t=%d w=%d (%s:count=%d): insn.reg",
748 relo->is_typeless, relo->is_weak, relo->name, ref);
749}
750
751/* Expects:
752 * BPF_REG_8 - pointer to instruction
753 */
754static void emit_relo_ksym_typeless(struct bpf_gen *gen,
755 struct ksym_relo_desc *relo, int insn)
756{
757 struct ksym_desc *kdesc;
758
759 kdesc = get_ksym_desc(gen, relo);
760 if (!kdesc)
761 return;
762 /* try to copy from existing ldimm64 insn */
763 if (kdesc->ref > 1) {
764 move_blob2blob(gen, off: insn + offsetof(struct bpf_insn, imm), size: 4,
765 blob_off: kdesc->insn + offsetof(struct bpf_insn, imm));
766 move_blob2blob(gen, off: insn + sizeof(struct bpf_insn) + offsetof(struct bpf_insn, imm), size: 4,
767 blob_off: kdesc->insn + sizeof(struct bpf_insn) + offsetof(struct bpf_insn, imm));
768 goto log;
769 }
770 /* remember insn offset, so we can copy ksym addr later */
771 kdesc->insn = insn;
772 /* skip typeless ksym_desc in fd closing loop in cleanup_relos */
773 kdesc->typeless = true;
774 emit_bpf_kallsyms_lookup_name(gen, relo);
775 emit(gen, BPF_JMP_IMM(BPF_JEQ, BPF_REG_7, -ENOENT, 1));
776 emit_check_err(gen);
777 /* store lower half of addr into insn[insn_idx].imm */
778 emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_8, BPF_REG_9, offsetof(struct bpf_insn, imm)));
779 /* store upper half of addr into insn[insn_idx + 1].imm */
780 emit(gen, BPF_ALU64_IMM(BPF_RSH, BPF_REG_9, 32));
781 emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_8, BPF_REG_9,
782 sizeof(struct bpf_insn) + offsetof(struct bpf_insn, imm)));
783log:
784 emit_ksym_relo_log(gen, relo, ref: kdesc->ref);
785}
786
787static __u32 src_reg_mask(void)
788{
789#if defined(__LITTLE_ENDIAN_BITFIELD)
790 return 0x0f; /* src_reg,dst_reg,... */
791#elif defined(__BIG_ENDIAN_BITFIELD)
792 return 0xf0; /* dst_reg,src_reg,... */
793#else
794#error "Unsupported bit endianness, cannot proceed"
795#endif
796}
797
798/* Expects:
799 * BPF_REG_8 - pointer to instruction
800 */
801static void emit_relo_ksym_btf(struct bpf_gen *gen, struct ksym_relo_desc *relo, int insn)
802{
803 struct ksym_desc *kdesc;
804 __u32 reg_mask;
805
806 kdesc = get_ksym_desc(gen, relo);
807 if (!kdesc)
808 return;
809 /* try to copy from existing ldimm64 insn */
810 if (kdesc->ref > 1) {
811 move_blob2blob(gen, off: insn + sizeof(struct bpf_insn) + offsetof(struct bpf_insn, imm), size: 4,
812 blob_off: kdesc->insn + sizeof(struct bpf_insn) + offsetof(struct bpf_insn, imm));
813 move_blob2blob(gen, off: insn + offsetof(struct bpf_insn, imm), size: 4,
814 blob_off: kdesc->insn + offsetof(struct bpf_insn, imm));
815 /* jump over src_reg adjustment if imm (btf_id) is not 0, reuse BPF_REG_0 from move_blob2blob
816 * If btf_id is zero, clear BPF_PSEUDO_BTF_ID flag in src_reg of ld_imm64 insn
817 */
818 emit(gen, BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 3));
819 goto clear_src_reg;
820 }
821 /* remember insn offset, so we can copy BTF ID and FD later */
822 kdesc->insn = insn;
823 emit_bpf_find_by_name_kind(gen, relo);
824 if (!relo->is_weak)
825 emit_check_err(gen);
826 /* jump to success case */
827 emit(gen, BPF_JMP_IMM(BPF_JSGE, BPF_REG_7, 0, 3));
828 /* set values for insn[insn_idx].imm, insn[insn_idx + 1].imm as 0 */
829 emit(gen, BPF_ST_MEM(BPF_W, BPF_REG_8, offsetof(struct bpf_insn, imm), 0));
830 emit(gen, BPF_ST_MEM(BPF_W, BPF_REG_8, sizeof(struct bpf_insn) + offsetof(struct bpf_insn, imm), 0));
831 /* skip success case for ret < 0 */
832 emit(gen, BPF_JMP_IMM(BPF_JA, 0, 0, 4));
833 /* store btf_id into insn[insn_idx].imm */
834 emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_8, BPF_REG_7, offsetof(struct bpf_insn, imm)));
835 /* store btf_obj_fd into insn[insn_idx + 1].imm */
836 emit(gen, BPF_ALU64_IMM(BPF_RSH, BPF_REG_7, 32));
837 emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_8, BPF_REG_7,
838 sizeof(struct bpf_insn) + offsetof(struct bpf_insn, imm)));
839 /* skip src_reg adjustment */
840 emit(gen, BPF_JMP_IMM(BPF_JA, 0, 0, 3));
841clear_src_reg:
842 /* clear bpf_object__relocate_data's src_reg assignment, otherwise we get a verifier failure */
843 reg_mask = src_reg_mask();
844 emit(gen, BPF_LDX_MEM(BPF_B, BPF_REG_9, BPF_REG_8, offsetofend(struct bpf_insn, code)));
845 emit(gen, BPF_ALU32_IMM(BPF_AND, BPF_REG_9, reg_mask));
846 emit(gen, BPF_STX_MEM(BPF_B, BPF_REG_8, BPF_REG_9, offsetofend(struct bpf_insn, code)));
847
848 emit_ksym_relo_log(gen, relo, ref: kdesc->ref);
849}
850
851void bpf_gen__record_relo_core(struct bpf_gen *gen,
852 const struct bpf_core_relo *core_relo)
853{
854 struct bpf_core_relo *relos;
855
856 relos = libbpf_reallocarray(ptr: gen->core_relos, nmemb: gen->core_relo_cnt + 1, size: sizeof(*relos));
857 if (!relos) {
858 gen->error = -ENOMEM;
859 return;
860 }
861 gen->core_relos = relos;
862 relos += gen->core_relo_cnt;
863 memcpy(relos, core_relo, sizeof(*relos));
864 gen->core_relo_cnt++;
865}
866
867static void emit_relo(struct bpf_gen *gen, struct ksym_relo_desc *relo, int insns)
868{
869 int insn;
870
871 pr_debug("gen: emit_relo (%d): %s at %d %s\n",
872 relo->kind, relo->name, relo->insn_idx, relo->is_ld64 ? "ld64" : "call");
873 insn = insns + sizeof(struct bpf_insn) * relo->insn_idx;
874 emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_8, BPF_PSEUDO_MAP_IDX_VALUE, 0, 0, 0, insn));
875 if (relo->is_ld64) {
876 if (relo->is_typeless)
877 emit_relo_ksym_typeless(gen, relo, insn);
878 else
879 emit_relo_ksym_btf(gen, relo, insn);
880 } else {
881 emit_relo_kfunc_btf(gen, relo, insn);
882 }
883}
884
885static void emit_relos(struct bpf_gen *gen, int insns)
886{
887 int i;
888
889 for (i = 0; i < gen->relo_cnt; i++)
890 emit_relo(gen, relo: gen->relos + i, insns);
891}
892
893static void cleanup_core_relo(struct bpf_gen *gen)
894{
895 if (!gen->core_relo_cnt)
896 return;
897 free(gen->core_relos);
898 gen->core_relo_cnt = 0;
899 gen->core_relos = NULL;
900}
901
902static void cleanup_relos(struct bpf_gen *gen, int insns)
903{
904 struct ksym_desc *kdesc;
905 int i, insn;
906
907 for (i = 0; i < gen->nr_ksyms; i++) {
908 kdesc = &gen->ksyms[i];
909 /* only close fds for typed ksyms and kfuncs */
910 if (kdesc->is_ld64 && !kdesc->typeless) {
911 /* close fd recorded in insn[insn_idx + 1].imm */
912 insn = kdesc->insn;
913 insn += sizeof(struct bpf_insn) + offsetof(struct bpf_insn, imm);
914 emit_sys_close_blob(gen, blob_off: insn);
915 } else if (!kdesc->is_ld64) {
916 emit_sys_close_blob(gen, blob_off: blob_fd_array_off(gen, index: kdesc->off));
917 if (kdesc->off < MAX_FD_ARRAY_SZ)
918 gen->nr_fd_array--;
919 }
920 }
921 if (gen->nr_ksyms) {
922 free(gen->ksyms);
923 gen->nr_ksyms = 0;
924 gen->ksyms = NULL;
925 }
926 if (gen->relo_cnt) {
927 free(gen->relos);
928 gen->relo_cnt = 0;
929 gen->relos = NULL;
930 }
931 cleanup_core_relo(gen);
932}
933
934void bpf_gen__prog_load(struct bpf_gen *gen,
935 enum bpf_prog_type prog_type, const char *prog_name,
936 const char *license, struct bpf_insn *insns, size_t insn_cnt,
937 struct bpf_prog_load_opts *load_attr, int prog_idx)
938{
939 int prog_load_attr, license_off, insns_off, func_info, line_info, core_relos;
940 int attr_size = offsetofend(union bpf_attr, core_relo_rec_size);
941 union bpf_attr attr;
942
943 memset(&attr, 0, attr_size);
944 pr_debug("gen: prog_load: type %d insns_cnt %zd progi_idx %d\n",
945 prog_type, insn_cnt, prog_idx);
946 /* add license string to blob of bytes */
947 license_off = add_data(gen, data: license, strlen(license) + 1);
948 /* add insns to blob of bytes */
949 insns_off = add_data(gen, data: insns, size: insn_cnt * sizeof(struct bpf_insn));
950
951 attr.prog_type = prog_type;
952 attr.expected_attach_type = load_attr->expected_attach_type;
953 attr.attach_btf_id = load_attr->attach_btf_id;
954 attr.prog_ifindex = load_attr->prog_ifindex;
955 attr.kern_version = 0;
956 attr.insn_cnt = (__u32)insn_cnt;
957 attr.prog_flags = load_attr->prog_flags;
958
959 attr.func_info_rec_size = load_attr->func_info_rec_size;
960 attr.func_info_cnt = load_attr->func_info_cnt;
961 func_info = add_data(gen, data: load_attr->func_info,
962 size: attr.func_info_cnt * attr.func_info_rec_size);
963
964 attr.line_info_rec_size = load_attr->line_info_rec_size;
965 attr.line_info_cnt = load_attr->line_info_cnt;
966 line_info = add_data(gen, data: load_attr->line_info,
967 size: attr.line_info_cnt * attr.line_info_rec_size);
968
969 attr.core_relo_rec_size = sizeof(struct bpf_core_relo);
970 attr.core_relo_cnt = gen->core_relo_cnt;
971 core_relos = add_data(gen, data: gen->core_relos,
972 size: attr.core_relo_cnt * attr.core_relo_rec_size);
973
974 libbpf_strlcpy(dst: attr.prog_name, src: prog_name, sz: sizeof(attr.prog_name));
975 prog_load_attr = add_data(gen, data: &attr, size: attr_size);
976
977 /* populate union bpf_attr with a pointer to license */
978 emit_rel_store(gen, attr_field(prog_load_attr, license), data: license_off);
979
980 /* populate union bpf_attr with a pointer to instructions */
981 emit_rel_store(gen, attr_field(prog_load_attr, insns), data: insns_off);
982
983 /* populate union bpf_attr with a pointer to func_info */
984 emit_rel_store(gen, attr_field(prog_load_attr, func_info), data: func_info);
985
986 /* populate union bpf_attr with a pointer to line_info */
987 emit_rel_store(gen, attr_field(prog_load_attr, line_info), data: line_info);
988
989 /* populate union bpf_attr with a pointer to core_relos */
990 emit_rel_store(gen, attr_field(prog_load_attr, core_relos), data: core_relos);
991
992 /* populate union bpf_attr fd_array with a pointer to data where map_fds are saved */
993 emit_rel_store(gen, attr_field(prog_load_attr, fd_array), data: gen->fd_array);
994
995 /* populate union bpf_attr with user provided log details */
996 move_ctx2blob(gen, attr_field(prog_load_attr, log_level), size: 4,
997 offsetof(struct bpf_loader_ctx, log_level), check_non_zero: false);
998 move_ctx2blob(gen, attr_field(prog_load_attr, log_size), size: 4,
999 offsetof(struct bpf_loader_ctx, log_size), check_non_zero: false);
1000 move_ctx2blob(gen, attr_field(prog_load_attr, log_buf), size: 8,
1001 offsetof(struct bpf_loader_ctx, log_buf), check_non_zero: false);
1002 /* populate union bpf_attr with btf_fd saved in the stack earlier */
1003 move_stack2blob(gen, attr_field(prog_load_attr, prog_btf_fd), size: 4,
1004 stack_off(btf_fd));
1005 if (gen->attach_kind) {
1006 emit_find_attach_target(gen);
1007 /* populate union bpf_attr with btf_id and btf_obj_fd found by helper */
1008 emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_0, BPF_PSEUDO_MAP_IDX_VALUE,
1009 0, 0, 0, prog_load_attr));
1010 emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_0, BPF_REG_7,
1011 offsetof(union bpf_attr, attach_btf_id)));
1012 emit(gen, BPF_ALU64_IMM(BPF_RSH, BPF_REG_7, 32));
1013 emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_0, BPF_REG_7,
1014 offsetof(union bpf_attr, attach_btf_obj_fd)));
1015 }
1016 emit_relos(gen, insns: insns_off);
1017 /* emit PROG_LOAD command */
1018 emit_sys_bpf(gen, cmd: BPF_PROG_LOAD, attr: prog_load_attr, attr_size);
1019 debug_ret(gen, fmt: "prog_load %s insn_cnt %d", attr.prog_name, attr.insn_cnt);
1020 /* successful or not, close btf module FDs used in extern ksyms and attach_btf_obj_fd */
1021 cleanup_relos(gen, insns: insns_off);
1022 if (gen->attach_kind) {
1023 emit_sys_close_blob(gen,
1024 attr_field(prog_load_attr, attach_btf_obj_fd));
1025 gen->attach_kind = 0;
1026 }
1027 emit_check_err(gen);
1028 /* remember prog_fd in the stack, if successful */
1029 emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_10, BPF_REG_7,
1030 stack_off(prog_fd[gen->nr_progs])));
1031 gen->nr_progs++;
1032}
1033
1034void bpf_gen__map_update_elem(struct bpf_gen *gen, int map_idx, void *pvalue,
1035 __u32 value_size)
1036{
1037 int attr_size = offsetofend(union bpf_attr, flags);
1038 int map_update_attr, value, key;
1039 union bpf_attr attr;
1040 int zero = 0;
1041
1042 memset(&attr, 0, attr_size);
1043 pr_debug("gen: map_update_elem: idx %d\n", map_idx);
1044
1045 value = add_data(gen, data: pvalue, size: value_size);
1046 key = add_data(gen, data: &zero, size: sizeof(zero));
1047
1048 /* if (map_desc[map_idx].initial_value) {
1049 * if (ctx->flags & BPF_SKEL_KERNEL)
1050 * bpf_probe_read_kernel(value, value_size, initial_value);
1051 * else
1052 * bpf_copy_from_user(value, value_size, initial_value);
1053 * }
1054 */
1055 emit(gen, BPF_LDX_MEM(BPF_DW, BPF_REG_3, BPF_REG_6,
1056 sizeof(struct bpf_loader_ctx) +
1057 sizeof(struct bpf_map_desc) * map_idx +
1058 offsetof(struct bpf_map_desc, initial_value)));
1059 emit(gen, BPF_JMP_IMM(BPF_JEQ, BPF_REG_3, 0, 8));
1060 emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_1, BPF_PSEUDO_MAP_IDX_VALUE,
1061 0, 0, 0, value));
1062 emit(gen, BPF_MOV64_IMM(BPF_REG_2, value_size));
1063 emit(gen, BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_6,
1064 offsetof(struct bpf_loader_ctx, flags)));
1065 emit(gen, BPF_JMP_IMM(BPF_JSET, BPF_REG_0, BPF_SKEL_KERNEL, 2));
1066 emit(gen, BPF_EMIT_CALL(BPF_FUNC_copy_from_user));
1067 emit(gen, BPF_JMP_IMM(BPF_JA, 0, 0, 1));
1068 emit(gen, BPF_EMIT_CALL(BPF_FUNC_probe_read_kernel));
1069
1070 map_update_attr = add_data(gen, data: &attr, size: attr_size);
1071 move_blob2blob(gen, attr_field(map_update_attr, map_fd), size: 4,
1072 blob_off: blob_fd_array_off(gen, index: map_idx));
1073 emit_rel_store(gen, attr_field(map_update_attr, key), data: key);
1074 emit_rel_store(gen, attr_field(map_update_attr, value), data: value);
1075 /* emit MAP_UPDATE_ELEM command */
1076 emit_sys_bpf(gen, cmd: BPF_MAP_UPDATE_ELEM, attr: map_update_attr, attr_size);
1077 debug_ret(gen, fmt: "update_elem idx %d value_size %d", map_idx, value_size);
1078 emit_check_err(gen);
1079}
1080
1081void bpf_gen__populate_outer_map(struct bpf_gen *gen, int outer_map_idx, int slot,
1082 int inner_map_idx)
1083{
1084 int attr_size = offsetofend(union bpf_attr, flags);
1085 int map_update_attr, key;
1086 union bpf_attr attr;
1087
1088 memset(&attr, 0, attr_size);
1089 pr_debug("gen: populate_outer_map: outer %d key %d inner %d\n",
1090 outer_map_idx, slot, inner_map_idx);
1091
1092 key = add_data(gen, data: &slot, size: sizeof(slot));
1093
1094 map_update_attr = add_data(gen, data: &attr, size: attr_size);
1095 move_blob2blob(gen, attr_field(map_update_attr, map_fd), size: 4,
1096 blob_off: blob_fd_array_off(gen, index: outer_map_idx));
1097 emit_rel_store(gen, attr_field(map_update_attr, key), data: key);
1098 emit_rel_store(gen, attr_field(map_update_attr, value),
1099 data: blob_fd_array_off(gen, index: inner_map_idx));
1100
1101 /* emit MAP_UPDATE_ELEM command */
1102 emit_sys_bpf(gen, cmd: BPF_MAP_UPDATE_ELEM, attr: map_update_attr, attr_size);
1103 debug_ret(gen, fmt: "populate_outer_map outer %d key %d inner %d",
1104 outer_map_idx, slot, inner_map_idx);
1105 emit_check_err(gen);
1106}
1107
1108void bpf_gen__map_freeze(struct bpf_gen *gen, int map_idx)
1109{
1110 int attr_size = offsetofend(union bpf_attr, map_fd);
1111 int map_freeze_attr;
1112 union bpf_attr attr;
1113
1114 memset(&attr, 0, attr_size);
1115 pr_debug("gen: map_freeze: idx %d\n", map_idx);
1116 map_freeze_attr = add_data(gen, data: &attr, size: attr_size);
1117 move_blob2blob(gen, attr_field(map_freeze_attr, map_fd), size: 4,
1118 blob_off: blob_fd_array_off(gen, index: map_idx));
1119 /* emit MAP_FREEZE command */
1120 emit_sys_bpf(gen, cmd: BPF_MAP_FREEZE, attr: map_freeze_attr, attr_size);
1121 debug_ret(gen, fmt: "map_freeze");
1122 emit_check_err(gen);
1123}
1124

source code of linux/tools/lib/bpf/gen_loader.c