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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, 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, insn1);
107 emit(gen, 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_fd_array_off(gen, 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, 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, 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(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, 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(buf, " r=%d");
313 len = strlen(buf) + 1;
314 addr = add_data(gen, buf, 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, BPF_REG_7, -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, BPF_REG_9, BPF_REG_0, "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 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), 4,
387 stack_off(prog_fd[i]));
388 for (i = 0; i < gen->nr_maps; i++)
389 move_blob2ctx(gen,
390 sizeof(struct bpf_loader_ctx) +
391 sizeof(struct bpf_map_desc) * i +
392 offsetof(struct bpf_map_desc, map_fd), 4,
393 blob_fd_array_off(gen, 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, btf_raw_data, btf_raw_size);
427
428 attr.btf_size = btf_raw_size;
429 btf_load_attr = add_data(gen, &attr, 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), 4,
433 offsetof(struct bpf_loader_ctx, log_level), false);
434 move_ctx2blob(gen, attr_field(btf_load_attr, btf_log_size), 4,
435 offsetof(struct bpf_loader_ctx, log_size), false);
436 move_ctx2blob(gen, attr_field(btf_load_attr, btf_log_buf), 8,
437 offsetof(struct bpf_loader_ctx, log_buf), false);
438 /* populate union bpf_attr with a pointer to the BTF data */
439 emit_rel_store(gen, attr_field(btf_load_attr, btf), btf_data);
440 /* emit BTF_LOAD command */
441 emit_sys_bpf(gen, BPF_BTF_LOAD, btf_load_attr, attr_size);
442 debug_ret(gen, "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(attr.map_name, map_name, 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, &attr, 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), 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), 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), 4,
494 sizeof(struct bpf_loader_ctx) +
495 sizeof(struct bpf_map_desc) * map_idx +
496 offsetof(struct bpf_map_desc, max_entries),
497 true /* check that max_entries != 0 */);
498 /* emit MAP_CREATE command */
499 emit_sys_bpf(gen, BPF_MAP_CREATE, map_create_attr, attr_size);
500 debug_ret(gen, "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, 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(type, &prefix, &kind);
533 gen->attach_kind = kind;
534 ret = snprintf(gen->attach_target, sizeof(gen->attach_target), "%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, gen->attach_target, 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, "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, int kind, int insn_idx)
564{
565 struct ksym_relo_desc *relo;
566
567 relo = libbpf_reallocarray(gen->relos, gen->relo_cnt + 1, 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->kind = kind;
578 relo->insn_idx = insn_idx;
579 gen->relo_cnt++;
580}
581
582/* returns existing ksym_desc with ref incremented, or inserts a new one */
583static struct ksym_desc *get_ksym_desc(struct bpf_gen *gen, struct ksym_relo_desc *relo)
584{
585 struct ksym_desc *kdesc;
586 int i;
587
588 for (i = 0; i < gen->nr_ksyms; i++) {
589 if (!strcmp(gen->ksyms[i].name, relo->name)) {
590 gen->ksyms[i].ref++;
591 return &gen->ksyms[i];
592 }
593 }
594 kdesc = libbpf_reallocarray(gen->ksyms, gen->nr_ksyms + 1, sizeof(*kdesc));
595 if (!kdesc) {
596 gen->error = -ENOMEM;
597 return NULL;
598 }
599 gen->ksyms = kdesc;
600 kdesc = &gen->ksyms[gen->nr_ksyms++];
601 kdesc->name = relo->name;
602 kdesc->kind = relo->kind;
603 kdesc->ref = 1;
604 kdesc->off = 0;
605 kdesc->insn = 0;
606 return kdesc;
607}
608
609/* Overwrites BPF_REG_{0, 1, 2, 3, 4, 7}
610 * Returns result in BPF_REG_7
611 */
612static void emit_bpf_find_by_name_kind(struct bpf_gen *gen, struct ksym_relo_desc *relo)
613{
614 int name_off, len = strlen(relo->name) + 1;
615
616 name_off = add_data(gen, relo->name, len);
617 emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_1, BPF_PSEUDO_MAP_IDX_VALUE,
618 0, 0, 0, name_off));
619 emit(gen, BPF_MOV64_IMM(BPF_REG_2, len));
620 emit(gen, BPF_MOV64_IMM(BPF_REG_3, relo->kind));
621 emit(gen, BPF_MOV64_IMM(BPF_REG_4, 0));
622 emit(gen, BPF_EMIT_CALL(BPF_FUNC_btf_find_by_name_kind));
623 emit(gen, BPF_MOV64_REG(BPF_REG_7, BPF_REG_0));
624 debug_ret(gen, "find_by_name_kind(%s,%d)", relo->name, relo->kind);
625}
626
627/* Overwrites BPF_REG_{0, 1, 2, 3, 4, 7}
628 * Returns result in BPF_REG_7
629 * Returns u64 symbol addr in BPF_REG_9
630 */
631static void emit_bpf_kallsyms_lookup_name(struct bpf_gen *gen, struct ksym_relo_desc *relo)
632{
633 int name_off, len = strlen(relo->name) + 1, res_off;
634
635 name_off = add_data(gen, relo->name, len);
636 res_off = add_data(gen, NULL, 8); /* res is u64 */
637 emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_1, BPF_PSEUDO_MAP_IDX_VALUE,
638 0, 0, 0, name_off));
639 emit(gen, BPF_MOV64_IMM(BPF_REG_2, len));
640 emit(gen, BPF_MOV64_IMM(BPF_REG_3, 0));
641 emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_4, BPF_PSEUDO_MAP_IDX_VALUE,
642 0, 0, 0, res_off));
643 emit(gen, BPF_MOV64_REG(BPF_REG_7, BPF_REG_4));
644 emit(gen, BPF_EMIT_CALL(BPF_FUNC_kallsyms_lookup_name));
645 emit(gen, BPF_LDX_MEM(BPF_DW, BPF_REG_9, BPF_REG_7, 0));
646 emit(gen, BPF_MOV64_REG(BPF_REG_7, BPF_REG_0));
647 debug_ret(gen, "kallsyms_lookup_name(%s,%d)", relo->name, relo->kind);
648}
649
650/* Expects:
651 * BPF_REG_8 - pointer to instruction
652 *
653 * We need to reuse BTF fd for same symbol otherwise each relocation takes a new
654 * index, while kernel limits total kfunc BTFs to 256. For duplicate symbols,
655 * this would mean a new BTF fd index for each entry. By pairing symbol name
656 * with index, we get the insn->imm, insn->off pairing that kernel uses for
657 * kfunc_tab, which becomes the effective limit even though all of them may
658 * share same index in fd_array (such that kfunc_btf_tab has 1 element).
659 */
660static void emit_relo_kfunc_btf(struct bpf_gen *gen, struct ksym_relo_desc *relo, int insn)
661{
662 struct ksym_desc *kdesc;
663 int btf_fd_idx;
664
665 kdesc = get_ksym_desc(gen, relo);
666 if (!kdesc)
667 return;
668 /* try to copy from existing bpf_insn */
669 if (kdesc->ref > 1) {
670 move_blob2blob(gen, insn + offsetof(struct bpf_insn, imm), 4,
671 kdesc->insn + offsetof(struct bpf_insn, imm));
672 move_blob2blob(gen, insn + offsetof(struct bpf_insn, off), 2,
673 kdesc->insn + offsetof(struct bpf_insn, off));
674 goto log;
675 }
676 /* remember insn offset, so we can copy BTF ID and FD later */
677 kdesc->insn = insn;
678 emit_bpf_find_by_name_kind(gen, relo);
679 if (!relo->is_weak)
680 emit_check_err(gen);
681 /* get index in fd_array to store BTF FD at */
682 btf_fd_idx = add_kfunc_btf_fd(gen);
683 if (btf_fd_idx > INT16_MAX) {
684 pr_warn("BTF fd off %d for kfunc %s exceeds INT16_MAX, cannot process relocation\n",
685 btf_fd_idx, relo->name);
686 gen->error = -E2BIG;
687 return;
688 }
689 kdesc->off = btf_fd_idx;
690 /* jump to success case */
691 emit(gen, BPF_JMP_IMM(BPF_JSGE, BPF_REG_7, 0, 3));
692 /* set value for imm, off as 0 */
693 emit(gen, BPF_ST_MEM(BPF_W, BPF_REG_8, offsetof(struct bpf_insn, imm), 0));
694 emit(gen, BPF_ST_MEM(BPF_H, BPF_REG_8, offsetof(struct bpf_insn, off), 0));
695 /* skip success case for ret < 0 */
696 emit(gen, BPF_JMP_IMM(BPF_JA, 0, 0, 10));
697 /* store btf_id into insn[insn_idx].imm */
698 emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_8, BPF_REG_7, offsetof(struct bpf_insn, imm)));
699 /* obtain fd in BPF_REG_9 */
700 emit(gen, BPF_MOV64_REG(BPF_REG_9, BPF_REG_7));
701 emit(gen, BPF_ALU64_IMM(BPF_RSH, BPF_REG_9, 32));
702 /* jump to fd_array store if fd denotes module BTF */
703 emit(gen, BPF_JMP_IMM(BPF_JNE, BPF_REG_9, 0, 2));
704 /* set the default value for off */
705 emit(gen, BPF_ST_MEM(BPF_H, BPF_REG_8, offsetof(struct bpf_insn, off), 0));
706 /* skip BTF fd store for vmlinux BTF */
707 emit(gen, BPF_JMP_IMM(BPF_JA, 0, 0, 4));
708 /* load fd_array slot pointer */
709 emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_0, BPF_PSEUDO_MAP_IDX_VALUE,
710 0, 0, 0, blob_fd_array_off(gen, btf_fd_idx)));
711 /* store BTF fd in slot */
712 emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_0, BPF_REG_9, 0));
713 /* store index into insn[insn_idx].off */
714 emit(gen, BPF_ST_MEM(BPF_H, BPF_REG_8, offsetof(struct bpf_insn, off), btf_fd_idx));
715log:
716 if (!gen->log_level)
717 return;
718 emit(gen, BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_8,
719 offsetof(struct bpf_insn, imm)));
720 emit(gen, BPF_LDX_MEM(BPF_H, BPF_REG_9, BPF_REG_8,
721 offsetof(struct bpf_insn, off)));
722 debug_regs(gen, BPF_REG_7, BPF_REG_9, " func (%s:count=%d): imm: %%d, off: %%d",
723 relo->name, kdesc->ref);
724 emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_0, BPF_PSEUDO_MAP_IDX_VALUE,
725 0, 0, 0, blob_fd_array_off(gen, kdesc->off)));
726 emit(gen, BPF_LDX_MEM(BPF_W, BPF_REG_9, BPF_REG_0, 0));
727 debug_regs(gen, BPF_REG_9, -1, " func (%s:count=%d): btf_fd",
728 relo->name, kdesc->ref);
729}
730
731static void emit_ksym_relo_log(struct bpf_gen *gen, struct ksym_relo_desc *relo,
732 int ref)
733{
734 if (!gen->log_level)
735 return;
736 emit(gen, BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_8,
737 offsetof(struct bpf_insn, imm)));
738 emit(gen, BPF_LDX_MEM(BPF_H, BPF_REG_9, BPF_REG_8, sizeof(struct bpf_insn) +
739 offsetof(struct bpf_insn, imm)));
740 debug_regs(gen, BPF_REG_7, BPF_REG_9, " var t=%d w=%d (%s:count=%d): imm[0]: %%d, imm[1]: %%d",
741 relo->is_typeless, relo->is_weak, relo->name, ref);
742 emit(gen, BPF_LDX_MEM(BPF_B, BPF_REG_9, BPF_REG_8, offsetofend(struct bpf_insn, code)));
743 debug_regs(gen, BPF_REG_9, -1, " var t=%d w=%d (%s:count=%d): insn.reg",
744 relo->is_typeless, relo->is_weak, relo->name, ref);
745}
746
747/* Expects:
748 * BPF_REG_8 - pointer to instruction
749 */
750static void emit_relo_ksym_typeless(struct bpf_gen *gen,
751 struct ksym_relo_desc *relo, int insn)
752{
753 struct ksym_desc *kdesc;
754
755 kdesc = get_ksym_desc(gen, relo);
756 if (!kdesc)
757 return;
758 /* try to copy from existing ldimm64 insn */
759 if (kdesc->ref > 1) {
760 move_blob2blob(gen, insn + offsetof(struct bpf_insn, imm), 4,
761 kdesc->insn + offsetof(struct bpf_insn, imm));
762 move_blob2blob(gen, insn + sizeof(struct bpf_insn) + offsetof(struct bpf_insn, imm), 4,
763 kdesc->insn + sizeof(struct bpf_insn) + offsetof(struct bpf_insn, imm));
764 goto log;
765 }
766 /* remember insn offset, so we can copy ksym addr later */
767 kdesc->insn = insn;
768 /* skip typeless ksym_desc in fd closing loop in cleanup_relos */
769 kdesc->typeless = true;
770 emit_bpf_kallsyms_lookup_name(gen, relo);
771 emit(gen, BPF_JMP_IMM(BPF_JEQ, BPF_REG_7, -ENOENT, 1));
772 emit_check_err(gen);
773 /* store lower half of addr into insn[insn_idx].imm */
774 emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_8, BPF_REG_9, offsetof(struct bpf_insn, imm)));
775 /* store upper half of addr into insn[insn_idx + 1].imm */
776 emit(gen, BPF_ALU64_IMM(BPF_RSH, BPF_REG_9, 32));
777 emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_8, BPF_REG_9,
778 sizeof(struct bpf_insn) + offsetof(struct bpf_insn, imm)));
779log:
780 emit_ksym_relo_log(gen, relo, kdesc->ref);
781}
782
783static __u32 src_reg_mask(void)
784{
785#if defined(__LITTLE_ENDIAN_BITFIELD)
786 return 0x0f; /* src_reg,dst_reg,... */
787#elif defined(__BIG_ENDIAN_BITFIELD)
788 return 0xf0; /* dst_reg,src_reg,... */
789#else
790#error "Unsupported bit endianness, cannot proceed"
791#endif
792}
793
794/* Expects:
795 * BPF_REG_8 - pointer to instruction
796 */
797static void emit_relo_ksym_btf(struct bpf_gen *gen, struct ksym_relo_desc *relo, int insn)
798{
799 struct ksym_desc *kdesc;
800 __u32 reg_mask;
801
802 kdesc = get_ksym_desc(gen, relo);
803 if (!kdesc)
804 return;
805 /* try to copy from existing ldimm64 insn */
806 if (kdesc->ref > 1) {
807 move_blob2blob(gen, insn + offsetof(struct bpf_insn, imm), 4,
808 kdesc->insn + offsetof(struct bpf_insn, imm));
809 move_blob2blob(gen, insn + sizeof(struct bpf_insn) + offsetof(struct bpf_insn, imm), 4,
810 kdesc->insn + sizeof(struct bpf_insn) + offsetof(struct bpf_insn, imm));
811 /* jump over src_reg adjustment if imm is not 0, reuse BPF_REG_0 from move_blob2blob */
812 emit(gen, BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 3));
813 goto clear_src_reg;
814 }
815 /* remember insn offset, so we can copy BTF ID and FD later */
816 kdesc->insn = insn;
817 emit_bpf_find_by_name_kind(gen, relo);
818 if (!relo->is_weak)
819 emit_check_err(gen);
820 /* jump to success case */
821 emit(gen, BPF_JMP_IMM(BPF_JSGE, BPF_REG_7, 0, 3));
822 /* set values for insn[insn_idx].imm, insn[insn_idx + 1].imm as 0 */
823 emit(gen, BPF_ST_MEM(BPF_W, BPF_REG_8, offsetof(struct bpf_insn, imm), 0));
824 emit(gen, BPF_ST_MEM(BPF_W, BPF_REG_8, sizeof(struct bpf_insn) + offsetof(struct bpf_insn, imm), 0));
825 /* skip success case for ret < 0 */
826 emit(gen, BPF_JMP_IMM(BPF_JA, 0, 0, 4));
827 /* store btf_id into insn[insn_idx].imm */
828 emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_8, BPF_REG_7, offsetof(struct bpf_insn, imm)));
829 /* store btf_obj_fd into insn[insn_idx + 1].imm */
830 emit(gen, BPF_ALU64_IMM(BPF_RSH, BPF_REG_7, 32));
831 emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_8, BPF_REG_7,
832 sizeof(struct bpf_insn) + offsetof(struct bpf_insn, imm)));
833 /* skip src_reg adjustment */
834 emit(gen, BPF_JMP_IMM(BPF_JSGE, BPF_REG_7, 0, 3));
835clear_src_reg:
836 /* clear bpf_object__relocate_data's src_reg assignment, otherwise we get a verifier failure */
837 reg_mask = src_reg_mask();
838 emit(gen, BPF_LDX_MEM(BPF_B, BPF_REG_9, BPF_REG_8, offsetofend(struct bpf_insn, code)));
839 emit(gen, BPF_ALU32_IMM(BPF_AND, BPF_REG_9, reg_mask));
840 emit(gen, BPF_STX_MEM(BPF_B, BPF_REG_8, BPF_REG_9, offsetofend(struct bpf_insn, code)));
841
842 emit_ksym_relo_log(gen, relo, kdesc->ref);
843}
844
845void bpf_gen__record_relo_core(struct bpf_gen *gen,
846 const struct bpf_core_relo *core_relo)
847{
848 struct bpf_core_relo *relos;
849
850 relos = libbpf_reallocarray(gen->core_relos, gen->core_relo_cnt + 1, sizeof(*relos));
851 if (!relos) {
852 gen->error = -ENOMEM;
853 return;
854 }
855 gen->core_relos = relos;
856 relos += gen->core_relo_cnt;
857 memcpy(relos, core_relo, sizeof(*relos));
858 gen->core_relo_cnt++;
859}
860
861static void emit_relo(struct bpf_gen *gen, struct ksym_relo_desc *relo, int insns)
862{
863 int insn;
864
865 pr_debug("gen: emit_relo (%d): %s at %d\n", relo->kind, relo->name, relo->insn_idx);
866 insn = insns + sizeof(struct bpf_insn) * relo->insn_idx;
867 emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_8, BPF_PSEUDO_MAP_IDX_VALUE, 0, 0, 0, insn));
868 switch (relo->kind) {
869 case BTF_KIND_VAR:
870 if (relo->is_typeless)
871 emit_relo_ksym_typeless(gen, relo, insn);
872 else
873 emit_relo_ksym_btf(gen, relo, insn);
874 break;
875 case BTF_KIND_FUNC:
876 emit_relo_kfunc_btf(gen, relo, insn);
877 break;
878 default:
879 pr_warn("Unknown relocation kind '%d'\n", relo->kind);
880 gen->error = -EDOM;
881 return;
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, 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 int i, insn;
905
906 for (i = 0; i < gen->nr_ksyms; i++) {
907 /* only close fds for typed ksyms and kfuncs */
908 if (gen->ksyms[i].kind == BTF_KIND_VAR && !gen->ksyms[i].typeless) {
909 /* close fd recorded in insn[insn_idx + 1].imm */
910 insn = gen->ksyms[i].insn;
911 insn += sizeof(struct bpf_insn) + offsetof(struct bpf_insn, imm);
912 emit_sys_close_blob(gen, insn);
913 } else if (gen->ksyms[i].kind == BTF_KIND_FUNC) {
914 emit_sys_close_blob(gen, blob_fd_array_off(gen, gen->ksyms[i].off));
915 if (gen->ksyms[i].off < MAX_FD_ARRAY_SZ)
916 gen->nr_fd_array--;
917 }
918 }
919 if (gen->nr_ksyms) {
920 free(gen->ksyms);
921 gen->nr_ksyms = 0;
922 gen->ksyms = NULL;
923 }
924 if (gen->relo_cnt) {
925 free(gen->relos);
926 gen->relo_cnt = 0;
927 gen->relos = NULL;
928 }
929 cleanup_core_relo(gen);
930}
931
932void bpf_gen__prog_load(struct bpf_gen *gen,
933 enum bpf_prog_type prog_type, const char *prog_name,
934 const char *license, struct bpf_insn *insns, size_t insn_cnt,
935 struct bpf_prog_load_opts *load_attr, int prog_idx)
936{
937 int prog_load_attr, license_off, insns_off, func_info, line_info, core_relos;
938 int attr_size = offsetofend(union bpf_attr, core_relo_rec_size);
939 union bpf_attr attr;
940
941 memset(&attr, 0, attr_size);
942 pr_debug("gen: prog_load: type %d insns_cnt %zd progi_idx %d\n",
943 prog_type, insn_cnt, prog_idx);
944 /* add license string to blob of bytes */
945 license_off = add_data(gen, license, strlen(license) + 1);
946 /* add insns to blob of bytes */
947 insns_off = add_data(gen, insns, insn_cnt * sizeof(struct bpf_insn));
948
949 attr.prog_type = prog_type;
950 attr.expected_attach_type = load_attr->expected_attach_type;
951 attr.attach_btf_id = load_attr->attach_btf_id;
952 attr.prog_ifindex = load_attr->prog_ifindex;
953 attr.kern_version = 0;
954 attr.insn_cnt = (__u32)insn_cnt;
955 attr.prog_flags = load_attr->prog_flags;
956
957 attr.func_info_rec_size = load_attr->func_info_rec_size;
958 attr.func_info_cnt = load_attr->func_info_cnt;
959 func_info = add_data(gen, load_attr->func_info,
960 attr.func_info_cnt * attr.func_info_rec_size);
961
962 attr.line_info_rec_size = load_attr->line_info_rec_size;
963 attr.line_info_cnt = load_attr->line_info_cnt;
964 line_info = add_data(gen, load_attr->line_info,
965 attr.line_info_cnt * attr.line_info_rec_size);
966
967 attr.core_relo_rec_size = sizeof(struct bpf_core_relo);
968 attr.core_relo_cnt = gen->core_relo_cnt;
969 core_relos = add_data(gen, gen->core_relos,
970 attr.core_relo_cnt * attr.core_relo_rec_size);
971
972 libbpf_strlcpy(attr.prog_name, prog_name, sizeof(attr.prog_name));
973 prog_load_attr = add_data(gen, &attr, attr_size);
974
975 /* populate union bpf_attr with a pointer to license */
976 emit_rel_store(gen, attr_field(prog_load_attr, license), license_off);
977
978 /* populate union bpf_attr with a pointer to instructions */
979 emit_rel_store(gen, attr_field(prog_load_attr, insns), insns_off);
980
981 /* populate union bpf_attr with a pointer to func_info */
982 emit_rel_store(gen, attr_field(prog_load_attr, func_info), func_info);
983
984 /* populate union bpf_attr with a pointer to line_info */
985 emit_rel_store(gen, attr_field(prog_load_attr, line_info), line_info);
986
987 /* populate union bpf_attr with a pointer to core_relos */
988 emit_rel_store(gen, attr_field(prog_load_attr, core_relos), core_relos);
989
990 /* populate union bpf_attr fd_array with a pointer to data where map_fds are saved */
991 emit_rel_store(gen, attr_field(prog_load_attr, fd_array), gen->fd_array);
992
993 /* populate union bpf_attr with user provided log details */
994 move_ctx2blob(gen, attr_field(prog_load_attr, log_level), 4,
995 offsetof(struct bpf_loader_ctx, log_level), false);
996 move_ctx2blob(gen, attr_field(prog_load_attr, log_size), 4,
997 offsetof(struct bpf_loader_ctx, log_size), false);
998 move_ctx2blob(gen, attr_field(prog_load_attr, log_buf), 8,
999 offsetof(struct bpf_loader_ctx, log_buf), false);
1000 /* populate union bpf_attr with btf_fd saved in the stack earlier */
1001 move_stack2blob(gen, attr_field(prog_load_attr, prog_btf_fd), 4,
1002 stack_off(btf_fd));
1003 if (gen->attach_kind) {
1004 emit_find_attach_target(gen);
1005 /* populate union bpf_attr with btf_id and btf_obj_fd found by helper */
1006 emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_0, BPF_PSEUDO_MAP_IDX_VALUE,
1007 0, 0, 0, prog_load_attr));
1008 emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_0, BPF_REG_7,
1009 offsetof(union bpf_attr, attach_btf_id)));
1010 emit(gen, BPF_ALU64_IMM(BPF_RSH, BPF_REG_7, 32));
1011 emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_0, BPF_REG_7,
1012 offsetof(union bpf_attr, attach_btf_obj_fd)));
1013 }
1014 emit_relos(gen, insns_off);
1015 /* emit PROG_LOAD command */
1016 emit_sys_bpf(gen, BPF_PROG_LOAD, prog_load_attr, attr_size);
1017 debug_ret(gen, "prog_load %s insn_cnt %d", attr.prog_name, attr.insn_cnt);
1018 /* successful or not, close btf module FDs used in extern ksyms and attach_btf_obj_fd */
1019 cleanup_relos(gen, insns_off);
1020 if (gen->attach_kind) {
1021 emit_sys_close_blob(gen,
1022 attr_field(prog_load_attr, attach_btf_obj_fd));
1023 gen->attach_kind = 0;
1024 }
1025 emit_check_err(gen);
1026 /* remember prog_fd in the stack, if successful */
1027 emit(gen, BPF_STX_MEM(BPF_W, BPF_REG_10, BPF_REG_7,
1028 stack_off(prog_fd[gen->nr_progs])));
1029 gen->nr_progs++;
1030}
1031
1032void bpf_gen__map_update_elem(struct bpf_gen *gen, int map_idx, void *pvalue,
1033 __u32 value_size)
1034{
1035 int attr_size = offsetofend(union bpf_attr, flags);
1036 int map_update_attr, value, key;
1037 union bpf_attr attr;
1038 int zero = 0;
1039
1040 memset(&attr, 0, attr_size);
1041 pr_debug("gen: map_update_elem: idx %d\n", map_idx);
1042
1043 value = add_data(gen, pvalue, value_size);
1044 key = add_data(gen, &zero, sizeof(zero));
1045
1046 /* if (map_desc[map_idx].initial_value) {
1047 * if (ctx->flags & BPF_SKEL_KERNEL)
1048 * bpf_probe_read_kernel(value, value_size, initial_value);
1049 * else
1050 * bpf_copy_from_user(value, value_size, initial_value);
1051 * }
1052 */
1053 emit(gen, BPF_LDX_MEM(BPF_DW, BPF_REG_3, BPF_REG_6,
1054 sizeof(struct bpf_loader_ctx) +
1055 sizeof(struct bpf_map_desc) * map_idx +
1056 offsetof(struct bpf_map_desc, initial_value)));
1057 emit(gen, BPF_JMP_IMM(BPF_JEQ, BPF_REG_3, 0, 8));
1058 emit2(gen, BPF_LD_IMM64_RAW_FULL(BPF_REG_1, BPF_PSEUDO_MAP_IDX_VALUE,
1059 0, 0, 0, value));
1060 emit(gen, BPF_MOV64_IMM(BPF_REG_2, value_size));
1061 emit(gen, BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_6,
1062 offsetof(struct bpf_loader_ctx, flags)));
1063 emit(gen, BPF_JMP_IMM(BPF_JSET, BPF_REG_0, BPF_SKEL_KERNEL, 2));
1064 emit(gen, BPF_EMIT_CALL(BPF_FUNC_copy_from_user));
1065 emit(gen, BPF_JMP_IMM(BPF_JA, 0, 0, 1));
1066 emit(gen, BPF_EMIT_CALL(BPF_FUNC_probe_read_kernel));
1067
1068 map_update_attr = add_data(gen, &attr, attr_size);
1069 move_blob2blob(gen, attr_field(map_update_attr, map_fd), 4,
1070 blob_fd_array_off(gen, map_idx));
1071 emit_rel_store(gen, attr_field(map_update_attr, key), key);
1072 emit_rel_store(gen, attr_field(map_update_attr, value), value);
1073 /* emit MAP_UPDATE_ELEM command */
1074 emit_sys_bpf(gen, BPF_MAP_UPDATE_ELEM, map_update_attr, attr_size);
1075 debug_ret(gen, "update_elem idx %d value_size %d", map_idx, value_size);
1076 emit_check_err(gen);
1077}
1078
1079void bpf_gen__populate_outer_map(struct bpf_gen *gen, int outer_map_idx, int slot,
1080 int inner_map_idx)
1081{
1082 int attr_size = offsetofend(union bpf_attr, flags);
1083 int map_update_attr, key;
1084 union bpf_attr attr;
1085
1086 memset(&attr, 0, attr_size);
1087 pr_debug("gen: populate_outer_map: outer %d key %d inner %d\n",
1088 outer_map_idx, slot, inner_map_idx);
1089
1090 key = add_data(gen, &slot, sizeof(slot));
1091
1092 map_update_attr = add_data(gen, &attr, attr_size);
1093 move_blob2blob(gen, attr_field(map_update_attr, map_fd), 4,
1094 blob_fd_array_off(gen, outer_map_idx));
1095 emit_rel_store(gen, attr_field(map_update_attr, key), key);
1096 emit_rel_store(gen, attr_field(map_update_attr, value),
1097 blob_fd_array_off(gen, inner_map_idx));
1098
1099 /* emit MAP_UPDATE_ELEM command */
1100 emit_sys_bpf(gen, BPF_MAP_UPDATE_ELEM, map_update_attr, attr_size);
1101 debug_ret(gen, "populate_outer_map outer %d key %d inner %d",
1102 outer_map_idx, slot, inner_map_idx);
1103 emit_check_err(gen);
1104}
1105
1106void bpf_gen__map_freeze(struct bpf_gen *gen, int map_idx)
1107{
1108 int attr_size = offsetofend(union bpf_attr, map_fd);
1109 int map_freeze_attr;
1110 union bpf_attr attr;
1111
1112 memset(&attr, 0, attr_size);
1113 pr_debug("gen: map_freeze: idx %d\n", map_idx);
1114 map_freeze_attr = add_data(gen, &attr, attr_size);
1115 move_blob2blob(gen, attr_field(map_freeze_attr, map_fd), 4,
1116 blob_fd_array_off(gen, map_idx));
1117 /* emit MAP_FREEZE command */
1118 emit_sys_bpf(gen, BPF_MAP_FREEZE, map_freeze_attr, attr_size);
1119 debug_ret(gen, "map_freeze");
1120 emit_check_err(gen);
1121}