1 // SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
2 /* Copyright (C) 2016-2018 Netronome Systems, Inc. */
3
4 #include <linux/bpf.h>
5 #include <linux/bpf_verifier.h>
6 #include <linux/kernel.h>
7 #include <linux/netdevice.h>
8 #include <linux/pkt_cls.h>
9
10 #include "../nfp_app.h"
11 #include "../nfp_main.h"
12 #include "../nfp_net.h"
13 #include "fw.h"
14 #include "main.h"
15
16 #define pr_vlog(env, fmt, ...) \
17 bpf_verifier_log_write(env, "[nfp] " fmt, ##__VA_ARGS__)
18
19 struct nfp_insn_meta *
nfp_bpf_goto_meta(struct nfp_prog * nfp_prog,struct nfp_insn_meta * meta,unsigned int insn_idx)20 nfp_bpf_goto_meta(struct nfp_prog *nfp_prog, struct nfp_insn_meta *meta,
21 unsigned int insn_idx)
22 {
23 unsigned int forward, backward, i;
24
25 backward = meta->n - insn_idx;
26 forward = insn_idx - meta->n;
27
28 if (min(forward, backward) > nfp_prog->n_insns - insn_idx - 1) {
29 backward = nfp_prog->n_insns - insn_idx - 1;
30 meta = nfp_prog_last_meta(nfp_prog);
31 }
32 if (min(forward, backward) > insn_idx && backward > insn_idx) {
33 forward = insn_idx;
34 meta = nfp_prog_first_meta(nfp_prog);
35 }
36
37 if (forward < backward)
38 for (i = 0; i < forward; i++)
39 meta = nfp_meta_next(meta);
40 else
41 for (i = 0; i < backward; i++)
42 meta = nfp_meta_prev(meta);
43
44 return meta;
45 }
46
47 static void
nfp_record_adjust_head(struct nfp_app_bpf * bpf,struct nfp_prog * nfp_prog,struct nfp_insn_meta * meta,const struct bpf_reg_state * reg2)48 nfp_record_adjust_head(struct nfp_app_bpf *bpf, struct nfp_prog *nfp_prog,
49 struct nfp_insn_meta *meta,
50 const struct bpf_reg_state *reg2)
51 {
52 unsigned int location = UINT_MAX;
53 int imm;
54
55 /* Datapath usually can give us guarantees on how much adjust head
56 * can be done without the need for any checks. Optimize the simple
57 * case where there is only one adjust head by a constant.
58 */
59 if (reg2->type != SCALAR_VALUE || !tnum_is_const(reg2->var_off))
60 goto exit_set_location;
61 imm = reg2->var_off.value;
62 /* Translator will skip all checks, we need to guarantee min pkt len */
63 if (imm > ETH_ZLEN - ETH_HLEN)
64 goto exit_set_location;
65 if (imm > (int)bpf->adjust_head.guaranteed_add ||
66 imm < -bpf->adjust_head.guaranteed_sub)
67 goto exit_set_location;
68
69 if (nfp_prog->adjust_head_location) {
70 /* Only one call per program allowed */
71 if (nfp_prog->adjust_head_location != meta->n)
72 goto exit_set_location;
73
74 if (meta->arg2.reg.var_off.value != imm)
75 goto exit_set_location;
76 }
77
78 location = meta->n;
79 exit_set_location:
80 nfp_prog->adjust_head_location = location;
81 }
82
nfp_bpf_map_update_value_ok(struct bpf_verifier_env * env)83 static bool nfp_bpf_map_update_value_ok(struct bpf_verifier_env *env)
84 {
85 const struct bpf_reg_state *reg1 = cur_regs(env) + BPF_REG_1;
86 const struct bpf_reg_state *reg3 = cur_regs(env) + BPF_REG_3;
87 struct bpf_offloaded_map *offmap;
88 struct bpf_func_state *state;
89 struct nfp_bpf_map *nfp_map;
90 int off, i;
91
92 state = env->cur_state->frame[reg3->frameno];
93
94 /* We need to record each time update happens with non-zero words,
95 * in case such word is used in atomic operations.
96 * Implicitly depend on nfp_bpf_stack_arg_ok(reg3) being run before.
97 */
98
99 offmap = map_to_offmap(reg1->map_ptr);
100 nfp_map = offmap->dev_priv;
101 off = reg3->off + reg3->var_off.value;
102
103 for (i = 0; i < offmap->map.value_size; i++) {
104 struct bpf_stack_state *stack_entry;
105 unsigned int soff;
106
107 soff = -(off + i) - 1;
108 stack_entry = &state->stack[soff / BPF_REG_SIZE];
109 if (stack_entry->slot_type[soff % BPF_REG_SIZE] == STACK_ZERO)
110 continue;
111
112 if (nfp_map->use_map[i / 4].type == NFP_MAP_USE_ATOMIC_CNT) {
113 pr_vlog(env, "value at offset %d/%d may be non-zero, bpf_map_update_elem() is required to initialize atomic counters to zero to avoid offload endian issues\n",
114 i, soff);
115 return false;
116 }
117 nfp_map->use_map[i / 4].non_zero_update = 1;
118 }
119
120 return true;
121 }
122
123 static int
nfp_bpf_stack_arg_ok(const char * fname,struct bpf_verifier_env * env,const struct bpf_reg_state * reg,struct nfp_bpf_reg_state * old_arg)124 nfp_bpf_stack_arg_ok(const char *fname, struct bpf_verifier_env *env,
125 const struct bpf_reg_state *reg,
126 struct nfp_bpf_reg_state *old_arg)
127 {
128 s64 off, old_off;
129
130 if (reg->type != PTR_TO_STACK) {
131 pr_vlog(env, "%s: unsupported ptr type %d\n",
132 fname, reg->type);
133 return false;
134 }
135 if (!tnum_is_const(reg->var_off)) {
136 pr_vlog(env, "%s: variable pointer\n", fname);
137 return false;
138 }
139
140 off = reg->var_off.value + reg->off;
141 if (-off % 4) {
142 pr_vlog(env, "%s: unaligned stack pointer %lld\n", fname, -off);
143 return false;
144 }
145
146 /* Rest of the checks is only if we re-parse the same insn */
147 if (!old_arg)
148 return true;
149
150 old_off = old_arg->reg.var_off.value + old_arg->reg.off;
151 old_arg->var_off |= off != old_off;
152
153 return true;
154 }
155
156 static bool
nfp_bpf_map_call_ok(const char * fname,struct bpf_verifier_env * env,struct nfp_insn_meta * meta,u32 helper_tgt,const struct bpf_reg_state * reg1)157 nfp_bpf_map_call_ok(const char *fname, struct bpf_verifier_env *env,
158 struct nfp_insn_meta *meta,
159 u32 helper_tgt, const struct bpf_reg_state *reg1)
160 {
161 if (!helper_tgt) {
162 pr_vlog(env, "%s: not supported by FW\n", fname);
163 return false;
164 }
165
166 return true;
167 }
168
169 static int
nfp_bpf_check_helper_call(struct nfp_prog * nfp_prog,struct bpf_verifier_env * env,struct nfp_insn_meta * meta)170 nfp_bpf_check_helper_call(struct nfp_prog *nfp_prog,
171 struct bpf_verifier_env *env,
172 struct nfp_insn_meta *meta)
173 {
174 const struct bpf_reg_state *reg1 = cur_regs(env) + BPF_REG_1;
175 const struct bpf_reg_state *reg2 = cur_regs(env) + BPF_REG_2;
176 const struct bpf_reg_state *reg3 = cur_regs(env) + BPF_REG_3;
177 struct nfp_app_bpf *bpf = nfp_prog->bpf;
178 u32 func_id = meta->insn.imm;
179
180 switch (func_id) {
181 case BPF_FUNC_xdp_adjust_head:
182 if (!bpf->adjust_head.off_max) {
183 pr_vlog(env, "adjust_head not supported by FW\n");
184 return -EOPNOTSUPP;
185 }
186 if (!(bpf->adjust_head.flags & NFP_BPF_ADJUST_HEAD_NO_META)) {
187 pr_vlog(env, "adjust_head: FW requires shifting metadata, not supported by the driver\n");
188 return -EOPNOTSUPP;
189 }
190
191 nfp_record_adjust_head(bpf, nfp_prog, meta, reg2);
192 break;
193
194 case BPF_FUNC_xdp_adjust_tail:
195 if (!bpf->adjust_tail) {
196 pr_vlog(env, "adjust_tail not supported by FW\n");
197 return -EOPNOTSUPP;
198 }
199 break;
200
201 case BPF_FUNC_map_lookup_elem:
202 if (!nfp_bpf_map_call_ok("map_lookup", env, meta,
203 bpf->helpers.map_lookup, reg1) ||
204 !nfp_bpf_stack_arg_ok("map_lookup", env, reg2,
205 meta->func_id ? &meta->arg2 : NULL))
206 return -EOPNOTSUPP;
207 break;
208
209 case BPF_FUNC_map_update_elem:
210 if (!nfp_bpf_map_call_ok("map_update", env, meta,
211 bpf->helpers.map_update, reg1) ||
212 !nfp_bpf_stack_arg_ok("map_update", env, reg2,
213 meta->func_id ? &meta->arg2 : NULL) ||
214 !nfp_bpf_stack_arg_ok("map_update", env, reg3, NULL) ||
215 !nfp_bpf_map_update_value_ok(env))
216 return -EOPNOTSUPP;
217 break;
218
219 case BPF_FUNC_map_delete_elem:
220 if (!nfp_bpf_map_call_ok("map_delete", env, meta,
221 bpf->helpers.map_delete, reg1) ||
222 !nfp_bpf_stack_arg_ok("map_delete", env, reg2,
223 meta->func_id ? &meta->arg2 : NULL))
224 return -EOPNOTSUPP;
225 break;
226
227 case BPF_FUNC_get_prandom_u32:
228 if (bpf->pseudo_random)
229 break;
230 pr_vlog(env, "bpf_get_prandom_u32(): FW doesn't support random number generation\n");
231 return -EOPNOTSUPP;
232
233 case BPF_FUNC_perf_event_output:
234 BUILD_BUG_ON(NFP_BPF_SCALAR_VALUE != SCALAR_VALUE ||
235 NFP_BPF_MAP_VALUE != PTR_TO_MAP_VALUE ||
236 NFP_BPF_STACK != PTR_TO_STACK ||
237 NFP_BPF_PACKET_DATA != PTR_TO_PACKET);
238
239 if (!bpf->helpers.perf_event_output) {
240 pr_vlog(env, "event_output: not supported by FW\n");
241 return -EOPNOTSUPP;
242 }
243
244 /* Force current CPU to make sure we can report the event
245 * wherever we get the control message from FW.
246 */
247 if (reg3->var_off.mask & BPF_F_INDEX_MASK ||
248 (reg3->var_off.value & BPF_F_INDEX_MASK) !=
249 BPF_F_CURRENT_CPU) {
250 char tn_buf[48];
251
252 tnum_strn(tn_buf, sizeof(tn_buf), reg3->var_off);
253 pr_vlog(env, "event_output: must use BPF_F_CURRENT_CPU, var_off: %s\n",
254 tn_buf);
255 return -EOPNOTSUPP;
256 }
257
258 /* Save space in meta, we don't care about arguments other
259 * than 4th meta, shove it into arg1.
260 */
261 reg1 = cur_regs(env) + BPF_REG_4;
262
263 if (reg1->type != SCALAR_VALUE /* NULL ptr */ &&
264 reg1->type != PTR_TO_STACK &&
265 reg1->type != PTR_TO_MAP_VALUE &&
266 reg1->type != PTR_TO_PACKET) {
267 pr_vlog(env, "event_output: unsupported ptr type: %d\n",
268 reg1->type);
269 return -EOPNOTSUPP;
270 }
271
272 if (reg1->type == PTR_TO_STACK &&
273 !nfp_bpf_stack_arg_ok("event_output", env, reg1, NULL))
274 return -EOPNOTSUPP;
275
276 /* Warn user that on offload NFP may return success even if map
277 * is not going to accept the event, since the event output is
278 * fully async and device won't know the state of the map.
279 * There is also FW limitation on the event length.
280 *
281 * Lost events will not show up on the perf ring, driver
282 * won't see them at all. Events may also get reordered.
283 */
284 dev_warn_once(&nfp_prog->bpf->app->pf->pdev->dev,
285 "bpf: note: return codes and behavior of bpf_event_output() helper differs for offloaded programs!\n");
286 pr_vlog(env, "warning: return codes and behavior of event_output helper differ for offload!\n");
287
288 if (!meta->func_id)
289 break;
290
291 if (reg1->type != meta->arg1.type) {
292 pr_vlog(env, "event_output: ptr type changed: %d %d\n",
293 meta->arg1.type, reg1->type);
294 return -EINVAL;
295 }
296 break;
297
298 default:
299 pr_vlog(env, "unsupported function id: %d\n", func_id);
300 return -EOPNOTSUPP;
301 }
302
303 meta->func_id = func_id;
304 meta->arg1 = *reg1;
305 meta->arg2.reg = *reg2;
306
307 return 0;
308 }
309
310 static int
nfp_bpf_check_exit(struct nfp_prog * nfp_prog,struct bpf_verifier_env * env)311 nfp_bpf_check_exit(struct nfp_prog *nfp_prog,
312 struct bpf_verifier_env *env)
313 {
314 const struct bpf_reg_state *reg0 = cur_regs(env) + BPF_REG_0;
315 u64 imm;
316
317 if (nfp_prog->type == BPF_PROG_TYPE_XDP)
318 return 0;
319
320 if (!(reg0->type == SCALAR_VALUE && tnum_is_const(reg0->var_off))) {
321 char tn_buf[48];
322
323 tnum_strn(tn_buf, sizeof(tn_buf), reg0->var_off);
324 pr_vlog(env, "unsupported exit state: %d, var_off: %s\n",
325 reg0->type, tn_buf);
326 return -EINVAL;
327 }
328
329 imm = reg0->var_off.value;
330 if (nfp_prog->type == BPF_PROG_TYPE_SCHED_CLS &&
331 imm <= TC_ACT_REDIRECT &&
332 imm != TC_ACT_SHOT && imm != TC_ACT_STOLEN &&
333 imm != TC_ACT_QUEUED) {
334 pr_vlog(env, "unsupported exit state: %d, imm: %llx\n",
335 reg0->type, imm);
336 return -EINVAL;
337 }
338
339 return 0;
340 }
341
342 static int
nfp_bpf_check_stack_access(struct nfp_prog * nfp_prog,struct nfp_insn_meta * meta,const struct bpf_reg_state * reg,struct bpf_verifier_env * env)343 nfp_bpf_check_stack_access(struct nfp_prog *nfp_prog,
344 struct nfp_insn_meta *meta,
345 const struct bpf_reg_state *reg,
346 struct bpf_verifier_env *env)
347 {
348 s32 old_off, new_off;
349
350 if (reg->frameno != env->cur_state->curframe)
351 meta->flags |= FLAG_INSN_PTR_CALLER_STACK_FRAME;
352
353 if (!tnum_is_const(reg->var_off)) {
354 pr_vlog(env, "variable ptr stack access\n");
355 return -EINVAL;
356 }
357
358 if (meta->ptr.type == NOT_INIT)
359 return 0;
360
361 old_off = meta->ptr.off + meta->ptr.var_off.value;
362 new_off = reg->off + reg->var_off.value;
363
364 meta->ptr_not_const |= old_off != new_off;
365
366 if (!meta->ptr_not_const)
367 return 0;
368
369 if (old_off % 4 == new_off % 4)
370 return 0;
371
372 pr_vlog(env, "stack access changed location was:%d is:%d\n",
373 old_off, new_off);
374 return -EINVAL;
375 }
376
nfp_bpf_map_use_name(enum nfp_bpf_map_use use)377 static const char *nfp_bpf_map_use_name(enum nfp_bpf_map_use use)
378 {
379 static const char * const names[] = {
380 [NFP_MAP_UNUSED] = "unused",
381 [NFP_MAP_USE_READ] = "read",
382 [NFP_MAP_USE_WRITE] = "write",
383 [NFP_MAP_USE_ATOMIC_CNT] = "atomic",
384 };
385
386 if (use >= ARRAY_SIZE(names) || !names[use])
387 return "unknown";
388 return names[use];
389 }
390
391 static int
nfp_bpf_map_mark_used_one(struct bpf_verifier_env * env,struct nfp_bpf_map * nfp_map,unsigned int off,enum nfp_bpf_map_use use)392 nfp_bpf_map_mark_used_one(struct bpf_verifier_env *env,
393 struct nfp_bpf_map *nfp_map,
394 unsigned int off, enum nfp_bpf_map_use use)
395 {
396 if (nfp_map->use_map[off / 4].type != NFP_MAP_UNUSED &&
397 nfp_map->use_map[off / 4].type != use) {
398 pr_vlog(env, "map value use type conflict %s vs %s off: %u\n",
399 nfp_bpf_map_use_name(nfp_map->use_map[off / 4].type),
400 nfp_bpf_map_use_name(use), off);
401 return -EOPNOTSUPP;
402 }
403
404 if (nfp_map->use_map[off / 4].non_zero_update &&
405 use == NFP_MAP_USE_ATOMIC_CNT) {
406 pr_vlog(env, "atomic counter in map value may already be initialized to non-zero value off: %u\n",
407 off);
408 return -EOPNOTSUPP;
409 }
410
411 nfp_map->use_map[off / 4].type = use;
412
413 return 0;
414 }
415
416 static int
nfp_bpf_map_mark_used(struct bpf_verifier_env * env,struct nfp_insn_meta * meta,const struct bpf_reg_state * reg,enum nfp_bpf_map_use use)417 nfp_bpf_map_mark_used(struct bpf_verifier_env *env, struct nfp_insn_meta *meta,
418 const struct bpf_reg_state *reg,
419 enum nfp_bpf_map_use use)
420 {
421 struct bpf_offloaded_map *offmap;
422 struct nfp_bpf_map *nfp_map;
423 unsigned int size, off;
424 int i, err;
425
426 if (!tnum_is_const(reg->var_off)) {
427 pr_vlog(env, "map value offset is variable\n");
428 return -EOPNOTSUPP;
429 }
430
431 off = reg->var_off.value + meta->insn.off + reg->off;
432 size = BPF_LDST_BYTES(&meta->insn);
433 offmap = map_to_offmap(reg->map_ptr);
434 nfp_map = offmap->dev_priv;
435
436 if (off + size > offmap->map.value_size) {
437 pr_vlog(env, "map value access out-of-bounds\n");
438 return -EINVAL;
439 }
440
441 for (i = 0; i < size; i += 4 - (off + i) % 4) {
442 err = nfp_bpf_map_mark_used_one(env, nfp_map, off + i, use);
443 if (err)
444 return err;
445 }
446
447 return 0;
448 }
449
450 static int
nfp_bpf_check_ptr(struct nfp_prog * nfp_prog,struct nfp_insn_meta * meta,struct bpf_verifier_env * env,u8 reg_no)451 nfp_bpf_check_ptr(struct nfp_prog *nfp_prog, struct nfp_insn_meta *meta,
452 struct bpf_verifier_env *env, u8 reg_no)
453 {
454 const struct bpf_reg_state *reg = cur_regs(env) + reg_no;
455 int err;
456
457 if (reg->type != PTR_TO_CTX &&
458 reg->type != PTR_TO_STACK &&
459 reg->type != PTR_TO_MAP_VALUE &&
460 reg->type != PTR_TO_PACKET) {
461 pr_vlog(env, "unsupported ptr type: %d\n", reg->type);
462 return -EINVAL;
463 }
464
465 if (reg->type == PTR_TO_STACK) {
466 err = nfp_bpf_check_stack_access(nfp_prog, meta, reg, env);
467 if (err)
468 return err;
469 }
470
471 if (reg->type == PTR_TO_MAP_VALUE) {
472 if (is_mbpf_load(meta)) {
473 err = nfp_bpf_map_mark_used(env, meta, reg,
474 NFP_MAP_USE_READ);
475 if (err)
476 return err;
477 }
478 if (is_mbpf_store(meta)) {
479 pr_vlog(env, "map writes not supported\n");
480 return -EOPNOTSUPP;
481 }
482 if (is_mbpf_atomic(meta)) {
483 err = nfp_bpf_map_mark_used(env, meta, reg,
484 NFP_MAP_USE_ATOMIC_CNT);
485 if (err)
486 return err;
487 }
488 }
489
490 if (meta->ptr.type != NOT_INIT && meta->ptr.type != reg->type) {
491 pr_vlog(env, "ptr type changed for instruction %d -> %d\n",
492 meta->ptr.type, reg->type);
493 return -EINVAL;
494 }
495
496 meta->ptr = *reg;
497
498 return 0;
499 }
500
501 static int
nfp_bpf_check_store(struct nfp_prog * nfp_prog,struct nfp_insn_meta * meta,struct bpf_verifier_env * env)502 nfp_bpf_check_store(struct nfp_prog *nfp_prog, struct nfp_insn_meta *meta,
503 struct bpf_verifier_env *env)
504 {
505 const struct bpf_reg_state *reg = cur_regs(env) + meta->insn.dst_reg;
506
507 if (reg->type == PTR_TO_CTX) {
508 if (nfp_prog->type == BPF_PROG_TYPE_XDP) {
509 /* XDP ctx accesses must be 4B in size */
510 switch (meta->insn.off) {
511 case offsetof(struct xdp_md, rx_queue_index):
512 if (nfp_prog->bpf->queue_select)
513 goto exit_check_ptr;
514 pr_vlog(env, "queue selection not supported by FW\n");
515 return -EOPNOTSUPP;
516 }
517 }
518 pr_vlog(env, "unsupported store to context field\n");
519 return -EOPNOTSUPP;
520 }
521 exit_check_ptr:
522 return nfp_bpf_check_ptr(nfp_prog, meta, env, meta->insn.dst_reg);
523 }
524
525 static int
nfp_bpf_check_atomic(struct nfp_prog * nfp_prog,struct nfp_insn_meta * meta,struct bpf_verifier_env * env)526 nfp_bpf_check_atomic(struct nfp_prog *nfp_prog, struct nfp_insn_meta *meta,
527 struct bpf_verifier_env *env)
528 {
529 const struct bpf_reg_state *sreg = cur_regs(env) + meta->insn.src_reg;
530 const struct bpf_reg_state *dreg = cur_regs(env) + meta->insn.dst_reg;
531
532 if (meta->insn.imm != BPF_ADD) {
533 pr_vlog(env, "atomic op not implemented: %d\n", meta->insn.imm);
534 return -EOPNOTSUPP;
535 }
536
537 if (dreg->type != PTR_TO_MAP_VALUE) {
538 pr_vlog(env, "atomic add not to a map value pointer: %d\n",
539 dreg->type);
540 return -EOPNOTSUPP;
541 }
542 if (sreg->type != SCALAR_VALUE) {
543 pr_vlog(env, "atomic add not of a scalar: %d\n", sreg->type);
544 return -EOPNOTSUPP;
545 }
546
547 meta->xadd_over_16bit |=
548 sreg->var_off.value > 0xffff || sreg->var_off.mask > 0xffff;
549 meta->xadd_maybe_16bit |=
550 (sreg->var_off.value & ~sreg->var_off.mask) <= 0xffff;
551
552 return nfp_bpf_check_ptr(nfp_prog, meta, env, meta->insn.dst_reg);
553 }
554
555 static int
nfp_bpf_check_alu(struct nfp_prog * nfp_prog,struct nfp_insn_meta * meta,struct bpf_verifier_env * env)556 nfp_bpf_check_alu(struct nfp_prog *nfp_prog, struct nfp_insn_meta *meta,
557 struct bpf_verifier_env *env)
558 {
559 const struct bpf_reg_state *sreg =
560 cur_regs(env) + meta->insn.src_reg;
561 const struct bpf_reg_state *dreg =
562 cur_regs(env) + meta->insn.dst_reg;
563
564 meta->umin_src = min(meta->umin_src, sreg->umin_value);
565 meta->umax_src = max(meta->umax_src, sreg->umax_value);
566 meta->umin_dst = min(meta->umin_dst, dreg->umin_value);
567 meta->umax_dst = max(meta->umax_dst, dreg->umax_value);
568
569 /* NFP supports u16 and u32 multiplication.
570 *
571 * For ALU64, if either operand is beyond u32's value range, we reject
572 * it. One thing to note, if the source operand is BPF_K, then we need
573 * to check "imm" field directly, and we'd reject it if it is negative.
574 * Because for ALU64, "imm" (with s32 type) is expected to be sign
575 * extended to s64 which NFP mul doesn't support.
576 *
577 * For ALU32, it is fine for "imm" be negative though, because the
578 * result is 32-bits and there is no difference on the low halve of
579 * the result for signed/unsigned mul, so we will get correct result.
580 */
581 if (is_mbpf_mul(meta)) {
582 if (meta->umax_dst > U32_MAX) {
583 pr_vlog(env, "multiplier is not within u32 value range\n");
584 return -EINVAL;
585 }
586 if (mbpf_src(meta) == BPF_X && meta->umax_src > U32_MAX) {
587 pr_vlog(env, "multiplicand is not within u32 value range\n");
588 return -EINVAL;
589 }
590 if (mbpf_class(meta) == BPF_ALU64 &&
591 mbpf_src(meta) == BPF_K && meta->insn.imm < 0) {
592 pr_vlog(env, "sign extended multiplicand won't be within u32 value range\n");
593 return -EINVAL;
594 }
595 }
596
597 /* NFP doesn't have divide instructions, we support divide by constant
598 * through reciprocal multiplication. Given NFP support multiplication
599 * no bigger than u32, we'd require divisor and dividend no bigger than
600 * that as well.
601 *
602 * Also eBPF doesn't support signed divide and has enforced this on C
603 * language level by failing compilation. However LLVM assembler hasn't
604 * enforced this, so it is possible for negative constant to leak in as
605 * a BPF_K operand through assembly code, we reject such cases as well.
606 */
607 if (is_mbpf_div(meta)) {
608 if (meta->umax_dst > U32_MAX) {
609 pr_vlog(env, "dividend is not within u32 value range\n");
610 return -EINVAL;
611 }
612 if (mbpf_src(meta) == BPF_X) {
613 if (meta->umin_src != meta->umax_src) {
614 pr_vlog(env, "divisor is not constant\n");
615 return -EINVAL;
616 }
617 if (meta->umax_src > U32_MAX) {
618 pr_vlog(env, "divisor is not within u32 value range\n");
619 return -EINVAL;
620 }
621 }
622 if (mbpf_src(meta) == BPF_K && meta->insn.imm < 0) {
623 pr_vlog(env, "divide by negative constant is not supported\n");
624 return -EINVAL;
625 }
626 }
627
628 return 0;
629 }
630
nfp_verify_insn(struct bpf_verifier_env * env,int insn_idx,int prev_insn_idx)631 int nfp_verify_insn(struct bpf_verifier_env *env, int insn_idx,
632 int prev_insn_idx)
633 {
634 struct nfp_prog *nfp_prog = env->prog->aux->offload->dev_priv;
635 struct nfp_insn_meta *meta = nfp_prog->verifier_meta;
636
637 meta = nfp_bpf_goto_meta(nfp_prog, meta, insn_idx);
638 nfp_prog->verifier_meta = meta;
639
640 if (!nfp_bpf_supported_opcode(meta->insn.code)) {
641 pr_vlog(env, "instruction %#02x not supported\n",
642 meta->insn.code);
643 return -EINVAL;
644 }
645
646 if (meta->insn.src_reg >= MAX_BPF_REG ||
647 meta->insn.dst_reg >= MAX_BPF_REG) {
648 pr_vlog(env, "program uses extended registers - jit hardening?\n");
649 return -EINVAL;
650 }
651
652 if (is_mbpf_helper_call(meta))
653 return nfp_bpf_check_helper_call(nfp_prog, env, meta);
654 if (meta->insn.code == (BPF_JMP | BPF_EXIT))
655 return nfp_bpf_check_exit(nfp_prog, env);
656
657 if (is_mbpf_load(meta))
658 return nfp_bpf_check_ptr(nfp_prog, meta, env,
659 meta->insn.src_reg);
660 if (is_mbpf_store(meta))
661 return nfp_bpf_check_store(nfp_prog, meta, env);
662
663 if (is_mbpf_atomic(meta))
664 return nfp_bpf_check_atomic(nfp_prog, meta, env);
665
666 if (is_mbpf_alu(meta))
667 return nfp_bpf_check_alu(nfp_prog, meta, env);
668
669 return 0;
670 }
671
672 static int
nfp_assign_subprog_idx_and_regs(struct bpf_verifier_env * env,struct nfp_prog * nfp_prog)673 nfp_assign_subprog_idx_and_regs(struct bpf_verifier_env *env,
674 struct nfp_prog *nfp_prog)
675 {
676 struct nfp_insn_meta *meta;
677 int index = 0;
678
679 list_for_each_entry(meta, &nfp_prog->insns, l) {
680 if (nfp_is_subprog_start(meta))
681 index++;
682 meta->subprog_idx = index;
683
684 if (meta->insn.dst_reg >= BPF_REG_6 &&
685 meta->insn.dst_reg <= BPF_REG_9)
686 nfp_prog->subprog[index].needs_reg_push = 1;
687 }
688
689 if (index + 1 != nfp_prog->subprog_cnt) {
690 pr_vlog(env, "BUG: number of processed BPF functions is not consistent (processed %d, expected %d)\n",
691 index + 1, nfp_prog->subprog_cnt);
692 return -EFAULT;
693 }
694
695 return 0;
696 }
697
nfp_bpf_get_stack_usage(struct nfp_prog * nfp_prog)698 static unsigned int nfp_bpf_get_stack_usage(struct nfp_prog *nfp_prog)
699 {
700 struct nfp_insn_meta *meta = nfp_prog_first_meta(nfp_prog);
701 unsigned int max_depth = 0, depth = 0, frame = 0;
702 struct nfp_insn_meta *ret_insn[MAX_CALL_FRAMES];
703 unsigned short frame_depths[MAX_CALL_FRAMES];
704 unsigned short ret_prog[MAX_CALL_FRAMES];
705 unsigned short idx = meta->subprog_idx;
706
707 /* Inspired from check_max_stack_depth() from kernel verifier.
708 * Starting from main subprogram, walk all instructions and recursively
709 * walk all callees that given subprogram can call. Since recursion is
710 * prevented by the kernel verifier, this algorithm only needs a local
711 * stack of MAX_CALL_FRAMES to remember callsites.
712 */
713 process_subprog:
714 frame_depths[frame] = nfp_prog->subprog[idx].stack_depth;
715 frame_depths[frame] = round_up(frame_depths[frame], STACK_FRAME_ALIGN);
716 depth += frame_depths[frame];
717 max_depth = max(max_depth, depth);
718
719 continue_subprog:
720 for (; meta != nfp_prog_last_meta(nfp_prog) && meta->subprog_idx == idx;
721 meta = nfp_meta_next(meta)) {
722 if (!is_mbpf_pseudo_call(meta))
723 continue;
724
725 /* We found a call to a subprogram. Remember instruction to
726 * return to and subprog id.
727 */
728 ret_insn[frame] = nfp_meta_next(meta);
729 ret_prog[frame] = idx;
730
731 /* Find the callee and start processing it. */
732 meta = nfp_bpf_goto_meta(nfp_prog, meta,
733 meta->n + 1 + meta->insn.imm);
734 idx = meta->subprog_idx;
735 frame++;
736 goto process_subprog;
737 }
738 /* End of for() loop means the last instruction of the subprog was
739 * reached. If we popped all stack frames, return; otherwise, go on
740 * processing remaining instructions from the caller.
741 */
742 if (frame == 0)
743 return max_depth;
744
745 depth -= frame_depths[frame];
746 frame--;
747 meta = ret_insn[frame];
748 idx = ret_prog[frame];
749 goto continue_subprog;
750 }
751
nfp_bpf_insn_flag_zext(struct nfp_prog * nfp_prog,struct bpf_insn_aux_data * aux)752 static void nfp_bpf_insn_flag_zext(struct nfp_prog *nfp_prog,
753 struct bpf_insn_aux_data *aux)
754 {
755 struct nfp_insn_meta *meta;
756
757 list_for_each_entry(meta, &nfp_prog->insns, l) {
758 if (aux[meta->n].zext_dst)
759 meta->flags |= FLAG_INSN_DO_ZEXT;
760 }
761 }
762
nfp_bpf_finalize(struct bpf_verifier_env * env)763 int nfp_bpf_finalize(struct bpf_verifier_env *env)
764 {
765 struct bpf_subprog_info *info;
766 struct nfp_prog *nfp_prog;
767 unsigned int max_stack;
768 struct nfp_net *nn;
769 int i;
770
771 nfp_prog = env->prog->aux->offload->dev_priv;
772 nfp_prog->subprog_cnt = env->subprog_cnt;
773 nfp_prog->subprog = kcalloc(nfp_prog->subprog_cnt,
774 sizeof(nfp_prog->subprog[0]), GFP_KERNEL);
775 if (!nfp_prog->subprog)
776 return -ENOMEM;
777
778 nfp_assign_subprog_idx_and_regs(env, nfp_prog);
779
780 info = env->subprog_info;
781 for (i = 0; i < nfp_prog->subprog_cnt; i++) {
782 nfp_prog->subprog[i].stack_depth = info[i].stack_depth;
783
784 if (i == 0)
785 continue;
786
787 /* Account for size of return address. */
788 nfp_prog->subprog[i].stack_depth += REG_WIDTH;
789 /* Account for size of saved registers, if necessary. */
790 if (nfp_prog->subprog[i].needs_reg_push)
791 nfp_prog->subprog[i].stack_depth += BPF_REG_SIZE * 4;
792 }
793
794 nn = netdev_priv(env->prog->aux->offload->netdev);
795 max_stack = nn_readb(nn, NFP_NET_CFG_BPF_STACK_SZ) * 64;
796 nfp_prog->stack_size = nfp_bpf_get_stack_usage(nfp_prog);
797 if (nfp_prog->stack_size > max_stack) {
798 pr_vlog(env, "stack too large: program %dB > FW stack %dB\n",
799 nfp_prog->stack_size, max_stack);
800 return -EOPNOTSUPP;
801 }
802
803 nfp_bpf_insn_flag_zext(nfp_prog, env->insn_aux_data);
804 return 0;
805 }
806
nfp_bpf_opt_replace_insn(struct bpf_verifier_env * env,u32 off,struct bpf_insn * insn)807 int nfp_bpf_opt_replace_insn(struct bpf_verifier_env *env, u32 off,
808 struct bpf_insn *insn)
809 {
810 struct nfp_prog *nfp_prog = env->prog->aux->offload->dev_priv;
811 struct bpf_insn_aux_data *aux_data = env->insn_aux_data;
812 struct nfp_insn_meta *meta = nfp_prog->verifier_meta;
813
814 meta = nfp_bpf_goto_meta(nfp_prog, meta, aux_data[off].orig_idx);
815 nfp_prog->verifier_meta = meta;
816
817 /* conditional jump to jump conversion */
818 if (is_mbpf_cond_jump(meta) &&
819 insn->code == (BPF_JMP | BPF_JA | BPF_K)) {
820 unsigned int tgt_off;
821
822 tgt_off = off + insn->off + 1;
823
824 if (!insn->off) {
825 meta->jmp_dst = list_next_entry(meta, l);
826 meta->jump_neg_op = false;
827 } else if (meta->jmp_dst->n != aux_data[tgt_off].orig_idx) {
828 pr_vlog(env, "branch hard wire at %d changes target %d -> %d\n",
829 off, meta->jmp_dst->n,
830 aux_data[tgt_off].orig_idx);
831 return -EINVAL;
832 }
833 return 0;
834 }
835
836 pr_vlog(env, "unsupported instruction replacement %hhx -> %hhx\n",
837 meta->insn.code, insn->code);
838 return -EINVAL;
839 }
840
nfp_bpf_opt_remove_insns(struct bpf_verifier_env * env,u32 off,u32 cnt)841 int nfp_bpf_opt_remove_insns(struct bpf_verifier_env *env, u32 off, u32 cnt)
842 {
843 struct nfp_prog *nfp_prog = env->prog->aux->offload->dev_priv;
844 struct bpf_insn_aux_data *aux_data = env->insn_aux_data;
845 struct nfp_insn_meta *meta = nfp_prog->verifier_meta;
846 unsigned int i;
847
848 meta = nfp_bpf_goto_meta(nfp_prog, meta, aux_data[off].orig_idx);
849
850 for (i = 0; i < cnt; i++) {
851 if (WARN_ON_ONCE(&meta->l == &nfp_prog->insns))
852 return -EINVAL;
853
854 /* doesn't count if it already has the flag */
855 if (meta->flags & FLAG_INSN_SKIP_VERIFIER_OPT)
856 i--;
857
858 meta->flags |= FLAG_INSN_SKIP_VERIFIER_OPT;
859 meta = list_next_entry(meta, l);
860 }
861
862 return 0;
863 }
864