1 // SPDX-License-Identifier: GPL-2.0
2
3 #include <linux/bpf.h>
4 #include <bpf/bpf_helpers.h>
5 #include "bpf_misc.h"
6
7 /* Check that precision marks propagate through scalar IDs.
8 * Registers r{0,1,2} have the same scalar ID at the moment when r0 is
9 * marked to be precise, this mark is immediately propagated to r{1,2}.
10 */
11 SEC("socket")
12 __success __log_level(2)
13 __msg("frame0: regs=r0,r1,r2 stack= before 4: (bf) r3 = r10")
14 __msg("frame0: regs=r0,r1,r2 stack= before 3: (bf) r2 = r0")
15 __msg("frame0: regs=r0,r1 stack= before 2: (bf) r1 = r0")
16 __msg("frame0: regs=r0 stack= before 1: (57) r0 &= 255")
17 __msg("frame0: regs=r0 stack= before 0: (85) call bpf_ktime_get_ns")
18 __flag(BPF_F_TEST_STATE_FREQ)
19 __naked void precision_same_state(void)
20 {
21 asm volatile (
22 /* r0 = random number up to 0xff */
23 "call %[bpf_ktime_get_ns];"
24 "r0 &= 0xff;"
25 /* tie r0.id == r1.id == r2.id */
26 "r1 = r0;"
27 "r2 = r0;"
28 /* force r0 to be precise, this immediately marks r1 and r2 as
29 * precise as well because of shared IDs
30 */
31 "r3 = r10;"
32 "r3 += r0;"
33 "r0 = 0;"
34 "exit;"
35 :
36 : __imm(bpf_ktime_get_ns)
37 : __clobber_all);
38 }
39
40 /* Same as precision_same_state, but mark propagates through state /
41 * parent state boundary.
42 */
43 SEC("socket")
44 __success __log_level(2)
45 __msg("frame0: last_idx 6 first_idx 5 subseq_idx -1")
46 __msg("frame0: regs=r0,r1,r2 stack= before 5: (bf) r3 = r10")
47 __msg("frame0: parent state regs=r0,r1,r2 stack=:")
48 __msg("frame0: regs=r0,r1,r2 stack= before 4: (05) goto pc+0")
49 __msg("frame0: regs=r0,r1,r2 stack= before 3: (bf) r2 = r0")
50 __msg("frame0: regs=r0,r1 stack= before 2: (bf) r1 = r0")
51 __msg("frame0: regs=r0 stack= before 1: (57) r0 &= 255")
52 __msg("frame0: parent state regs=r0 stack=:")
53 __msg("frame0: regs=r0 stack= before 0: (85) call bpf_ktime_get_ns")
54 __flag(BPF_F_TEST_STATE_FREQ)
55 __naked void precision_cross_state(void)
56 {
57 asm volatile (
58 /* r0 = random number up to 0xff */
59 "call %[bpf_ktime_get_ns];"
60 "r0 &= 0xff;"
61 /* tie r0.id == r1.id == r2.id */
62 "r1 = r0;"
63 "r2 = r0;"
64 /* force checkpoint */
65 "goto +0;"
66 /* force r0 to be precise, this immediately marks r1 and r2 as
67 * precise as well because of shared IDs
68 */
69 "r3 = r10;"
70 "r3 += r0;"
71 "r0 = 0;"
72 "exit;"
73 :
74 : __imm(bpf_ktime_get_ns)
75 : __clobber_all);
76 }
77
78 /* Same as precision_same_state, but break one of the
79 * links, note that r1 is absent from regs=... in __msg below.
80 */
81 SEC("socket")
82 __success __log_level(2)
83 __msg("frame0: regs=r0,r2 stack= before 5: (bf) r3 = r10")
84 __msg("frame0: regs=r0,r2 stack= before 4: (b7) r1 = 0")
85 __msg("frame0: regs=r0,r2 stack= before 3: (bf) r2 = r0")
86 __msg("frame0: regs=r0 stack= before 2: (bf) r1 = r0")
87 __msg("frame0: regs=r0 stack= before 1: (57) r0 &= 255")
88 __msg("frame0: regs=r0 stack= before 0: (85) call bpf_ktime_get_ns")
89 __flag(BPF_F_TEST_STATE_FREQ)
90 __naked void precision_same_state_broken_link(void)
91 {
92 asm volatile (
93 /* r0 = random number up to 0xff */
94 "call %[bpf_ktime_get_ns];"
95 "r0 &= 0xff;"
96 /* tie r0.id == r1.id == r2.id */
97 "r1 = r0;"
98 "r2 = r0;"
99 /* break link for r1, this is the only line that differs
100 * compared to the previous test
101 */
102 "r1 = 0;"
103 /* force r0 to be precise, this immediately marks r1 and r2 as
104 * precise as well because of shared IDs
105 */
106 "r3 = r10;"
107 "r3 += r0;"
108 "r0 = 0;"
109 "exit;"
110 :
111 : __imm(bpf_ktime_get_ns)
112 : __clobber_all);
113 }
114
115 /* Same as precision_same_state_broken_link, but with state /
116 * parent state boundary.
117 */
118 SEC("socket")
119 __success __log_level(2)
120 __msg("frame0: regs=r0,r2 stack= before 6: (bf) r3 = r10")
121 __msg("frame0: regs=r0,r2 stack= before 5: (b7) r1 = 0")
122 __msg("frame0: parent state regs=r0,r2 stack=:")
123 __msg("frame0: regs=r0,r1,r2 stack= before 4: (05) goto pc+0")
124 __msg("frame0: regs=r0,r1,r2 stack= before 3: (bf) r2 = r0")
125 __msg("frame0: regs=r0,r1 stack= before 2: (bf) r1 = r0")
126 __msg("frame0: regs=r0 stack= before 1: (57) r0 &= 255")
127 __msg("frame0: parent state regs=r0 stack=:")
128 __msg("frame0: regs=r0 stack= before 0: (85) call bpf_ktime_get_ns")
129 __flag(BPF_F_TEST_STATE_FREQ)
130 __naked void precision_cross_state_broken_link(void)
131 {
132 asm volatile (
133 /* r0 = random number up to 0xff */
134 "call %[bpf_ktime_get_ns];"
135 "r0 &= 0xff;"
136 /* tie r0.id == r1.id == r2.id */
137 "r1 = r0;"
138 "r2 = r0;"
139 /* force checkpoint, although link between r1 and r{0,2} is
140 * broken by the next statement current precision tracking
141 * algorithm can't react to it and propagates mark for r1 to
142 * the parent state.
143 */
144 "goto +0;"
145 /* break link for r1, this is the only line that differs
146 * compared to precision_cross_state()
147 */
148 "r1 = 0;"
149 /* force r0 to be precise, this immediately marks r1 and r2 as
150 * precise as well because of shared IDs
151 */
152 "r3 = r10;"
153 "r3 += r0;"
154 "r0 = 0;"
155 "exit;"
156 :
157 : __imm(bpf_ktime_get_ns)
158 : __clobber_all);
159 }
160
161 /* Check that precision marks propagate through scalar IDs.
162 * Use the same scalar ID in multiple stack frames, check that
163 * precision information is propagated up the call stack.
164 */
165 SEC("socket")
166 __success __log_level(2)
167 __msg("11: (0f) r2 += r1")
168 /* Current state */
169 __msg("frame2: last_idx 11 first_idx 10 subseq_idx -1")
170 __msg("frame2: regs=r1 stack= before 10: (bf) r2 = r10")
171 __msg("frame2: parent state regs=r1 stack=")
172 /* frame1.r{6,7} are marked because mark_precise_scalar_ids()
173 * looks for all registers with frame2.r1.id in the current state
174 */
175 __msg("frame1: parent state regs=r6,r7 stack=")
176 __msg("frame0: parent state regs=r6 stack=")
177 /* Parent state */
178 __msg("frame2: last_idx 8 first_idx 8 subseq_idx 10")
179 __msg("frame2: regs=r1 stack= before 8: (85) call pc+1")
180 /* frame1.r1 is marked because of backtracking of call instruction */
181 __msg("frame1: parent state regs=r1,r6,r7 stack=")
182 __msg("frame0: parent state regs=r6 stack=")
183 /* Parent state */
184 __msg("frame1: last_idx 7 first_idx 6 subseq_idx 8")
185 __msg("frame1: regs=r1,r6,r7 stack= before 7: (bf) r7 = r1")
186 __msg("frame1: regs=r1,r6 stack= before 6: (bf) r6 = r1")
187 __msg("frame1: parent state regs=r1 stack=")
188 __msg("frame0: parent state regs=r6 stack=")
189 /* Parent state */
190 __msg("frame1: last_idx 4 first_idx 4 subseq_idx 6")
191 __msg("frame1: regs=r1 stack= before 4: (85) call pc+1")
192 __msg("frame0: parent state regs=r1,r6 stack=")
193 /* Parent state */
194 __msg("frame0: last_idx 3 first_idx 1 subseq_idx 4")
195 __msg("frame0: regs=r0,r1,r6 stack= before 3: (bf) r6 = r0")
196 __msg("frame0: regs=r0,r1 stack= before 2: (bf) r1 = r0")
197 __msg("frame0: regs=r0 stack= before 1: (57) r0 &= 255")
198 __flag(BPF_F_TEST_STATE_FREQ)
199 __naked void precision_many_frames(void)
200 {
201 asm volatile (
202 /* r0 = random number up to 0xff */
203 "call %[bpf_ktime_get_ns];"
204 "r0 &= 0xff;"
205 /* tie r0.id == r1.id == r6.id */
206 "r1 = r0;"
207 "r6 = r0;"
208 "call precision_many_frames__foo;"
209 "exit;"
210 :
211 : __imm(bpf_ktime_get_ns)
212 : __clobber_all);
213 }
214
215 static __naked __noinline __used
216 void precision_many_frames__foo(void)
217 {
218 asm volatile (
219 /* conflate one of the register numbers (r6) with outer frame,
220 * to verify that those are tracked independently
221 */
222 "r6 = r1;"
223 "r7 = r1;"
224 "call precision_many_frames__bar;"
225 "exit"
226 ::: __clobber_all);
227 }
228
229 static __naked __noinline __used
230 void precision_many_frames__bar(void)
231 {
232 asm volatile (
233 /* force r1 to be precise, this immediately marks:
234 * - bar frame r1
235 * - foo frame r{1,6,7}
236 * - main frame r{1,6}
237 */
238 "r2 = r10;"
239 "r2 += r1;"
240 "r0 = 0;"
241 "exit;"
242 ::: __clobber_all);
243 }
244
245 /* Check that scalars with the same IDs are marked precise on stack as
246 * well as in registers.
247 */
248 SEC("socket")
249 __success __log_level(2)
250 /* foo frame */
251 __msg("frame1: regs=r1 stack=-8,-16 before 9: (bf) r2 = r10")
252 __msg("frame1: regs=r1 stack=-8,-16 before 8: (7b) *(u64 *)(r10 -16) = r1")
253 __msg("frame1: regs=r1 stack=-8 before 7: (7b) *(u64 *)(r10 -8) = r1")
254 __msg("frame1: regs=r1 stack= before 4: (85) call pc+2")
255 /* main frame */
256 __msg("frame0: regs=r0,r1 stack=-8 before 3: (7b) *(u64 *)(r10 -8) = r1")
257 __msg("frame0: regs=r0,r1 stack= before 2: (bf) r1 = r0")
258 __msg("frame0: regs=r0 stack= before 1: (57) r0 &= 255")
259 __flag(BPF_F_TEST_STATE_FREQ)
260 __naked void precision_stack(void)
261 {
262 asm volatile (
263 /* r0 = random number up to 0xff */
264 "call %[bpf_ktime_get_ns];"
265 "r0 &= 0xff;"
266 /* tie r0.id == r1.id == fp[-8].id */
267 "r1 = r0;"
268 "*(u64*)(r10 - 8) = r1;"
269 "call precision_stack__foo;"
270 "r0 = 0;"
271 "exit;"
272 :
273 : __imm(bpf_ktime_get_ns)
274 : __clobber_all);
275 }
276
277 static __naked __noinline __used
278 void precision_stack__foo(void)
279 {
280 asm volatile (
281 /* conflate one of the register numbers (r6) with outer frame,
282 * to verify that those are tracked independently
283 */
284 "*(u64*)(r10 - 8) = r1;"
285 "*(u64*)(r10 - 16) = r1;"
286 /* force r1 to be precise, this immediately marks:
287 * - foo frame r1,fp{-8,-16}
288 * - main frame r1,fp{-8}
289 */
290 "r2 = r10;"
291 "r2 += r1;"
292 "exit"
293 ::: __clobber_all);
294 }
295
296 /* Use two separate scalar IDs to check that these are propagated
297 * independently.
298 */
299 SEC("socket")
300 __success __log_level(2)
301 /* r{6,7} */
302 __msg("11: (0f) r3 += r7")
303 __msg("frame0: regs=r6,r7 stack= before 10: (bf) r3 = r10")
304 /* ... skip some insns ... */
305 __msg("frame0: regs=r6,r7 stack= before 3: (bf) r7 = r0")
306 __msg("frame0: regs=r0,r6 stack= before 2: (bf) r6 = r0")
307 /* r{8,9} */
308 __msg("12: (0f) r3 += r9")
309 __msg("frame0: regs=r8,r9 stack= before 11: (0f) r3 += r7")
310 /* ... skip some insns ... */
311 __msg("frame0: regs=r8,r9 stack= before 7: (bf) r9 = r0")
312 __msg("frame0: regs=r0,r8 stack= before 6: (bf) r8 = r0")
313 __flag(BPF_F_TEST_STATE_FREQ)
314 __naked void precision_two_ids(void)
315 {
316 asm volatile (
317 /* r6 = random number up to 0xff
318 * r6.id == r7.id
319 */
320 "call %[bpf_ktime_get_ns];"
321 "r0 &= 0xff;"
322 "r6 = r0;"
323 "r7 = r0;"
324 /* same, but for r{8,9} */
325 "call %[bpf_ktime_get_ns];"
326 "r0 &= 0xff;"
327 "r8 = r0;"
328 "r9 = r0;"
329 /* clear r0 id */
330 "r0 = 0;"
331 /* force checkpoint */
332 "goto +0;"
333 "r3 = r10;"
334 /* force r7 to be precise, this also marks r6 */
335 "r3 += r7;"
336 /* force r9 to be precise, this also marks r8 */
337 "r3 += r9;"
338 "exit;"
339 :
340 : __imm(bpf_ktime_get_ns)
341 : __clobber_all);
342 }
343
344 /* Verify that check_ids() is used by regsafe() for scalars.
345 *
346 * r9 = ... some pointer with range X ...
347 * r6 = ... unbound scalar ID=a ...
348 * r7 = ... unbound scalar ID=b ...
349 * if (r6 > r7) goto +1
350 * r7 = r6
351 * if (r7 > X) goto exit
352 * r9 += r6
353 * ... access memory using r9 ...
354 *
355 * The memory access is safe only if r7 is bounded,
356 * which is true for one branch and not true for another.
357 */
358 SEC("socket")
359 __failure __msg("register with unbounded min value")
360 __flag(BPF_F_TEST_STATE_FREQ)
361 __naked void check_ids_in_regsafe(void)
362 {
363 asm volatile (
364 /* Bump allocated stack */
365 "r1 = 0;"
366 "*(u64*)(r10 - 8) = r1;"
367 /* r9 = pointer to stack */
368 "r9 = r10;"
369 "r9 += -8;"
370 /* r7 = ktime_get_ns() */
371 "call %[bpf_ktime_get_ns];"
372 "r7 = r0;"
373 /* r6 = ktime_get_ns() */
374 "call %[bpf_ktime_get_ns];"
375 "r6 = r0;"
376 /* if r6 > r7 is an unpredictable jump */
377 "if r6 > r7 goto l1_%=;"
378 "r7 = r6;"
379 "l1_%=:"
380 /* if r7 > 4 ...; transfers range to r6 on one execution path
381 * but does not transfer on another
382 */
383 "if r7 > 4 goto l2_%=;"
384 /* Access memory at r9[r6], r6 is not always bounded */
385 "r9 += r6;"
386 "r0 = *(u8*)(r9 + 0);"
387 "l2_%=:"
388 "r0 = 0;"
389 "exit;"
390 :
391 : __imm(bpf_ktime_get_ns)
392 : __clobber_all);
393 }
394
395 /* Similar to check_ids_in_regsafe.
396 * The l0 could be reached in two states:
397 *
398 * (1) r6{.id=A}, r7{.id=A}, r8{.id=B}
399 * (2) r6{.id=B}, r7{.id=A}, r8{.id=B}
400 *
401 * Where (2) is not safe, as "r7 > 4" check won't propagate range for it.
402 * This example would be considered safe without changes to
403 * mark_chain_precision() to track scalar values with equal IDs.
404 */
405 SEC("socket")
406 __failure __msg("register with unbounded min value")
407 __flag(BPF_F_TEST_STATE_FREQ)
408 __naked void check_ids_in_regsafe_2(void)
409 {
410 asm volatile (
411 /* Bump allocated stack */
412 "r1 = 0;"
413 "*(u64*)(r10 - 8) = r1;"
414 /* r9 = pointer to stack */
415 "r9 = r10;"
416 "r9 += -8;"
417 /* r8 = ktime_get_ns() */
418 "call %[bpf_ktime_get_ns];"
419 "r8 = r0;"
420 /* r7 = ktime_get_ns() */
421 "call %[bpf_ktime_get_ns];"
422 "r7 = r0;"
423 /* r6 = ktime_get_ns() */
424 "call %[bpf_ktime_get_ns];"
425 "r6 = r0;"
426 /* scratch .id from r0 */
427 "r0 = 0;"
428 /* if r6 > r7 is an unpredictable jump */
429 "if r6 > r7 goto l1_%=;"
430 /* tie r6 and r7 .id */
431 "r6 = r7;"
432 "l0_%=:"
433 /* if r7 > 4 exit(0) */
434 "if r7 > 4 goto l2_%=;"
435 /* Access memory at r9[r6] */
436 "r9 += r6;"
437 "r0 = *(u8*)(r9 + 0);"
438 "l2_%=:"
439 "r0 = 0;"
440 "exit;"
441 "l1_%=:"
442 /* tie r6 and r8 .id */
443 "r6 = r8;"
444 "goto l0_%=;"
445 :
446 : __imm(bpf_ktime_get_ns)
447 : __clobber_all);
448 }
449
450 /* Check that scalar IDs *are not* generated on register to register
451 * assignments if source register is a constant.
452 *
453 * If such IDs *are* generated the 'l1' below would be reached in
454 * two states:
455 *
456 * (1) r1{.id=A}, r2{.id=A}
457 * (2) r1{.id=C}, r2{.id=C}
458 *
459 * Thus forcing 'if r1 == r2' verification twice.
460 */
461 SEC("socket")
462 __success __log_level(2)
463 __msg("11: (1d) if r3 == r4 goto pc+0")
464 __msg("frame 0: propagating r3,r4")
465 __msg("11: safe")
466 __msg("processed 15 insns")
467 __flag(BPF_F_TEST_STATE_FREQ)
468 __naked void no_scalar_id_for_const(void)
469 {
470 asm volatile (
471 "call %[bpf_ktime_get_ns];"
472 /* unpredictable jump */
473 "if r0 > 7 goto l0_%=;"
474 /* possibly generate same scalar ids for r3 and r4 */
475 "r1 = 0;"
476 "r1 = r1;"
477 "r3 = r1;"
478 "r4 = r1;"
479 "goto l1_%=;"
480 "l0_%=:"
481 /* possibly generate different scalar ids for r3 and r4 */
482 "r1 = 0;"
483 "r2 = 0;"
484 "r3 = r1;"
485 "r4 = r2;"
486 "l1_%=:"
487 /* predictable jump, marks r3 and r4 precise */
488 "if r3 == r4 goto +0;"
489 "r0 = 0;"
490 "exit;"
491 :
492 : __imm(bpf_ktime_get_ns)
493 : __clobber_all);
494 }
495
496 /* Same as no_scalar_id_for_const() but for 32-bit values */
497 SEC("socket")
498 __success __log_level(2)
499 __msg("11: (1e) if w3 == w4 goto pc+0")
500 __msg("frame 0: propagating r3,r4")
501 __msg("11: safe")
502 __msg("processed 15 insns")
503 __flag(BPF_F_TEST_STATE_FREQ)
504 __naked void no_scalar_id_for_const32(void)
505 {
506 asm volatile (
507 "call %[bpf_ktime_get_ns];"
508 /* unpredictable jump */
509 "if r0 > 7 goto l0_%=;"
510 /* possibly generate same scalar ids for r3 and r4 */
511 "w1 = 0;"
512 "w1 = w1;"
513 "w3 = w1;"
514 "w4 = w1;"
515 "goto l1_%=;"
516 "l0_%=:"
517 /* possibly generate different scalar ids for r3 and r4 */
518 "w1 = 0;"
519 "w2 = 0;"
520 "w3 = w1;"
521 "w4 = w2;"
522 "l1_%=:"
523 /* predictable jump, marks r1 and r2 precise */
524 "if w3 == w4 goto +0;"
525 "r0 = 0;"
526 "exit;"
527 :
528 : __imm(bpf_ktime_get_ns)
529 : __clobber_all);
530 }
531
532 /* Check that unique scalar IDs are ignored when new verifier state is
533 * compared to cached verifier state. For this test:
534 * - cached state has no id on r1
535 * - new state has a unique id on r1
536 */
537 SEC("socket")
538 __success __log_level(2)
539 __msg("6: (25) if r6 > 0x7 goto pc+1")
540 __msg("7: (57) r1 &= 255")
541 __msg("8: (bf) r2 = r10")
542 __msg("from 6 to 8: safe")
543 __msg("processed 12 insns")
544 __flag(BPF_F_TEST_STATE_FREQ)
545 __naked void ignore_unique_scalar_ids_cur(void)
546 {
547 asm volatile (
548 "call %[bpf_ktime_get_ns];"
549 "r6 = r0;"
550 "call %[bpf_ktime_get_ns];"
551 "r0 &= 0xff;"
552 /* r1.id == r0.id */
553 "r1 = r0;"
554 /* make r1.id unique */
555 "r0 = 0;"
556 "if r6 > 7 goto l0_%=;"
557 /* clear r1 id, but keep the range compatible */
558 "r1 &= 0xff;"
559 "l0_%=:"
560 /* get here in two states:
561 * - first: r1 has no id (cached state)
562 * - second: r1 has a unique id (should be considered equivalent)
563 */
564 "r2 = r10;"
565 "r2 += r1;"
566 "exit;"
567 :
568 : __imm(bpf_ktime_get_ns)
569 : __clobber_all);
570 }
571
572 /* Check that unique scalar IDs are ignored when new verifier state is
573 * compared to cached verifier state. For this test:
574 * - cached state has a unique id on r1
575 * - new state has no id on r1
576 */
577 SEC("socket")
578 __success __log_level(2)
579 __msg("6: (25) if r6 > 0x7 goto pc+1")
580 __msg("7: (05) goto pc+1")
581 __msg("9: (bf) r2 = r10")
582 __msg("9: safe")
583 __msg("processed 13 insns")
584 __flag(BPF_F_TEST_STATE_FREQ)
585 __naked void ignore_unique_scalar_ids_old(void)
586 {
587 asm volatile (
588 "call %[bpf_ktime_get_ns];"
589 "r6 = r0;"
590 "call %[bpf_ktime_get_ns];"
591 "r0 &= 0xff;"
592 /* r1.id == r0.id */
593 "r1 = r0;"
594 /* make r1.id unique */
595 "r0 = 0;"
596 "if r6 > 7 goto l1_%=;"
597 "goto l0_%=;"
598 "l1_%=:"
599 /* clear r1 id, but keep the range compatible */
600 "r1 &= 0xff;"
601 "l0_%=:"
602 /* get here in two states:
603 * - first: r1 has a unique id (cached state)
604 * - second: r1 has no id (should be considered equivalent)
605 */
606 "r2 = r10;"
607 "r2 += r1;"
608 "exit;"
609 :
610 : __imm(bpf_ktime_get_ns)
611 : __clobber_all);
612 }
613
614 /* Check that two different scalar IDs in a verified state can't be
615 * mapped to the same scalar ID in current state.
616 */
617 SEC("socket")
618 __success __log_level(2)
619 /* The exit instruction should be reachable from two states,
620 * use two matches and "processed .. insns" to ensure this.
621 */
622 __msg("13: (95) exit")
623 __msg("13: (95) exit")
624 __msg("processed 18 insns")
625 __flag(BPF_F_TEST_STATE_FREQ)
626 __naked void two_old_ids_one_cur_id(void)
627 {
628 asm volatile (
629 /* Give unique scalar IDs to r{6,7} */
630 "call %[bpf_ktime_get_ns];"
631 "r0 &= 0xff;"
632 "r6 = r0;"
633 "call %[bpf_ktime_get_ns];"
634 "r0 &= 0xff;"
635 "r7 = r0;"
636 "r0 = 0;"
637 /* Maybe make r{6,7} IDs identical */
638 "if r6 > r7 goto l0_%=;"
639 "goto l1_%=;"
640 "l0_%=:"
641 "r6 = r7;"
642 "l1_%=:"
643 /* Mark r{6,7} precise.
644 * Get here in two states:
645 * - first: r6{.id=A}, r7{.id=B} (cached state)
646 * - second: r6{.id=A}, r7{.id=A}
647 * Currently we don't want to consider such states equivalent.
648 * Thus "exit;" would be verified twice.
649 */
650 "r2 = r10;"
651 "r2 += r6;"
652 "r2 += r7;"
653 "exit;"
654 :
655 : __imm(bpf_ktime_get_ns)
656 : __clobber_all);
657 }
658
659 char _license[] SEC("license") = "GPL";
660
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