1 // SPDX-License-Identifier: GPL-2.0
2 #include <string.h>
3 #include "perf_regs.h"
4 #include "thread.h"
5 #include "map.h"
6 #include "maps.h"
7 #include "event.h"
8 #include "debug.h"
9 #include "tests/tests.h"
10 
11 #define STACK_SIZE 8192
12 
13 static int sample_ustack(struct perf_sample *sample,
14 			 struct thread *thread, u64 *regs)
15 {
16 	struct stack_dump *stack = &sample->user_stack;
17 	struct map *map;
18 	unsigned long sp;
19 	u64 stack_size, *buf;
20 
21 	buf = malloc(STACK_SIZE);
22 	if (!buf) {
23 		pr_debug("failed to allocate sample uregs data\n");
24 		return -1;
25 	}
26 
27 	sp = (unsigned long) regs[PERF_REG_X86_SP];
28 
29 	map = maps__find(thread->maps, (u64)sp);
30 	if (!map) {
31 		pr_debug("failed to get stack map\n");
32 		free(buf);
33 		return -1;
34 	}
35 
36 	stack_size = map->end - sp;
37 	stack_size = stack_size > STACK_SIZE ? STACK_SIZE : stack_size;
38 
39 	memcpy(buf, (void *) sp, stack_size);
40 #ifdef MEMORY_SANITIZER
41 	/*
42 	 * Copying the stack may copy msan poison, avoid false positives in the
43 	 * unwinder by removing the poison here.
44 	 */
45 	__msan_unpoison(buf, stack_size);
46 #endif
47 	stack->data = (char *) buf;
48 	stack->size = stack_size;
49 	return 0;
50 }
51 
52 int test__arch_unwind_sample(struct perf_sample *sample,
53 			     struct thread *thread)
54 {
55 	struct regs_dump *regs = &sample->user_regs;
56 	u64 *buf;
57 
58 	buf = malloc(sizeof(u64) * PERF_REGS_MAX);
59 	if (!buf) {
60 		pr_debug("failed to allocate sample uregs data\n");
61 		return -1;
62 	}
63 
64 #ifdef MEMORY_SANITIZER
65 	/*
66 	 * Assignments to buf in the assembly function perf_regs_load aren't
67 	 * seen by memory sanitizer. Zero the memory to convince memory
68 	 * sanitizer the memory is initialized.
69 	 */
70 	memset(buf, 0, sizeof(u64) * PERF_REGS_MAX);
71 #endif
72 	perf_regs_load(buf);
73 	regs->abi  = PERF_SAMPLE_REGS_ABI;
74 	regs->regs = buf;
75 	regs->mask = PERF_REGS_MASK;
76 
77 	return sample_ustack(sample, thread, buf);
78 }
79