1 // SPDX-License-Identifier: GPL-2.0
2 #include "arm64-frame-pointer-unwind-support.h"
3 #include "callchain.h"
4 #include "event.h"
5 #include "perf_regs.h" // SMPL_REG_MASK
6 #include "unwind.h"
7 
8 #define perf_event_arm_regs perf_event_arm64_regs
9 #include "../../arch/arm64/include/uapi/asm/perf_regs.h"
10 #undef perf_event_arm_regs
11 
12 struct entries {
13 	u64 stack[2];
14 	size_t length;
15 };
16 
17 static bool get_leaf_frame_caller_enabled(struct perf_sample *sample)
18 {
19 	return callchain_param.record_mode == CALLCHAIN_FP && sample->user_regs.regs
20 		&& sample->user_regs.mask & SMPL_REG_MASK(PERF_REG_ARM64_LR);
21 }
22 
23 static int add_entry(struct unwind_entry *entry, void *arg)
24 {
25 	struct entries *entries = arg;
26 
27 	entries->stack[entries->length++] = entry->ip;
28 	return 0;
29 }
30 
31 u64 get_leaf_frame_caller_aarch64(struct perf_sample *sample, struct thread *thread, int usr_idx)
32 {
33 	int ret;
34 	struct entries entries = {};
35 	struct regs_dump old_regs = sample->user_regs;
36 
37 	if (!get_leaf_frame_caller_enabled(sample))
38 		return 0;
39 
40 	/*
41 	 * If PC and SP are not recorded, get the value of PC from the stack
42 	 * and set its mask. SP is not used when doing the unwinding but it
43 	 * still needs to be set to prevent failures.
44 	 */
45 
46 	if (!(sample->user_regs.mask & SMPL_REG_MASK(PERF_REG_ARM64_PC))) {
47 		sample->user_regs.cache_mask |= SMPL_REG_MASK(PERF_REG_ARM64_PC);
48 		sample->user_regs.cache_regs[PERF_REG_ARM64_PC] = sample->callchain->ips[usr_idx+1];
49 	}
50 
51 	if (!(sample->user_regs.mask & SMPL_REG_MASK(PERF_REG_ARM64_SP))) {
52 		sample->user_regs.cache_mask |= SMPL_REG_MASK(PERF_REG_ARM64_SP);
53 		sample->user_regs.cache_regs[PERF_REG_ARM64_SP] = 0;
54 	}
55 
56 	ret = unwind__get_entries(add_entry, &entries, thread, sample, 2);
57 	sample->user_regs = old_regs;
58 
59 	if (ret || entries.length != 2)
60 		return ret;
61 
62 	return callchain_param.order == ORDER_CALLER ? entries.stack[0] : entries.stack[1];
63 }
64