1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 *
4 * Copyright (C) 2015 Naveen N. Rao, IBM Corporation
5 */
6
7#include "dso.h"
8#include "symbol.h"
9#include "map.h"
10#include "probe-event.h"
11#include "probe-file.h"
12
13int arch__choose_best_symbol(struct symbol *syma,
14			     struct symbol *symb __maybe_unused)
15{
16	char *sym = syma->name;
17
18#if !defined(_CALL_ELF) || _CALL_ELF != 2
19	/* Skip over any initial dot */
20	if (*sym == '.')
21		sym++;
22#endif
23
24	/* Avoid "SyS" kernel syscall aliases */
25	if (strlen(sym) >= 3 && !strncmp(sym, "SyS", 3))
26		return SYMBOL_B;
27	if (strlen(sym) >= 10 && !strncmp(sym, "compat_SyS", 10))
28		return SYMBOL_B;
29
30	return SYMBOL_A;
31}
32
33#if !defined(_CALL_ELF) || _CALL_ELF != 2
34/* Allow matching against dot variants */
35int arch__compare_symbol_names(const char *namea, const char *nameb)
36{
37	/* Skip over initial dot */
38	if (*namea == '.')
39		namea++;
40	if (*nameb == '.')
41		nameb++;
42
43	return strcmp(namea, nameb);
44}
45
46int arch__compare_symbol_names_n(const char *namea, const char *nameb,
47				 unsigned int n)
48{
49	/* Skip over initial dot */
50	if (*namea == '.')
51		namea++;
52	if (*nameb == '.')
53		nameb++;
54
55	return strncmp(namea, nameb, n);
56}
57
58const char *arch__normalize_symbol_name(const char *name)
59{
60	/* Skip over initial dot */
61	if (name && *name == '.')
62		name++;
63	return name;
64}
65#endif
66
67#if defined(_CALL_ELF) && _CALL_ELF == 2
68
69#ifdef HAVE_LIBELF_SUPPORT
70void arch__sym_update(struct symbol *s, GElf_Sym *sym)
71{
72	s->arch_sym = sym->st_other;
73}
74#endif
75
76#define PPC64LE_LEP_OFFSET	8
77
78void arch__fix_tev_from_maps(struct perf_probe_event *pev,
79			     struct probe_trace_event *tev, struct map *map,
80			     struct symbol *sym)
81{
82	int lep_offset;
83
84	/*
85	 * When probing at a function entry point, we normally always want the
86	 * LEP since that catches calls to the function through both the GEP and
87	 * the LEP. Hence, we would like to probe at an offset of 8 bytes if
88	 * the user only specified the function entry.
89	 *
90	 * However, if the user specifies an offset, we fall back to using the
91	 * GEP since all userspace applications (objdump/readelf) show function
92	 * disassembly with offsets from the GEP.
93	 */
94	if (pev->point.offset || !map || !sym)
95		return;
96
97	/* For kretprobes, add an offset only if the kernel supports it */
98	if (!pev->uprobes && pev->point.retprobe) {
99#ifdef HAVE_LIBELF_SUPPORT
100		if (!kretprobe_offset_is_supported())
101#endif
102			return;
103	}
104
105	lep_offset = PPC64_LOCAL_ENTRY_OFFSET(sym->arch_sym);
106
107	if (map__dso(map)->symtab_type == DSO_BINARY_TYPE__KALLSYMS)
108		tev->point.offset += PPC64LE_LEP_OFFSET;
109	else if (lep_offset) {
110		if (pev->uprobes)
111			tev->point.address += lep_offset;
112		else
113			tev->point.offset += lep_offset;
114	}
115}
116
117#ifdef HAVE_LIBELF_SUPPORT
118void arch__post_process_probe_trace_events(struct perf_probe_event *pev,
119					   int ntevs)
120{
121	struct probe_trace_event *tev;
122	struct map *map;
123	struct symbol *sym = NULL;
124	struct rb_node *tmp;
125	int i = 0;
126
127	map = get_target_map(pev->target, pev->nsi, pev->uprobes);
128	if (!map || map__load(map) < 0)
129		return;
130
131	for (i = 0; i < ntevs; i++) {
132		tev = &pev->tevs[i];
133		map__for_each_symbol(map, sym, tmp) {
134			if (map__unmap_ip(map, sym->start) == tev->point.address) {
135				arch__fix_tev_from_maps(pev, tev, map, sym);
136				break;
137			}
138		}
139	}
140}
141#endif /* HAVE_LIBELF_SUPPORT */
142
143#endif
144