1 /* 2 * This program is free software; you can redistribute it and/or modify 3 * it under the terms of the GNU General Public License, version 2, as 4 * published by the Free Software Foundation. 5 * 6 * Copyright (C) 2015 Naveen N. Rao, IBM Corporation 7 */ 8 9 #include "debug.h" 10 #include "symbol.h" 11 #include "map.h" 12 #include "probe-event.h" 13 #include "probe-file.h" 14 15 #ifdef HAVE_LIBELF_SUPPORT 16 bool elf__needs_adjust_symbols(GElf_Ehdr ehdr) 17 { 18 return ehdr.e_type == ET_EXEC || 19 ehdr.e_type == ET_REL || 20 ehdr.e_type == ET_DYN; 21 } 22 23 #endif 24 25 int arch__choose_best_symbol(struct symbol *syma, 26 struct symbol *symb __maybe_unused) 27 { 28 char *sym = syma->name; 29 30 #if !defined(_CALL_ELF) || _CALL_ELF != 2 31 /* Skip over any initial dot */ 32 if (*sym == '.') 33 sym++; 34 #endif 35 36 /* Avoid "SyS" kernel syscall aliases */ 37 if (strlen(sym) >= 3 && !strncmp(sym, "SyS", 3)) 38 return SYMBOL_B; 39 if (strlen(sym) >= 10 && !strncmp(sym, "compat_SyS", 10)) 40 return SYMBOL_B; 41 42 return SYMBOL_A; 43 } 44 45 #if !defined(_CALL_ELF) || _CALL_ELF != 2 46 /* Allow matching against dot variants */ 47 int arch__compare_symbol_names(const char *namea, const char *nameb) 48 { 49 /* Skip over initial dot */ 50 if (*namea == '.') 51 namea++; 52 if (*nameb == '.') 53 nameb++; 54 55 return strcmp(namea, nameb); 56 } 57 58 int arch__compare_symbol_names_n(const char *namea, const char *nameb, 59 unsigned int n) 60 { 61 /* Skip over initial dot */ 62 if (*namea == '.') 63 namea++; 64 if (*nameb == '.') 65 nameb++; 66 67 return strncmp(namea, nameb, n); 68 } 69 70 const char *arch__normalize_symbol_name(const char *name) 71 { 72 /* Skip over initial dot */ 73 if (name && *name == '.') 74 name++; 75 return name; 76 } 77 #endif 78 79 #if defined(_CALL_ELF) && _CALL_ELF == 2 80 81 #ifdef HAVE_LIBELF_SUPPORT 82 void arch__sym_update(struct symbol *s, GElf_Sym *sym) 83 { 84 s->arch_sym = sym->st_other; 85 } 86 #endif 87 88 #define PPC64LE_LEP_OFFSET 8 89 90 void arch__fix_tev_from_maps(struct perf_probe_event *pev, 91 struct probe_trace_event *tev, struct map *map, 92 struct symbol *sym) 93 { 94 int lep_offset; 95 96 /* 97 * When probing at a function entry point, we normally always want the 98 * LEP since that catches calls to the function through both the GEP and 99 * the LEP. Hence, we would like to probe at an offset of 8 bytes if 100 * the user only specified the function entry. 101 * 102 * However, if the user specifies an offset, we fall back to using the 103 * GEP since all userspace applications (objdump/readelf) show function 104 * disassembly with offsets from the GEP. 105 */ 106 if (pev->point.offset || !map || !sym) 107 return; 108 109 /* For kretprobes, add an offset only if the kernel supports it */ 110 if (!pev->uprobes && pev->point.retprobe) { 111 #ifdef HAVE_LIBELF_SUPPORT 112 if (!kretprobe_offset_is_supported()) 113 #endif 114 return; 115 } 116 117 lep_offset = PPC64_LOCAL_ENTRY_OFFSET(sym->arch_sym); 118 119 if (map->dso->symtab_type == DSO_BINARY_TYPE__KALLSYMS) 120 tev->point.offset += PPC64LE_LEP_OFFSET; 121 else if (lep_offset) { 122 if (pev->uprobes) 123 tev->point.address += lep_offset; 124 else 125 tev->point.offset += lep_offset; 126 } 127 } 128 129 #ifdef HAVE_LIBELF_SUPPORT 130 void arch__post_process_probe_trace_events(struct perf_probe_event *pev, 131 int ntevs) 132 { 133 struct probe_trace_event *tev; 134 struct map *map; 135 struct symbol *sym = NULL; 136 struct rb_node *tmp; 137 int i = 0; 138 139 map = get_target_map(pev->target, pev->nsi, pev->uprobes); 140 if (!map || map__load(map) < 0) 141 return; 142 143 for (i = 0; i < ntevs; i++) { 144 tev = &pev->tevs[i]; 145 map__for_each_symbol(map, sym, tmp) { 146 if (map->unmap_ip(map, sym->start) == tev->point.address) { 147 arch__fix_tev_from_maps(pev, tev, map, sym); 148 break; 149 } 150 } 151 } 152 } 153 #endif /* HAVE_LIBELF_SUPPORT */ 154 155 #endif 156