tools/perf/arch/powerpc/util/sym-handling.c

   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