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
  14 #ifdef HAVE_LIBELF_SUPPORT
  15 bool elf__needs_adjust_symbols(GElf_Ehdr ehdr)
  16 {
  17         return ehdr.e_type == ET_EXEC ||
  18                ehdr.e_type == ET_REL ||
  19                ehdr.e_type == ET_DYN;
  20 }
  21
  22 #endif
  23
  24 #if !defined(_CALL_ELF) || _CALL_ELF != 2
  25 int arch__choose_best_symbol(struct symbol *syma,
  26                              struct symbol *symb __maybe_unused)
  27 {
  28         char *sym = syma->name;
  29
  30         /* Skip over any initial dot */
  31         if (*sym == '.')
  32                 sym++;
  33
  34         /* Avoid "SyS" kernel syscall aliases */
  35         if (strlen(sym) >= 3 && !strncmp(sym, "SyS", 3))
  36                 return SYMBOL_B;
  37         if (strlen(sym) >= 10 && !strncmp(sym, "compat_SyS", 10))
  38                 return SYMBOL_B;
  39
  40         return SYMBOL_A;
  41 }
  42
  43 /* Allow matching against dot variants */
  44 int arch__compare_symbol_names(const char *namea, const char *nameb)
  45 {
  46         /* Skip over initial dot */
  47         if (*namea == '.')
  48                 namea++;
  49         if (*nameb == '.')
  50                 nameb++;
  51
  52         return strcmp(namea, nameb);
  53 }
  54 #endif
  55
  56 #if defined(_CALL_ELF) && _CALL_ELF == 2
  57
  58 #ifdef HAVE_LIBELF_SUPPORT
  59 void arch__sym_update(struct symbol *s, GElf_Sym *sym)
  60 {
  61         s->arch_sym = sym->st_other;
  62 }
  63 #endif
  64
  65 #define PPC64LE_LEP_OFFSET      8
  66
  67 void arch__fix_tev_from_maps(struct perf_probe_event *pev,
  68                              struct probe_trace_event *tev, struct map *map,
  69                              struct symbol *sym)
  70 {
  71         int lep_offset;
  72
  73         /*
  74          * When probing at a function entry point, we normally always want the
  75          * LEP since that catches calls to the function through both the GEP and
  76          * the LEP. Hence, we would like to probe at an offset of 8 bytes if
  77          * the user only specified the function entry.
  78          *
  79          * However, if the user specifies an offset, we fall back to using the
  80          * GEP since all userspace applications (objdump/readelf) show function
  81          * disassembly with offsets from the GEP.
  82          *
  83          * In addition, we shouldn't specify an offset for kretprobes.
  84          */
  85         if (pev->point.offset || pev->point.retprobe || !map || !sym)
  86                 return;
  87
  88         lep_offset = PPC64_LOCAL_ENTRY_OFFSET(sym->arch_sym);
  89
  90         if (map->dso->symtab_type == DSO_BINARY_TYPE__KALLSYMS)
  91                 tev->point.offset += PPC64LE_LEP_OFFSET;
  92         else if (lep_offset) {
  93                 if (pev->uprobes)
  94                         tev->point.address += lep_offset;
  95                 else
  96                         tev->point.offset += lep_offset;
  97         }
  98 }
  99
 100 #ifdef HAVE_LIBELF_SUPPORT
 101 void arch__post_process_probe_trace_events(struct perf_probe_event *pev,
 102                                            int ntevs)
 103 {
 104         struct probe_trace_event *tev;
 105         struct map *map;
 106         struct symbol *sym = NULL;
 107         struct rb_node *tmp;
 108         int i = 0;
 109
 110         map = get_target_map(pev->target, pev->uprobes);
 111         if (!map || map__load(map, NULL) < 0)
 112                 return;
 113
 114         for (i = 0; i < ntevs; i++) {
 115                 tev = &pev->tevs[i];
 116                 map__for_each_symbol(map, sym, tmp) {
 117                         if (map->unmap_ip(map, sym->start) == tev->point.address)
 118                                 arch__fix_tev_from_maps(pev, tev, map, sym);
 119                 }
 120         }
 121 }
 122 #endif /* HAVE_LIBELF_SUPPORT */
 123
 124 #endif