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

   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
  13 int 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 */
  35 int 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
  46 int 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
  58 const 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
  70 void 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
  78 void 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->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
 118 void 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