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