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
  14#ifdef HAVE_LIBELF_SUPPORT
  15bool 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
  25int 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 */
  44int 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
  59void 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
  67void 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->uprobes && pev->point.retprobe) ||
  86            !map || !sym)
  87                return;
  88
  89        lep_offset = PPC64_LOCAL_ENTRY_OFFSET(sym->arch_sym);
  90
  91        if (map->dso->symtab_type == DSO_BINARY_TYPE__KALLSYMS)
  92                tev->point.offset += PPC64LE_LEP_OFFSET;
  93        else if (lep_offset) {
  94                if (pev->uprobes)
  95                        tev->point.address += lep_offset;
  96                else
  97                        tev->point.offset += lep_offset;
  98        }
  99}
 100
 101#ifdef HAVE_LIBELF_SUPPORT
 102void arch__post_process_probe_trace_events(struct perf_probe_event *pev,
 103                                           int ntevs)
 104{
 105        struct probe_trace_event *tev;
 106        struct map *map;
 107        struct symbol *sym = NULL;
 108        struct rb_node *tmp;
 109        int i = 0;
 110
 111        map = get_target_map(pev->target, pev->uprobes);
 112        if (!map || map__load(map) < 0)
 113                return;
 114
 115        for (i = 0; i < ntevs; i++) {
 116                tev = &pev->tevs[i];
 117                map__for_each_symbol(map, sym, tmp) {
 118                        if (map->unmap_ip(map, sym->start) == tev->point.address)
 119                                arch__fix_tev_from_maps(pev, tev, map, sym);
 120                }
 121        }
 122}
 123#endif /* HAVE_LIBELF_SUPPORT */
 124
 125#endif
 126