LXR linux/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
  13int 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 */
  35int 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
  46int 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
  58const 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
  70void 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
  78void 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
 118void 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
 144