1/* Copyright (C) 2000-2015 Free Software Foundation, Inc. 2 Contributed by Richard Henderson <rth@cygnus.com>. 3 4 This file is part of GCC. 5 6 GCC is free software; you can redistribute it and/or modify 7 it under the terms of the GNU General Public License as published by 8 the Free Software Foundation; either version 3, or (at your option) 9 any later version. 10 11 GCC is distributed in the hope that it will be useful, 12 but WITHOUT ANY WARRANTY; without even the implied warranty of 13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 GNU General Public License for more details. 15 16 Under Section 7 of GPL version 3, you are granted additional 17 permissions described in the GCC Runtime Library Exception, version 18 3.1, as published by the Free Software Foundation. 19 20 You should have received a copy of the GNU General Public License and 21 a copy of the GCC Runtime Library Exception along with this program; 22 see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 23 <http://www.gnu.org/licenses/>. */ 24 25/* Locate the FDE entry for a given address, using glibc ld.so routines 26 to avoid register/deregister calls at DSO load/unload. */ 27 28#ifndef _GNU_SOURCE 29#define _GNU_SOURCE 1 30#endif 31#include "config.h" 32#include <stddef.h> 33#include <stdlib.h> 34#include <link.h> 35#include "unwind-ia64.h" 36 37#if __GLIBC__ < 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ < 2) \ 38 || (__GLIBC__ == 2 && __GLIBC_MINOR__ == 2 && !defined(DT_CONFIG)) 39# error You need GLIBC 2.2.4 or later on IA-64 Linux 40#endif 41 42struct unw_ia64_callback_data 43{ 44 Elf64_Addr pc; 45 unsigned long *segment_base; 46 unsigned long *gp; 47 struct unw_table_entry *ret; 48}; 49 50static int 51_Unwind_IteratePhdrCallback (struct dl_phdr_info *info, size_t size, void *ptr) 52{ 53 struct unw_ia64_callback_data *data = (struct unw_ia64_callback_data *) ptr; 54 const Elf64_Phdr *phdr, *p_unwind, *p_dynamic; 55 long n, match; 56 Elf64_Addr load_base, seg_base; 57 struct unw_table_entry *f_base, *f; 58 size_t lo, hi; 59 60 /* Make sure struct dl_phdr_info is at least as big as we need. */ 61 if (size < offsetof (struct dl_phdr_info, dlpi_phnum) 62 + sizeof (info->dlpi_phnum)) 63 return -1; 64 65 match = 0; 66 phdr = info->dlpi_phdr; 67 load_base = info->dlpi_addr; 68 p_unwind = NULL; 69 p_dynamic = NULL; 70 seg_base = ~(Elf64_Addr) 0; 71 72 /* See if PC falls into one of the loaded segments. Find the unwind 73 segment at the same time. */ 74 for (n = info->dlpi_phnum; --n >= 0; phdr++) 75 { 76 if (phdr->p_type == PT_LOAD) 77 { 78 Elf64_Addr vaddr = phdr->p_vaddr + load_base; 79 if (data->pc >= vaddr && data->pc < vaddr + phdr->p_memsz) 80 match = 1; 81 if (vaddr < seg_base) 82 seg_base = vaddr; 83 } 84 else if (phdr->p_type == PT_IA_64_UNWIND) 85 p_unwind = phdr; 86 else if (phdr->p_type == PT_DYNAMIC) 87 p_dynamic = phdr; 88 } 89 if (!match || !p_unwind) 90 return 0; 91 92 /* Search for the FDE within the unwind segment. */ 93 94 f_base = (struct unw_table_entry *) (p_unwind->p_vaddr + load_base); 95 lo = 0; 96 hi = p_unwind->p_memsz / sizeof (struct unw_table_entry); 97 98 while (lo < hi) 99 { 100 size_t mid = (lo + hi) / 2; 101 102 f = f_base + mid; 103 if (data->pc < f->start_offset + seg_base) 104 hi = mid; 105 else if (data->pc >= f->end_offset + seg_base) 106 lo = mid + 1; 107 else 108 goto found; 109 } 110 /* No need to search for further libraries when we know pc is contained 111 in this library. */ 112 return 1; 113 114 found: 115 *data->segment_base = seg_base; 116 *data->gp = 0; 117 data->ret = f; 118 119 if (p_dynamic) 120 { 121 /* For dynamically linked executables and shared libraries, 122 DT_PLTGOT is the gp value for that object. */ 123 Elf64_Dyn *dyn = (Elf64_Dyn *)(p_dynamic->p_vaddr + load_base); 124 for (; dyn->d_tag != DT_NULL ; dyn++) 125 if (dyn->d_tag == DT_PLTGOT) 126 { 127 /* On IA-64, _DYNAMIC is writable and GLIBC has relocated it. */ 128 *data->gp = dyn->d_un.d_ptr; 129 break; 130 } 131 } 132 else 133 { 134 /* Otherwise this is a static executable with no _DYNAMIC. 135 The gp is constant program-wide. */ 136 register unsigned long gp __asm__("gp"); 137 *data->gp = gp; 138 } 139 140 return 1; 141} 142 143/* Return a pointer to the unwind table entry for the function 144 containing PC. */ 145 146struct unw_table_entry * 147_Unwind_FindTableEntry (void *pc, unw_word *segment_base, unw_word *gp, 148 struct unw_table_entry *ent ATTRIBUTE_UNUSED) 149{ 150 struct unw_ia64_callback_data data; 151 152 data.pc = (Elf64_Addr) pc; 153 data.segment_base = segment_base; 154 data.gp = gp; 155 data.ret = NULL; 156 157 if (dl_iterate_phdr (_Unwind_IteratePhdrCallback, &data) < 0) 158 return NULL; 159 160 return data.ret; 161} 162