1 /* Copyright (C) 2000-2022 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 #ifndef inhibit_libc 33 #include <stddef.h> 34 #include <stdlib.h> 35 #include <link.h> 36 #include "unwind-ia64.h" 37 38 #if __GLIBC__ < 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ < 2) \ 39 || (__GLIBC__ == 2 && __GLIBC_MINOR__ == 2 && !defined(DT_CONFIG)) 40 # error You need GLIBC 2.2.4 or later on IA-64 Linux 41 #endif 42 43 struct unw_ia64_callback_data 44 { 45 Elf64_Addr pc; 46 unsigned long *segment_base; 47 unsigned long *gp; 48 struct unw_table_entry *ret; 49 }; 50 51 static int 52 _Unwind_IteratePhdrCallback (struct dl_phdr_info *info, size_t size, void *ptr) 53 { 54 struct unw_ia64_callback_data *data = (struct unw_ia64_callback_data *) ptr; 55 const Elf64_Phdr *phdr, *p_unwind, *p_dynamic; 56 long n, match; 57 Elf64_Addr load_base, seg_base; 58 struct unw_table_entry *f_base, *f; 59 size_t lo, hi; 60 61 /* Make sure struct dl_phdr_info is at least as big as we need. */ 62 if (size < offsetof (struct dl_phdr_info, dlpi_phnum) 63 + sizeof (info->dlpi_phnum)) 64 return -1; 65 66 match = 0; 67 phdr = info->dlpi_phdr; 68 load_base = info->dlpi_addr; 69 p_unwind = NULL; 70 p_dynamic = NULL; 71 seg_base = ~(Elf64_Addr) 0; 72 73 /* See if PC falls into one of the loaded segments. Find the unwind 74 segment at the same time. */ 75 for (n = info->dlpi_phnum; --n >= 0; phdr++) 76 { 77 if (phdr->p_type == PT_LOAD) 78 { 79 Elf64_Addr vaddr = phdr->p_vaddr + load_base; 80 if (data->pc >= vaddr && data->pc < vaddr + phdr->p_memsz) 81 match = 1; 82 if (vaddr < seg_base) 83 seg_base = vaddr; 84 } 85 else if (phdr->p_type == PT_IA_64_UNWIND) 86 p_unwind = phdr; 87 else if (phdr->p_type == PT_DYNAMIC) 88 p_dynamic = phdr; 89 } 90 if (!match || !p_unwind) 91 return 0; 92 93 /* Search for the FDE within the unwind segment. */ 94 95 f_base = (struct unw_table_entry *) (p_unwind->p_vaddr + load_base); 96 lo = 0; 97 hi = p_unwind->p_memsz / sizeof (struct unw_table_entry); 98 99 while (lo < hi) 100 { 101 size_t mid = (lo + hi) / 2; 102 103 f = f_base + mid; 104 if (data->pc < f->start_offset + seg_base) 105 hi = mid; 106 else if (data->pc >= f->end_offset + seg_base) 107 lo = mid + 1; 108 else 109 goto found; 110 } 111 /* No need to search for further libraries when we know pc is contained 112 in this library. */ 113 return 1; 114 115 found: 116 *data->segment_base = seg_base; 117 *data->gp = 0; 118 data->ret = f; 119 120 if (p_dynamic) 121 { 122 /* For dynamically linked executables and shared libraries, 123 DT_PLTGOT is the gp value for that object. */ 124 Elf64_Dyn *dyn = (Elf64_Dyn *)(p_dynamic->p_vaddr + load_base); 125 for (; dyn->d_tag != DT_NULL ; dyn++) 126 if (dyn->d_tag == DT_PLTGOT) 127 { 128 /* On IA-64, _DYNAMIC is writable and GLIBC has relocated it. */ 129 *data->gp = dyn->d_un.d_ptr; 130 break; 131 } 132 } 133 else 134 { 135 /* Otherwise this is a static executable with no _DYNAMIC. 136 The gp is constant program-wide. */ 137 register unsigned long gp __asm__("gp"); 138 *data->gp = gp; 139 } 140 141 return 1; 142 } 143 144 /* Return a pointer to the unwind table entry for the function 145 containing PC. */ 146 147 struct unw_table_entry * 148 _Unwind_FindTableEntry (void *pc, unw_word *segment_base, unw_word *gp, 149 struct unw_table_entry *ent ATTRIBUTE_UNUSED) 150 { 151 struct unw_ia64_callback_data data; 152 153 data.pc = (Elf64_Addr) pc; 154 data.segment_base = segment_base; 155 data.gp = gp; 156 data.ret = NULL; 157 158 if (dl_iterate_phdr (_Unwind_IteratePhdrCallback, &data) < 0) 159 return NULL; 160 161 return data.ret; 162 } 163 #endif 164