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1 | /* Copyright (C) 2000 Free Software Foundation, Inc. |
2 | Contributed by Richard Henderson <rth@cygnus.com>. | |
3 | ||
4 | This file is part of GNU CC. | |
5 | ||
6 | GNU CC 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 2, or (at your option) | |
9 | any later version. | |
10 | ||
11 | GNU CC 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 | You should have received a copy of the GNU General Public License | |
17 | along with GNU CC; see the file COPYING. If not, write to | |
18 | the Free Software Foundation, 59 Temple Place - Suite 330, | |
19 | Boston, MA 02111-1307, USA. */ | |
20 | ||
21 | /* As a special exception, if you link this library with other files, | |
22 | some of which are compiled with GCC, to produce an executable, | |
23 | this library does not by itself cause the resulting executable | |
24 | to be covered by the GNU General Public License. | |
25 | This exception does not however invalidate any other reasons why | |
26 | the executable file might be covered by the GNU General Public License. */ | |
27 | ||
28 | /* Locate the FDE entry for a given address, using glibc ld.so routines | |
29 | to avoid register/deregister calls at DSO load/unload. */ | |
30 | ||
31 | #include <stdlib.h> | |
32 | #include <link.h> | |
33 | #include <bits/libc-lock.h> | |
34 | #include "frame-ia64.h" | |
35 | ||
36 | ||
37 | /* Initialized by crtbegin from the main application. */ | |
38 | extern Elf64_Ehdr *__ia64_app_header; | |
39 | ||
40 | /* ??? A redeclaration of the lock in ld.so. Perhaps this should | |
41 | appear in <link.h> in a new glibc version. */ | |
42 | __libc_lock_define (extern, _dl_load_lock) | |
43 | ||
44 | /* ??? _dl_load_lock is not exported from glibc 2.1, but it is | |
45 | from glibc 2.2. Remove this when folks have migrated. */ | |
46 | #pragma weak _dl_load_lock | |
47 | ||
48 | /* This always exists, even in a static application. */ | |
49 | extern struct link_map *_dl_loaded; | |
50 | ||
51 | static fde * | |
52 | find_fde_for_dso (Elf64_Addr pc, Elf64_Ehdr *ehdr) | |
53 | { | |
54 | Elf64_Phdr *phdr, *p_unwind; | |
55 | long n, match; | |
56 | Elf64_Addr load_base, seg_base; | |
57 | fde *f; | |
58 | ||
59 | /* Verify that we are looking at an ELF header. */ | |
60 | if (ehdr->e_ident[0] != 0x7f | |
61 | || ehdr->e_ident[1] != 'E' | |
62 | || ehdr->e_ident[2] != 'L' | |
63 | || ehdr->e_ident[3] != 'F' | |
64 | || ehdr->e_ident[EI_CLASS] != ELFCLASS64 | |
65 | || ehdr->e_ident[EI_DATA] != ELFDATA2LSB | |
66 | || ehdr->e_machine != EM_IA_64) | |
67 | abort (); | |
68 | ||
69 | match = 0; | |
70 | phdr = (Elf64_Phdr *)((char *)ehdr + ehdr->e_phoff); | |
71 | load_base = (ehdr->e_type == ET_DYN ? (Elf64_Addr)ehdr : 0); | |
72 | p_unwind = NULL; | |
73 | ||
74 | /* See if PC falls into one of the loaded segments. Find the unwind | |
75 | segment at the same time. */ | |
76 | for (n = ehdr->e_phnum; --n >= 0; phdr++) | |
77 | { | |
78 | if (phdr->p_type == PT_LOAD) | |
79 | { | |
80 | Elf64_Addr vaddr = phdr->p_vaddr + load_base; | |
81 | if (pc >= vaddr && pc < vaddr + phdr->p_memsz) | |
82 | match = 1; | |
83 | } | |
84 | else if (phdr->p_type == PT_IA_64_UNWIND) | |
85 | p_unwind = phdr; | |
86 | } | |
87 | if (!match || !p_unwind) | |
88 | return NULL; | |
89 | ||
90 | /* Search for the FDE within the unwind segment. */ | |
91 | /* ??? Ideally ld would have sorted this for us by address. Until | |
92 | that's fixed, we must do a linear search. */ | |
93 | ||
94 | f = (fde *) (p_unwind->p_vaddr + load_base); | |
95 | seg_base = (Elf64_Addr) ehdr; | |
96 | for (n = p_unwind->p_memsz / sizeof (fde); --n >= 0; ++f) | |
97 | if (pc >= f->start_offset + seg_base && pc < f->end_offset + seg_base) | |
98 | return f; | |
99 | ||
100 | return NULL; | |
101 | } | |
102 | ||
103 | /* Return a pointer to the FDE for the function containing PC. */ | |
104 | fde * | |
105 | __ia64_find_fde (void *pc, void **pc_base) | |
106 | { | |
107 | fde *ret; | |
108 | struct link_map *map; | |
109 | ||
110 | /* Check the main application first, hoping that most of the user's | |
111 | code is there instead of in some library. */ | |
112 | ret = find_fde_for_dso ((Elf64_Addr)pc, __ia64_app_header); | |
113 | if (ret) | |
114 | { | |
115 | *pc_base = __ia64_app_header; | |
116 | return ret; | |
117 | } | |
118 | ||
119 | /* Glibc is probably unique in that we can (with certain restrictions) | |
120 | dynamicly load libraries into staticly linked applications. Thus | |
121 | we _always_ check _dl_loaded. */ | |
122 | ||
123 | if (&_dl_load_lock) | |
124 | __libc_lock_lock (_dl_load_lock); | |
125 | ||
126 | for (map = _dl_loaded; map ; map = map->l_next) | |
127 | { | |
128 | /* Skip the main application's entry. */ | |
129 | if (map->l_name[0] == 0) | |
130 | continue; | |
131 | ret = find_fde_for_dso ((Elf64_Addr)pc, (Elf64_Ehdr *)map->l_addr); | |
132 | if (ret) | |
133 | break; | |
134 | } | |
135 | ||
136 | if (&_dl_load_lock) | |
137 | __libc_lock_unlock (_dl_load_lock); | |
138 | ||
139 | *pc_base = (void *)(map ? map->l_addr : 0); | |
140 | return ret; | |
141 | } |