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-rw-r--r--arch/mips/kernel/module-elf32.c250
1 files changed, 250 insertions, 0 deletions
diff --git a/arch/mips/kernel/module-elf32.c b/arch/mips/kernel/module-elf32.c
new file mode 100644
index 000000000000..ffd216d6d6dc
--- /dev/null
+++ b/arch/mips/kernel/module-elf32.c
@@ -0,0 +1,250 @@
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 as published by
4 * the Free Software Foundation; either version 2 of the License, or
5 * (at your option) any later version.
6 *
7 * This program is distributed in the hope that it will be useful,
8 * but WITHOUT ANY WARRANTY; without even the implied warranty of
9 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
10 * GNU General Public License for more details.
11 *
12 * You should have received a copy of the GNU General Public License
13 * along with this program; if not, write to the Free Software
14 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
15 *
16 * Copyright (C) 2001 Rusty Russell.
17 * Copyright (C) 2003, 2004 Ralf Baechle (ralf@linux-mips.org)
18 */
19
20#undef DEBUG
21
22#include <linux/moduleloader.h>
23#include <linux/elf.h>
24#include <linux/vmalloc.h>
25#include <linux/slab.h>
26#include <linux/fs.h>
27#include <linux/string.h>
28#include <linux/kernel.h>
29
30struct mips_hi16 {
31 struct mips_hi16 *next;
32 Elf32_Addr *addr;
33 Elf32_Addr value;
34};
35
36static struct mips_hi16 *mips_hi16_list;
37
38void *module_alloc(unsigned long size)
39{
40 if (size == 0)
41 return NULL;
42 return vmalloc(size);
43}
44
45
46/* Free memory returned from module_alloc */
47void module_free(struct module *mod, void *module_region)
48{
49 vfree(module_region);
50 /* FIXME: If module_region == mod->init_region, trim exception
51 table entries. */
52}
53
54int module_frob_arch_sections(Elf_Ehdr *hdr,
55 Elf_Shdr *sechdrs,
56 char *secstrings,
57 struct module *mod)
58{
59 return 0;
60}
61
62static int apply_r_mips_none(struct module *me, uint32_t *location,
63 Elf32_Addr v)
64{
65 return 0;
66}
67
68static int apply_r_mips_32(struct module *me, uint32_t *location,
69 Elf32_Addr v)
70{
71 *location += v;
72
73 return 0;
74}
75
76static int apply_r_mips_26(struct module *me, uint32_t *location,
77 Elf32_Addr v)
78{
79 if (v % 4) {
80 printk(KERN_ERR "module %s: dangerous relocation\n", me->name);
81 return -ENOEXEC;
82 }
83
84 if ((v & 0xf0000000) != (((unsigned long)location + 4) & 0xf0000000)) {
85 printk(KERN_ERR
86 "module %s: relocation overflow\n",
87 me->name);
88 return -ENOEXEC;
89 }
90
91 *location = (*location & ~0x03ffffff) |
92 ((*location + (v >> 2)) & 0x03ffffff);
93
94 return 0;
95}
96
97static int apply_r_mips_hi16(struct module *me, uint32_t *location,
98 Elf32_Addr v)
99{
100 struct mips_hi16 *n;
101
102 /*
103 * We cannot relocate this one now because we don't know the value of
104 * the carry we need to add. Save the information, and let LO16 do the
105 * actual relocation.
106 */
107 n = kmalloc(sizeof *n, GFP_KERNEL);
108 if (!n)
109 return -ENOMEM;
110
111 n->addr = location;
112 n->value = v;
113 n->next = mips_hi16_list;
114 mips_hi16_list = n;
115
116 return 0;
117}
118
119static int apply_r_mips_lo16(struct module *me, uint32_t *location,
120 Elf32_Addr v)
121{
122 unsigned long insnlo = *location;
123 Elf32_Addr val, vallo;
124
125 /* Sign extend the addend we extract from the lo insn. */
126 vallo = ((insnlo & 0xffff) ^ 0x8000) - 0x8000;
127
128 if (mips_hi16_list != NULL) {
129 struct mips_hi16 *l;
130
131 l = mips_hi16_list;
132 while (l != NULL) {
133 struct mips_hi16 *next;
134 unsigned long insn;
135
136 /*
137 * The value for the HI16 had best be the same.
138 */
139 if (v != l->value)
140 goto out_danger;
141
142 /*
143 * Do the HI16 relocation. Note that we actually don't
144 * need to know anything about the LO16 itself, except
145 * where to find the low 16 bits of the addend needed
146 * by the LO16.
147 */
148 insn = *l->addr;
149 val = ((insn & 0xffff) << 16) + vallo;
150 val += v;
151
152 /*
153 * Account for the sign extension that will happen in
154 * the low bits.
155 */
156 val = ((val >> 16) + ((val & 0x8000) != 0)) & 0xffff;
157
158 insn = (insn & ~0xffff) | val;
159 *l->addr = insn;
160
161 next = l->next;
162 kfree(l);
163 l = next;
164 }
165
166 mips_hi16_list = NULL;
167 }
168
169 /*
170 * Ok, we're done with the HI16 relocs. Now deal with the LO16.
171 */
172 val = v + vallo;
173 insnlo = (insnlo & ~0xffff) | (val & 0xffff);
174 *location = insnlo;
175
176 return 0;
177
178out_danger:
179 printk(KERN_ERR "module %s: dangerous " "relocation\n", me->name);
180
181 return -ENOEXEC;
182}
183
184static int (*reloc_handlers[]) (struct module *me, uint32_t *location,
185 Elf32_Addr v) = {
186 [R_MIPS_NONE] = apply_r_mips_none,
187 [R_MIPS_32] = apply_r_mips_32,
188 [R_MIPS_26] = apply_r_mips_26,
189 [R_MIPS_HI16] = apply_r_mips_hi16,
190 [R_MIPS_LO16] = apply_r_mips_lo16
191};
192
193int apply_relocate(Elf32_Shdr *sechdrs,
194 const char *strtab,
195 unsigned int symindex,
196 unsigned int relsec,
197 struct module *me)
198{
199 Elf32_Rel *rel = (void *) sechdrs[relsec].sh_addr;
200 Elf32_Sym *sym;
201 uint32_t *location;
202 unsigned int i;
203 Elf32_Addr v;
204 int res;
205
206 pr_debug("Applying relocate section %u to %u\n", relsec,
207 sechdrs[relsec].sh_info);
208
209 for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
210 Elf32_Word r_info = rel[i].r_info;
211
212 /* This is where to make the change */
213 location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
214 + rel[i].r_offset;
215 /* This is the symbol it is referring to */
216 sym = (Elf32_Sym *)sechdrs[symindex].sh_addr
217 + ELF32_R_SYM(r_info);
218 if (!sym->st_value) {
219 printk(KERN_WARNING "%s: Unknown symbol %s\n",
220 me->name, strtab + sym->st_name);
221 return -ENOENT;
222 }
223
224 v = sym->st_value;
225
226 res = reloc_handlers[ELF32_R_TYPE(r_info)](me, location, v);
227 if (res)
228 return res;
229 }
230
231 return 0;
232}
233
234int apply_relocate_add(Elf32_Shdr *sechdrs,
235 const char *strtab,
236 unsigned int symindex,
237 unsigned int relsec,
238 struct module *me)
239{
240 /*
241 * Current binutils always generate .rela relocations. Keep smiling
242 * if it's empty, abort otherwise.
243 */
244 if (!sechdrs[relsec].sh_size)
245 return 0;
246
247 printk(KERN_ERR "module %s: ADD RELOCATION unsupported\n",
248 me->name);
249 return -ENOEXEC;
250}