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189 lines · 4.9 KiB

1/*
2 * arch/xtensa/kernel/module.c
3 *
4 * Module support.
5 *
6 * This file is subject to the terms and conditions of the GNU General Public
7 * License. See the file "COPYING" in the main directory of this archive
8 * for more details.
9 *
10 * Copyright (C) 2001 - 2006 Tensilica Inc.
11 *
12 * Chris Zankel <[email protected]>
13 *
14 */
15
16#include <linux/module.h>
17#include <linux/moduleloader.h>
18#include <linux/elf.h>
19#include <linux/vmalloc.h>
20#include <linux/fs.h>
21#include <linux/string.h>
22#include <linux/kernel.h>
23#include <linux/cache.h>
24
25static int
26decode_calln_opcode (unsigned char *location)
27{
28#ifdef __XTENSA_EB__
29 return (location[0] & 0xf0) == 0x50;
30#endif
31#ifdef __XTENSA_EL__
32 return (location[0] & 0xf) == 0x5;
33#endif
34}
35
36static int
37decode_l32r_opcode (unsigned char *location)
38{
39#ifdef __XTENSA_EB__
40 return (location[0] & 0xf0) == 0x10;
41#endif
42#ifdef __XTENSA_EL__
43 return (location[0] & 0xf) == 0x1;
44#endif
45}
46
47int apply_relocate_add(Elf32_Shdr *sechdrs,
48 const char *strtab,
49 unsigned int symindex,
50 unsigned int relsec,
51 struct module *mod)
52{
53 unsigned int i;
54 Elf32_Rela *rela = (void *)sechdrs[relsec].sh_addr;
55 Elf32_Sym *sym;
56 unsigned char *location;
57 uint32_t value;
58
59 pr_debug("Applying relocate section %u to %u\n", relsec,
60 sechdrs[relsec].sh_info);
61
62 for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rela); i++) {
63 location = (char *)sechdrs[sechdrs[relsec].sh_info].sh_addr
64 + rela[i].r_offset;
65 sym = (Elf32_Sym *)sechdrs[symindex].sh_addr
66 + ELF32_R_SYM(rela[i].r_info);
67 value = sym->st_value + rela[i].r_addend;
68
69 switch (ELF32_R_TYPE(rela[i].r_info)) {
70 case R_XTENSA_NONE:
71 case R_XTENSA_DIFF8:
72 case R_XTENSA_DIFF16:
73 case R_XTENSA_DIFF32:
74 case R_XTENSA_ASM_EXPAND:
75 break;
76
77 case R_XTENSA_32:
78 case R_XTENSA_PLT:
79 *(uint32_t *)location += value;
80 break;
81
82 case R_XTENSA_SLOT0_OP:
83 if (decode_calln_opcode(location)) {
84 value -= ((unsigned long)location & -4) + 4;
85 if ((value & 3) != 0 ||
86 ((value + (1 << 19)) >> 20) != 0) {
87 pr_err("%s: relocation out of range, "
88 "section %d reloc %d "
89 "sym '%s'\n",
90 mod->name, relsec, i,
91 strtab + sym->st_name);
92 return -ENOEXEC;
93 }
94 value = (signed int)value >> 2;
95#ifdef __XTENSA_EB__
96 location[0] = ((location[0] & ~0x3) |
97 ((value >> 16) & 0x3));
98 location[1] = (value >> 8) & 0xff;
99 location[2] = value & 0xff;
100#endif
101#ifdef __XTENSA_EL__
102 location[0] = ((location[0] & ~0xc0) |
103 ((value << 6) & 0xc0));
104 location[1] = (value >> 2) & 0xff;
105 location[2] = (value >> 10) & 0xff;
106#endif
107 } else if (decode_l32r_opcode(location)) {
108 value -= (((unsigned long)location + 3) & -4);
109 if ((value & 3) != 0 ||
110 (signed int)value >> 18 != -1) {
111 pr_err("%s: relocation out of range, "
112 "section %d reloc %d "
113 "sym '%s'\n",
114 mod->name, relsec, i,
115 strtab + sym->st_name);
116 return -ENOEXEC;
117 }
118 value = (signed int)value >> 2;
119
120#ifdef __XTENSA_EB__
121 location[1] = (value >> 8) & 0xff;
122 location[2] = value & 0xff;
123#endif
124#ifdef __XTENSA_EL__
125 location[1] = value & 0xff;
126 location[2] = (value >> 8) & 0xff;
127#endif
128 }
129 /* FIXME: Ignore any other opcodes. The Xtensa
130 assembler currently assumes that the linker will
131 always do relaxation and so all PC-relative
132 operands need relocations. (The assembler also
133 writes out the tentative PC-relative values,
134 assuming no link-time relaxation, so it is usually
135 safe to ignore the relocations.) If the
136 assembler's "--no-link-relax" flag can be made to
137 work, and if all kernel modules can be assembled
138 with that flag, then unexpected relocations could
139 be detected here. */
140 break;
141
142 case R_XTENSA_SLOT1_OP:
143 case R_XTENSA_SLOT2_OP:
144 case R_XTENSA_SLOT3_OP:
145 case R_XTENSA_SLOT4_OP:
146 case R_XTENSA_SLOT5_OP:
147 case R_XTENSA_SLOT6_OP:
148 case R_XTENSA_SLOT7_OP:
149 case R_XTENSA_SLOT8_OP:
150 case R_XTENSA_SLOT9_OP:
151 case R_XTENSA_SLOT10_OP:
152 case R_XTENSA_SLOT11_OP:
153 case R_XTENSA_SLOT12_OP:
154 case R_XTENSA_SLOT13_OP:
155 case R_XTENSA_SLOT14_OP:
156 pr_err("%s: unexpected FLIX relocation: %u\n",
157 mod->name,
158 ELF32_R_TYPE(rela[i].r_info));
159 return -ENOEXEC;
160
161 case R_XTENSA_SLOT0_ALT:
162 case R_XTENSA_SLOT1_ALT:
163 case R_XTENSA_SLOT2_ALT:
164 case R_XTENSA_SLOT3_ALT:
165 case R_XTENSA_SLOT4_ALT:
166 case R_XTENSA_SLOT5_ALT:
167 case R_XTENSA_SLOT6_ALT:
168 case R_XTENSA_SLOT7_ALT:
169 case R_XTENSA_SLOT8_ALT:
170 case R_XTENSA_SLOT9_ALT:
171 case R_XTENSA_SLOT10_ALT:
172 case R_XTENSA_SLOT11_ALT:
173 case R_XTENSA_SLOT12_ALT:
174 case R_XTENSA_SLOT13_ALT:
175 case R_XTENSA_SLOT14_ALT:
176 pr_err("%s: unexpected ALT relocation: %u\n",
177 mod->name,
178 ELF32_R_TYPE(rela[i].r_info));
179 return -ENOEXEC;
180
181 default:
182 pr_err("%s: unexpected relocation: %u\n",
183 mod->name,
184 ELF32_R_TYPE(rela[i].r_info));
185 return -ENOEXEC;
186 }
187 }
188 return 0;
189}