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b920de1b DH |
1 | /* MN10300 Kernel module helper routines |
2 | * | |
5ae8606d | 3 | * Copyright (C) 2007, 2008, 2009 Red Hat, Inc. All Rights Reserved. |
b920de1b DH |
4 | * Written by Mark Salter (msalter@redhat.com) |
5 | * - Derived from arch/i386/kernel/module.c | |
6 | * | |
7 | * This program is free software; you can redistribute it and/or modify | |
8 | * it under the terms of the GNU General Public Licence as published by | |
9 | * the Free Software Foundation; either version 2 of the Licence, or | |
10 | * (at your option) any later version. | |
11 | * | |
12 | * This program is distributed in the hope that it will be useful, | |
13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
15 | * GNU General Public Licence for more details. | |
16 | * | |
17 | * You should have received a copy of the GNU General Public Licence | |
18 | * along with this program; if not, write to the Free Software | |
19 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA | |
20 | */ | |
21 | #include <linux/moduleloader.h> | |
22 | #include <linux/elf.h> | |
23 | #include <linux/vmalloc.h> | |
24 | #include <linux/fs.h> | |
25 | #include <linux/string.h> | |
26 | #include <linux/kernel.h> | |
18f6db95 | 27 | #include <linux/bug.h> |
b920de1b DH |
28 | |
29 | #if 0 | |
30 | #define DEBUGP printk | |
31 | #else | |
32 | #define DEBUGP(fmt, ...) | |
33 | #endif | |
34 | ||
b920de1b DH |
35 | static void reloc_put16(uint8_t *p, uint32_t val) |
36 | { | |
37 | p[0] = val & 0xff; | |
38 | p[1] = (val >> 8) & 0xff; | |
39 | } | |
40 | ||
41 | static void reloc_put24(uint8_t *p, uint32_t val) | |
42 | { | |
43 | reloc_put16(p, val); | |
44 | p[2] = (val >> 16) & 0xff; | |
45 | } | |
46 | ||
47 | static void reloc_put32(uint8_t *p, uint32_t val) | |
48 | { | |
49 | reloc_put16(p, val); | |
50 | reloc_put16(p+2, val >> 16); | |
51 | } | |
52 | ||
b920de1b DH |
53 | /* |
54 | * apply a RELA relocation | |
55 | */ | |
56 | int apply_relocate_add(Elf32_Shdr *sechdrs, | |
57 | const char *strtab, | |
58 | unsigned int symindex, | |
59 | unsigned int relsec, | |
60 | struct module *me) | |
61 | { | |
5ae8606d | 62 | unsigned int i, sym_diff_seen = 0; |
b920de1b DH |
63 | Elf32_Rela *rel = (void *)sechdrs[relsec].sh_addr; |
64 | Elf32_Sym *sym; | |
5ae8606d | 65 | Elf32_Addr relocation, sym_diff_val = 0; |
b920de1b DH |
66 | uint8_t *location; |
67 | uint32_t value; | |
68 | ||
69 | DEBUGP("Applying relocate section %u to %u\n", | |
70 | relsec, sechdrs[relsec].sh_info); | |
71 | ||
72 | for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) { | |
73 | /* this is where to make the change */ | |
74 | location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr | |
75 | + rel[i].r_offset; | |
76 | ||
77 | /* this is the symbol the relocation is referring to (note that | |
78 | * all undefined symbols have been resolved by the caller) */ | |
79 | sym = (Elf32_Sym *)sechdrs[symindex].sh_addr | |
80 | + ELF32_R_SYM(rel[i].r_info); | |
81 | ||
82 | /* this is the adjustment to be made */ | |
83 | relocation = sym->st_value + rel[i].r_addend; | |
84 | ||
5ae8606d MS |
85 | if (sym_diff_seen) { |
86 | switch (ELF32_R_TYPE(rel[i].r_info)) { | |
87 | case R_MN10300_32: | |
88 | case R_MN10300_24: | |
89 | case R_MN10300_16: | |
90 | case R_MN10300_8: | |
91 | relocation -= sym_diff_val; | |
92 | sym_diff_seen = 0; | |
93 | break; | |
94 | default: | |
95 | printk(KERN_ERR "module %s: Unexpected SYM_DIFF relocation: %u\n", | |
96 | me->name, ELF32_R_TYPE(rel[i].r_info)); | |
97 | return -ENOEXEC; | |
98 | } | |
99 | } | |
100 | ||
b920de1b | 101 | switch (ELF32_R_TYPE(rel[i].r_info)) { |
1122b19b MS |
102 | /* for the first four relocation types, we simply |
103 | * store the adjustment at the location given */ | |
b920de1b | 104 | case R_MN10300_32: |
1122b19b | 105 | reloc_put32(location, relocation); |
b920de1b DH |
106 | break; |
107 | case R_MN10300_24: | |
1122b19b | 108 | reloc_put24(location, relocation); |
b920de1b DH |
109 | break; |
110 | case R_MN10300_16: | |
1122b19b | 111 | reloc_put16(location, relocation); |
b920de1b DH |
112 | break; |
113 | case R_MN10300_8: | |
1122b19b | 114 | *location = relocation; |
b920de1b DH |
115 | break; |
116 | ||
117 | /* for the next three relocation types, we write the | |
118 | * adjustment with the address subtracted over the | |
119 | * value at the location given */ | |
120 | case R_MN10300_PCREL32: | |
121 | value = relocation - (uint32_t) location; | |
122 | reloc_put32(location, value); | |
123 | break; | |
124 | case R_MN10300_PCREL16: | |
125 | value = relocation - (uint32_t) location; | |
126 | reloc_put16(location, value); | |
127 | break; | |
128 | case R_MN10300_PCREL8: | |
129 | *location = relocation - (uint32_t) location; | |
130 | break; | |
131 | ||
5ae8606d MS |
132 | case R_MN10300_SYM_DIFF: |
133 | /* This is used to adjust the next reloc as required | |
134 | * by relaxation. */ | |
135 | sym_diff_seen = 1; | |
136 | sym_diff_val = sym->st_value; | |
137 | break; | |
138 | ||
139 | case R_MN10300_ALIGN: | |
140 | /* Just ignore the ALIGN relocs. | |
141 | * Only interesting if kernel performed relaxation. */ | |
142 | continue; | |
143 | ||
b920de1b DH |
144 | default: |
145 | printk(KERN_ERR "module %s: Unknown relocation: %u\n", | |
146 | me->name, ELF32_R_TYPE(rel[i].r_info)); | |
147 | return -ENOEXEC; | |
148 | } | |
149 | } | |
5ae8606d MS |
150 | if (sym_diff_seen) { |
151 | printk(KERN_ERR "module %s: Nothing follows SYM_DIFF relocation: %u\n", | |
152 | me->name, ELF32_R_TYPE(rel[i].r_info)); | |
153 | return -ENOEXEC; | |
154 | } | |
b920de1b DH |
155 | return 0; |
156 | } |