summaryrefslogtreecommitdiff
path: root/arch/mn10300/kernel/module.c
blob: 6aea7fd76993b931f31f2dda76e72aecc1e31b4d (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
/* MN10300 Kernel module helper routines
 *
 * Copyright (C) 2007, 2008, 2009 Red Hat, Inc. All Rights Reserved.
 * Written by Mark Salter (msalter@redhat.com)
 * - Derived from arch/i386/kernel/module.c
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public Licence as published by
 * the Free Software Foundation; either version 2 of the Licence, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public Licence for more details.
 *
 * You should have received a copy of the GNU General Public Licence
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */
#include <linux/moduleloader.h>
#include <linux/elf.h>
#include <linux/vmalloc.h>
#include <linux/fs.h>
#include <linux/string.h>
#include <linux/kernel.h>
#include <linux/bug.h>

#if 0
#define DEBUGP printk
#else
#define DEBUGP(fmt, ...)
#endif

/*
 * allocate storage for a module
 */
void *module_alloc(unsigned long size)
{
	if (size == 0)
		return NULL;
	return vmalloc_exec(size);
}

/*
 * free memory returned from module_alloc()
 */
void module_free(struct module *mod, void *module_region)
{
	vfree(module_region);
}

/*
 * allow the arch to fix up the section table
 * - we don't need anything special
 */
int module_frob_arch_sections(Elf_Ehdr *hdr,
			      Elf_Shdr *sechdrs,
			      char *secstrings,
			      struct module *mod)
{
	return 0;
}

static void reloc_put16(uint8_t *p, uint32_t val)
{
	p[0] = val & 0xff;
	p[1] = (val >> 8) & 0xff;
}

static void reloc_put24(uint8_t *p, uint32_t val)
{
	reloc_put16(p, val);
	p[2] = (val >> 16) & 0xff;
}

static void reloc_put32(uint8_t *p, uint32_t val)
{
	reloc_put16(p, val);
	reloc_put16(p+2, val >> 16);
}

/*
 * apply a REL relocation
 */
int apply_relocate(Elf32_Shdr *sechdrs,
		   const char *strtab,
		   unsigned int symindex,
		   unsigned int relsec,
		   struct module *me)
{
	printk(KERN_ERR "module %s: RELOCATION unsupported\n",
	       me->name);
	return -ENOEXEC;
}

/*
 * apply a RELA relocation
 */
int apply_relocate_add(Elf32_Shdr *sechdrs,
		       const char *strtab,
		       unsigned int symindex,
		       unsigned int relsec,
		       struct module *me)
{
	unsigned int i, sym_diff_seen = 0;
	Elf32_Rela *rel = (void *)sechdrs[relsec].sh_addr;
	Elf32_Sym *sym;
	Elf32_Addr relocation, sym_diff_val = 0;
	uint8_t *location;
	uint32_t value;

	DEBUGP("Applying relocate section %u to %u\n",
	       relsec, sechdrs[relsec].sh_info);

	for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
		/* this is where to make the change */
		location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
			+ rel[i].r_offset;

		/* this is the symbol the relocation is referring to (note that
		 * all undefined symbols have been resolved by the caller) */
		sym = (Elf32_Sym *)sechdrs[symindex].sh_addr
			+ ELF32_R_SYM(rel[i].r_info);

		/* this is the adjustment to be made */
		relocation = sym->st_value + rel[i].r_addend;

		if (sym_diff_seen) {
			switch (ELF32_R_TYPE(rel[i].r_info)) {
			case R_MN10300_32:
			case R_MN10300_24:
			case R_MN10300_16:
			case R_MN10300_8:
				relocation -= sym_diff_val;
				sym_diff_seen = 0;
				break;
			default:
				printk(KERN_ERR "module %s: Unexpected SYM_DIFF relocation: %u\n",
				       me->name, ELF32_R_TYPE(rel[i].r_info));
				return -ENOEXEC;
			}
		}

		switch (ELF32_R_TYPE(rel[i].r_info)) {
			/* for the first four relocation types, we simply
			 * store the adjustment at the location given */
		case R_MN10300_32:
			reloc_put32(location, relocation);
			break;
		case R_MN10300_24:
			reloc_put24(location, relocation);
			break;
		case R_MN10300_16:
			reloc_put16(location, relocation);
			break;
		case R_MN10300_8:
			*location = relocation;
			break;

			/* for the next three relocation types, we write the
			 * adjustment with the address subtracted over the
			 * value at the location given */
		case R_MN10300_PCREL32:
			value = relocation - (uint32_t) location;
			reloc_put32(location, value);
			break;
		case R_MN10300_PCREL16:
			value = relocation - (uint32_t) location;
			reloc_put16(location, value);
			break;
		case R_MN10300_PCREL8:
			*location = relocation - (uint32_t) location;
			break;

		case R_MN10300_SYM_DIFF:
			/* This is used to adjust the next reloc as required
			 * by relaxation. */
			sym_diff_seen = 1;
			sym_diff_val = sym->st_value;
			break;

		case R_MN10300_ALIGN:
			/* Just ignore the ALIGN relocs.
			 * Only interesting if kernel performed relaxation. */
			continue;

		default:
			printk(KERN_ERR "module %s: Unknown relocation: %u\n",
			       me->name, ELF32_R_TYPE(rel[i].r_info));
			return -ENOEXEC;
		}
	}
	if (sym_diff_seen) {
		printk(KERN_ERR "module %s: Nothing follows SYM_DIFF relocation: %u\n",
				       me->name, ELF32_R_TYPE(rel[i].r_info));
		return -ENOEXEC;
	}
	return 0;
}

/*
 * finish loading the module
 */
int module_finalize(const Elf_Ehdr *hdr,
		    const Elf_Shdr *sechdrs,
		    struct module *me)
{
	return module_bug_finalize(hdr, sechdrs, me);
}

/*
 * finish clearing the module
 */
void module_arch_cleanup(struct module *mod)
{
	module_bug_cleanup(mod);
}