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 *  Copyright (C) 2005 Thiemo Seufer
19 */
20
21#include <linux/elf.h>
22#include <linux/err.h>
23#include <linux/errno.h>
24#include <linux/moduleloader.h>
25
26extern int apply_r_mips_none(struct module *me, u32 *location, Elf_Addr v);
27
28static int apply_r_mips_32_rela(struct module *me, u32 *location, Elf_Addr v)
29{
30	*location = v;
31
32	return 0;
33}
34
35static int apply_r_mips_26_rela(struct module *me, u32 *location, Elf_Addr v)
36{
37	if (v % 4) {
38		pr_err("module %s: dangerous R_MIPS_26 RELArelocation\n",
39		       me->name);
40		return -ENOEXEC;
41	}
42
43	if ((v & 0xf0000000) != (((unsigned long)location + 4) & 0xf0000000)) {
44		printk(KERN_ERR
45		       "module %s: relocation overflow\n",
46		       me->name);
47		return -ENOEXEC;
48	}
49
50	*location = (*location & ~0x03ffffff) | ((v >> 2) & 0x03ffffff);
51
52	return 0;
53}
54
55static int apply_r_mips_hi16_rela(struct module *me, u32 *location, Elf_Addr v)
56{
57	*location = (*location & 0xffff0000) |
58		    ((((long long) v + 0x8000LL) >> 16) & 0xffff);
59
60	return 0;
61}
62
63static int apply_r_mips_lo16_rela(struct module *me, u32 *location, Elf_Addr v)
64{
65	*location = (*location & 0xffff0000) | (v & 0xffff);
66
67	return 0;
68}
69
70static int apply_r_mips_64_rela(struct module *me, u32 *location, Elf_Addr v)
71{
72	*(Elf_Addr *)location = v;
73
74	return 0;
75}
76
77static int apply_r_mips_higher_rela(struct module *me, u32 *location,
78				    Elf_Addr v)
79{
80	*location = (*location & 0xffff0000) |
81		    ((((long long) v + 0x80008000LL) >> 32) & 0xffff);
82
83	return 0;
84}
85
86static int apply_r_mips_highest_rela(struct module *me, u32 *location,
87				     Elf_Addr v)
88{
89	*location = (*location & 0xffff0000) |
90		    ((((long long) v + 0x800080008000LL) >> 48) & 0xffff);
91
92	return 0;
93}
94
95static int (*reloc_handlers_rela[]) (struct module *me, u32 *location,
96				Elf_Addr v) = {
97	[R_MIPS_NONE]		= apply_r_mips_none,
98	[R_MIPS_32]		= apply_r_mips_32_rela,
99	[R_MIPS_26]		= apply_r_mips_26_rela,
100	[R_MIPS_HI16]		= apply_r_mips_hi16_rela,
101	[R_MIPS_LO16]		= apply_r_mips_lo16_rela,
102	[R_MIPS_64]		= apply_r_mips_64_rela,
103	[R_MIPS_HIGHER]		= apply_r_mips_higher_rela,
104	[R_MIPS_HIGHEST]	= apply_r_mips_highest_rela
105};
106
107int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab,
108		       unsigned int symindex, unsigned int relsec,
109		       struct module *me)
110{
111	Elf_Mips_Rela *rel = (void *) sechdrs[relsec].sh_addr;
112	Elf_Sym *sym;
113	u32 *location;
114	unsigned int i;
115	Elf_Addr v;
116	int res;
117
118	pr_debug("Applying relocate section %u to %u\n", relsec,
119	       sechdrs[relsec].sh_info);
120
121	for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
122		/* This is where to make the change */
123		location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
124			+ rel[i].r_offset;
125		/* This is the symbol it is referring to */
126		sym = (Elf_Sym *)sechdrs[symindex].sh_addr
127			+ ELF_MIPS_R_SYM(rel[i]);
128		if (IS_ERR_VALUE(sym->st_value)) {
129			/* Ignore unresolved weak symbol */
130			if (ELF_ST_BIND(sym->st_info) == STB_WEAK)
131				continue;
132			printk(KERN_WARNING "%s: Unknown symbol %s\n",
133			       me->name, strtab + sym->st_name);
134			return -ENOENT;
135		}
136
137		v = sym->st_value + rel[i].r_addend;
138
139		res = reloc_handlers_rela[ELF_MIPS_R_TYPE(rel[i])](me, location, v);
140		if (res)
141			return res;
142	}
143
144	return 0;
145}
146