xref: /openbmc/linux/arch/openrisc/kernel/module.c (revision ca55b2fe)
1 /*
2  * OpenRISC module.c
3  *
4  * Linux architectural port borrowing liberally from similar works of
5  * others.  All original copyrights apply as per the original source
6  * declaration.
7  *
8  * Modifications for the OpenRISC architecture:
9  * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
10  *
11  *      This program is free software; you can redistribute it and/or
12  *      modify it under the terms of the GNU General Public License
13  *      as published by the Free Software Foundation; either version
14  *      2 of the License, or (at your option) any later version.
15  */
16 
17 #include <linux/moduleloader.h>
18 #include <linux/elf.h>
19 
20 int apply_relocate_add(Elf32_Shdr *sechdrs,
21 		       const char *strtab,
22 		       unsigned int symindex,
23 		       unsigned int relsec,
24 		       struct module *me)
25 {
26 	unsigned int i;
27 	Elf32_Rela *rel = (void *)sechdrs[relsec].sh_addr;
28 	Elf32_Sym *sym;
29 	uint32_t *location;
30 	uint32_t value;
31 
32 	pr_debug("Applying relocate section %u to %u\n", relsec,
33 		 sechdrs[relsec].sh_info);
34 	for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
35 		/* This is where to make the change */
36 		location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
37 			+ rel[i].r_offset;
38 
39 		/* This is the symbol it is referring to.  Note that all
40 		   undefined symbols have been resolved.  */
41 		sym = (Elf32_Sym *)sechdrs[symindex].sh_addr
42 			+ ELF32_R_SYM(rel[i].r_info);
43 		value = sym->st_value + rel[i].r_addend;
44 
45 		switch (ELF32_R_TYPE(rel[i].r_info)) {
46 		case R_OR32_32:
47 			*location = value;
48 			break;
49 		case R_OR32_CONST:
50 			*((uint16_t *)location + 1) = value;
51 			break;
52 		case R_OR32_CONSTH:
53 			*((uint16_t *)location + 1) = value >> 16;
54 			break;
55 		case R_OR32_JUMPTARG:
56 			value -= (uint32_t)location;
57 			value >>= 2;
58 			value &= 0x03ffffff;
59 			value |= *location & 0xfc000000;
60 			*location = value;
61 			break;
62 		default:
63 			pr_err("module %s: Unknown relocation: %u\n",
64 			       me->name, ELF32_R_TYPE(rel[i].r_info));
65 			break;
66 		}
67 	}
68 
69 	return 0;
70 }
71