1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * OpenRISC module.c
4 *
5 * Linux architectural port borrowing liberally from similar works of
6 * others. All original copyrights apply as per the original source
7 * declaration.
8 *
9 * Modifications for the OpenRISC architecture:
10 * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
11 */
12
13#include <linux/moduleloader.h>
14#include <linux/elf.h>
15
16int apply_relocate_add(Elf32_Shdr *sechdrs,
17 const char *strtab,
18 unsigned int symindex,
19 unsigned int relsec,
20 struct module *me)
21{
22 unsigned int i;
23 Elf32_Rela *rel = (void *)sechdrs[relsec].sh_addr;
24 Elf32_Sym *sym;
25 uint32_t *location;
26 uint32_t value;
27
28 pr_debug("Applying relocate section %u to %u\n", relsec,
29 sechdrs[relsec].sh_info);
30 for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
31 /* This is where to make the change */
32 location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
33 + rel[i].r_offset;
34
35 /* This is the symbol it is referring to. Note that all
36 undefined symbols have been resolved. */
37 sym = (Elf32_Sym *)sechdrs[symindex].sh_addr
38 + ELF32_R_SYM(rel[i].r_info);
39 value = sym->st_value + rel[i].r_addend;
40
41 switch (ELF32_R_TYPE(rel[i].r_info)) {
42 case R_OR1K_32:
43 *location = value;
44 break;
45 case R_OR1K_LO_16_IN_INSN:
46 *((uint16_t *)location + 1) = value;
47 break;
48 case R_OR1K_HI_16_IN_INSN:
49 *((uint16_t *)location + 1) = value >> 16;
50 break;
51 case R_OR1K_INSN_REL_26:
52 value -= (uint32_t)location;
53 value >>= 2;
54 value &= 0x03ffffff;
55 value |= *location & 0xfc000000;
56 *location = value;
57 break;
58 case R_OR1K_32_PCREL:
59 value -= (uint32_t)location;
60 *location = value;
61 break;
62 case R_OR1K_AHI16:
63 /* Adjust the operand to match with a signed LO16. */
64 value += 0x8000;
65 *((uint16_t *)location + 1) = value >> 16;
66 break;
67 case R_OR1K_SLO16:
68 /* Split value lower 16-bits. */
69 value = ((value & 0xf800) << 10) | (value & 0x7ff);
70 *location = (*location & ~0x3e007ff) | value;
71 break;
72 default:
73 pr_err("module %s: Unknown relocation: %u\n",
74 me->name, ELF32_R_TYPE(rel[i].r_info));
75 break;
76 }
77 }
78
79 return 0;
80}
81

source code of linux/arch/openrisc/kernel/module.c