1/*
2 * Kernel module support for Nios II.
3 *
4 * Copyright (C) 2004 Microtronix Datacom Ltd.
5 * Written by Wentao Xu <xuwentao@microtronix.com>
6 * Copyright (C) 2001, 2003 Rusty Russell
7 *
8 * This file is subject to the terms and conditions of the GNU General
9 * Public License. See the file COPYING in the main directory of this
10 * archive for more details.
11 */
12
13#include <linux/moduleloader.h>
14#include <linux/elf.h>
15#include <linux/mm.h>
16#include <linux/vmalloc.h>
17#include <linux/slab.h>
18#include <linux/fs.h>
19#include <linux/string.h>
20#include <linux/kernel.h>
21
22#include <asm/cacheflush.h>
23
24/*
25 * Modules should NOT be allocated with kmalloc for (obvious) reasons.
26 * But we do it for now to avoid relocation issues. CALL26/PCREL26 cannot reach
27 * from 0x80000000 (vmalloc area) to 0xc00000000 (kernel) (kmalloc returns
28 * addresses in 0xc0000000)
29 */
30void *module_alloc(unsigned long size)
31{
32 if (size == 0)
33 return NULL;
34 return kmalloc(size, GFP_KERNEL);
35}
36
37/* Free memory returned from module_alloc */
38void module_memfree(void *module_region)
39{
40 kfree(objp: module_region);
41}
42
43int apply_relocate_add(Elf32_Shdr *sechdrs, const char *strtab,
44 unsigned int symindex, unsigned int relsec,
45 struct module *mod)
46{
47 unsigned int i;
48 Elf32_Rela *rela = (void *)sechdrs[relsec].sh_addr;
49
50 pr_debug("Applying relocate section %u to %u\n", relsec,
51 sechdrs[relsec].sh_info);
52
53 for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rela); i++) {
54 /* This is where to make the change */
55 uint32_t word;
56 uint32_t *loc
57 = ((void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
58 + rela[i].r_offset);
59 /* This is the symbol it is referring to. Note that all
60 undefined symbols have been resolved. */
61 Elf32_Sym *sym
62 = ((Elf32_Sym *)sechdrs[symindex].sh_addr
63 + ELF32_R_SYM(rela[i].r_info));
64 uint32_t v = sym->st_value + rela[i].r_addend;
65
66 pr_debug("reltype %d 0x%x name:<%s>\n",
67 ELF32_R_TYPE(rela[i].r_info),
68 rela[i].r_offset, strtab + sym->st_name);
69
70 switch (ELF32_R_TYPE(rela[i].r_info)) {
71 case R_NIOS2_NONE:
72 break;
73 case R_NIOS2_BFD_RELOC_32:
74 *loc += v;
75 break;
76 case R_NIOS2_PCREL16:
77 v -= (uint32_t)loc + 4;
78 if ((int32_t)v > 0x7fff ||
79 (int32_t)v < -(int32_t)0x8000) {
80 pr_err("module %s: relocation overflow\n",
81 mod->name);
82 return -ENOEXEC;
83 }
84 word = *loc;
85 *loc = ((((word >> 22) << 16) | (v & 0xffff)) << 6) |
86 (word & 0x3f);
87 break;
88 case R_NIOS2_CALL26:
89 if (v & 3) {
90 pr_err("module %s: dangerous relocation\n",
91 mod->name);
92 return -ENOEXEC;
93 }
94 if ((v >> 28) != ((uint32_t)loc >> 28)) {
95 pr_err("module %s: relocation overflow\n",
96 mod->name);
97 return -ENOEXEC;
98 }
99 *loc = (*loc & 0x3f) | ((v >> 2) << 6);
100 break;
101 case R_NIOS2_HI16:
102 word = *loc;
103 *loc = ((((word >> 22) << 16) |
104 ((v >> 16) & 0xffff)) << 6) | (word & 0x3f);
105 break;
106 case R_NIOS2_LO16:
107 word = *loc;
108 *loc = ((((word >> 22) << 16) | (v & 0xffff)) << 6) |
109 (word & 0x3f);
110 break;
111 case R_NIOS2_HIADJ16:
112 {
113 Elf32_Addr word2;
114
115 word = *loc;
116 word2 = ((v >> 16) + ((v >> 15) & 1)) & 0xffff;
117 *loc = ((((word >> 22) << 16) | word2) << 6) |
118 (word & 0x3f);
119 }
120 break;
121
122 default:
123 pr_err("module %s: Unknown reloc: %u\n",
124 mod->name, ELF32_R_TYPE(rela[i].r_info));
125 return -ENOEXEC;
126 }
127 }
128
129 return 0;
130}
131
132int module_finalize(const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs,
133 struct module *me)
134{
135 flush_cache_all();
136 return 0;
137}
138

source code of linux/arch/nios2/kernel/module.c