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(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