xref: /linux/arch/sh/kernel/module.c (revision 367b8112fe2ea5c39a7bb4d263dcdd9b612fae18)
1 /*  Kernel module help for SH.
2 
3     SHcompact version by Kaz Kojima and Paul Mundt.
4 
5     SHmedia bits:
6 
7 	Copyright 2004 SuperH (UK) Ltd
8 	Author: Richard Curnow
9 
10 	Based on the sh version, and on code from the sh64-specific parts of
11 	modutils, originally written by Richard Curnow and Ben Gaster.
12 
13     This program is free software; you can redistribute it and/or modify
14     it under the terms of the GNU General Public License as published by
15     the Free Software Foundation; either version 2 of the License, or
16     (at your option) any later version.
17 
18     This program is distributed in the hope that it will be useful,
19     but WITHOUT ANY WARRANTY; without even the implied warranty of
20     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
21     GNU General Public License for more details.
22 
23     You should have received a copy of the GNU General Public License
24     along with this program; if not, write to the Free Software
25     Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
26 */
27 #include <linux/moduleloader.h>
28 #include <linux/elf.h>
29 #include <linux/vmalloc.h>
30 #include <linux/bug.h>
31 #include <linux/fs.h>
32 #include <linux/string.h>
33 #include <linux/kernel.h>
34 #include <asm/unaligned.h>
35 
36 void *module_alloc(unsigned long size)
37 {
38 	if (size == 0)
39 		return NULL;
40 
41 	return vmalloc_exec(size);
42 }
43 
44 
45 /* Free memory returned from module_alloc */
46 void module_free(struct module *mod, void *module_region)
47 {
48 	vfree(module_region);
49 	/* FIXME: If module_region == mod->init_region, trim exception
50            table entries. */
51 }
52 
53 /* We don't need anything special. */
54 int module_frob_arch_sections(Elf_Ehdr *hdr,
55 			      Elf_Shdr *sechdrs,
56 			      char *secstrings,
57 			      struct module *mod)
58 {
59 	return 0;
60 }
61 
62 int apply_relocate_add(Elf32_Shdr *sechdrs,
63 		   const char *strtab,
64 		   unsigned int symindex,
65 		   unsigned int relsec,
66 		   struct module *me)
67 {
68 	unsigned int i;
69 	Elf32_Rela *rel = (void *)sechdrs[relsec].sh_addr;
70 	Elf32_Sym *sym;
71 	Elf32_Addr relocation;
72 	uint32_t *location;
73 	uint32_t value;
74 
75 	pr_debug("Applying relocate section %u to %u\n", relsec,
76 		 sechdrs[relsec].sh_info);
77 	for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
78 		/* This is where to make the change */
79 		location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
80 			+ rel[i].r_offset;
81 		/* This is the symbol it is referring to.  Note that all
82 		   undefined symbols have been resolved.  */
83 		sym = (Elf32_Sym *)sechdrs[symindex].sh_addr
84 			+ ELF32_R_SYM(rel[i].r_info);
85 		relocation = sym->st_value + rel[i].r_addend;
86 
87 #ifdef CONFIG_SUPERH64
88 		/* For text addresses, bit2 of the st_other field indicates
89 		 * whether the symbol is SHmedia (1) or SHcompact (0).  If
90 		 * SHmedia, the LSB of the symbol needs to be asserted
91 		 * for the CPU to be in SHmedia mode when it starts executing
92 		 * the branch target. */
93 		relocation |= (sym->st_other & 4);
94 #endif
95 
96 		switch (ELF32_R_TYPE(rel[i].r_info)) {
97 		case R_SH_DIR32:
98 			value = get_unaligned(location);
99 			value += relocation;
100 			put_unaligned(value, location);
101 			break;
102 		case R_SH_REL32:
103 			relocation = (relocation - (Elf32_Addr) location);
104 			value = get_unaligned(location);
105 			value += relocation;
106 			put_unaligned(value, location);
107 			break;
108 		case R_SH_IMM_LOW16:
109 			*location = (*location & ~0x3fffc00) |
110 				((relocation & 0xffff) << 10);
111 			break;
112 		case R_SH_IMM_MEDLOW16:
113 			*location = (*location & ~0x3fffc00) |
114 				(((relocation >> 16) & 0xffff) << 10);
115 			break;
116 		case R_SH_IMM_LOW16_PCREL:
117 			relocation -= (Elf32_Addr) location;
118 			*location = (*location & ~0x3fffc00) |
119 				((relocation & 0xffff) << 10);
120 			break;
121 		case R_SH_IMM_MEDLOW16_PCREL:
122 			relocation -= (Elf32_Addr) location;
123 			*location = (*location & ~0x3fffc00) |
124 				(((relocation >> 16) & 0xffff) << 10);
125 			break;
126 		default:
127 			printk(KERN_ERR "module %s: Unknown relocation: %u\n",
128 			       me->name, ELF32_R_TYPE(rel[i].r_info));
129 			return -ENOEXEC;
130 		}
131 	}
132 	return 0;
133 }
134 
135 int apply_relocate(Elf32_Shdr *sechdrs,
136 		       const char *strtab,
137 		       unsigned int symindex,
138 		       unsigned int relsec,
139 		       struct module *me)
140 {
141 	printk(KERN_ERR "module %s: REL RELOCATION unsupported\n",
142 	       me->name);
143 	return -ENOEXEC;
144 }
145 
146 int module_finalize(const Elf_Ehdr *hdr,
147 		    const Elf_Shdr *sechdrs,
148 		    struct module *me)
149 {
150 	return module_bug_finalize(hdr, sechdrs, me);
151 }
152 
153 void module_arch_cleanup(struct module *mod)
154 {
155 	module_bug_cleanup(mod);
156 }
157