xref: /openbmc/linux/arch/sh/kernel/module.c (revision 732a675a)
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/fs.h>
31 #include <linux/string.h>
32 #include <linux/kernel.h>
33 #include <asm/unaligned.h>
34 
35 void *module_alloc(unsigned long size)
36 {
37 	if (size == 0)
38 		return NULL;
39 	return vmalloc(size);
40 }
41 
42 
43 /* Free memory returned from module_alloc */
44 void module_free(struct module *mod, void *module_region)
45 {
46 	vfree(module_region);
47 	/* FIXME: If module_region == mod->init_region, trim exception
48            table entries. */
49 }
50 
51 /* We don't need anything special. */
52 int module_frob_arch_sections(Elf_Ehdr *hdr,
53 			      Elf_Shdr *sechdrs,
54 			      char *secstrings,
55 			      struct module *mod)
56 {
57 	return 0;
58 }
59 
60 int apply_relocate_add(Elf32_Shdr *sechdrs,
61 		   const char *strtab,
62 		   unsigned int symindex,
63 		   unsigned int relsec,
64 		   struct module *me)
65 {
66 	unsigned int i;
67 	Elf32_Rela *rel = (void *)sechdrs[relsec].sh_addr;
68 	Elf32_Sym *sym;
69 	Elf32_Addr relocation;
70 	uint32_t *location;
71 	uint32_t value;
72 
73 	pr_debug("Applying relocate section %u to %u\n", relsec,
74 		 sechdrs[relsec].sh_info);
75 	for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
76 		/* This is where to make the change */
77 		location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
78 			+ rel[i].r_offset;
79 		/* This is the symbol it is referring to.  Note that all
80 		   undefined symbols have been resolved.  */
81 		sym = (Elf32_Sym *)sechdrs[symindex].sh_addr
82 			+ ELF32_R_SYM(rel[i].r_info);
83 		relocation = sym->st_value + rel[i].r_addend;
84 
85 #ifdef CONFIG_SUPERH64
86 		/* For text addresses, bit2 of the st_other field indicates
87 		 * whether the symbol is SHmedia (1) or SHcompact (0).  If
88 		 * SHmedia, the LSB of the symbol needs to be asserted
89 		 * for the CPU to be in SHmedia mode when it starts executing
90 		 * the branch target. */
91 		relocation |= (sym->st_other & 4);
92 #endif
93 
94 		switch (ELF32_R_TYPE(rel[i].r_info)) {
95 		case R_SH_DIR32:
96 			value = get_unaligned(location);
97 			value += relocation;
98 			put_unaligned(value, location);
99 			break;
100 		case R_SH_REL32:
101 			relocation = (relocation - (Elf32_Addr) location);
102 			value = get_unaligned(location);
103 			value += relocation;
104 			put_unaligned(value, location);
105 			break;
106 		case R_SH_IMM_LOW16:
107 			*location = (*location & ~0x3fffc00) |
108 				((relocation & 0xffff) << 10);
109 			break;
110 		case R_SH_IMM_MEDLOW16:
111 			*location = (*location & ~0x3fffc00) |
112 				(((relocation >> 16) & 0xffff) << 10);
113 			break;
114 		case R_SH_IMM_LOW16_PCREL:
115 			relocation -= (Elf32_Addr) location;
116 			*location = (*location & ~0x3fffc00) |
117 				((relocation & 0xffff) << 10);
118 			break;
119 		case R_SH_IMM_MEDLOW16_PCREL:
120 			relocation -= (Elf32_Addr) location;
121 			*location = (*location & ~0x3fffc00) |
122 				(((relocation >> 16) & 0xffff) << 10);
123 			break;
124 		default:
125 			printk(KERN_ERR "module %s: Unknown relocation: %u\n",
126 			       me->name, ELF32_R_TYPE(rel[i].r_info));
127 			return -ENOEXEC;
128 		}
129 	}
130 	return 0;
131 }
132 
133 int apply_relocate(Elf32_Shdr *sechdrs,
134 		       const char *strtab,
135 		       unsigned int symindex,
136 		       unsigned int relsec,
137 		       struct module *me)
138 {
139 	printk(KERN_ERR "module %s: REL RELOCATION unsupported\n",
140 	       me->name);
141 	return -ENOEXEC;
142 }
143 
144 int module_finalize(const Elf_Ehdr *hdr,
145 		    const Elf_Shdr *sechdrs,
146 		    struct module *me)
147 {
148 	return 0;
149 }
150 
151 void module_arch_cleanup(struct module *mod)
152 {
153 }
154