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/arch/mips/kernel/module-elf64.c

https://bitbucket.org/evzijst/gittest
C | 274 lines | 177 code | 49 blank | 48 comment | 17 complexity | a4d41edaacfe0a0ffa68e260218c6ed2 MD5 | raw file
  1/*
  2 *  This program is free software; you can redistribute it and/or modify
  3 *  it under the terms of the GNU General Public License as published by
  4 *  the Free Software Foundation; either version 2 of the License, or
  5 *  (at your option) any later version.
  6 *
  7 *  This program is distributed in the hope that it will be useful,
  8 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  9 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 10 *  GNU General Public License for more details.
 11 *
 12 *  You should have received a copy of the GNU General Public License
 13 *  along with this program; if not, write to the Free Software
 14 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 15 *
 16 *  Copyright (C) 2001 Rusty Russell.
 17 *  Copyright (C) 2003, 2004 Ralf Baechle (ralf@linux-mips.org)
 18 */
 19
 20#undef DEBUG
 21
 22#include <linux/moduleloader.h>
 23#include <linux/elf.h>
 24#include <linux/vmalloc.h>
 25#include <linux/slab.h>
 26#include <linux/fs.h>
 27#include <linux/string.h>
 28#include <linux/kernel.h>
 29
 30struct mips_hi16 {
 31	struct mips_hi16 *next;
 32	Elf32_Addr *addr;
 33	Elf64_Addr value;
 34};
 35
 36static struct mips_hi16 *mips_hi16_list;
 37
 38void *module_alloc(unsigned long size)
 39{
 40	if (size == 0)
 41		return NULL;
 42	return vmalloc(size);
 43}
 44
 45
 46/* Free memory returned from module_alloc */
 47void module_free(struct module *mod, void *module_region)
 48{
 49	vfree(module_region);
 50	/* FIXME: If module_region == mod->init_region, trim exception
 51           table entries. */
 52}
 53
 54int module_frob_arch_sections(Elf_Ehdr *hdr,
 55			      Elf_Shdr *sechdrs,
 56			      char *secstrings,
 57			      struct module *mod)
 58{
 59	return 0;
 60}
 61
 62int apply_relocate(Elf64_Shdr *sechdrs,
 63		   const char *strtab,
 64		   unsigned int symindex,
 65		   unsigned int relsec,
 66		   struct module *me)
 67{
 68	/*
 69	 * We don't want to deal with REL relocations - RELA is so much saner.
 70	 */
 71	if (!sechdrs[relsec].sh_size)
 72		return 0;
 73
 74	printk(KERN_ERR "module %s: REL relocation unsupported\n",
 75	       me->name);
 76	return -ENOEXEC;
 77}
 78
 79static int apply_r_mips_none(struct module *me, uint32_t *location,
 80	Elf64_Addr v)
 81{
 82	return 0;
 83}
 84
 85static int apply_r_mips_32(struct module *me, uint32_t *location,
 86	Elf64_Addr v)
 87{
 88	*location = v;
 89
 90	return 0;
 91}
 92
 93static int apply_r_mips_26(struct module *me, uint32_t *location,
 94	Elf64_Addr v)
 95{
 96	if (v % 4) {
 97		printk(KERN_ERR "module %s: dangerous relocation\n", me->name);
 98		return -ENOEXEC;
 99	}
100
101	if ((v & 0xf0000000) != (((unsigned long)location + 4) & 0xf0000000)) {
102		printk(KERN_ERR
103		       "module %s: relocation overflow\n",
104		       me->name);
105		return -ENOEXEC;
106	}
107
108	*location = (*location & ~0x03ffffff) | ((v >> 2) & 0x03ffffff);
109
110	return 0;
111}
112
113static int apply_r_mips_hi16(struct module *me, uint32_t *location,
114	Elf64_Addr v)
115{
116	struct mips_hi16 *n;
117
118	/*
119	 * We cannot relocate this one now because we don't know the value of
120	 * the carry we need to add.  Save the information, and let LO16 do the
121	 * actual relocation.
122	 */
123	n = kmalloc(sizeof *n, GFP_KERNEL);
124	if (!n)
125		return -ENOMEM;
126
127	n->addr = location;
128	n->value = v;
129	n->next = mips_hi16_list;
130	mips_hi16_list = n;
131
132	return 0;
133}
134
135static int apply_r_mips_lo16(struct module *me, uint32_t *location,
136	Elf64_Addr v)
137{
138	unsigned long insnlo = *location;
139	Elf32_Addr val, vallo;
140
141	/* Sign extend the addend we extract from the lo insn.  */
142	vallo = ((insnlo & 0xffff) ^ 0x8000) - 0x8000;
143
144	if (mips_hi16_list != NULL) {
145		struct mips_hi16 *l;
146
147		l = mips_hi16_list;
148		while (l != NULL) {
149			struct mips_hi16 *next;
150			unsigned long insn;
151
152			/*
153			 * The value for the HI16 had best be the same.
154			 */
155			if (v != l->value)
156				goto out_danger;
157
158			/*
159			 * Do the HI16 relocation.  Note that we actually don't
160			 * need to know anything about the LO16 itself, except
161			 * where to find the low 16 bits of the addend needed
162			 * by the LO16.
163			 */
164			insn = *l->addr;
165			val = ((insn & 0xffff) << 16) + vallo;
166			val += v;
167
168			/*
169			 * Account for the sign extension that will happen in
170			 * the low bits.
171			 */
172			val = ((val >> 16) + ((val & 0x8000) != 0)) & 0xffff;
173
174			insn = (insn & ~0xffff) | val;
175			*l->addr = insn;
176
177			next = l->next;
178			kfree(l);
179			l = next;
180		}
181
182		mips_hi16_list = NULL;
183	}
184
185	/*
186	 * Ok, we're done with the HI16 relocs.  Now deal with the LO16.
187	 */
188	insnlo = (insnlo & ~0xffff) | (v & 0xffff);
189	*location = insnlo;
190
191	return 0;
192
193out_danger:
194	printk(KERN_ERR "module %s: dangerous " "relocation\n", me->name);
195
196	return -ENOEXEC;
197}
198
199static int apply_r_mips_64(struct module *me, uint32_t *location,
200	Elf64_Addr v)
201{
202	*(uint64_t *) location = v;
203
204	return 0;
205}
206
207
208static int apply_r_mips_higher(struct module *me, uint32_t *location,
209	Elf64_Addr v)
210{
211	*location = (*location & 0xffff0000) |
212	            ((((long long) v + 0x80008000LL) >> 32) & 0xffff);
213
214	return 0;
215}
216
217static int apply_r_mips_highest(struct module *me, uint32_t *location,
218	Elf64_Addr v)
219{
220	*location = (*location & 0xffff0000) |
221	            ((((long long) v + 0x800080008000LL) >> 48) & 0xffff);
222
223	return 0;
224}
225
226static int (*reloc_handlers[]) (struct module *me, uint32_t *location,
227	Elf64_Addr v) = {
228	[R_MIPS_NONE]		= apply_r_mips_none,
229	[R_MIPS_32]		= apply_r_mips_32,
230	[R_MIPS_26]		= apply_r_mips_26,
231	[R_MIPS_HI16]		= apply_r_mips_hi16,
232	[R_MIPS_LO16]		= apply_r_mips_lo16,
233	[R_MIPS_64]		= apply_r_mips_64,
234	[R_MIPS_HIGHER]		= apply_r_mips_higher,
235	[R_MIPS_HIGHEST]	= apply_r_mips_highest
236};
237
238int apply_relocate_add(Elf64_Shdr *sechdrs,
239		       const char *strtab,
240		       unsigned int symindex,
241		       unsigned int relsec,
242		       struct module *me)
243{
244	Elf64_Mips_Rela *rel = (void *) sechdrs[relsec].sh_addr;
245	Elf64_Sym *sym;
246	uint32_t *location;
247	unsigned int i;
248	Elf64_Addr v;
249	int res;
250
251	pr_debug("Applying relocate section %u to %u\n", relsec,
252	       sechdrs[relsec].sh_info);
253
254	for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
255		/* This is where to make the change */
256		location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
257			+ rel[i].r_offset;
258		/* This is the symbol it is referring to */
259		sym = (Elf64_Sym *)sechdrs[symindex].sh_addr + rel[i].r_sym;
260		if (!sym->st_value) {
261			printk(KERN_WARNING "%s: Unknown symbol %s\n",
262			       me->name, strtab + sym->st_name);
263			return -ENOENT;
264		}
265
266		v = sym->st_value;
267
268		res = reloc_handlers[rel[i].r_type](me, location, v);
269		if (res)
270			return res;
271	}
272
273	return 0;
274}