[linux-2.6-block.git] / arch / mips / kernel / module.c

/*
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 *  Copyright (C) 2001 Rusty Russell.
 *  Copyright (C) 2003, 2004 Ralf Baechle (ralf@linux-mips.org)
 *  Copyright (C) 2005 Thiemo Seufer
 */

#undef DEBUG

#include <linux/moduleloader.h>
#include <linux/elf.h>
#include <linux/mm.h>
#include <linux/numa.h>
#include <linux/vmalloc.h>
#include <linux/slab.h>
#include <linux/fs.h>
#include <linux/string.h>
#include <linux/kernel.h>
#include <linux/spinlock.h>
#include <linux/jump_label.h>

#include <asm/pgtable.h>	/* MODULE_START */

struct mips_hi16 {
	struct mips_hi16 *next;
	Elf_Addr *addr;
	Elf_Addr value;
};

static LIST_HEAD(dbe_list);
static DEFINE_SPINLOCK(dbe_lock);

#ifdef MODULE_START
void *module_alloc(unsigned long size)
{
	return __vmalloc_node_range(size, 1, MODULE_START, MODULE_END,
				GFP_KERNEL, PAGE_KERNEL, 0, NUMA_NO_NODE,
				__builtin_return_address(0));
}
#endif

int apply_r_mips_none(struct module *me, u32 *location, Elf_Addr v)
{
	return 0;
}

static int apply_r_mips_32_rel(struct module *me, u32 *location, Elf_Addr v)
{
	*location += v;

	return 0;
}

static int apply_r_mips_26_rel(struct module *me, u32 *location, Elf_Addr v)
{
	if (v % 4) {
		pr_err("module %s: dangerous R_MIPS_26 REL relocation\n",
		       me->name);
		return -ENOEXEC;
	}

	if ((v & 0xf0000000) != (((unsigned long)location + 4) & 0xf0000000)) {
		printk(KERN_ERR
		       "module %s: relocation overflow\n",
		       me->name);
		return -ENOEXEC;
	}

	*location = (*location & ~0x03ffffff) |
		    ((*location + (v >> 2)) & 0x03ffffff);

	return 0;
}

static int apply_r_mips_hi16_rel(struct module *me, u32 *location, Elf_Addr v)
{
	struct mips_hi16 *n;

	/*
	 * We cannot relocate this one now because we don't know the value of
	 * the carry we need to add.  Save the information, and let LO16 do the
	 * actual relocation.
	 */
	n = kmalloc(sizeof *n, GFP_KERNEL);
	if (!n)
		return -ENOMEM;

	n->addr = (Elf_Addr *)location;
	n->value = v;
	n->next = me->arch.r_mips_hi16_list;
	me->arch.r_mips_hi16_list = n;

	return 0;
}

static void free_relocation_chain(struct mips_hi16 *l)
{
	struct mips_hi16 *next;

	while (l) {
		next = l->next;
		kfree(l);
		l = next;
	}
}

static int apply_r_mips_lo16_rel(struct module *me, u32 *location, Elf_Addr v)
{
	unsigned long insnlo = *location;
	struct mips_hi16 *l;
	Elf_Addr val, vallo;

	/* Sign extend the addend we extract from the lo insn.	*/
	vallo = ((insnlo & 0xffff) ^ 0x8000) - 0x8000;

	if (me->arch.r_mips_hi16_list != NULL) {
		l = me->arch.r_mips_hi16_list;
		while (l != NULL) {
			struct mips_hi16 *next;
			unsigned long insn;

			/*
			 * The value for the HI16 had best be the same.
			 */
			if (v != l->value)
				goto out_danger;

			/*
			 * Do the HI16 relocation.  Note that we actually don't
			 * need to know anything about the LO16 itself, except
			 * where to find the low 16 bits of the addend needed
			 * by the LO16.
			 */
			insn = *l->addr;
			val = ((insn & 0xffff) << 16) + vallo;
			val += v;

			/*
			 * Account for the sign extension that will happen in
			 * the low bits.
			 */
			val = ((val >> 16) + ((val & 0x8000) != 0)) & 0xffff;

			insn = (insn & ~0xffff) | val;
			*l->addr = insn;

			next = l->next;
			kfree(l);
			l = next;
		}

		me->arch.r_mips_hi16_list = NULL;
	}

	/*
	 * Ok, we're done with the HI16 relocs.	 Now deal with the LO16.
	 */
	val = v + vallo;
	insnlo = (insnlo & ~0xffff) | (val & 0xffff);
	*location = insnlo;

	return 0;

out_danger:
	free_relocation_chain(l);
	me->arch.r_mips_hi16_list = NULL;

	pr_err("module %s: dangerous R_MIPS_LO16 REL relocation\n", me->name);

	return -ENOEXEC;
}

static int (*reloc_handlers_rel[]) (struct module *me, u32 *location,
				Elf_Addr v) = {
	[R_MIPS_NONE]		= apply_r_mips_none,
	[R_MIPS_32]		= apply_r_mips_32_rel,
	[R_MIPS_26]		= apply_r_mips_26_rel,
	[R_MIPS_HI16]		= apply_r_mips_hi16_rel,
	[R_MIPS_LO16]		= apply_r_mips_lo16_rel
};

int apply_relocate(Elf_Shdr *sechdrs, const char *strtab,
		   unsigned int symindex, unsigned int relsec,
		   struct module *me)
{
	Elf_Mips_Rel *rel = (void *) sechdrs[relsec].sh_addr;
	int (*handler)(struct module *me, u32 *location, Elf_Addr v);
	Elf_Sym *sym;
	u32 *location;
	unsigned int i, type;
	Elf_Addr v;
	int res;

	pr_debug("Applying relocate section %u to %u\n", relsec,
	       sechdrs[relsec].sh_info);

	me->arch.r_mips_hi16_list = NULL;
	for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
		/* This is where to make the change */
		location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
			+ rel[i].r_offset;
		/* This is the symbol it is referring to */
		sym = (Elf_Sym *)sechdrs[symindex].sh_addr
			+ ELF_MIPS_R_SYM(rel[i]);
		if (IS_ERR_VALUE(sym->st_value)) {
			/* Ignore unresolved weak symbol */
			if (ELF_ST_BIND(sym->st_info) == STB_WEAK)
				continue;
			printk(KERN_WARNING "%s: Unknown symbol %s\n",
			       me->name, strtab + sym->st_name);
			return -ENOENT;
		}

		type = ELF_MIPS_R_TYPE(rel[i]);

		if (type < ARRAY_SIZE(reloc_handlers_rel))
			handler = reloc_handlers_rel[type];
		else
			handler = NULL;

		if (!handler) {
			pr_err("%s: Unknown relocation type %u\n",
			       me->name, type);
			return -EINVAL;
		}

		v = sym->st_value;
		res = handler(me, location, v);
		if (res)
			return res;
	}

	/*
	 * Normally the hi16 list should be deallocated at this point.	A
	 * malformed binary however could contain a series of R_MIPS_HI16
	 * relocations not followed by a R_MIPS_LO16 relocation.  In that
	 * case, free up the list and return an error.
	 */
	if (me->arch.r_mips_hi16_list) {
		free_relocation_chain(me->arch.r_mips_hi16_list);
		me->arch.r_mips_hi16_list = NULL;

		return -ENOEXEC;
	}

	return 0;
}

/* Given an address, look for it in the module exception tables. */
const struct exception_table_entry *search_module_dbetables(unsigned long addr)
{
	unsigned long flags;
	const struct exception_table_entry *e = NULL;
	struct mod_arch_specific *dbe;

	spin_lock_irqsave(&dbe_lock, flags);
	list_for_each_entry(dbe, &dbe_list, dbe_list) {
		e = search_extable(dbe->dbe_start, dbe->dbe_end - 1, addr);
		if (e)
			break;
	}
	spin_unlock_irqrestore(&dbe_lock, flags);

	/* Now, if we found one, we are running inside it now, hence
	   we cannot unload the module, hence no refcnt needed. */
	return e;
}

/* Put in dbe list if necessary. */
int module_finalize(const Elf_Ehdr *hdr,
		    const Elf_Shdr *sechdrs,
		    struct module *me)
{
	const Elf_Shdr *s;
	char *secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;

	/* Make jump label nops. */
	jump_label_apply_nops(me);

	INIT_LIST_HEAD(&me->arch.dbe_list);
	for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) {
		if (strcmp("__dbe_table", secstrings + s->sh_name) != 0)
			continue;
		me->arch.dbe_start = (void *)s->sh_addr;
		me->arch.dbe_end = (void *)s->sh_addr + s->sh_size;
		spin_lock_irq(&dbe_lock);
		list_add(&me->arch.dbe_list, &dbe_list);
		spin_unlock_irq(&dbe_lock);
	}
	return 0;
}

void module_arch_cleanup(struct module *mod)
{
	spin_lock_irq(&dbe_lock);
	list_del(&mod->arch.dbe_list);
	spin_unlock_irq(&dbe_lock);
}
Commit	Line	Data
4e6a05fe TS	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	* Copyright (C) 2005 Thiemo Seufer
	19	*/
	20
	21	#undef DEBUG
	22
	23	#include <linux/moduleloader.h>
	24	#include <linux/elf.h>
27ac792c	25	#include <linux/mm.h>
761845f0	26	#include <linux/numa.h>
4e6a05fe TS	27	#include <linux/vmalloc.h>
	28	#include <linux/slab.h>
	29	#include <linux/fs.h>
	30	#include <linux/string.h>
	31	#include <linux/kernel.h>
1da177e4	32	#include <linux/spinlock.h>
94bb0c1a DD	33	#include <linux/jump_label.h>
94bb0c1a DD	34
656be92f	35	#include <asm/pgtable.h> /* MODULE_START */
1da177e4	36
4e6a05fe TS	37	struct mips_hi16 {
	38	struct mips_hi16 *next;
	39	Elf_Addr *addr;
	40	Elf_Addr value;
	41	};
	42
1da177e4 LT	43	static LIST_HEAD(dbe_list);
	44	static DEFINE_SPINLOCK(dbe_lock);
	45
66574cc0	46	#ifdef MODULE_START
4e6a05fe TS	47	void *module_alloc(unsigned long size)
4e6a05fe TS	48	{
d0a21265	49	return __vmalloc_node_range(size, 1, MODULE_START, MODULE_END,
cb9e3c29	50	GFP_KERNEL, PAGE_KERNEL, 0, NUMA_NO_NODE,
d0a21265	51	__builtin_return_address(0));
4e6a05fe	52	}
66574cc0	53	#endif
4e6a05fe	54
6ede8123	55	int apply_r_mips_none(struct module me, u32 location, Elf_Addr v)
4e6a05fe TS	56	{
	57	return 0;
	58	}
	59
	60	static int apply_r_mips_32_rel(struct module me, u32 location, Elf_Addr v)
	61	{
	62	*location += v;
	63
	64	return 0;
	65	}
	66
4e6a05fe TS	67	static int apply_r_mips_26_rel(struct module me, u32 location, Elf_Addr v)
	68	{
	69	if (v % 4) {
6f9fdeb6 RB	70	pr_err("module %s: dangerous R_MIPS_26 REL relocation\n",
6f9fdeb6 RB	71	me->name);
4e6a05fe TS	72	return -ENOEXEC;
	73	}
	74
	75	if ((v & 0xf0000000) != (((unsigned long)location + 4) & 0xf0000000)) {
	76	printk(KERN_ERR
	77	"module %s: relocation overflow\n",
	78	me->name);
	79	return -ENOEXEC;
	80	}
	81
	82	location = (location & ~0x03ffffff) \|
70342287	83	((*location + (v >> 2)) & 0x03ffffff);
4e6a05fe TS	84
	85	return 0;
	86	}
	87
4e6a05fe TS	88	static int apply_r_mips_hi16_rel(struct module me, u32 location, Elf_Addr v)
	89	{
	90	struct mips_hi16 *n;
	91
	92	/*
	93	* We cannot relocate this one now because we don't know the value of
	94	* the carry we need to add. Save the information, and let LO16 do the
	95	* actual relocation.
	96	*/
	97	n = kmalloc(sizeof *n, GFP_KERNEL);
	98	if (!n)
	99	return -ENOMEM;
	100
	101	n->addr = (Elf_Addr *)location;
	102	n->value = v;
861667dc RB	103	n->next = me->arch.r_mips_hi16_list;
861667dc RB	104	me->arch.r_mips_hi16_list = n;
4e6a05fe TS	105
	106	return 0;
	107	}
	108
c54de490 RB	109	static void free_relocation_chain(struct mips_hi16 *l)
	110	{
	111	struct mips_hi16 *next;
	112
	113	while (l) {
	114	next = l->next;
	115	kfree(l);
	116	l = next;
	117	}
	118	}
	119
4e6a05fe TS	120	static int apply_r_mips_lo16_rel(struct module me, u32 location, Elf_Addr v)
	121	{
	122	unsigned long insnlo = *location;
c54de490	123	struct mips_hi16 *l;
4e6a05fe TS	124	Elf_Addr val, vallo;
4e6a05fe TS	125
70342287	126	/* Sign extend the addend we extract from the lo insn. */
4e6a05fe TS	127	vallo = ((insnlo & 0xffff) ^ 0x8000) - 0x8000;
4e6a05fe TS	128
861667dc	129	if (me->arch.r_mips_hi16_list != NULL) {
861667dc	130	l = me->arch.r_mips_hi16_list;
4e6a05fe	131	while (l != NULL) {
c54de490	132	struct mips_hi16 *next;
4e6a05fe TS	133	unsigned long insn;
	134
	135	/*
	136	* The value for the HI16 had best be the same.
	137	*/
	138	if (v != l->value)
	139	goto out_danger;
	140
	141	/*
	142	* Do the HI16 relocation. Note that we actually don't
	143	* need to know anything about the LO16 itself, except
	144	* where to find the low 16 bits of the addend needed
	145	* by the LO16.
	146	*/
	147	insn = *l->addr;
	148	val = ((insn & 0xffff) << 16) + vallo;
	149	val += v;
	150
	151	/*
	152	* Account for the sign extension that will happen in
	153	* the low bits.
	154	*/
	155	val = ((val >> 16) + ((val & 0x8000) != 0)) & 0xffff;
	156
	157	insn = (insn & ~0xffff) \| val;
	158	*l->addr = insn;
	159
	160	next = l->next;
	161	kfree(l);
	162	l = next;
	163	}
	164
861667dc	165	me->arch.r_mips_hi16_list = NULL;
4e6a05fe TS	166	}
	167
	168	/*
70342287	169	* Ok, we're done with the HI16 relocs. Now deal with the LO16.
4e6a05fe TS	170	*/
	171	val = v + vallo;
	172	insnlo = (insnlo & ~0xffff) \| (val & 0xffff);
	173	*location = insnlo;
	174
	175	return 0;
	176
	177	out_danger:
c54de490 RB	178	free_relocation_chain(l);
c54de490 RB	179	me->arch.r_mips_hi16_list = NULL;
d3cac35c	180
6f9fdeb6	181	pr_err("module %s: dangerous R_MIPS_LO16 REL relocation\n", me->name);
4e6a05fe TS	182
	183	return -ENOEXEC;
	184	}
	185
4e6a05fe TS	186	static int (reloc_handlers_rel[]) (struct module me, u32 *location,
	187	Elf_Addr v) = {
	188	[R_MIPS_NONE] = apply_r_mips_none,
	189	[R_MIPS_32] = apply_r_mips_32_rel,
	190	[R_MIPS_26] = apply_r_mips_26_rel,
	191	[R_MIPS_HI16] = apply_r_mips_hi16_rel,
	192	[R_MIPS_LO16] = apply_r_mips_lo16_rel
	193	};
	194
4e6a05fe TS	195	int apply_relocate(Elf_Shdr sechdrs, const char strtab,
	196	unsigned int symindex, unsigned int relsec,
	197	struct module *me)
	198	{
	199	Elf_Mips_Rel rel = (void ) sechdrs[relsec].sh_addr;
04211a57	200	int (handler)(struct module me, u32 *location, Elf_Addr v);
4e6a05fe TS	201	Elf_Sym *sym;
4e6a05fe TS	202	u32 *location;
04211a57	203	unsigned int i, type;
4e6a05fe TS	204	Elf_Addr v;
	205	int res;
	206
	207	pr_debug("Applying relocate section %u to %u\n", relsec,
	208	sechdrs[relsec].sh_info);
	209
861667dc	210	me->arch.r_mips_hi16_list = NULL;
4e6a05fe TS	211	for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
	212	/* This is where to make the change */
	213	location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
	214	+ rel[i].r_offset;
	215	/* This is the symbol it is referring to */
	216	sym = (Elf_Sym *)sechdrs[symindex].sh_addr
	217	+ ELF_MIPS_R_SYM(rel[i]);
0e66fff8	218	if (IS_ERR_VALUE(sym->st_value)) {
f3bf07b9 AN	219	/* Ignore unresolved weak symbol */
	220	if (ELF_ST_BIND(sym->st_info) == STB_WEAK)
	221	continue;
4e6a05fe TS	222	printk(KERN_WARNING "%s: Unknown symbol %s\n",
	223	me->name, strtab + sym->st_name);
	224	return -ENOENT;
	225	}
	226
04211a57 PB	227	type = ELF_MIPS_R_TYPE(rel[i]);
	228
	229	if (type < ARRAY_SIZE(reloc_handlers_rel))
	230	handler = reloc_handlers_rel[type];
	231	else
	232	handler = NULL;
4e6a05fe	233
04211a57 PB	234	if (!handler) {
	235	pr_err("%s: Unknown relocation type %u\n",
	236	me->name, type);
	237	return -EINVAL;
	238	}
	239
	240	v = sym->st_value;
	241	res = handler(me, location, v);
4e6a05fe TS	242	if (res)
	243	return res;
	244	}
	245
c54de490	246	/*
70342287	247	* Normally the hi16 list should be deallocated at this point. A
c54de490 RB	248	* malformed binary however could contain a series of R_MIPS_HI16
	249	* relocations not followed by a R_MIPS_LO16 relocation. In that
	250	* case, free up the list and return an error.
	251	*/
	252	if (me->arch.r_mips_hi16_list) {
	253	free_relocation_chain(me->arch.r_mips_hi16_list);
	254	me->arch.r_mips_hi16_list = NULL;
	255
	256	return -ENOEXEC;
	257	}
	258
4e6a05fe TS	259	return 0;
	260	}
	261
1da177e4 LT	262	/* Given an address, look for it in the module exception tables. */
	263	const struct exception_table_entry *search_module_dbetables(unsigned long addr)
	264	{
	265	unsigned long flags;
	266	const struct exception_table_entry *e = NULL;
	267	struct mod_arch_specific *dbe;
	268
	269	spin_lock_irqsave(&dbe_lock, flags);
	270	list_for_each_entry(dbe, &dbe_list, dbe_list) {
	271	e = search_extable(dbe->dbe_start, dbe->dbe_end - 1, addr);
	272	if (e)
	273	break;
	274	}
	275	spin_unlock_irqrestore(&dbe_lock, flags);
	276
	277	/* Now, if we found one, we are running inside it now, hence
70342287	278	we cannot unload the module, hence no refcnt needed. */
1da177e4 LT	279	return e;
	280	}
	281
3a4fa0a2	282	/* Put in dbe list if necessary. */
1da177e4 LT	283	int module_finalize(const Elf_Ehdr *hdr,
	284	const Elf_Shdr *sechdrs,
	285	struct module *me)
	286	{
	287	const Elf_Shdr *s;
	288	char secstrings = (void )hdr + sechdrs[hdr->e_shstrndx].sh_offset;
	289
94bb0c1a DD	290	/* Make jump label nops. */
	291	jump_label_apply_nops(me);
	292
1da177e4 LT	293	INIT_LIST_HEAD(&me->arch.dbe_list);
	294	for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) {
	295	if (strcmp("__dbe_table", secstrings + s->sh_name) != 0)
	296	continue;
	297	me->arch.dbe_start = (void *)s->sh_addr;
	298	me->arch.dbe_end = (void *)s->sh_addr + s->sh_size;
	299	spin_lock_irq(&dbe_lock);
	300	list_add(&me->arch.dbe_list, &dbe_list);
	301	spin_unlock_irq(&dbe_lock);
	302	}
	303	return 0;
	304	}
	305
	306	void module_arch_cleanup(struct module *mod)
	307	{
	308	spin_lock_irq(&dbe_lock);
	309	list_del(&mod->arch.dbe_list);
	310	spin_unlock_irq(&dbe_lock);
	311	}