[linux-2.6-block.git] / arch / x86 / kernel / module.c

/*  Kernel module help for x86.
    Copyright (C) 2001 Rusty Russell.

    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
*/

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/moduleloader.h>
#include <linux/elf.h>
#include <linux/vmalloc.h>
#include <linux/fs.h>
#include <linux/string.h>
#include <linux/kernel.h>
#include <linux/bug.h>
#include <linux/mm.h>
#include <linux/gfp.h>
#include <linux/jump_label.h>
#include <linux/random.h>

#include <asm/page.h>
#include <asm/pgtable.h>

#if 0
#define DEBUGP(fmt, ...)				\
	printk(KERN_DEBUG fmt, ##__VA_ARGS__)
#else
#define DEBUGP(fmt, ...)				\
do {							\
	if (0)						\
		printk(KERN_DEBUG fmt, ##__VA_ARGS__);	\
} while (0)
#endif

#ifdef CONFIG_RANDOMIZE_BASE
static unsigned long module_load_offset;
static int randomize_modules = 1;

/* Mutex protects the module_load_offset. */
static DEFINE_MUTEX(module_kaslr_mutex);

static int __init parse_nokaslr(char *p)
{
	randomize_modules = 0;
	return 0;
}
early_param("nokaslr", parse_nokaslr);

static unsigned long int get_module_load_offset(void)
{
	if (randomize_modules) {
		mutex_lock(&module_kaslr_mutex);
		/*
		 * Calculate the module_load_offset the first time this
		 * code is called. Once calculated it stays the same until
		 * reboot.
		 */
		if (module_load_offset == 0)
			module_load_offset =
				(get_random_int() % 1024 + 1) * PAGE_SIZE;
		mutex_unlock(&module_kaslr_mutex);
	}
	return module_load_offset;
}
#else
static unsigned long int get_module_load_offset(void)
{
	return 0;
}
#endif

void *module_alloc(unsigned long size)
{
	if (PAGE_ALIGN(size) > MODULES_LEN)
		return NULL;
	return __vmalloc_node_range(size, 1,
				    MODULES_VADDR + get_module_load_offset(),
				    MODULES_END, GFP_KERNEL | __GFP_HIGHMEM,
				    PAGE_KERNEL_EXEC, 0, NUMA_NO_NODE,
				    __builtin_return_address(0));
}

#ifdef CONFIG_X86_32
int apply_relocate(Elf32_Shdr *sechdrs,
		   const char *strtab,
		   unsigned int symindex,
		   unsigned int relsec,
		   struct module *me)
{
	unsigned int i;
	Elf32_Rel *rel = (void *)sechdrs[relsec].sh_addr;
	Elf32_Sym *sym;
	uint32_t *location;

	DEBUGP("Applying relocate section %u to %u\n",
	       relsec, sechdrs[relsec].sh_info);
	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.  Note that all
		   undefined symbols have been resolved.  */
		sym = (Elf32_Sym *)sechdrs[symindex].sh_addr
			+ ELF32_R_SYM(rel[i].r_info);

		switch (ELF32_R_TYPE(rel[i].r_info)) {
		case R_386_32:
			/* We add the value into the location given */
			*location += sym->st_value;
			break;
		case R_386_PC32:
			/* Add the value, subtract its position */
			*location += sym->st_value - (uint32_t)location;
			break;
		default:
			pr_err("%s: Unknown relocation: %u\n",
			       me->name, ELF32_R_TYPE(rel[i].r_info));
			return -ENOEXEC;
		}
	}
	return 0;
}
#else /*X86_64*/
int apply_relocate_add(Elf64_Shdr *sechdrs,
		   const char *strtab,
		   unsigned int symindex,
		   unsigned int relsec,
		   struct module *me)
{
	unsigned int i;
	Elf64_Rela *rel = (void *)sechdrs[relsec].sh_addr;
	Elf64_Sym *sym;
	void *loc;
	u64 val;

	DEBUGP("Applying relocate section %u to %u\n",
	       relsec, sechdrs[relsec].sh_info);
	for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
		/* This is where to make the change */
		loc = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
			+ rel[i].r_offset;

		/* This is the symbol it is referring to.  Note that all
		   undefined symbols have been resolved.  */
		sym = (Elf64_Sym *)sechdrs[symindex].sh_addr
			+ ELF64_R_SYM(rel[i].r_info);

		DEBUGP("type %d st_value %Lx r_addend %Lx loc %Lx\n",
		       (int)ELF64_R_TYPE(rel[i].r_info),
		       sym->st_value, rel[i].r_addend, (u64)loc);

		val = sym->st_value + rel[i].r_addend;

		switch (ELF64_R_TYPE(rel[i].r_info)) {
		case R_X86_64_NONE:
			break;
		case R_X86_64_64:
			*(u64 *)loc = val;
			break;
		case R_X86_64_32:
			*(u32 *)loc = val;
			if (val != *(u32 *)loc)
				goto overflow;
			break;
		case R_X86_64_32S:
			*(s32 *)loc = val;
			if ((s64)val != *(s32 *)loc)
				goto overflow;
			break;
		case R_X86_64_PC32:
			val -= (u64)loc;
			*(u32 *)loc = val;
#if 0
			if ((s64)val != *(s32 *)loc)
				goto overflow;
#endif
			break;
		default:
			pr_err("%s: Unknown rela relocation: %llu\n",
			       me->name, ELF64_R_TYPE(rel[i].r_info));
			return -ENOEXEC;
		}
	}
	return 0;

overflow:
	pr_err("overflow in relocation type %d val %Lx\n",
	       (int)ELF64_R_TYPE(rel[i].r_info), val);
	pr_err("`%s' likely not compiled with -mcmodel=kernel\n",
	       me->name);
	return -ENOEXEC;
}
#endif

int module_finalize(const Elf_Ehdr *hdr,
		    const Elf_Shdr *sechdrs,
		    struct module *me)
{
	const Elf_Shdr *s, *text = NULL, *alt = NULL, *locks = NULL,
		*para = NULL;
	char *secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;

	for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) {
		if (!strcmp(".text", secstrings + s->sh_name))
			text = s;
		if (!strcmp(".altinstructions", secstrings + s->sh_name))
			alt = s;
		if (!strcmp(".smp_locks", secstrings + s->sh_name))
			locks = s;
		if (!strcmp(".parainstructions", secstrings + s->sh_name))
			para = s;
	}

	if (alt) {
		/* patch .altinstructions */
		void *aseg = (void *)alt->sh_addr;
		apply_alternatives(aseg, aseg + alt->sh_size);
	}
	if (locks && text) {
		void *lseg = (void *)locks->sh_addr;
		void *tseg = (void *)text->sh_addr;
		alternatives_smp_module_add(me, me->name,
					    lseg, lseg + locks->sh_size,
					    tseg, tseg + text->sh_size);
	}

	if (para) {
		void *pseg = (void *)para->sh_addr;
		apply_paravirt(pseg, pseg + para->sh_size);
	}

	/* make jump label nops */
	jump_label_apply_nops(me);

	return 0;
}

void module_arch_cleanup(struct module *mod)
{
	alternatives_smp_module_del(mod);
}
Commit	Line	Data
2d5bf28f AW	1	/* Kernel module help for x86.
	2	Copyright (C) 2001 Rusty Russell.
	3
	4	This program is free software; you can redistribute it and/or modify
	5	it under the terms of the GNU General Public License as published by
	6	the Free Software Foundation; either version 2 of the License, or
	7	(at your option) any later version.
	8
	9	This program is distributed in the hope that it will be useful,
	10	but WITHOUT ANY WARRANTY; without even the implied warranty of
	11	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	12	GNU General Public License for more details.
	13
	14	You should have received a copy of the GNU General Public License
	15	along with this program; if not, write to the Free Software
	16	Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
	17	*/
c767a54b JP	18
	19	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
	20
2d5bf28f AW	21	#include <linux/moduleloader.h>
	22	#include <linux/elf.h>
	23	#include <linux/vmalloc.h>
	24	#include <linux/fs.h>
	25	#include <linux/string.h>
	26	#include <linux/kernel.h>
	27	#include <linux/bug.h>
	28	#include <linux/mm.h>
5a0e3ad6	29	#include <linux/gfp.h>
d430d3d7	30	#include <linux/jump_label.h>
e2b32e67	31	#include <linux/random.h>
2d5bf28f	32
2d5bf28f AW	33	#include <asm/page.h>
	34	#include <asm/pgtable.h>
	35
	36	#if 0
c767a54b JP	37	#define DEBUGP(fmt, ...) \
c767a54b JP	38	printk(KERN_DEBUG fmt, ##__VA_ARGS__)
2d5bf28f	39	#else
c767a54b JP	40	#define DEBUGP(fmt, ...) \
	41	do { \
	42	if (0) \
	43	printk(KERN_DEBUG fmt, ##__VA_ARGS__); \
	44	} while (0)
2d5bf28f AW	45	#endif
2d5bf28f AW	46
e2b32e67 KC	47	#ifdef CONFIG_RANDOMIZE_BASE
	48	static unsigned long module_load_offset;
	49	static int randomize_modules = 1;
	50
9dd721c6 KC	51	/* Mutex protects the module_load_offset. */
	52	static DEFINE_MUTEX(module_kaslr_mutex);
	53
e2b32e67 KC	54	static int __init parse_nokaslr(char *p)
	55	{
	56	randomize_modules = 0;
	57	return 0;
	58	}
	59	early_param("nokaslr", parse_nokaslr);
	60
	61	static unsigned long int get_module_load_offset(void)
	62	{
	63	if (randomize_modules) {
9dd721c6	64	mutex_lock(&module_kaslr_mutex);
e2b32e67 KC	65	/*
	66	* Calculate the module_load_offset the first time this
	67	* code is called. Once calculated it stays the same until
	68	* reboot.
	69	*/
	70	if (module_load_offset == 0)
	71	module_load_offset =
	72	(get_random_int() % 1024 + 1) * PAGE_SIZE;
9dd721c6	73	mutex_unlock(&module_kaslr_mutex);
e2b32e67 KC	74	}
	75	return module_load_offset;
	76	}
	77	#else
	78	static unsigned long int get_module_load_offset(void)
	79	{
	80	return 0;
	81	}
	82	#endif
	83
0fdc83b9 AW	84	void *module_alloc(unsigned long size)
0fdc83b9 AW	85	{
d0a21265	86	if (PAGE_ALIGN(size) > MODULES_LEN)
0fdc83b9	87	return NULL;
e2b32e67 KC	88	return __vmalloc_node_range(size, 1,
	89	MODULES_VADDR + get_module_load_offset(),
	90	MODULES_END, GFP_KERNEL \| __GFP_HIGHMEM,
cb9e3c29	91	PAGE_KERNEL_EXEC, 0, NUMA_NO_NODE,
e2b32e67	92	__builtin_return_address(0));
0fdc83b9	93	}
0fdc83b9	94
0fdc83b9 AW	95	#ifdef CONFIG_X86_32
	96	int apply_relocate(Elf32_Shdr *sechdrs,
	97	const char *strtab,
	98	unsigned int symindex,
	99	unsigned int relsec,
	100	struct module *me)
	101	{
	102	unsigned int i;
	103	Elf32_Rel rel = (void )sechdrs[relsec].sh_addr;
	104	Elf32_Sym *sym;
	105	uint32_t *location;
	106
c767a54b JP	107	DEBUGP("Applying relocate section %u to %u\n",
c767a54b JP	108	relsec, sechdrs[relsec].sh_info);
0fdc83b9 AW	109	for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
	110	/* This is where to make the change */
	111	location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
	112	+ rel[i].r_offset;
	113	/* This is the symbol it is referring to. Note that all
	114	undefined symbols have been resolved. */
	115	sym = (Elf32_Sym *)sechdrs[symindex].sh_addr
	116	+ ELF32_R_SYM(rel[i].r_info);
	117
	118	switch (ELF32_R_TYPE(rel[i].r_info)) {
	119	case R_386_32:
	120	/* We add the value into the location given */
	121	*location += sym->st_value;
	122	break;
	123	case R_386_PC32:
2e76c283	124	/* Add the value, subtract its position */
0fdc83b9 AW	125	*location += sym->st_value - (uint32_t)location;
	126	break;
	127	default:
c767a54b	128	pr_err("%s: Unknown relocation: %u\n",
0fdc83b9 AW	129	me->name, ELF32_R_TYPE(rel[i].r_info));
	130	return -ENOEXEC;
	131	}
	132	}
	133	return 0;
	134	}
0fdc83b9 AW	135	#else /X86_64/
	136	int apply_relocate_add(Elf64_Shdr *sechdrs,
	137	const char *strtab,
	138	unsigned int symindex,
	139	unsigned int relsec,
	140	struct module *me)
	141	{
	142	unsigned int i;
	143	Elf64_Rela rel = (void )sechdrs[relsec].sh_addr;
	144	Elf64_Sym *sym;
	145	void *loc;
	146	u64 val;
	147
c767a54b JP	148	DEBUGP("Applying relocate section %u to %u\n",
c767a54b JP	149	relsec, sechdrs[relsec].sh_info);
0fdc83b9 AW	150	for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
	151	/* This is where to make the change */
	152	loc = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
	153	+ rel[i].r_offset;
	154
	155	/* This is the symbol it is referring to. Note that all
	156	undefined symbols have been resolved. */
	157	sym = (Elf64_Sym *)sechdrs[symindex].sh_addr
	158	+ ELF64_R_SYM(rel[i].r_info);
	159
	160	DEBUGP("type %d st_value %Lx r_addend %Lx loc %Lx\n",
c767a54b JP	161	(int)ELF64_R_TYPE(rel[i].r_info),
c767a54b JP	162	sym->st_value, rel[i].r_addend, (u64)loc);
0fdc83b9 AW	163
	164	val = sym->st_value + rel[i].r_addend;
	165
	166	switch (ELF64_R_TYPE(rel[i].r_info)) {
	167	case R_X86_64_NONE:
	168	break;
	169	case R_X86_64_64:
	170	(u64 )loc = val;
	171	break;
	172	case R_X86_64_32:
	173	(u32 )loc = val;
	174	if (val != (u32 )loc)
	175	goto overflow;
	176	break;
	177	case R_X86_64_32S:
	178	(s32 )loc = val;
	179	if ((s64)val != (s32 )loc)
	180	goto overflow;
	181	break;
	182	case R_X86_64_PC32:
	183	val -= (u64)loc;
	184	(u32 )loc = val;
	185	#if 0
	186	if ((s64)val != (s32 )loc)
	187	goto overflow;
	188	#endif
	189	break;
	190	default:
c767a54b	191	pr_err("%s: Unknown rela relocation: %llu\n",
0fdc83b9 AW	192	me->name, ELF64_R_TYPE(rel[i].r_info));
	193	return -ENOEXEC;
	194	}
	195	}
	196	return 0;
	197
	198	overflow:
c767a54b	199	pr_err("overflow in relocation type %d val %Lx\n",
0fdc83b9	200	(int)ELF64_R_TYPE(rel[i].r_info), val);
c767a54b	201	pr_err("`%s' likely not compiled with -mcmodel=kernel\n",
0fdc83b9 AW	202	me->name);
	203	return -ENOEXEC;
	204	}
0fdc83b9 AW	205	#endif
0fdc83b9 AW	206
2d5bf28f AW	207	int module_finalize(const Elf_Ehdr *hdr,
	208	const Elf_Shdr *sechdrs,
	209	struct module *me)
	210	{
	211	const Elf_Shdr s, text = NULL, alt = NULL, locks = NULL,
	212	*para = NULL;
	213	char secstrings = (void )hdr + sechdrs[hdr->e_shstrndx].sh_offset;
	214
	215	for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) {
	216	if (!strcmp(".text", secstrings + s->sh_name))
	217	text = s;
	218	if (!strcmp(".altinstructions", secstrings + s->sh_name))
	219	alt = s;
	220	if (!strcmp(".smp_locks", secstrings + s->sh_name))
	221	locks = s;
	222	if (!strcmp(".parainstructions", secstrings + s->sh_name))
	223	para = s;
	224	}
	225
	226	if (alt) {
	227	/* patch .altinstructions */
	228	void aseg = (void )alt->sh_addr;
	229	apply_alternatives(aseg, aseg + alt->sh_size);
	230	}
	231	if (locks && text) {
	232	void lseg = (void )locks->sh_addr;
	233	void tseg = (void )text->sh_addr;
	234	alternatives_smp_module_add(me, me->name,
	235	lseg, lseg + locks->sh_size,
	236	tseg, tseg + text->sh_size);
	237	}
	238
	239	if (para) {
	240	void pseg = (void )para->sh_addr;
	241	apply_paravirt(pseg, pseg + para->sh_size);
	242	}
	243
d9f5ab7b JB	244	/* make jump label nops */
	245	jump_label_apply_nops(me);
	246
5336377d	247	return 0;
2d5bf28f AW	248	}
	249
	250	void module_arch_cleanup(struct module *mod)
	251	{
	252	alternatives_smp_module_del(mod);
2d5bf28f	253	}