[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/kasan.h>
#include <linux/bug.h>
#include <linux/mm.h>
#include <linux/gfp.h>
#include <linux/jump_label.h>
#include <linux/random.h>

#include <asm/text-patching.h>
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/setup.h>
#include <asm/unwind.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;

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

static unsigned long int get_module_load_offset(void)
{
	if (kaslr_enabled()) {
		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)
{
	void *p;

	if (PAGE_ALIGN(size) > MODULES_LEN)
		return NULL;

	p = __vmalloc_node_range(size, MODULE_ALIGN,
				    MODULES_VADDR + get_module_load_offset(),
				    MODULES_END, GFP_KERNEL,
				    PAGE_KERNEL_EXEC, 0, NUMA_NO_NODE,
				    __builtin_return_address(0));
	if (p && (kasan_module_alloc(p, size) < 0)) {
		vfree(p);
		return NULL;
	}

	return p;
}

#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:
			if (*(u64 *)loc != 0)
				goto invalid_relocation;
			*(u64 *)loc = val;
			break;
		case R_X86_64_32:
			if (*(u32 *)loc != 0)
				goto invalid_relocation;
			*(u32 *)loc = val;
			if (val != *(u32 *)loc)
				goto overflow;
			break;
		case R_X86_64_32S:
			if (*(s32 *)loc != 0)
				goto invalid_relocation;
			*(s32 *)loc = val;
			if ((s64)val != *(s32 *)loc)
				goto overflow;
			break;
		case R_X86_64_PC32:
		case R_X86_64_PLT32:
			if (*(u32 *)loc != 0)
				goto invalid_relocation;
			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;

invalid_relocation:
	pr_err("x86/modules: Skipping invalid relocation target, existing value is nonzero for type %d, loc %p, val %Lx\n",
	       (int)ELF64_R_TYPE(rel[i].r_info), loc, val);
	return -ENOEXEC;

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, *orc = NULL, *orc_ip = 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 (!strcmp(".orc_unwind", secstrings + s->sh_name))
			orc = s;
		if (!strcmp(".orc_unwind_ip", secstrings + s->sh_name))
			orc_ip = 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);

	if (orc && orc_ip)
		unwind_module_init(me, (void *)orc_ip->sh_addr, orc_ip->sh_size,
				   (void *)orc->sh_addr, orc->sh_size);

	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>
bebf56a1	27	#include <linux/kasan.h>
2d5bf28f AW	28	#include <linux/bug.h>
2d5bf28f AW	29	#include <linux/mm.h>
5a0e3ad6	30	#include <linux/gfp.h>
d430d3d7	31	#include <linux/jump_label.h>
e2b32e67	32	#include <linux/random.h>
2d5bf28f	33
35de5b06	34	#include <asm/text-patching.h>
2d5bf28f AW	35	#include <asm/page.h>
2d5bf28f AW	36	#include <asm/pgtable.h>
78cac48c	37	#include <asm/setup.h>
ee9f8fce	38	#include <asm/unwind.h>
2d5bf28f AW	39
2d5bf28f AW	40	#if 0
c767a54b JP	41	#define DEBUGP(fmt, ...) \
c767a54b JP	42	printk(KERN_DEBUG fmt, ##__VA_ARGS__)
2d5bf28f	43	#else
c767a54b JP	44	#define DEBUGP(fmt, ...) \
	45	do { \
	46	if (0) \
	47	printk(KERN_DEBUG fmt, ##__VA_ARGS__); \
	48	} while (0)
2d5bf28f AW	49	#endif
2d5bf28f AW	50
e2b32e67 KC	51	#ifdef CONFIG_RANDOMIZE_BASE
e2b32e67 KC	52	static unsigned long module_load_offset;
e2b32e67	53
9dd721c6 KC	54	/* Mutex protects the module_load_offset. */
	55	static DEFINE_MUTEX(module_kaslr_mutex);
	56
e2b32e67 KC	57	static unsigned long int get_module_load_offset(void)
e2b32e67 KC	58	{
78cac48c	59	if (kaslr_enabled()) {
9dd721c6	60	mutex_lock(&module_kaslr_mutex);
e2b32e67 KC	61	/*
	62	* Calculate the module_load_offset the first time this
	63	* code is called. Once calculated it stays the same until
	64	* reboot.
	65	*/
	66	if (module_load_offset == 0)
	67	module_load_offset =
	68	(get_random_int() % 1024 + 1) * PAGE_SIZE;
9dd721c6	69	mutex_unlock(&module_kaslr_mutex);
e2b32e67 KC	70	}
	71	return module_load_offset;
	72	}
	73	#else
	74	static unsigned long int get_module_load_offset(void)
	75	{
	76	return 0;
	77	}
	78	#endif
	79
0fdc83b9 AW	80	void *module_alloc(unsigned long size)
0fdc83b9 AW	81	{
bebf56a1 AR	82	void *p;
bebf56a1 AR	83
d0a21265	84	if (PAGE_ALIGN(size) > MODULES_LEN)
0fdc83b9	85	return NULL;
bebf56a1 AR	86
bebf56a1 AR	87	p = __vmalloc_node_range(size, MODULE_ALIGN,
e2b32e67	88	MODULES_VADDR + get_module_load_offset(),
19809c2d	89	MODULES_END, GFP_KERNEL,
cb9e3c29	90	PAGE_KERNEL_EXEC, 0, NUMA_NO_NODE,
e2b32e67	91	__builtin_return_address(0));
bebf56a1 AR	92	if (p && (kasan_module_alloc(p, size) < 0)) {
	93	vfree(p);
	94	return NULL;
	95	}
	96
	97	return p;
0fdc83b9	98	}
0fdc83b9	99
0fdc83b9 AW	100	#ifdef CONFIG_X86_32
	101	int apply_relocate(Elf32_Shdr *sechdrs,
	102	const char *strtab,
	103	unsigned int symindex,
	104	unsigned int relsec,
	105	struct module *me)
	106	{
	107	unsigned int i;
	108	Elf32_Rel rel = (void )sechdrs[relsec].sh_addr;
	109	Elf32_Sym *sym;
	110	uint32_t *location;
	111
c767a54b JP	112	DEBUGP("Applying relocate section %u to %u\n",
c767a54b JP	113	relsec, sechdrs[relsec].sh_info);
0fdc83b9 AW	114	for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
	115	/* This is where to make the change */
	116	location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
	117	+ rel[i].r_offset;
	118	/* This is the symbol it is referring to. Note that all
	119	undefined symbols have been resolved. */
	120	sym = (Elf32_Sym *)sechdrs[symindex].sh_addr
	121	+ ELF32_R_SYM(rel[i].r_info);
	122
	123	switch (ELF32_R_TYPE(rel[i].r_info)) {
	124	case R_386_32:
	125	/* We add the value into the location given */
	126	*location += sym->st_value;
	127	break;
	128	case R_386_PC32:
2e76c283	129	/* Add the value, subtract its position */
0fdc83b9 AW	130	*location += sym->st_value - (uint32_t)location;
	131	break;
	132	default:
c767a54b	133	pr_err("%s: Unknown relocation: %u\n",
0fdc83b9 AW	134	me->name, ELF32_R_TYPE(rel[i].r_info));
	135	return -ENOEXEC;
	136	}
	137	}
	138	return 0;
	139	}
0fdc83b9 AW	140	#else /X86_64/
	141	int apply_relocate_add(Elf64_Shdr *sechdrs,
	142	const char *strtab,
	143	unsigned int symindex,
	144	unsigned int relsec,
	145	struct module *me)
	146	{
	147	unsigned int i;
	148	Elf64_Rela rel = (void )sechdrs[relsec].sh_addr;
	149	Elf64_Sym *sym;
	150	void *loc;
	151	u64 val;
	152
c767a54b JP	153	DEBUGP("Applying relocate section %u to %u\n",
c767a54b JP	154	relsec, sechdrs[relsec].sh_info);
0fdc83b9 AW	155	for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
	156	/* This is where to make the change */
	157	loc = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
	158	+ rel[i].r_offset;
	159
	160	/* This is the symbol it is referring to. Note that all
	161	undefined symbols have been resolved. */
	162	sym = (Elf64_Sym *)sechdrs[symindex].sh_addr
	163	+ ELF64_R_SYM(rel[i].r_info);
	164
	165	DEBUGP("type %d st_value %Lx r_addend %Lx loc %Lx\n",
c767a54b JP	166	(int)ELF64_R_TYPE(rel[i].r_info),
c767a54b JP	167	sym->st_value, rel[i].r_addend, (u64)loc);
0fdc83b9 AW	168
	169	val = sym->st_value + rel[i].r_addend;
	170
	171	switch (ELF64_R_TYPE(rel[i].r_info)) {
	172	case R_X86_64_NONE:
	173	break;
	174	case R_X86_64_64:
eda9cec4 JP	175	if ((u64 )loc != 0)
eda9cec4 JP	176	goto invalid_relocation;
0fdc83b9 AW	177	(u64 )loc = val;
	178	break;
	179	case R_X86_64_32:
eda9cec4 JP	180	if ((u32 )loc != 0)
eda9cec4 JP	181	goto invalid_relocation;
0fdc83b9 AW	182	(u32 )loc = val;
	183	if (val != (u32 )loc)
	184	goto overflow;
	185	break;
	186	case R_X86_64_32S:
eda9cec4 JP	187	if ((s32 )loc != 0)
eda9cec4 JP	188	goto invalid_relocation;
0fdc83b9 AW	189	(s32 )loc = val;
	190	if ((s64)val != (s32 )loc)
	191	goto overflow;
	192	break;
	193	case R_X86_64_PC32:
b21ebf2f	194	case R_X86_64_PLT32:
eda9cec4 JP	195	if ((u32 )loc != 0)
eda9cec4 JP	196	goto invalid_relocation;
0fdc83b9 AW	197	val -= (u64)loc;
	198	(u32 )loc = val;
	199	#if 0
	200	if ((s64)val != (s32 )loc)
	201	goto overflow;
	202	#endif
	203	break;
	204	default:
c767a54b	205	pr_err("%s: Unknown rela relocation: %llu\n",
0fdc83b9 AW	206	me->name, ELF64_R_TYPE(rel[i].r_info));
	207	return -ENOEXEC;
	208	}
	209	}
	210	return 0;
	211
eda9cec4 JP	212	invalid_relocation:
	213	pr_err("x86/modules: Skipping invalid relocation target, existing value is nonzero for type %d, loc %p, val %Lx\n",
	214	(int)ELF64_R_TYPE(rel[i].r_info), loc, val);
	215	return -ENOEXEC;
	216
0fdc83b9	217	overflow:
c767a54b	218	pr_err("overflow in relocation type %d val %Lx\n",
0fdc83b9	219	(int)ELF64_R_TYPE(rel[i].r_info), val);
c767a54b	220	pr_err("`%s' likely not compiled with -mcmodel=kernel\n",
0fdc83b9 AW	221	me->name);
	222	return -ENOEXEC;
	223	}
0fdc83b9 AW	224	#endif
0fdc83b9 AW	225
2d5bf28f AW	226	int module_finalize(const Elf_Ehdr *hdr,
	227	const Elf_Shdr *sechdrs,
	228	struct module *me)
	229	{
	230	const Elf_Shdr s, text = NULL, alt = NULL, locks = NULL,
ee9f8fce	231	para = NULL, orc = NULL, *orc_ip = NULL;
2d5bf28f AW	232	char secstrings = (void )hdr + sechdrs[hdr->e_shstrndx].sh_offset;
	233
	234	for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) {
	235	if (!strcmp(".text", secstrings + s->sh_name))
	236	text = s;
	237	if (!strcmp(".altinstructions", secstrings + s->sh_name))
	238	alt = s;
	239	if (!strcmp(".smp_locks", secstrings + s->sh_name))
	240	locks = s;
	241	if (!strcmp(".parainstructions", secstrings + s->sh_name))
	242	para = s;
ee9f8fce JP	243	if (!strcmp(".orc_unwind", secstrings + s->sh_name))
	244	orc = s;
	245	if (!strcmp(".orc_unwind_ip", secstrings + s->sh_name))
	246	orc_ip = s;
2d5bf28f AW	247	}
	248
	249	if (alt) {
	250	/* patch .altinstructions */
	251	void aseg = (void )alt->sh_addr;
	252	apply_alternatives(aseg, aseg + alt->sh_size);
	253	}
	254	if (locks && text) {
	255	void lseg = (void )locks->sh_addr;
	256	void tseg = (void )text->sh_addr;
	257	alternatives_smp_module_add(me, me->name,
	258	lseg, lseg + locks->sh_size,
	259	tseg, tseg + text->sh_size);
	260	}
	261
	262	if (para) {
	263	void pseg = (void )para->sh_addr;
	264	apply_paravirt(pseg, pseg + para->sh_size);
	265	}
	266
d9f5ab7b JB	267	/* make jump label nops */
	268	jump_label_apply_nops(me);
	269
ee9f8fce JP	270	if (orc && orc_ip)
	271	unwind_module_init(me, (void *)orc_ip->sh_addr, orc_ip->sh_size,
	272	(void *)orc->sh_addr, orc->sh_size);
	273
5336377d	274	return 0;
2d5bf28f AW	275	}
	276
	277	void module_arch_cleanup(struct module *mod)
	278	{
	279	alternatives_smp_module_del(mod);
2d5bf28f	280	}