[deliverable/linux.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/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)
{
	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 | __GFP_HIGHMEM,
				    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:
			*(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>
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
2d5bf28f AW	34	#include <asm/page.h>
	35	#include <asm/pgtable.h>
	36
	37	#if 0
c767a54b JP	38	#define DEBUGP(fmt, ...) \
c767a54b JP	39	printk(KERN_DEBUG fmt, ##__VA_ARGS__)
2d5bf28f	40	#else
c767a54b JP	41	#define DEBUGP(fmt, ...) \
	42	do { \
	43	if (0) \
	44	printk(KERN_DEBUG fmt, ##__VA_ARGS__); \
	45	} while (0)
2d5bf28f AW	46	#endif
2d5bf28f AW	47
e2b32e67 KC	48	#ifdef CONFIG_RANDOMIZE_BASE
e2b32e67 KC	49	static unsigned long module_load_offset;
69797daf	50	static int randomize_modules = 1;
e2b32e67	51
9dd721c6 KC	52	/* Mutex protects the module_load_offset. */
	53	static DEFINE_MUTEX(module_kaslr_mutex);
	54
69797daf BP	55	static int __init parse_nokaslr(char *p)
	56	{
	57	randomize_modules = 0;
	58	return 0;
	59	}
	60	early_param("nokaslr", parse_nokaslr);
	61
e2b32e67 KC	62	static unsigned long int get_module_load_offset(void)
e2b32e67 KC	63	{
69797daf	64	if (randomize_modules) {
9dd721c6	65	mutex_lock(&module_kaslr_mutex);
e2b32e67 KC	66	/*
	67	* Calculate the module_load_offset the first time this
	68	* code is called. Once calculated it stays the same until
	69	* reboot.
	70	*/
	71	if (module_load_offset == 0)
	72	module_load_offset =
	73	(get_random_int() % 1024 + 1) * PAGE_SIZE;
9dd721c6	74	mutex_unlock(&module_kaslr_mutex);
e2b32e67 KC	75	}
	76	return module_load_offset;
	77	}
	78	#else
	79	static unsigned long int get_module_load_offset(void)
	80	{
	81	return 0;
	82	}
	83	#endif
	84
0fdc83b9 AW	85	void *module_alloc(unsigned long size)
0fdc83b9 AW	86	{
bebf56a1 AR	87	void *p;
bebf56a1 AR	88
d0a21265	89	if (PAGE_ALIGN(size) > MODULES_LEN)
0fdc83b9	90	return NULL;
bebf56a1 AR	91
bebf56a1 AR	92	p = __vmalloc_node_range(size, MODULE_ALIGN,
e2b32e67 KC	93	MODULES_VADDR + get_module_load_offset(),
e2b32e67 KC	94	MODULES_END, GFP_KERNEL \| __GFP_HIGHMEM,
cb9e3c29	95	PAGE_KERNEL_EXEC, 0, NUMA_NO_NODE,
e2b32e67	96	__builtin_return_address(0));
bebf56a1 AR	97	if (p && (kasan_module_alloc(p, size) < 0)) {
	98	vfree(p);
	99	return NULL;
	100	}
	101
	102	return p;
0fdc83b9	103	}
0fdc83b9	104
0fdc83b9 AW	105	#ifdef CONFIG_X86_32
	106	int apply_relocate(Elf32_Shdr *sechdrs,
	107	const char *strtab,
	108	unsigned int symindex,
	109	unsigned int relsec,
	110	struct module *me)
	111	{
	112	unsigned int i;
	113	Elf32_Rel rel = (void )sechdrs[relsec].sh_addr;
	114	Elf32_Sym *sym;
	115	uint32_t *location;
	116
c767a54b JP	117	DEBUGP("Applying relocate section %u to %u\n",
c767a54b JP	118	relsec, sechdrs[relsec].sh_info);
0fdc83b9 AW	119	for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
	120	/* This is where to make the change */
	121	location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
	122	+ rel[i].r_offset;
	123	/* This is the symbol it is referring to. Note that all
	124	undefined symbols have been resolved. */
	125	sym = (Elf32_Sym *)sechdrs[symindex].sh_addr
	126	+ ELF32_R_SYM(rel[i].r_info);
	127
	128	switch (ELF32_R_TYPE(rel[i].r_info)) {
	129	case R_386_32:
	130	/* We add the value into the location given */
	131	*location += sym->st_value;
	132	break;
	133	case R_386_PC32:
2e76c283	134	/* Add the value, subtract its position */
0fdc83b9 AW	135	*location += sym->st_value - (uint32_t)location;
	136	break;
	137	default:
c767a54b	138	pr_err("%s: Unknown relocation: %u\n",
0fdc83b9 AW	139	me->name, ELF32_R_TYPE(rel[i].r_info));
	140	return -ENOEXEC;
	141	}
	142	}
	143	return 0;
	144	}
0fdc83b9 AW	145	#else /X86_64/
	146	int apply_relocate_add(Elf64_Shdr *sechdrs,
	147	const char *strtab,
	148	unsigned int symindex,
	149	unsigned int relsec,
	150	struct module *me)
	151	{
	152	unsigned int i;
	153	Elf64_Rela rel = (void )sechdrs[relsec].sh_addr;
	154	Elf64_Sym *sym;
	155	void *loc;
	156	u64 val;
	157
c767a54b JP	158	DEBUGP("Applying relocate section %u to %u\n",
c767a54b JP	159	relsec, sechdrs[relsec].sh_info);
0fdc83b9 AW	160	for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
	161	/* This is where to make the change */
	162	loc = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
	163	+ rel[i].r_offset;
	164
	165	/* This is the symbol it is referring to. Note that all
	166	undefined symbols have been resolved. */
	167	sym = (Elf64_Sym *)sechdrs[symindex].sh_addr
	168	+ ELF64_R_SYM(rel[i].r_info);
	169
	170	DEBUGP("type %d st_value %Lx r_addend %Lx loc %Lx\n",
c767a54b JP	171	(int)ELF64_R_TYPE(rel[i].r_info),
c767a54b JP	172	sym->st_value, rel[i].r_addend, (u64)loc);
0fdc83b9 AW	173
	174	val = sym->st_value + rel[i].r_addend;
	175
	176	switch (ELF64_R_TYPE(rel[i].r_info)) {
	177	case R_X86_64_NONE:
	178	break;
	179	case R_X86_64_64:
	180	(u64 )loc = val;
	181	break;
	182	case R_X86_64_32:
	183	(u32 )loc = val;
	184	if (val != (u32 )loc)
	185	goto overflow;
	186	break;
	187	case R_X86_64_32S:
	188	(s32 )loc = val;
	189	if ((s64)val != (s32 )loc)
	190	goto overflow;
	191	break;
	192	case R_X86_64_PC32:
	193	val -= (u64)loc;
	194	(u32 )loc = val;
	195	#if 0
	196	if ((s64)val != (s32 )loc)
	197	goto overflow;
	198	#endif
	199	break;
	200	default:
c767a54b	201	pr_err("%s: Unknown rela relocation: %llu\n",
0fdc83b9 AW	202	me->name, ELF64_R_TYPE(rel[i].r_info));
	203	return -ENOEXEC;
	204	}
	205	}
	206	return 0;
	207
	208	overflow:
c767a54b	209	pr_err("overflow in relocation type %d val %Lx\n",
0fdc83b9	210	(int)ELF64_R_TYPE(rel[i].r_info), val);
c767a54b	211	pr_err("`%s' likely not compiled with -mcmodel=kernel\n",
0fdc83b9 AW	212	me->name);
	213	return -ENOEXEC;
	214	}
0fdc83b9 AW	215	#endif
0fdc83b9 AW	216
2d5bf28f AW	217	int module_finalize(const Elf_Ehdr *hdr,
	218	const Elf_Shdr *sechdrs,
	219	struct module *me)
	220	{
	221	const Elf_Shdr s, text = NULL, alt = NULL, locks = NULL,
	222	*para = NULL;
	223	char secstrings = (void )hdr + sechdrs[hdr->e_shstrndx].sh_offset;
	224
	225	for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) {
	226	if (!strcmp(".text", secstrings + s->sh_name))
	227	text = s;
	228	if (!strcmp(".altinstructions", secstrings + s->sh_name))
	229	alt = s;
	230	if (!strcmp(".smp_locks", secstrings + s->sh_name))
	231	locks = s;
	232	if (!strcmp(".parainstructions", secstrings + s->sh_name))
	233	para = s;
	234	}
	235
	236	if (alt) {
	237	/* patch .altinstructions */
	238	void aseg = (void )alt->sh_addr;
	239	apply_alternatives(aseg, aseg + alt->sh_size);
	240	}
	241	if (locks && text) {
	242	void lseg = (void )locks->sh_addr;
	243	void tseg = (void )text->sh_addr;
	244	alternatives_smp_module_add(me, me->name,
	245	lseg, lseg + locks->sh_size,
	246	tseg, tseg + text->sh_size);
	247	}
	248
	249	if (para) {
	250	void pseg = (void )para->sh_addr;
	251	apply_paravirt(pseg, pseg + para->sh_size);
	252	}
	253
d9f5ab7b JB	254	/* make jump label nops */
	255	jump_label_apply_nops(me);
	256
5336377d	257	return 0;
2d5bf28f AW	258	}
	259
	260	void module_arch_cleanup(struct module *mod)
	261	{
	262	alternatives_smp_module_del(mod);
2d5bf28f	263	}