[mirror_ubuntu-artful-kernel.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>

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