[mirror_ubuntu-bionic-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
*/
#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 <asm/system.h>
#include <asm/page.h>
#include <asm/pgtable.h>

#if 0
#define DEBUGP printk
#else
#define DEBUGP(fmt...)
#endif

void *module_alloc(unsigned long size)
{
	struct vm_struct *area;

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

	area = __get_vm_area(size, VM_ALLOC, MODULES_VADDR, MODULES_END);
	if (!area)
		return NULL;

	return __vmalloc_area(area, GFP_KERNEL | __GFP_HIGHMEM,
					PAGE_KERNEL_EXEC);
}

/* Free memory returned from module_alloc */
void module_free(struct module *mod, void *module_region)
{
	vfree(module_region);
}

/* We don't need anything special. */
int module_frob_arch_sections(Elf_Ehdr *hdr,
			      Elf_Shdr *sechdrs,
			      char *secstrings,
			      struct module *mod)
{
	return 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 postition */
			*location += sym->st_value - (uint32_t)location;
			break;
		default:
			printk(KERN_ERR "module %s: Unknown relocation: %u\n",
			       me->name, ELF32_R_TYPE(rel[i].r_info));
			return -ENOEXEC;
		}
	}
	return 0;
}

int apply_relocate_add(Elf32_Shdr *sechdrs,
		       const char *strtab,
		       unsigned int symindex,
		       unsigned int relsec,
		       struct module *me)
{
	printk(KERN_ERR "module %s: ADD RELOCATION unsupported\n",
	       me->name);
	return -ENOEXEC;
}
#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:
			printk(KERN_ERR "module %s: Unknown rela relocation: %llu\n",
			       me->name, ELF64_R_TYPE(rel[i].r_info));
			return -ENOEXEC;
		}
	}
	return 0;

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

int apply_relocate(Elf_Shdr *sechdrs,
		   const char *strtab,
		   unsigned int symindex,
		   unsigned int relsec,
		   struct module *me)
{
	printk(KERN_ERR "non add relocation not supported\n");
	return -ENOSYS;
}

#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);
	}

	return module_bug_finalize(hdr, sechdrs, me);
}

void module_arch_cleanup(struct module *mod)
{
	alternatives_smp_module_del(mod);
	module_bug_cleanup(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	*/
	18	#include <linux/moduleloader.h>
	19	#include <linux/elf.h>
	20	#include <linux/vmalloc.h>
	21	#include <linux/fs.h>
	22	#include <linux/string.h>
	23	#include <linux/kernel.h>
	24	#include <linux/bug.h>
	25	#include <linux/mm.h>
	26
	27	#include <asm/system.h>
	28	#include <asm/page.h>
	29	#include <asm/pgtable.h>
	30
	31	#if 0
	32	#define DEBUGP printk
	33	#else
	34	#define DEBUGP(fmt...)
	35	#endif
	36
0fdc83b9 AW	37	void *module_alloc(unsigned long size)
	38	{
	39	struct vm_struct *area;
	40
	41	if (!size)
	42	return NULL;
	43	size = PAGE_ALIGN(size);
	44	if (size > MODULES_LEN)
	45	return NULL;
	46
	47	area = __get_vm_area(size, VM_ALLOC, MODULES_VADDR, MODULES_END);
	48	if (!area)
	49	return NULL;
	50
c398df30 AW	51	return __vmalloc_area(area, GFP_KERNEL \| __GFP_HIGHMEM,
c398df30 AW	52	PAGE_KERNEL_EXEC);
0fdc83b9	53	}
0fdc83b9	54
2d5bf28f AW	55	/* Free memory returned from module_alloc */
	56	void module_free(struct module mod, void module_region)
	57	{
	58	vfree(module_region);
2d5bf28f AW	59	}
	60
	61	/* We don't need anything special. */
	62	int module_frob_arch_sections(Elf_Ehdr *hdr,
	63	Elf_Shdr *sechdrs,
	64	char *secstrings,
	65	struct module *mod)
	66	{
	67	return 0;
	68	}
	69
0fdc83b9 AW	70	#ifdef CONFIG_X86_32
	71	int apply_relocate(Elf32_Shdr *sechdrs,
	72	const char *strtab,
	73	unsigned int symindex,
	74	unsigned int relsec,
	75	struct module *me)
	76	{
	77	unsigned int i;
	78	Elf32_Rel rel = (void )sechdrs[relsec].sh_addr;
	79	Elf32_Sym *sym;
	80	uint32_t *location;
	81
	82	DEBUGP("Applying relocate section %u to %u\n", relsec,
	83	sechdrs[relsec].sh_info);
	84	for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
	85	/* This is where to make the change */
	86	location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
	87	+ rel[i].r_offset;
	88	/* This is the symbol it is referring to. Note that all
	89	undefined symbols have been resolved. */
	90	sym = (Elf32_Sym *)sechdrs[symindex].sh_addr
	91	+ ELF32_R_SYM(rel[i].r_info);
	92
	93	switch (ELF32_R_TYPE(rel[i].r_info)) {
	94	case R_386_32:
	95	/* We add the value into the location given */
	96	*location += sym->st_value;
	97	break;
	98	case R_386_PC32:
	99	/* Add the value, subtract its postition */
	100	*location += sym->st_value - (uint32_t)location;
	101	break;
	102	default:
	103	printk(KERN_ERR "module %s: Unknown relocation: %u\n",
	104	me->name, ELF32_R_TYPE(rel[i].r_info));
	105	return -ENOEXEC;
	106	}
	107	}
	108	return 0;
	109	}
	110
	111	int apply_relocate_add(Elf32_Shdr *sechdrs,
	112	const char *strtab,
	113	unsigned int symindex,
	114	unsigned int relsec,
	115	struct module *me)
	116	{
	117	printk(KERN_ERR "module %s: ADD RELOCATION unsupported\n",
	118	me->name);
	119	return -ENOEXEC;
	120	}
	121	#else /X86_64/
	122	int apply_relocate_add(Elf64_Shdr *sechdrs,
	123	const char *strtab,
	124	unsigned int symindex,
	125	unsigned int relsec,
	126	struct module *me)
	127	{
	128	unsigned int i;
	129	Elf64_Rela rel = (void )sechdrs[relsec].sh_addr;
	130	Elf64_Sym *sym;
	131	void *loc;
	132	u64 val;
	133
134	DEBUGP("Applying relocate section %u to %u\n", relsec,
135	sechdrs[relsec].sh_info);
136	for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
137	/* This is where to make the change */
138	loc = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
139	+ rel[i].r_offset;
140
141	/* This is the symbol it is referring to. Note that all
142	undefined symbols have been resolved. */
143	sym = (Elf64_Sym *)sechdrs[symindex].sh_addr
144	+ ELF64_R_SYM(rel[i].r_info);
145
146	DEBUGP("type %d st_value %Lx r_addend %Lx loc %Lx\n",
147	(int)ELF64_R_TYPE(rel[i].r_info),
148	sym->st_value, rel[i].r_addend, (u64)loc);
149
150	val = sym->st_value + rel[i].r_addend;
151
152	switch (ELF64_R_TYPE(rel[i].r_info)) {
153	case R_X86_64_NONE:
154	break;
155	case R_X86_64_64:
156	(u64 )loc = val;
157	break;
158	case R_X86_64_32:
159	(u32 )loc = val;
160	if (val != (u32 )loc)
161	goto overflow;
162	break;
163	case R_X86_64_32S:
164	(s32 )loc = val;
165	if ((s64)val != (s32 )loc)
166	goto overflow;
167	break;
168	case R_X86_64_PC32:
169	val -= (u64)loc;
170	(u32 )loc = val;
171	#if 0
172	if ((s64)val != (s32 )loc)
173	goto overflow;
174	#endif
175	break;
176	default:
177	printk(KERN_ERR "module %s: Unknown rela relocation: %llu\n",
178	me->name, ELF64_R_TYPE(rel[i].r_info));
179	return -ENOEXEC;
180	}
181	}
182	return 0;
183
184	overflow:
185	printk(KERN_ERR "overflow in relocation type %d val %Lx\n",
186	(int)ELF64_R_TYPE(rel[i].r_info), val);
187	printk(KERN_ERR "`%s' likely not compiled with -mcmodel=kernel\n",
188	me->name);
189	return -ENOEXEC;
190	}
191
192	int apply_relocate(Elf_Shdr *sechdrs,
193	const char *strtab,
194	unsigned int symindex,
195	unsigned int relsec,
196	struct module *me)
197	{
198	printk(KERN_ERR "non add relocation not supported\n");
199	return -ENOSYS;
200	}
201
202	#endif
203
2d5bf28f AW	204	int module_finalize(const Elf_Ehdr *hdr,
	205	const Elf_Shdr *sechdrs,
	206	struct module *me)
	207	{
	208	const Elf_Shdr s, text = NULL, alt = NULL, locks = NULL,
	209	*para = NULL;
	210	char secstrings = (void )hdr + sechdrs[hdr->e_shstrndx].sh_offset;
	211
	212	for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) {
	213	if (!strcmp(".text", secstrings + s->sh_name))
	214	text = s;
	215	if (!strcmp(".altinstructions", secstrings + s->sh_name))
	216	alt = s;
	217	if (!strcmp(".smp_locks", secstrings + s->sh_name))
	218	locks = s;
	219	if (!strcmp(".parainstructions", secstrings + s->sh_name))
	220	para = s;
	221	}
	222
	223	if (alt) {
	224	/* patch .altinstructions */
	225	void aseg = (void )alt->sh_addr;
	226	apply_alternatives(aseg, aseg + alt->sh_size);
	227	}
	228	if (locks && text) {
	229	void lseg = (void )locks->sh_addr;
	230	void tseg = (void )text->sh_addr;
	231	alternatives_smp_module_add(me, me->name,
	232	lseg, lseg + locks->sh_size,
	233	tseg, tseg + text->sh_size);
	234	}
	235
	236	if (para) {
	237	void pseg = (void )para->sh_addr;
	238	apply_paravirt(pseg, pseg + para->sh_size);
	239	}
	240
	241	return module_bug_finalize(hdr, sechdrs, me);
	242	}
	243
	244	void module_arch_cleanup(struct module *mod)
	245	{
	246	alternatives_smp_module_del(mod);
	247	module_bug_cleanup(mod);
	248	}