/*  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_BASEstatic 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;}#elsestatic 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_32int 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);}