// SPDX-License-Identifier: GPL-2.0-or-later/* * *  Copyright (C) 2001 Rusty Russell. *  Copyright (C) 2003, 2004 Ralf Baechle (ralf@linux-mips.org) *  Copyright (C) 2005 Thiemo Seufer */ #undef DEBUG #include <linux/extable.h>#include <linux/moduleloader.h>#include <linux/elf.h>#include <linux/mm.h>#include <linux/numa.h>#include <linux/vmalloc.h>#include <linux/slab.h>#include <linux/fs.h>#include <linux/string.h>#include <linux/kernel.h>#include <linux/spinlock.h>#include <linux/jump_label.h> extern void jump_label_apply_nops(struct module *mod); struct mips_hi16 {	struct mips_hi16 *next;	Elf_Addr *addr;	Elf_Addr value;}; static LIST_HEAD(dbe_list);static DEFINE_SPINLOCK(dbe_lock); #ifdef MODULE_STARTvoid *module_alloc(unsigned long size){	return __vmalloc_node_range(size, 1, MODULE_START, MODULE_END,				GFP_KERNEL, PAGE_KERNEL, 0, NUMA_NO_NODE,				__builtin_return_address(0));}#endif static void apply_r_mips_32(u32 *location, u32 base, Elf_Addr v){	*location = base + v;} static int apply_r_mips_26(struct module *me, u32 *location, u32 base,			   Elf_Addr v){	if (v % 4) {		pr_err("module %s: dangerous R_MIPS_26 relocation\n",		       me->name);		return -ENOEXEC;	} 	if ((v & 0xf0000000) != (((unsigned long)location + 4) & 0xf0000000)) {		pr_err("module %s: relocation overflow\n",		       me->name);		return -ENOEXEC;	} 	*location = (*location & ~0x03ffffff) |		    ((base + (v >> 2)) & 0x03ffffff); 	return 0;} static int apply_r_mips_hi16(struct module *me, u32 *location, Elf_Addr v,			     bool rela){	struct mips_hi16 *n; 	if (rela) {		*location = (*location & 0xffff0000) |			    ((((long long) v + 0x8000LL) >> 16) & 0xffff);		return 0;	} 	/*	 * We cannot relocate this one now because we don't know the value of	 * the carry we need to add.  Save the information, and let LO16 do the	 * actual relocation.	 */	n = kmalloc(sizeof *n, GFP_KERNEL);	if (!n)		return -ENOMEM; 	n->addr = (Elf_Addr *)location;	n->value = v;	n->next = me->arch.r_mips_hi16_list;	me->arch.r_mips_hi16_list = n; 	return 0;} static void free_relocation_chain(struct mips_hi16 *l){	struct mips_hi16 *next; 	while (l) {		next = l->next;		kfree(l);		l = next;	}} static int apply_r_mips_lo16(struct module *me, u32 *location,			     u32 base, Elf_Addr v, bool rela){	unsigned long insnlo = base;	struct mips_hi16 *l;	Elf_Addr val, vallo; 	if (rela) {		*location = (*location & 0xffff0000) | (v & 0xffff);		return 0;	} 	/* Sign extend the addend we extract from the lo insn.	*/	vallo = ((insnlo & 0xffff) ^ 0x8000) - 0x8000; 	if (me->arch.r_mips_hi16_list != NULL) {		l = me->arch.r_mips_hi16_list;		while (l != NULL) {			struct mips_hi16 *next;			unsigned long insn; 			/*			 * The value for the HI16 had best be the same.			 */			if (v != l->value)				goto out_danger; 			/*			 * Do the HI16 relocation.  Note that we actually don't			 * need to know anything about the LO16 itself, except			 * where to find the low 16 bits of the addend needed			 * by the LO16.			 */			insn = *l->addr;			val = ((insn & 0xffff) << 16) + vallo;			val += v; 			/*			 * Account for the sign extension that will happen in			 * the low bits.			 */			val = ((val >> 16) + ((val & 0x8000) != 0)) & 0xffff; 			insn = (insn & ~0xffff) | val;			*l->addr = insn; 			next = l->next;			kfree(l);			l = next;		} 		me->arch.r_mips_hi16_list = NULL;	} 	/*	 * Ok, we're done with the HI16 relocs.	 Now deal with the LO16.	 */	val = v + vallo;	insnlo = (insnlo & ~0xffff) | (val & 0xffff);	*location = insnlo; 	return 0; out_danger:	free_relocation_chain(l);	me->arch.r_mips_hi16_list = NULL; 	pr_err("module %s: dangerous R_MIPS_LO16 relocation\n", me->name); 	return -ENOEXEC;} static int apply_r_mips_pc(struct module *me, u32 *location, u32 base,			   Elf_Addr v, unsigned int bits){	unsigned long mask = GENMASK(bits - 1, 0);	unsigned long se_bits;	long offset; 	if (v % 4) {		pr_err("module %s: dangerous R_MIPS_PC%u relocation\n",		       me->name, bits);		return -ENOEXEC;	} 	/* retrieve & sign extend implicit addend if any */	offset = base & mask;	offset |= (offset & BIT(bits - 1)) ? ~mask : 0; 	offset += ((long)v - (long)location) >> 2; 	/* check the sign bit onwards are identical - ie. we didn't overflow */	se_bits = (offset & BIT(bits - 1)) ? ~0ul : 0;	if ((offset & ~mask) != (se_bits & ~mask)) {		pr_err("module %s: relocation overflow\n", me->name);		return -ENOEXEC;	} 	*location = (*location & ~mask) | (offset & mask); 	return 0;} static int apply_r_mips_pc16(struct module *me, u32 *location, u32 base,			     Elf_Addr v){	return apply_r_mips_pc(me, location, base, v, 16);} static int apply_r_mips_pc21(struct module *me, u32 *location, u32 base,			     Elf_Addr v){	return apply_r_mips_pc(me, location, base, v, 21);} static int apply_r_mips_pc26(struct module *me, u32 *location, u32 base,			     Elf_Addr v){	return apply_r_mips_pc(me, location, base, v, 26);} static int apply_r_mips_64(u32 *location, Elf_Addr v, bool rela){	if (WARN_ON(!rela))		return -EINVAL; 	*(Elf_Addr *)location = v; 	return 0;} static int apply_r_mips_higher(u32 *location, Elf_Addr v, bool rela){	if (WARN_ON(!rela))		return -EINVAL; 	*location = (*location & 0xffff0000) |		    ((((long long)v + 0x80008000LL) >> 32) & 0xffff); 	return 0;} static int apply_r_mips_highest(u32 *location, Elf_Addr v, bool rela){	if (WARN_ON(!rela))		return -EINVAL; 	*location = (*location & 0xffff0000) |		    ((((long long)v + 0x800080008000LL) >> 48) & 0xffff); 	return 0;} /** * reloc_handler() - Apply a particular relocation to a module * @type: type of the relocation to apply * @me: the module to apply the reloc to * @location: the address at which the reloc is to be applied * @base: the existing value at location for REL-style; 0 for RELA-style * @v: the value of the reloc, with addend for RELA-style * @rela: indication of is this a RELA (true) or REL (false) relocation * * Each implemented relocation function applies a particular type of * relocation to the module @me. Relocs that may be found in either REL or RELA * variants can be handled by making use of the @base & @v parameters which are * set to values which abstract the difference away from the particular reloc * implementations. * * Return: 0 upon success, else -ERRNO */static int reloc_handler(u32 type, struct module *me, u32 *location, u32 base,			 Elf_Addr v, bool rela){	switch (type) {	case R_MIPS_NONE:		break;	case R_MIPS_32:		apply_r_mips_32(location, base, v);		break;	case R_MIPS_26:		return apply_r_mips_26(me, location, base, v);	case R_MIPS_HI16:		return apply_r_mips_hi16(me, location, v, rela);	case R_MIPS_LO16:		return apply_r_mips_lo16(me, location, base, v, rela);	case R_MIPS_PC16:		return apply_r_mips_pc16(me, location, base, v);	case R_MIPS_PC21_S2:		return apply_r_mips_pc21(me, location, base, v);	case R_MIPS_PC26_S2:		return apply_r_mips_pc26(me, location, base, v);	case R_MIPS_64:		return apply_r_mips_64(location, v, rela);	case R_MIPS_HIGHER:		return apply_r_mips_higher(location, v, rela);	case R_MIPS_HIGHEST:		return apply_r_mips_highest(location, v, rela);	default:		pr_err("%s: Unknown relocation type %u\n", me->name, type);		return -EINVAL;	} 	return 0;} static int __apply_relocate(Elf_Shdr *sechdrs, const char *strtab,			    unsigned int symindex, unsigned int relsec,			    struct module *me, bool rela){	union {		Elf_Mips_Rel *rel;		Elf_Mips_Rela *rela;	} r;	Elf_Sym *sym;	u32 *location, base;	unsigned int i, type;	Elf_Addr v;	int err = 0;	size_t reloc_sz; 	pr_debug("Applying relocate section %u to %u\n", relsec,	       sechdrs[relsec].sh_info); 	r.rel = (void *)sechdrs[relsec].sh_addr;	reloc_sz = rela ? sizeof(*r.rela) : sizeof(*r.rel);	me->arch.r_mips_hi16_list = NULL;	for (i = 0; i < sechdrs[relsec].sh_size / reloc_sz; i++) {		/* This is where to make the change */		location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr			+ r.rel->r_offset;		/* This is the symbol it is referring to */		sym = (Elf_Sym *)sechdrs[symindex].sh_addr			+ ELF_MIPS_R_SYM(*r.rel);		if (sym->st_value >= -MAX_ERRNO) {			/* Ignore unresolved weak symbol */			if (ELF_ST_BIND(sym->st_info) == STB_WEAK)				continue;			pr_warn("%s: Unknown symbol %s\n",				me->name, strtab + sym->st_name);			err = -ENOENT;			goto out;		} 		type = ELF_MIPS_R_TYPE(*r.rel); 		if (rela) {			v = sym->st_value + r.rela->r_addend;			base = 0;			r.rela = &r.rela[1];		} else {			v = sym->st_value;			base = *location;			r.rel = &r.rel[1];		} 		err = reloc_handler(type, me, location, base, v, rela);		if (err)			goto out;	} out:	/*	 * Normally the hi16 list should be deallocated at this point. A	 * malformed binary however could contain a series of R_MIPS_HI16	 * relocations not followed by a R_MIPS_LO16 relocation, or if we hit	 * an error processing a reloc we might have gotten here before	 * reaching the R_MIPS_LO16. In either case, free up the list and	 * return an error.	 */	if (me->arch.r_mips_hi16_list) {		free_relocation_chain(me->arch.r_mips_hi16_list);		me->arch.r_mips_hi16_list = NULL;		err = err ?: -ENOEXEC;	} 	return err;} int apply_relocate(Elf_Shdr *sechdrs, const char *strtab,		   unsigned int symindex, unsigned int relsec,		   struct module *me){	return __apply_relocate(sechdrs, strtab, symindex, relsec, me, false);} #ifdef CONFIG_MODULES_USE_ELF_RELAint apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab,		       unsigned int symindex, unsigned int relsec,		       struct module *me){	return __apply_relocate(sechdrs, strtab, symindex, relsec, me, true);}#endif /* CONFIG_MODULES_USE_ELF_RELA */ /* Given an address, look for it in the module exception tables. */const struct exception_table_entry *search_module_dbetables(unsigned long addr){	unsigned long flags;	const struct exception_table_entry *e = NULL;	struct mod_arch_specific *dbe; 	spin_lock_irqsave(&dbe_lock, flags);	list_for_each_entry(dbe, &dbe_list, dbe_list) {		e = search_extable(dbe->dbe_start,				   dbe->dbe_end - dbe->dbe_start, addr);		if (e)			break;	}	spin_unlock_irqrestore(&dbe_lock, flags); 	/* Now, if we found one, we are running inside it now, hence	   we cannot unload the module, hence no refcnt needed. */	return e;} /* Put in dbe list if necessary. */int module_finalize(const Elf_Ehdr *hdr,		    const Elf_Shdr *sechdrs,		    struct module *me){	const Elf_Shdr *s;	char *secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset; 	if (IS_ENABLED(CONFIG_JUMP_LABEL))		jump_label_apply_nops(me); 	INIT_LIST_HEAD(&me->arch.dbe_list);	for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) {		if (strcmp("__dbe_table", secstrings + s->sh_name) != 0)			continue;		me->arch.dbe_start = (void *)s->sh_addr;		me->arch.dbe_end = (void *)s->sh_addr + s->sh_size;		spin_lock_irq(&dbe_lock);		list_add(&me->arch.dbe_list, &dbe_list);		spin_unlock_irq(&dbe_lock);	}	return 0;} void module_arch_cleanup(struct module *mod){	spin_lock_irq(&dbe_lock);	list_del(&mod->arch.dbe_list);	spin_unlock_irq(&dbe_lock);}