[linux-block.git] / arch / mips / kernel / module.c

// 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>


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_START
void *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 int apply_r_mips_none(struct module *me, u32 *location,
			     u32 base, Elf_Addr v, bool rela)
{
	return 0;
}

static int apply_r_mips_32(struct module *me, u32 *location,
			   u32 base, Elf_Addr v, bool rela)
{
	*location = base + v;

	return 0;
}

static int apply_r_mips_26(struct module *me, u32 *location,
			   u32 base, Elf_Addr v, bool rela)
{
	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,
			     u32 base, 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, bool rela)
{
	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, bool rela)
{
	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, bool rela)
{
	return apply_r_mips_pc(me, location, base, v, 26);
}

static int apply_r_mips_64(struct module *me, u32 *location,
			   u32 base, Elf_Addr v, bool rela)
{
	if (WARN_ON(!rela))
		return -EINVAL;

	*(Elf_Addr *)location = v;

	return 0;
}

static int apply_r_mips_higher(struct module *me, u32 *location,
			       u32 base, 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(struct module *me, u32 *location,
				u32 base, 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
 * @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
 *
 * Each implemented reloc_handler 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
 */
typedef int (*reloc_handler)(struct module *me, u32 *location,
			     u32 base, Elf_Addr v, bool rela);

/* The handlers for known reloc types */
static reloc_handler reloc_handlers[] = {
	[R_MIPS_NONE]		= apply_r_mips_none,
	[R_MIPS_32]		= apply_r_mips_32,
	[R_MIPS_26]		= apply_r_mips_26,
	[R_MIPS_HI16]		= apply_r_mips_hi16,
	[R_MIPS_LO16]		= apply_r_mips_lo16,
	[R_MIPS_PC16]		= apply_r_mips_pc16,
	[R_MIPS_64]		= apply_r_mips_64,
	[R_MIPS_HIGHER]		= apply_r_mips_higher,
	[R_MIPS_HIGHEST]	= apply_r_mips_highest,
	[R_MIPS_PC21_S2]	= apply_r_mips_pc21,
	[R_MIPS_PC26_S2]	= apply_r_mips_pc26,
};

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;
	reloc_handler handler;
	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 (type < ARRAY_SIZE(reloc_handlers))
			handler = reloc_handlers[type];
		else
			handler = NULL;

		if (!handler) {
			pr_err("%s: Unknown relocation type %u\n",
			       me->name, type);
			err = -EINVAL;
			goto out;
		}

		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 = handler(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_RELA
int 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;

	/* Make jump label nops. */
	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);
}
Commit	Line	Data
1a59d1b8	1	// SPDX-License-Identifier: GPL-2.0-or-later
4e6a05fe	2	/*
4e6a05fe TS	3	*
	4	* Copyright (C) 2001 Rusty Russell.
	5	* Copyright (C) 2003, 2004 Ralf Baechle (ralf@linux-mips.org)
	6	* Copyright (C) 2005 Thiemo Seufer
	7	*/
	8
	9	#undef DEBUG
	10
9f3b8081	11	#include <linux/extable.h>
4e6a05fe TS	12	#include <linux/moduleloader.h>
4e6a05fe TS	13	#include <linux/elf.h>
27ac792c	14	#include <linux/mm.h>
761845f0	15	#include <linux/numa.h>
4e6a05fe TS	16	#include <linux/vmalloc.h>
	17	#include <linux/slab.h>
	18	#include <linux/fs.h>
	19	#include <linux/string.h>
	20	#include <linux/kernel.h>
1da177e4	21	#include <linux/spinlock.h>
94bb0c1a DD	22	#include <linux/jump_label.h>
94bb0c1a DD	23
1da177e4	24
4e6a05fe TS	25	struct mips_hi16 {
	26	struct mips_hi16 *next;
	27	Elf_Addr *addr;
	28	Elf_Addr value;
	29	};
	30
1da177e4 LT	31	static LIST_HEAD(dbe_list);
	32	static DEFINE_SPINLOCK(dbe_lock);
	33
66574cc0	34	#ifdef MODULE_START
4e6a05fe TS	35	void *module_alloc(unsigned long size)
4e6a05fe TS	36	{
d0a21265	37	return __vmalloc_node_range(size, 1, MODULE_START, MODULE_END,
cb9e3c29	38	GFP_KERNEL, PAGE_KERNEL, 0, NUMA_NO_NODE,
d0a21265	39	__builtin_return_address(0));
4e6a05fe	40	}
66574cc0	41	#endif
4e6a05fe	42
430d0b88 PB	43	static int apply_r_mips_none(struct module me, u32 location,
430d0b88 PB	44	u32 base, Elf_Addr v, bool rela)
4e6a05fe TS	45	{
	46	return 0;
	47	}
	48
430d0b88 PB	49	static int apply_r_mips_32(struct module me, u32 location,
430d0b88 PB	50	u32 base, Elf_Addr v, bool rela)
4e6a05fe	51	{
430d0b88	52	*location = base + v;
4e6a05fe TS	53
	54	return 0;
	55	}
	56
430d0b88 PB	57	static int apply_r_mips_26(struct module me, u32 location,
430d0b88 PB	58	u32 base, Elf_Addr v, bool rela)
4e6a05fe TS	59	{
4e6a05fe TS	60	if (v % 4) {
430d0b88	61	pr_err("module %s: dangerous R_MIPS_26 relocation\n",
6f9fdeb6	62	me->name);
4e6a05fe TS	63	return -ENOEXEC;
	64	}
	65
	66	if ((v & 0xf0000000) != (((unsigned long)location + 4) & 0xf0000000)) {
55d791f3	67	pr_err("module %s: relocation overflow\n",
4e6a05fe TS	68	me->name);
	69	return -ENOEXEC;
	70	}
	71
	72	location = (location & ~0x03ffffff) \|
430d0b88	73	((base + (v >> 2)) & 0x03ffffff);
4e6a05fe TS	74
	75	return 0;
	76	}
	77
430d0b88 PB	78	static int apply_r_mips_hi16(struct module me, u32 location,
430d0b88 PB	79	u32 base, Elf_Addr v, bool rela)
4e6a05fe TS	80	{
	81	struct mips_hi16 *n;
	82
430d0b88 PB	83	if (rela) {
	84	location = (location & 0xffff0000) \|
	85	((((long long) v + 0x8000LL) >> 16) & 0xffff);
	86	return 0;
	87	}
	88
4e6a05fe TS	89	/*
	90	* We cannot relocate this one now because we don't know the value of
	91	* the carry we need to add. Save the information, and let LO16 do the
	92	* actual relocation.
	93	*/
	94	n = kmalloc(sizeof *n, GFP_KERNEL);
	95	if (!n)
	96	return -ENOMEM;
	97
	98	n->addr = (Elf_Addr *)location;
	99	n->value = v;
861667dc RB	100	n->next = me->arch.r_mips_hi16_list;
861667dc RB	101	me->arch.r_mips_hi16_list = n;
4e6a05fe TS	102
	103	return 0;
	104	}
	105
c54de490 RB	106	static void free_relocation_chain(struct mips_hi16 *l)
	107	{
	108	struct mips_hi16 *next;
	109
	110	while (l) {
	111	next = l->next;
	112	kfree(l);
	113	l = next;
	114	}
	115	}
	116
430d0b88 PB	117	static int apply_r_mips_lo16(struct module me, u32 location,
430d0b88 PB	118	u32 base, Elf_Addr v, bool rela)
4e6a05fe	119	{
430d0b88	120	unsigned long insnlo = base;
c54de490	121	struct mips_hi16 *l;
4e6a05fe TS	122	Elf_Addr val, vallo;
4e6a05fe TS	123
430d0b88 PB	124	if (rela) {
	125	location = (location & 0xffff0000) \| (v & 0xffff);
	126	return 0;
	127	}
	128
70342287	129	/* Sign extend the addend we extract from the lo insn. */
4e6a05fe TS	130	vallo = ((insnlo & 0xffff) ^ 0x8000) - 0x8000;
4e6a05fe TS	131
861667dc	132	if (me->arch.r_mips_hi16_list != NULL) {
861667dc	133	l = me->arch.r_mips_hi16_list;
4e6a05fe	134	while (l != NULL) {
c54de490	135	struct mips_hi16 *next;
4e6a05fe TS	136	unsigned long insn;
	137
	138	/*
	139	* The value for the HI16 had best be the same.
	140	*/
	141	if (v != l->value)
	142	goto out_danger;
	143
	144	/*
	145	* Do the HI16 relocation. Note that we actually don't
	146	* need to know anything about the LO16 itself, except
	147	* where to find the low 16 bits of the addend needed
	148	* by the LO16.
	149	*/
	150	insn = *l->addr;
	151	val = ((insn & 0xffff) << 16) + vallo;
	152	val += v;
	153
	154	/*
	155	* Account for the sign extension that will happen in
	156	* the low bits.
	157	*/
	158	val = ((val >> 16) + ((val & 0x8000) != 0)) & 0xffff;
	159
	160	insn = (insn & ~0xffff) \| val;
	161	*l->addr = insn;
	162
	163	next = l->next;
	164	kfree(l);
	165	l = next;
	166	}
	167
861667dc	168	me->arch.r_mips_hi16_list = NULL;
4e6a05fe TS	169	}
	170
	171	/*
70342287	172	* Ok, we're done with the HI16 relocs. Now deal with the LO16.
4e6a05fe TS	173	*/
	174	val = v + vallo;
	175	insnlo = (insnlo & ~0xffff) \| (val & 0xffff);
	176	*location = insnlo;
	177
	178	return 0;
	179
	180	out_danger:
c54de490 RB	181	free_relocation_chain(l);
c54de490 RB	182	me->arch.r_mips_hi16_list = NULL;
d3cac35c	183
430d0b88	184	pr_err("module %s: dangerous R_MIPS_LO16 relocation\n", me->name);
4e6a05fe TS	185
	186	return -ENOEXEC;
	187	}
	188
430d0b88 PB	189	static int apply_r_mips_pc(struct module me, u32 location, u32 base,
430d0b88 PB	190	Elf_Addr v, unsigned int bits)
5d3c7925 PB	191	{
	192	unsigned long mask = GENMASK(bits - 1, 0);
	193	unsigned long se_bits;
	194	long offset;
	195
	196	if (v % 4) {
430d0b88	197	pr_err("module %s: dangerous R_MIPS_PC%u relocation\n",
5d3c7925 PB	198	me->name, bits);
	199	return -ENOEXEC;
	200	}
	201
430d0b88 PB	202	/* retrieve & sign extend implicit addend if any */
430d0b88 PB	203	offset = base & mask;
5d3c7925 PB	204	offset \|= (offset & BIT(bits - 1)) ? ~mask : 0;
	205
	206	offset += ((long)v - (long)location) >> 2;
	207
	208	/* check the sign bit onwards are identical - ie. we didn't overflow */
	209	se_bits = (offset & BIT(bits - 1)) ? ~0ul : 0;
	210	if ((offset & ~mask) != (se_bits & ~mask)) {
	211	pr_err("module %s: relocation overflow\n", me->name);
	212	return -ENOEXEC;
	213	}
	214
	215	location = (location & ~mask) \| (offset & mask);
	216
	217	return 0;
	218	}
	219
430d0b88 PB	220	static int apply_r_mips_pc16(struct module me, u32 location,
430d0b88 PB	221	u32 base, Elf_Addr v, bool rela)
5d3c7925	222	{
430d0b88	223	return apply_r_mips_pc(me, location, base, v, 16);
5d3c7925 PB	224	}
5d3c7925 PB	225
430d0b88 PB	226	static int apply_r_mips_pc21(struct module me, u32 location,
430d0b88 PB	227	u32 base, Elf_Addr v, bool rela)
5d3c7925	228	{
430d0b88	229	return apply_r_mips_pc(me, location, base, v, 21);
5d3c7925 PB	230	}
5d3c7925 PB	231
430d0b88 PB	232	static int apply_r_mips_pc26(struct module me, u32 location,
430d0b88 PB	233	u32 base, Elf_Addr v, bool rela)
5d3c7925	234	{
430d0b88	235	return apply_r_mips_pc(me, location, base, v, 26);
5d3c7925 PB	236	}
5d3c7925 PB	237
430d0b88 PB	238	static int apply_r_mips_64(struct module me, u32 location,
430d0b88 PB	239	u32 base, Elf_Addr v, bool rela)
5d3c7925	240	{
430d0b88 PB	241	if (WARN_ON(!rela))
	242	return -EINVAL;
	243
	244	(Elf_Addr )location = v;
	245
	246	return 0;
5d3c7925 PB	247	}
5d3c7925 PB	248
430d0b88 PB	249	static int apply_r_mips_higher(struct module me, u32 location,
430d0b88 PB	250	u32 base, Elf_Addr v, bool rela)
5d3c7925	251	{
430d0b88 PB	252	if (WARN_ON(!rela))
	253	return -EINVAL;
	254
	255	location = (location & 0xffff0000) \|
	256	((((long long)v + 0x80008000LL) >> 32) & 0xffff);
	257
	258	return 0;
5d3c7925 PB	259	}
5d3c7925 PB	260
430d0b88 PB	261	static int apply_r_mips_highest(struct module me, u32 location,
430d0b88 PB	262	u32 base, Elf_Addr v, bool rela)
5d3c7925	263	{
430d0b88 PB	264	if (WARN_ON(!rela))
	265	return -EINVAL;
	266
	267	location = (location & 0xffff0000) \|
	268	((((long long)v + 0x800080008000LL) >> 48) & 0xffff);
	269
	270	return 0;
5d3c7925 PB	271	}
5d3c7925 PB	272
430d0b88 PB	273	/**
	274	* reloc_handler() - Apply a particular relocation to a module
	275	* @me: the module to apply the reloc to
	276	* @location: the address at which the reloc is to be applied
	277	* @base: the existing value at location for REL-style; 0 for RELA-style
	278	* @v: the value of the reloc, with addend for RELA-style
	279	*
	280	* Each implemented reloc_handler function applies a particular type of
	281	* relocation to the module @me. Relocs that may be found in either REL or RELA
	282	* variants can be handled by making use of the @base & @v parameters which are
	283	* set to values which abstract the difference away from the particular reloc
	284	* implementations.
	285	*
	286	* Return: 0 upon success, else -ERRNO
	287	*/
	288	typedef int (reloc_handler)(struct module me, u32 *location,
	289	u32 base, Elf_Addr v, bool rela);
	290
	291	/* The handlers for known reloc types */
	292	static reloc_handler reloc_handlers[] = {
4e6a05fe	293	[R_MIPS_NONE] = apply_r_mips_none,
430d0b88 PB	294	[R_MIPS_32] = apply_r_mips_32,
	295	[R_MIPS_26] = apply_r_mips_26,
	296	[R_MIPS_HI16] = apply_r_mips_hi16,
	297	[R_MIPS_LO16] = apply_r_mips_lo16,
	298	[R_MIPS_PC16] = apply_r_mips_pc16,
	299	[R_MIPS_64] = apply_r_mips_64,
	300	[R_MIPS_HIGHER] = apply_r_mips_higher,
	301	[R_MIPS_HIGHEST] = apply_r_mips_highest,
	302	[R_MIPS_PC21_S2] = apply_r_mips_pc21,
	303	[R_MIPS_PC26_S2] = apply_r_mips_pc26,
4e6a05fe TS	304	};
4e6a05fe TS	305
430d0b88 PB	306	static int __apply_relocate(Elf_Shdr sechdrs, const char strtab,
	307	unsigned int symindex, unsigned int relsec,
	308	struct module *me, bool rela)
4e6a05fe	309	{
430d0b88 PB	310	union {
	311	Elf_Mips_Rel *rel;
	312	Elf_Mips_Rela *rela;
	313	} r;
	314	reloc_handler handler;
4e6a05fe	315	Elf_Sym *sym;
430d0b88	316	u32 *location, base;
04211a57	317	unsigned int i, type;
4e6a05fe	318	Elf_Addr v;
351b0940	319	int err = 0;
430d0b88	320	size_t reloc_sz;
4e6a05fe TS	321
	322	pr_debug("Applying relocate section %u to %u\n", relsec,
	323	sechdrs[relsec].sh_info);
	324
430d0b88 PB	325	r.rel = (void *)sechdrs[relsec].sh_addr;
430d0b88 PB	326	reloc_sz = rela ? sizeof(r.rela) : sizeof(r.rel);
861667dc	327	me->arch.r_mips_hi16_list = NULL;
430d0b88	328	for (i = 0; i < sechdrs[relsec].sh_size / reloc_sz; i++) {
4e6a05fe TS	329	/* This is where to make the change */
4e6a05fe TS	330	location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
430d0b88	331	+ r.rel->r_offset;
4e6a05fe TS	332	/* This is the symbol it is referring to */
4e6a05fe TS	333	sym = (Elf_Sym *)sechdrs[symindex].sh_addr
430d0b88	334	+ ELF_MIPS_R_SYM(*r.rel);
ba837d38	335	if (sym->st_value >= -MAX_ERRNO) {
f3bf07b9 AN	336	/* Ignore unresolved weak symbol */
	337	if (ELF_ST_BIND(sym->st_info) == STB_WEAK)
	338	continue;
55d791f3 SH	339	pr_warn("%s: Unknown symbol %s\n",
55d791f3 SH	340	me->name, strtab + sym->st_name);
351b0940 PB	341	err = -ENOENT;
351b0940 PB	342	goto out;
4e6a05fe TS	343	}
4e6a05fe TS	344
430d0b88 PB	345	type = ELF_MIPS_R_TYPE(*r.rel);
	346	if (type < ARRAY_SIZE(reloc_handlers))
	347	handler = reloc_handlers[type];
04211a57 PB	348	else
04211a57 PB	349	handler = NULL;
4e6a05fe	350
04211a57 PB	351	if (!handler) {
	352	pr_err("%s: Unknown relocation type %u\n",
	353	me->name, type);
351b0940 PB	354	err = -EINVAL;
351b0940 PB	355	goto out;
04211a57 PB	356	}
04211a57 PB	357
430d0b88 PB	358	if (rela) {
	359	v = sym->st_value + r.rela->r_addend;
	360	base = 0;
	361	r.rela = &r.rela[1];
	362	} else {
	363	v = sym->st_value;
	364	base = *location;
	365	r.rel = &r.rel[1];
	366	}
	367
	368	err = handler(me, location, base, v, rela);
351b0940 PB	369	if (err)
351b0940 PB	370	goto out;
4e6a05fe TS	371	}
4e6a05fe TS	372
351b0940	373	out:
c54de490	374	/*
351b0940	375	* Normally the hi16 list should be deallocated at this point. A
c54de490	376	* malformed binary however could contain a series of R_MIPS_HI16
351b0940 PB	377	* relocations not followed by a R_MIPS_LO16 relocation, or if we hit
	378	* an error processing a reloc we might have gotten here before
	379	* reaching the R_MIPS_LO16. In either case, free up the list and
	380	* return an error.
c54de490 RB	381	*/
	382	if (me->arch.r_mips_hi16_list) {
	383	free_relocation_chain(me->arch.r_mips_hi16_list);
	384	me->arch.r_mips_hi16_list = NULL;
351b0940	385	err = err ?: -ENOEXEC;
c54de490 RB	386	}
c54de490 RB	387
351b0940	388	return err;
4e6a05fe TS	389	}
4e6a05fe TS	390
430d0b88 PB	391	int apply_relocate(Elf_Shdr sechdrs, const char strtab,
	392	unsigned int symindex, unsigned int relsec,
	393	struct module *me)
	394	{
	395	return __apply_relocate(sechdrs, strtab, symindex, relsec, me, false);
	396	}
	397
	398	#ifdef CONFIG_MODULES_USE_ELF_RELA
	399	int apply_relocate_add(Elf_Shdr sechdrs, const char strtab,
	400	unsigned int symindex, unsigned int relsec,
	401	struct module *me)
	402	{
	403	return __apply_relocate(sechdrs, strtab, symindex, relsec, me, true);
4e6a05fe	404	}
430d0b88	405	#endif /* CONFIG_MODULES_USE_ELF_RELA */
4e6a05fe	406
1da177e4 LT	407	/* Given an address, look for it in the module exception tables. */
	408	const struct exception_table_entry *search_module_dbetables(unsigned long addr)
	409	{
	410	unsigned long flags;
	411	const struct exception_table_entry *e = NULL;
	412	struct mod_arch_specific *dbe;
	413
	414	spin_lock_irqsave(&dbe_lock, flags);
	415	list_for_each_entry(dbe, &dbe_list, dbe_list) {
a94c33dd TM	416	e = search_extable(dbe->dbe_start,
a94c33dd TM	417	dbe->dbe_end - dbe->dbe_start, addr);
1da177e4 LT	418	if (e)
	419	break;
	420	}
	421	spin_unlock_irqrestore(&dbe_lock, flags);
	422
	423	/* Now, if we found one, we are running inside it now, hence
70342287	424	we cannot unload the module, hence no refcnt needed. */
1da177e4 LT	425	return e;
	426	}
	427
3a4fa0a2	428	/* Put in dbe list if necessary. */
1da177e4 LT	429	int module_finalize(const Elf_Ehdr *hdr,
	430	const Elf_Shdr *sechdrs,
	431	struct module *me)
	432	{
	433	const Elf_Shdr *s;
	434	char secstrings = (void )hdr + sechdrs[hdr->e_shstrndx].sh_offset;
	435
94bb0c1a DD	436	/* Make jump label nops. */
	437	jump_label_apply_nops(me);
	438
1da177e4 LT	439	INIT_LIST_HEAD(&me->arch.dbe_list);
	440	for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) {
	441	if (strcmp("__dbe_table", secstrings + s->sh_name) != 0)
	442	continue;
	443	me->arch.dbe_start = (void *)s->sh_addr;
	444	me->arch.dbe_end = (void *)s->sh_addr + s->sh_size;
	445	spin_lock_irq(&dbe_lock);
	446	list_add(&me->arch.dbe_list, &dbe_list);
	447	spin_unlock_irq(&dbe_lock);
	448	}
	449	return 0;
	450	}
	451
	452	void module_arch_cleanup(struct module *mod)
	453	{
	454	spin_lock_irq(&dbe_lock);
	455	list_del(&mod->arch.dbe_list);
	456	spin_unlock_irq(&dbe_lock);
	457	}