arch/arm64/kernel/module.c - linux - Git at Google

 /*
  * AArch64 loadable module support.
  *
  * Copyright (C) 2012 ARM Limited
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation.
  *
  * 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, see <http://www.gnu.org/licenses/>.
  *
  * Author: Will Deacon <will.deacon@arm.com>
  */

 #include <linux/bitops.h>
 #include <linux/elf.h>
 #include <linux/gfp.h>
 #include <linux/kernel.h>
 #include <linux/mm.h>
 #include <linux/moduleloader.h>
 #include <linux/vmalloc.h>
 #include <asm/alternative.h>
 #include <asm/insn.h>
 #include <asm/sections.h>

 #define	AARCH64_INSN_IMM_MOVNZ		AARCH64_INSN_IMM_MAX
 #define	AARCH64_INSN_IMM_MOVK		AARCH64_INSN_IMM_16

 void *module_alloc(unsigned long size)
 {
 	return __vmalloc_node_range(size, 1, MODULES_VADDR, MODULES_END,
 				    GFP_KERNEL, PAGE_KERNEL_EXEC, 0,
 				    NUMA_NO_NODE, __builtin_return_address(0));
 }

 enum aarch64_reloc_op {
 	RELOC_OP_NONE,
 	RELOC_OP_ABS,
 	RELOC_OP_PREL,
 	RELOC_OP_PAGE,
 };

 static u64 do_reloc(enum aarch64_reloc_op reloc_op, void *place, u64 val)
 {
 	switch (reloc_op) {
 	case RELOC_OP_ABS:
 		return val;
 	case RELOC_OP_PREL:
 		return val - (u64)place;
 	case RELOC_OP_PAGE:
 		return (val & ~0xfff) - ((u64)place & ~0xfff);
 	case RELOC_OP_NONE:
 		return 0;
 	}

 	pr_err("do_reloc: unknown relocation operation %d\n", reloc_op);
 	return 0;
 }

 static int reloc_data(enum aarch64_reloc_op op, void *place, u64 val, int len)
 {
 	u64 imm_mask = (1 << len) - 1;
 	s64 sval = do_reloc(op, place, val);

 	switch (len) {
 	case 16:
 		*(s16 *)place = sval;
 		break;
 	case 32:
 		*(s32 *)place = sval;
 		break;
 	case 64:
 		*(s64 *)place = sval;
 		break;
 	default:
 		pr_err("Invalid length (%d) for data relocation\n", len);
 		return 0;
 	}

 	/*
 	 * Extract the upper value bits (including the sign bit) and
 	 * shift them to bit 0.
 	 */
 	sval = (s64)(sval & ~(imm_mask >> 1)) >> (len - 1);

 	/*
 	 * Overflow has occurred if the value is not representable in
 	 * len bits (i.e the bottom len bits are not sign-extended and
 	 * the top bits are not all zero).
 	 */
 	if ((u64)(sval + 1) > 2)
 		return -ERANGE;

 	return 0;
 }

 static int reloc_insn_movw(enum aarch64_reloc_op op, void *place, u64 val,
 			   int lsb, enum aarch64_insn_imm_type imm_type)
 {
 	u64 imm, limit = 0;
 	s64 sval;
 	u32 insn = le32_to_cpu(*(u32 *)place);

 	sval = do_reloc(op, place, val);
 	sval >>= lsb;
 	imm = sval & 0xffff;

 	if (imm_type == AARCH64_INSN_IMM_MOVNZ) {
 		/*
 		 * For signed MOVW relocations, we have to manipulate the
 		 * instruction encoding depending on whether or not the
 		 * immediate is less than zero.
 		 */
 		insn &= ~(3 << 29);
 		if ((s64)imm >= 0) {
 			/* >=0: Set the instruction to MOVZ (opcode 10b). */
 			insn |= 2 << 29;
 		} else {
 			/*
 			 * <0: Set the instruction to MOVN (opcode 00b).
 			 *     Since we've masked the opcode already, we
 			 *     don't need to do anything other than
 			 *     inverting the new immediate field.
 			 */
 			imm = ~imm;
 		}
 		imm_type = AARCH64_INSN_IMM_MOVK;
 	}

 	/* Update the instruction with the new encoding. */
 	insn = aarch64_insn_encode_immediate(imm_type, insn, imm);
 	*(u32 *)place = cpu_to_le32(insn);

 	/* Shift out the immediate field. */
 	sval >>= 16;

 	/*
 	 * For unsigned immediates, the overflow check is straightforward.
 	 * For signed immediates, the sign bit is actually the bit past the
 	 * most significant bit of the field.
 	 * The AARCH64_INSN_IMM_16 immediate type is unsigned.
 	 */
 	if (imm_type != AARCH64_INSN_IMM_16) {
 		sval++;
 		limit++;
 	}

 	/* Check the upper bits depending on the sign of the immediate. */
 	if ((u64)sval > limit)
 		return -ERANGE;

 	return 0;
 }

 static int reloc_insn_imm(enum aarch64_reloc_op op, void *place, u64 val,
 			  int lsb, int len, enum aarch64_insn_imm_type imm_type)
 {
 	u64 imm, imm_mask;
 	s64 sval;
 	u32 insn = le32_to_cpu(*(u32 *)place);

 	/* Calculate the relocation value. */
 	sval = do_reloc(op, place, val);
 	sval >>= lsb;

 	/* Extract the value bits and shift them to bit 0. */
 	imm_mask = (BIT(lsb + len) - 1) >> lsb;
 	imm = sval & imm_mask;

 	/* Update the instruction's immediate field. */
 	insn = aarch64_insn_encode_immediate(imm_type, insn, imm);
 	*(u32 *)place = cpu_to_le32(insn);

 	/*
 	 * Extract the upper value bits (including the sign bit) and
 	 * shift them to bit 0.
 	 */
 	sval = (s64)(sval & ~(imm_mask >> 1)) >> (len - 1);

 	/*
 	 * Overflow has occurred if the upper bits are not all equal to
 	 * the sign bit of the value.
 	 */
 	if ((u64)(sval + 1) >= 2)
 		return -ERANGE;

 	return 0;
 }

 int apply_relocate_add(Elf64_Shdr *sechdrs,
 		       const char *strtab,
 		       unsigned int symindex,
 		       unsigned int relsec,
 		       struct module *me)
 {
 	unsigned int i;
 	int ovf;
 	bool overflow_check;
 	Elf64_Sym *sym;
 	void *loc;
 	u64 val;
 	Elf64_Rela *rel = (void *)sechdrs[relsec].sh_addr;

 	for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
 		/* loc corresponds to P in the AArch64 ELF document. */
 		loc = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
 			+ rel[i].r_offset;

 		/* sym is the ELF symbol we're referring to. */
 		sym = (Elf64_Sym *)sechdrs[symindex].sh_addr
 			+ ELF64_R_SYM(rel[i].r_info);

 		/* val corresponds to (S + A) in the AArch64 ELF document. */
 		val = sym->st_value + rel[i].r_addend;

 		/* Check for overflow by default. */
 		overflow_check = true;

 		/* Perform the static relocation. */
 		switch (ELF64_R_TYPE(rel[i].r_info)) {
 		/* Null relocations. */
 		case R_ARM_NONE:
 		case R_AARCH64_NONE:
 			ovf = 0;
 			break;

 		/* Data relocations. */
 		case R_AARCH64_ABS64:
 			overflow_check = false;
 			ovf = reloc_data(RELOC_OP_ABS, loc, val, 64);
 			break;
 		case R_AARCH64_ABS32:
 			ovf = reloc_data(RELOC_OP_ABS, loc, val, 32);
 			break;
 		case R_AARCH64_ABS16:
 			ovf = reloc_data(RELOC_OP_ABS, loc, val, 16);
 			break;
 		case R_AARCH64_PREL64:
 			overflow_check = false;
 			ovf = reloc_data(RELOC_OP_PREL, loc, val, 64);
 			break;
 		case R_AARCH64_PREL32:
 			ovf = reloc_data(RELOC_OP_PREL, loc, val, 32);
 			break;
 		case R_AARCH64_PREL16:
 			ovf = reloc_data(RELOC_OP_PREL, loc, val, 16);
 			break;

 		/* MOVW instruction relocations. */
 		case R_AARCH64_MOVW_UABS_G0_NC:
 			overflow_check = false;
 		case R_AARCH64_MOVW_UABS_G0:
 			ovf = reloc_insn_movw(RELOC_OP_ABS, loc, val, 0,
 					      AARCH64_INSN_IMM_16);
 			break;
 		case R_AARCH64_MOVW_UABS_G1_NC:
 			overflow_check = false;
 		case R_AARCH64_MOVW_UABS_G1:
 			ovf = reloc_insn_movw(RELOC_OP_ABS, loc, val, 16,
 					      AARCH64_INSN_IMM_16);
 			break;
 		case R_AARCH64_MOVW_UABS_G2_NC:
 			overflow_check = false;
 		case R_AARCH64_MOVW_UABS_G2:
 			ovf = reloc_insn_movw(RELOC_OP_ABS, loc, val, 32,
 					      AARCH64_INSN_IMM_16);
 			break;
 		case R_AARCH64_MOVW_UABS_G3:
 			/* We're using the top bits so we can't overflow. */
 			overflow_check = false;
 			ovf = reloc_insn_movw(RELOC_OP_ABS, loc, val, 48,
 					      AARCH64_INSN_IMM_16);
 			break;
 		case R_AARCH64_MOVW_SABS_G0:
 			ovf = reloc_insn_movw(RELOC_OP_ABS, loc, val, 0,
 					      AARCH64_INSN_IMM_MOVNZ);
 			break;
 		case R_AARCH64_MOVW_SABS_G1:
 			ovf = reloc_insn_movw(RELOC_OP_ABS, loc, val, 16,
 					      AARCH64_INSN_IMM_MOVNZ);
 			break;
 		case R_AARCH64_MOVW_SABS_G2:
 			ovf = reloc_insn_movw(RELOC_OP_ABS, loc, val, 32,
 					      AARCH64_INSN_IMM_MOVNZ);
 			break;
 		case R_AARCH64_MOVW_PREL_G0_NC:
 			overflow_check = false;
 			ovf = reloc_insn_movw(RELOC_OP_PREL, loc, val, 0,
 					      AARCH64_INSN_IMM_MOVK);
 			break;
 		case R_AARCH64_MOVW_PREL_G0:
 			ovf = reloc_insn_movw(RELOC_OP_PREL, loc, val, 0,
 					      AARCH64_INSN_IMM_MOVNZ);
 			break;
 		case R_AARCH64_MOVW_PREL_G1_NC:
 			overflow_check = false;
 			ovf = reloc_insn_movw(RELOC_OP_PREL, loc, val, 16,
 					      AARCH64_INSN_IMM_MOVK);
 			break;
 		case R_AARCH64_MOVW_PREL_G1:
 			ovf = reloc_insn_movw(RELOC_OP_PREL, loc, val, 16,
 					      AARCH64_INSN_IMM_MOVNZ);
 			break;
 		case R_AARCH64_MOVW_PREL_G2_NC:
 			overflow_check = false;
 			ovf = reloc_insn_movw(RELOC_OP_PREL, loc, val, 32,
 					      AARCH64_INSN_IMM_MOVK);
 			break;
 		case R_AARCH64_MOVW_PREL_G2:
 			ovf = reloc_insn_movw(RELOC_OP_PREL, loc, val, 32,
 					      AARCH64_INSN_IMM_MOVNZ);
 			break;
 		case R_AARCH64_MOVW_PREL_G3:
 			/* We're using the top bits so we can't overflow. */
 			overflow_check = false;
 			ovf = reloc_insn_movw(RELOC_OP_PREL, loc, val, 48,
 					      AARCH64_INSN_IMM_MOVNZ);
 			break;

 		/* Immediate instruction relocations. */
 		case R_AARCH64_LD_PREL_LO19:
 			ovf = reloc_insn_imm(RELOC_OP_PREL, loc, val, 2, 19,
 					     AARCH64_INSN_IMM_19);
 			break;
 		case R_AARCH64_ADR_PREL_LO21:
 			ovf = reloc_insn_imm(RELOC_OP_PREL, loc, val, 0, 21,
 					     AARCH64_INSN_IMM_ADR);
 			break;
 		case R_AARCH64_ADR_PREL_PG_HI21_NC:
 			overflow_check = false;
 		case R_AARCH64_ADR_PREL_PG_HI21:
 			ovf = reloc_insn_imm(RELOC_OP_PAGE, loc, val, 12, 21,
 					     AARCH64_INSN_IMM_ADR);
 			break;
 		case R_AARCH64_ADD_ABS_LO12_NC:
 		case R_AARCH64_LDST8_ABS_LO12_NC:
 			overflow_check = false;
 			ovf = reloc_insn_imm(RELOC_OP_ABS, loc, val, 0, 12,
 					     AARCH64_INSN_IMM_12);
 			break;
 		case R_AARCH64_LDST16_ABS_LO12_NC:
 			overflow_check = false;
 			ovf = reloc_insn_imm(RELOC_OP_ABS, loc, val, 1, 11,
 					     AARCH64_INSN_IMM_12);
 			break;
 		case R_AARCH64_LDST32_ABS_LO12_NC:
 			overflow_check = false;
 			ovf = reloc_insn_imm(RELOC_OP_ABS, loc, val, 2, 10,
 					     AARCH64_INSN_IMM_12);
 			break;
 		case R_AARCH64_LDST64_ABS_LO12_NC:
 			overflow_check = false;
 			ovf = reloc_insn_imm(RELOC_OP_ABS, loc, val, 3, 9,
 					     AARCH64_INSN_IMM_12);
 			break;
 		case R_AARCH64_LDST128_ABS_LO12_NC:
 			overflow_check = false;
 			ovf = reloc_insn_imm(RELOC_OP_ABS, loc, val, 4, 8,
 					     AARCH64_INSN_IMM_12);
 			break;
 		case R_AARCH64_TSTBR14:
 			ovf = reloc_insn_imm(RELOC_OP_PREL, loc, val, 2, 14,
 					     AARCH64_INSN_IMM_14);
 			break;
 		case R_AARCH64_CONDBR19:
 			ovf = reloc_insn_imm(RELOC_OP_PREL, loc, val, 2, 19,
 					     AARCH64_INSN_IMM_19);
 			break;
 		case R_AARCH64_JUMP26:
 		case R_AARCH64_CALL26:
 			ovf = reloc_insn_imm(RELOC_OP_PREL, loc, val, 2, 26,
 					     AARCH64_INSN_IMM_26);
 			break;

 		default:
 			pr_err("module %s: unsupported RELA relocation: %llu\n",
 			       me->name, ELF64_R_TYPE(rel[i].r_info));
 			return -ENOEXEC;
 		}

 		if (overflow_check && ovf == -ERANGE)
 			goto overflow;

 	}

 	return 0;

 overflow:
 	pr_err("module %s: overflow in relocation type %d val %Lx\n",
 	       me->name, (int)ELF64_R_TYPE(rel[i].r_info), val);
 	return -ENOEXEC;
 }

 int module_finalize(const Elf_Ehdr *hdr,
 		    const Elf_Shdr *sechdrs,
 		    struct module *me)
 {
 	const Elf_Shdr *s, *se;
 	const char *secstrs = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;

 	for (s = sechdrs, se = sechdrs + hdr->e_shnum; s < se; s++) {
 		if (strcmp(".altinstructions", secstrs + s->sh_name) == 0) {
 			apply_alternatives((void *)s->sh_addr, s->sh_size);
 			return 0;
 		}
 	}

 	return 0;
 }
	/*
	* AArch64 loadable module support.
	*
	* Copyright (C) 2012 ARM Limited
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License version 2 as
	* published by the Free Software Foundation.
	*
	* 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, see <http://www.gnu.org/licenses/>.
	*
	* Author: Will Deacon <will.deacon@arm.com>
	*/

	#include <linux/bitops.h>
	#include <linux/elf.h>
	#include <linux/gfp.h>
	#include <linux/kernel.h>
	#include <linux/mm.h>
	#include <linux/moduleloader.h>
	#include <linux/vmalloc.h>
	#include <asm/alternative.h>
	#include <asm/insn.h>
	#include <asm/sections.h>

	#define AARCH64_INSN_IMM_MOVNZ AARCH64_INSN_IMM_MAX
	#define AARCH64_INSN_IMM_MOVK AARCH64_INSN_IMM_16

	void *module_alloc(unsigned long size)
	{
	return __vmalloc_node_range(size, 1, MODULES_VADDR, MODULES_END,
	GFP_KERNEL, PAGE_KERNEL_EXEC, 0,
	NUMA_NO_NODE, __builtin_return_address(0));
	}

	enum aarch64_reloc_op {
	RELOC_OP_NONE,
	RELOC_OP_ABS,
	RELOC_OP_PREL,
	RELOC_OP_PAGE,
	};

	static u64 do_reloc(enum aarch64_reloc_op reloc_op, void *place, u64 val)
	{
	switch (reloc_op) {
	case RELOC_OP_ABS:
	return val;
	case RELOC_OP_PREL:
	return val - (u64)place;
	case RELOC_OP_PAGE:
	return (val & ~0xfff) - ((u64)place & ~0xfff);
	case RELOC_OP_NONE:
	return 0;
	}

	pr_err("do_reloc: unknown relocation operation %d\n", reloc_op);
	return 0;
	}

	static int reloc_data(enum aarch64_reloc_op op, void *place, u64 val, int len)
	{
	u64 imm_mask = (1 << len) - 1;
	s64 sval = do_reloc(op, place, val);

	switch (len) {
	case 16:
	(s16 )place = sval;
	break;
	case 32:
	(s32 )place = sval;
	break;
	case 64:
	(s64 )place = sval;
	break;
	default:
	pr_err("Invalid length (%d) for data relocation\n", len);
	return 0;
	}

	/*
	* Extract the upper value bits (including the sign bit) and
	* shift them to bit 0.
	*/
	sval = (s64)(sval & ~(imm_mask >> 1)) >> (len - 1);

	/*
	* Overflow has occurred if the value is not representable in
	* len bits (i.e the bottom len bits are not sign-extended and
	* the top bits are not all zero).
	*/
	if ((u64)(sval + 1) > 2)
	return -ERANGE;

	return 0;
	}

	static int reloc_insn_movw(enum aarch64_reloc_op op, void *place, u64 val,
	int lsb, enum aarch64_insn_imm_type imm_type)
	{
	u64 imm, limit = 0;
	s64 sval;
	u32 insn = le32_to_cpu((u32 )place);

	sval = do_reloc(op, place, val);
	sval >>= lsb;
	imm = sval & 0xffff;

	if (imm_type == AARCH64_INSN_IMM_MOVNZ) {
	/*
	* For signed MOVW relocations, we have to manipulate the
	* instruction encoding depending on whether or not the
	* immediate is less than zero.
	*/
	insn &= ~(3 << 29);
	if ((s64)imm >= 0) {
	/* >=0: Set the instruction to MOVZ (opcode 10b). */
	insn \|= 2 << 29;
	} else {
	/*
	* <0: Set the instruction to MOVN (opcode 00b).
	* Since we've masked the opcode already, we
	* don't need to do anything other than
	* inverting the new immediate field.
	*/
	imm = ~imm;
	}
	imm_type = AARCH64_INSN_IMM_MOVK;
	}

	/* Update the instruction with the new encoding. */
	insn = aarch64_insn_encode_immediate(imm_type, insn, imm);
	(u32 )place = cpu_to_le32(insn);

	/* Shift out the immediate field. */
	sval >>= 16;

	/*
	* For unsigned immediates, the overflow check is straightforward.
	* For signed immediates, the sign bit is actually the bit past the
	* most significant bit of the field.
	* The AARCH64_INSN_IMM_16 immediate type is unsigned.
	*/
	if (imm_type != AARCH64_INSN_IMM_16) {
	sval++;
	limit++;
	}

	/* Check the upper bits depending on the sign of the immediate. */
	if ((u64)sval > limit)
	return -ERANGE;

	return 0;
	}

	static int reloc_insn_imm(enum aarch64_reloc_op op, void *place, u64 val,
	int lsb, int len, enum aarch64_insn_imm_type imm_type)
	{
	u64 imm, imm_mask;
	s64 sval;
	u32 insn = le32_to_cpu((u32 )place);

	/* Calculate the relocation value. */
	sval = do_reloc(op, place, val);
	sval >>= lsb;

	/* Extract the value bits and shift them to bit 0. */
	imm_mask = (BIT(lsb + len) - 1) >> lsb;
	imm = sval & imm_mask;

	/* Update the instruction's immediate field. */
	insn = aarch64_insn_encode_immediate(imm_type, insn, imm);
	(u32 )place = cpu_to_le32(insn);

	/*
	* Extract the upper value bits (including the sign bit) and
	* shift them to bit 0.
	*/
	sval = (s64)(sval & ~(imm_mask >> 1)) >> (len - 1);

	/*
	* Overflow has occurred if the upper bits are not all equal to
	* the sign bit of the value.
	*/
	if ((u64)(sval + 1) >= 2)
	return -ERANGE;

	return 0;
	}

	int apply_relocate_add(Elf64_Shdr *sechdrs,
	const char *strtab,
	unsigned int symindex,
	unsigned int relsec,
	struct module *me)
	{
	unsigned int i;
	int ovf;
	bool overflow_check;
	Elf64_Sym *sym;
	void *loc;
	u64 val;
	Elf64_Rela rel = (void )sechdrs[relsec].sh_addr;

	for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
	/* loc corresponds to P in the AArch64 ELF document. */
	loc = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
	+ rel[i].r_offset;

	/* sym is the ELF symbol we're referring to. */
	sym = (Elf64_Sym *)sechdrs[symindex].sh_addr
	+ ELF64_R_SYM(rel[i].r_info);

	/* val corresponds to (S + A) in the AArch64 ELF document. */
	val = sym->st_value + rel[i].r_addend;

	/* Check for overflow by default. */
	overflow_check = true;

	/* Perform the static relocation. */
	switch (ELF64_R_TYPE(rel[i].r_info)) {
	/* Null relocations. */
	case R_ARM_NONE:
	case R_AARCH64_NONE:
	ovf = 0;
	break;

	/* Data relocations. */
	case R_AARCH64_ABS64:
	overflow_check = false;
	ovf = reloc_data(RELOC_OP_ABS, loc, val, 64);
	break;
	case R_AARCH64_ABS32:
	ovf = reloc_data(RELOC_OP_ABS, loc, val, 32);
	break;
	case R_AARCH64_ABS16:
	ovf = reloc_data(RELOC_OP_ABS, loc, val, 16);
	break;
	case R_AARCH64_PREL64:
	overflow_check = false;
	ovf = reloc_data(RELOC_OP_PREL, loc, val, 64);
	break;
	case R_AARCH64_PREL32:
	ovf = reloc_data(RELOC_OP_PREL, loc, val, 32);
	break;
	case R_AARCH64_PREL16:
	ovf = reloc_data(RELOC_OP_PREL, loc, val, 16);
	break;

	/* MOVW instruction relocations. */
	case R_AARCH64_MOVW_UABS_G0_NC:
	overflow_check = false;
	case R_AARCH64_MOVW_UABS_G0:
	ovf = reloc_insn_movw(RELOC_OP_ABS, loc, val, 0,
	AARCH64_INSN_IMM_16);
	break;
	case R_AARCH64_MOVW_UABS_G1_NC:
	overflow_check = false;
	case R_AARCH64_MOVW_UABS_G1:
	ovf = reloc_insn_movw(RELOC_OP_ABS, loc, val, 16,
	AARCH64_INSN_IMM_16);
	break;
	case R_AARCH64_MOVW_UABS_G2_NC:
	overflow_check = false;
	case R_AARCH64_MOVW_UABS_G2:
	ovf = reloc_insn_movw(RELOC_OP_ABS, loc, val, 32,
	AARCH64_INSN_IMM_16);
	break;
	case R_AARCH64_MOVW_UABS_G3:
	/* We're using the top bits so we can't overflow. */
	overflow_check = false;
	ovf = reloc_insn_movw(RELOC_OP_ABS, loc, val, 48,
	AARCH64_INSN_IMM_16);
	break;
	case R_AARCH64_MOVW_SABS_G0:
	ovf = reloc_insn_movw(RELOC_OP_ABS, loc, val, 0,
	AARCH64_INSN_IMM_MOVNZ);
	break;
	case R_AARCH64_MOVW_SABS_G1:
	ovf = reloc_insn_movw(RELOC_OP_ABS, loc, val, 16,
	AARCH64_INSN_IMM_MOVNZ);
	break;
	case R_AARCH64_MOVW_SABS_G2:
	ovf = reloc_insn_movw(RELOC_OP_ABS, loc, val, 32,
	AARCH64_INSN_IMM_MOVNZ);
	break;
	case R_AARCH64_MOVW_PREL_G0_NC:
	overflow_check = false;
	ovf = reloc_insn_movw(RELOC_OP_PREL, loc, val, 0,
	AARCH64_INSN_IMM_MOVK);
	break;
	case R_AARCH64_MOVW_PREL_G0:
	ovf = reloc_insn_movw(RELOC_OP_PREL, loc, val, 0,
	AARCH64_INSN_IMM_MOVNZ);
	break;
	case R_AARCH64_MOVW_PREL_G1_NC:
	overflow_check = false;
	ovf = reloc_insn_movw(RELOC_OP_PREL, loc, val, 16,
	AARCH64_INSN_IMM_MOVK);
	break;
	case R_AARCH64_MOVW_PREL_G1:
	ovf = reloc_insn_movw(RELOC_OP_PREL, loc, val, 16,
	AARCH64_INSN_IMM_MOVNZ);
	break;
	case R_AARCH64_MOVW_PREL_G2_NC:
	overflow_check = false;
	ovf = reloc_insn_movw(RELOC_OP_PREL, loc, val, 32,
	AARCH64_INSN_IMM_MOVK);
	break;
	case R_AARCH64_MOVW_PREL_G2:
	ovf = reloc_insn_movw(RELOC_OP_PREL, loc, val, 32,
	AARCH64_INSN_IMM_MOVNZ);
	break;
	case R_AARCH64_MOVW_PREL_G3:
	/* We're using the top bits so we can't overflow. */
	overflow_check = false;
	ovf = reloc_insn_movw(RELOC_OP_PREL, loc, val, 48,
	AARCH64_INSN_IMM_MOVNZ);
	break;

	/* Immediate instruction relocations. */
	case R_AARCH64_LD_PREL_LO19:
	ovf = reloc_insn_imm(RELOC_OP_PREL, loc, val, 2, 19,
	AARCH64_INSN_IMM_19);
	break;
	case R_AARCH64_ADR_PREL_LO21:
	ovf = reloc_insn_imm(RELOC_OP_PREL, loc, val, 0, 21,
	AARCH64_INSN_IMM_ADR);
	break;
	case R_AARCH64_ADR_PREL_PG_HI21_NC:
	overflow_check = false;
	case R_AARCH64_ADR_PREL_PG_HI21:
	ovf = reloc_insn_imm(RELOC_OP_PAGE, loc, val, 12, 21,
	AARCH64_INSN_IMM_ADR);
	break;
	case R_AARCH64_ADD_ABS_LO12_NC:
	case R_AARCH64_LDST8_ABS_LO12_NC:
	overflow_check = false;
	ovf = reloc_insn_imm(RELOC_OP_ABS, loc, val, 0, 12,
	AARCH64_INSN_IMM_12);
	break;
	case R_AARCH64_LDST16_ABS_LO12_NC:
	overflow_check = false;
	ovf = reloc_insn_imm(RELOC_OP_ABS, loc, val, 1, 11,
	AARCH64_INSN_IMM_12);
	break;
	case R_AARCH64_LDST32_ABS_LO12_NC:
	overflow_check = false;
	ovf = reloc_insn_imm(RELOC_OP_ABS, loc, val, 2, 10,
	AARCH64_INSN_IMM_12);
	break;
	case R_AARCH64_LDST64_ABS_LO12_NC:
	overflow_check = false;
	ovf = reloc_insn_imm(RELOC_OP_ABS, loc, val, 3, 9,
	AARCH64_INSN_IMM_12);
	break;
	case R_AARCH64_LDST128_ABS_LO12_NC:
	overflow_check = false;
	ovf = reloc_insn_imm(RELOC_OP_ABS, loc, val, 4, 8,
	AARCH64_INSN_IMM_12);
	break;
	case R_AARCH64_TSTBR14:
	ovf = reloc_insn_imm(RELOC_OP_PREL, loc, val, 2, 14,
	AARCH64_INSN_IMM_14);
	break;
	case R_AARCH64_CONDBR19:
	ovf = reloc_insn_imm(RELOC_OP_PREL, loc, val, 2, 19,
	AARCH64_INSN_IMM_19);
	break;
	case R_AARCH64_JUMP26:
	case R_AARCH64_CALL26:
	ovf = reloc_insn_imm(RELOC_OP_PREL, loc, val, 2, 26,
	AARCH64_INSN_IMM_26);
	break;

	default:
	pr_err("module %s: unsupported RELA relocation: %llu\n",
	me->name, ELF64_R_TYPE(rel[i].r_info));
	return -ENOEXEC;
	}

	if (overflow_check && ovf == -ERANGE)
	goto overflow;

	}

	return 0;

	overflow:
	pr_err("module %s: overflow in relocation type %d val %Lx\n",
	me->name, (int)ELF64_R_TYPE(rel[i].r_info), val);
	return -ENOEXEC;
	}

	int module_finalize(const Elf_Ehdr *hdr,
	const Elf_Shdr *sechdrs,
	struct module *me)
	{
	const Elf_Shdr s, se;
	const char secstrs = (void )hdr + sechdrs[hdr->e_shstrndx].sh_offset;

	for (s = sechdrs, se = sechdrs + hdr->e_shnum; s < se; s++) {
	if (strcmp(".altinstructions", secstrs + s->sh_name) == 0) {
	apply_alternatives((void *)s->sh_addr, s->sh_size);
	return 0;
	}
	}

	return 0;
	}