arch/arm64/kernel/module.c - SHIFTPHONES/mainline/linux - Gitiles

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * AArch64 loadable module support.
  *
  * Copyright (C) 2012 ARM Limited
  *
  * Author: Will Deacon <will.deacon@arm.com>
  */

 #include <linux/bitops.h>
 #include <linux/elf.h>
 #include <linux/ftrace.h>
 #include <linux/gfp.h>
 #include <linux/kasan.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>

 void *module_alloc(unsigned long size)
 {
 	u64 module_alloc_end = module_alloc_base + MODULES_VSIZE;
 	gfp_t gfp_mask = GFP_KERNEL;
 	void *p;

 	/* Silence the initial allocation */
 	if (IS_ENABLED(CONFIG_ARM64_MODULE_PLTS))
 		gfp_mask |= __GFP_NOWARN;

 	if (IS_ENABLED(CONFIG_KASAN_GENERIC) ||
 	    IS_ENABLED(CONFIG_KASAN_SW_TAGS))
 		/* don't exceed the static module region - see below */
 		module_alloc_end = MODULES_END;

 	p = __vmalloc_node_range(size, MODULE_ALIGN, module_alloc_base,
 				module_alloc_end, gfp_mask, PAGE_KERNEL, VM_DEFER_KMEMLEAK,
 				NUMA_NO_NODE, __builtin_return_address(0));

 	if (!p && IS_ENABLED(CONFIG_ARM64_MODULE_PLTS) &&
 	    (IS_ENABLED(CONFIG_KASAN_VMALLOC) ||
 	     (!IS_ENABLED(CONFIG_KASAN_GENERIC) &&
 	      !IS_ENABLED(CONFIG_KASAN_SW_TAGS))))
 		/*
 		 * KASAN without KASAN_VMALLOC can only deal with module
 		 * allocations being served from the reserved module region,
 		 * since the remainder of the vmalloc region is already
 		 * backed by zero shadow pages, and punching holes into it
 		 * is non-trivial. Since the module region is not randomized
 		 * when KASAN is enabled without KASAN_VMALLOC, it is even
 		 * less likely that the module region gets exhausted, so we
 		 * can simply omit this fallback in that case.
 		 */
 		p = __vmalloc_node_range(size, MODULE_ALIGN, module_alloc_base,
 				module_alloc_base + SZ_2G, GFP_KERNEL,
 				PAGE_KERNEL, 0, NUMA_NO_NODE,
 				__builtin_return_address(0));

 	if (p && (kasan_module_alloc(p, size, gfp_mask) < 0)) {
 		vfree(p);
 		return NULL;
 	}

 	return p;
 }

 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, __le32 *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)
 {
 	s64 sval = do_reloc(op, place, val);

 	/*
 	 * The ELF psABI for AArch64 documents the 16-bit and 32-bit place
 	 * relative and absolute relocations as having a range of [-2^15, 2^16)
 	 * or [-2^31, 2^32), respectively. However, in order to be able to
 	 * detect overflows reliably, we have to choose whether we interpret
 	 * such quantities as signed or as unsigned, and stick with it.
 	 * The way we organize our address space requires a signed
 	 * interpretation of 32-bit relative references, so let's use that
 	 * for all R_AARCH64_PRELxx relocations. This means our upper
 	 * bound for overflow detection should be Sxx_MAX rather than Uxx_MAX.
 	 */

 	switch (len) {
 	case 16:
 		*(s16 *)place = sval;
 		switch (op) {
 		case RELOC_OP_ABS:
 			if (sval < 0 || sval > U16_MAX)
 				return -ERANGE;
 			break;
 		case RELOC_OP_PREL:
 			if (sval < S16_MIN || sval > S16_MAX)
 				return -ERANGE;
 			break;
 		default:
 			pr_err("Invalid 16-bit data relocation (%d)\n", op);
 			return 0;
 		}
 		break;
 	case 32:
 		*(s32 *)place = sval;
 		switch (op) {
 		case RELOC_OP_ABS:
 			if (sval < 0 || sval > U32_MAX)
 				return -ERANGE;
 			break;
 		case RELOC_OP_PREL:
 			if (sval < S32_MIN || sval > S32_MAX)
 				return -ERANGE;
 			break;
 		default:
 			pr_err("Invalid 32-bit data relocation (%d)\n", op);
 			return 0;
 		}
 		break;
 	case 64:
 		*(s64 *)place = sval;
 		break;
 	default:
 		pr_err("Invalid length (%d) for data relocation\n", len);
 		return 0;
 	}
 	return 0;
 }

 enum aarch64_insn_movw_imm_type {
 	AARCH64_INSN_IMM_MOVNZ,
 	AARCH64_INSN_IMM_MOVKZ,
 };

 static int reloc_insn_movw(enum aarch64_reloc_op op, __le32 *place, u64 val,
 			   int lsb, enum aarch64_insn_movw_imm_type imm_type)
 {
 	u64 imm;
 	s64 sval;
 	u32 insn = le32_to_cpu(*place);

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

 	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 (sval >= 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;
 		}
 	}

 	/* Update the instruction with the new encoding. */
 	insn = aarch64_insn_encode_immediate(AARCH64_INSN_IMM_16, insn, imm);
 	*place = cpu_to_le32(insn);

 	if (imm > U16_MAX)
 		return -ERANGE;

 	return 0;
 }

 static int reloc_insn_imm(enum aarch64_reloc_op op, __le32 *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(*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);
 	*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;
 }

 static int reloc_insn_adrp(struct module *mod, Elf64_Shdr *sechdrs,
 			   __le32 *place, u64 val)
 {
 	u32 insn;

 	if (!is_forbidden_offset_for_adrp(place))
 		return reloc_insn_imm(RELOC_OP_PAGE, place, val, 12, 21,
 				      AARCH64_INSN_IMM_ADR);

 	/* patch ADRP to ADR if it is in range */
 	if (!reloc_insn_imm(RELOC_OP_PREL, place, val & ~0xfff, 0, 21,
 			    AARCH64_INSN_IMM_ADR)) {
 		insn = le32_to_cpu(*place);
 		insn &= ~BIT(31);
 	} else {
 		/* out of range for ADR -> emit a veneer */
 		val = module_emit_veneer_for_adrp(mod, sechdrs, place, val & ~0xfff);
 		if (!val)
 			return -ENOEXEC;
 		insn = aarch64_insn_gen_branch_imm((u64)place, val,
 						   AARCH64_INSN_BRANCH_NOLINK);
 	}

 	*place = cpu_to_le32(insn);
 	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;
 			fallthrough;
 		case R_AARCH64_MOVW_UABS_G0:
 			ovf = reloc_insn_movw(RELOC_OP_ABS, loc, val, 0,
 					      AARCH64_INSN_IMM_MOVKZ);
 			break;
 		case R_AARCH64_MOVW_UABS_G1_NC:
 			overflow_check = false;
 			fallthrough;
 		case R_AARCH64_MOVW_UABS_G1:
 			ovf = reloc_insn_movw(RELOC_OP_ABS, loc, val, 16,
 					      AARCH64_INSN_IMM_MOVKZ);
 			break;
 		case R_AARCH64_MOVW_UABS_G2_NC:
 			overflow_check = false;
 			fallthrough;
 		case R_AARCH64_MOVW_UABS_G2:
 			ovf = reloc_insn_movw(RELOC_OP_ABS, loc, val, 32,
 					      AARCH64_INSN_IMM_MOVKZ);
 			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_MOVKZ);
 			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_MOVKZ);
 			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_MOVKZ);
 			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_MOVKZ);
 			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;
 			fallthrough;
 		case R_AARCH64_ADR_PREL_PG_HI21:
 			ovf = reloc_insn_adrp(me, sechdrs, loc, val);
 			if (ovf && ovf != -ERANGE)
 				return ovf;
 			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);

 			if (IS_ENABLED(CONFIG_ARM64_MODULE_PLTS) &&
 			    ovf == -ERANGE) {
 				val = module_emit_plt_entry(me, sechdrs, loc, &rel[i], sym);
 				if (!val)
 					return -ENOEXEC;
 				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;
 }

 static const Elf_Shdr *find_section(const Elf_Ehdr *hdr,
 				    const Elf_Shdr *sechdrs,
 				    const char *name)
 {
 	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(name, secstrs + s->sh_name) == 0)
 			return s;
 	}

 	return NULL;
 }

 static inline void __init_plt(struct plt_entry *plt, unsigned long addr)
 {
 	*plt = get_plt_entry(addr, plt);
 }

 static int module_init_ftrace_plt(const Elf_Ehdr *hdr,
 				  const Elf_Shdr *sechdrs,
 				  struct module *mod)
 {
 #if defined(CONFIG_ARM64_MODULE_PLTS) && defined(CONFIG_DYNAMIC_FTRACE)
 	const Elf_Shdr *s;
 	struct plt_entry *plts;

 	s = find_section(hdr, sechdrs, ".text.ftrace_trampoline");
 	if (!s)
 		return -ENOEXEC;

 	plts = (void *)s->sh_addr;

 	__init_plt(&plts[FTRACE_PLT_IDX], FTRACE_ADDR);

 	if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS))
 		__init_plt(&plts[FTRACE_REGS_PLT_IDX], FTRACE_REGS_ADDR);

 	mod->arch.ftrace_trampolines = plts;
 #endif
 	return 0;
 }

 int module_finalize(const Elf_Ehdr *hdr,
 		    const Elf_Shdr *sechdrs,
 		    struct module *me)
 {
 	const Elf_Shdr *s;
 	s = find_section(hdr, sechdrs, ".altinstructions");
 	if (s)
 		apply_alternatives_module((void *)s->sh_addr, s->sh_size);

 	return module_init_ftrace_plt(hdr, sechdrs, me);
 }
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* AArch64 loadable module support.
	*
	* Copyright (C) 2012 ARM Limited
	*
	* Author: Will Deacon <will.deacon@arm.com>
	*/

	#include <linux/bitops.h>
	#include <linux/elf.h>
	#include <linux/ftrace.h>
	#include <linux/gfp.h>
	#include <linux/kasan.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>

	void *module_alloc(unsigned long size)
	{
	u64 module_alloc_end = module_alloc_base + MODULES_VSIZE;
	gfp_t gfp_mask = GFP_KERNEL;
	void *p;

	/* Silence the initial allocation */
	if (IS_ENABLED(CONFIG_ARM64_MODULE_PLTS))
	gfp_mask \|= __GFP_NOWARN;

	if (IS_ENABLED(CONFIG_KASAN_GENERIC) \|\|
	IS_ENABLED(CONFIG_KASAN_SW_TAGS))
	/* don't exceed the static module region - see below */
	module_alloc_end = MODULES_END;

	p = __vmalloc_node_range(size, MODULE_ALIGN, module_alloc_base,
	module_alloc_end, gfp_mask, PAGE_KERNEL, VM_DEFER_KMEMLEAK,
	NUMA_NO_NODE, __builtin_return_address(0));

	if (!p && IS_ENABLED(CONFIG_ARM64_MODULE_PLTS) &&
	(IS_ENABLED(CONFIG_KASAN_VMALLOC) \|\|
	(!IS_ENABLED(CONFIG_KASAN_GENERIC) &&
	!IS_ENABLED(CONFIG_KASAN_SW_TAGS))))
	/*
	* KASAN without KASAN_VMALLOC can only deal with module
	* allocations being served from the reserved module region,
	* since the remainder of the vmalloc region is already
	* backed by zero shadow pages, and punching holes into it
	* is non-trivial. Since the module region is not randomized
	* when KASAN is enabled without KASAN_VMALLOC, it is even
	* less likely that the module region gets exhausted, so we
	* can simply omit this fallback in that case.
	*/
	p = __vmalloc_node_range(size, MODULE_ALIGN, module_alloc_base,
	module_alloc_base + SZ_2G, GFP_KERNEL,
	PAGE_KERNEL, 0, NUMA_NO_NODE,
	__builtin_return_address(0));

	if (p && (kasan_module_alloc(p, size, gfp_mask) < 0)) {
	vfree(p);
	return NULL;
	}

	return p;
	}

	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, __le32 *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)
	{
	s64 sval = do_reloc(op, place, val);

	/*
	* The ELF psABI for AArch64 documents the 16-bit and 32-bit place
	* relative and absolute relocations as having a range of [-2^15, 2^16)
	* or [-2^31, 2^32), respectively. However, in order to be able to
	* detect overflows reliably, we have to choose whether we interpret
	* such quantities as signed or as unsigned, and stick with it.
	* The way we organize our address space requires a signed
	* interpretation of 32-bit relative references, so let's use that
	* for all R_AARCH64_PRELxx relocations. This means our upper
	* bound for overflow detection should be Sxx_MAX rather than Uxx_MAX.
	*/

	switch (len) {
	case 16:
	(s16 )place = sval;
	switch (op) {
	case RELOC_OP_ABS:
	if (sval < 0 \|\| sval > U16_MAX)
	return -ERANGE;
	break;
	case RELOC_OP_PREL:
	if (sval < S16_MIN \|\| sval > S16_MAX)
	return -ERANGE;
	break;
	default:
	pr_err("Invalid 16-bit data relocation (%d)\n", op);
	return 0;
	}
	break;
	case 32:
	(s32 )place = sval;
	switch (op) {
	case RELOC_OP_ABS:
	if (sval < 0 \|\| sval > U32_MAX)
	return -ERANGE;
	break;
	case RELOC_OP_PREL:
	if (sval < S32_MIN \|\| sval > S32_MAX)
	return -ERANGE;
	break;
	default:
	pr_err("Invalid 32-bit data relocation (%d)\n", op);
	return 0;
	}
	break;
	case 64:
	(s64 )place = sval;
	break;
	default:
	pr_err("Invalid length (%d) for data relocation\n", len);
	return 0;
	}
	return 0;
	}

	enum aarch64_insn_movw_imm_type {
	AARCH64_INSN_IMM_MOVNZ,
	AARCH64_INSN_IMM_MOVKZ,
	};

	static int reloc_insn_movw(enum aarch64_reloc_op op, __le32 *place, u64 val,
	int lsb, enum aarch64_insn_movw_imm_type imm_type)
	{
	u64 imm;
	s64 sval;
	u32 insn = le32_to_cpu(*place);

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

	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 (sval >= 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;
	}
	}

	/* Update the instruction with the new encoding. */
	insn = aarch64_insn_encode_immediate(AARCH64_INSN_IMM_16, insn, imm);
	*place = cpu_to_le32(insn);

	if (imm > U16_MAX)
	return -ERANGE;

	return 0;
	}

	static int reloc_insn_imm(enum aarch64_reloc_op op, __le32 *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(*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);
	*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;
	}

	static int reloc_insn_adrp(struct module mod, Elf64_Shdr sechdrs,
	__le32 *place, u64 val)
	{
	u32 insn;

	if (!is_forbidden_offset_for_adrp(place))
	return reloc_insn_imm(RELOC_OP_PAGE, place, val, 12, 21,
	AARCH64_INSN_IMM_ADR);

	/* patch ADRP to ADR if it is in range */
	if (!reloc_insn_imm(RELOC_OP_PREL, place, val & ~0xfff, 0, 21,
	AARCH64_INSN_IMM_ADR)) {
	insn = le32_to_cpu(*place);
	insn &= ~BIT(31);
	} else {
	/* out of range for ADR -> emit a veneer */
	val = module_emit_veneer_for_adrp(mod, sechdrs, place, val & ~0xfff);
	if (!val)
	return -ENOEXEC;
	insn = aarch64_insn_gen_branch_imm((u64)place, val,
	AARCH64_INSN_BRANCH_NOLINK);
	}

	*place = cpu_to_le32(insn);
	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;
	fallthrough;
	case R_AARCH64_MOVW_UABS_G0:
	ovf = reloc_insn_movw(RELOC_OP_ABS, loc, val, 0,
	AARCH64_INSN_IMM_MOVKZ);
	break;
	case R_AARCH64_MOVW_UABS_G1_NC:
	overflow_check = false;
	fallthrough;
	case R_AARCH64_MOVW_UABS_G1:
	ovf = reloc_insn_movw(RELOC_OP_ABS, loc, val, 16,
	AARCH64_INSN_IMM_MOVKZ);
	break;
	case R_AARCH64_MOVW_UABS_G2_NC:
	overflow_check = false;
	fallthrough;
	case R_AARCH64_MOVW_UABS_G2:
	ovf = reloc_insn_movw(RELOC_OP_ABS, loc, val, 32,
	AARCH64_INSN_IMM_MOVKZ);
	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_MOVKZ);
	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_MOVKZ);
	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_MOVKZ);
	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_MOVKZ);
	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;
	fallthrough;
	case R_AARCH64_ADR_PREL_PG_HI21:
	ovf = reloc_insn_adrp(me, sechdrs, loc, val);
	if (ovf && ovf != -ERANGE)
	return ovf;
	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);

	if (IS_ENABLED(CONFIG_ARM64_MODULE_PLTS) &&
	ovf == -ERANGE) {
	val = module_emit_plt_entry(me, sechdrs, loc, &rel[i], sym);
	if (!val)
	return -ENOEXEC;
	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;
	}

	static const Elf_Shdr find_section(const Elf_Ehdr hdr,
	const Elf_Shdr *sechdrs,
	const char *name)
	{
	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(name, secstrs + s->sh_name) == 0)
	return s;
	}

	return NULL;
	}

	static inline void __init_plt(struct plt_entry *plt, unsigned long addr)
	{
	*plt = get_plt_entry(addr, plt);
	}

	static int module_init_ftrace_plt(const Elf_Ehdr *hdr,
	const Elf_Shdr *sechdrs,
	struct module *mod)
	{
	#if defined(CONFIG_ARM64_MODULE_PLTS) && defined(CONFIG_DYNAMIC_FTRACE)
	const Elf_Shdr *s;
	struct plt_entry *plts;

	s = find_section(hdr, sechdrs, ".text.ftrace_trampoline");
	if (!s)
	return -ENOEXEC;

	plts = (void *)s->sh_addr;

	__init_plt(&plts[FTRACE_PLT_IDX], FTRACE_ADDR);

	if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_REGS))
	__init_plt(&plts[FTRACE_REGS_PLT_IDX], FTRACE_REGS_ADDR);

	mod->arch.ftrace_trampolines = plts;
	#endif
	return 0;
	}

	int module_finalize(const Elf_Ehdr *hdr,
	const Elf_Shdr *sechdrs,
	struct module *me)
	{
	const Elf_Shdr *s;
	s = find_section(hdr, sechdrs, ".altinstructions");
	if (s)
	apply_alternatives_module((void *)s->sh_addr, s->sh_size);

	return module_init_ftrace_plt(hdr, sechdrs, me);
	}