text: // SPDX-License-Identifier: GPL-2.0+
  /*
   *  Kernel module help for s390.
   *
   *  S390 version
   *    Copyright IBM Corp. 2002, 2003
   *    Author(s): Arnd Bergmann (arndb@de.ibm.com)
   *		 Martin Schwidefsky (schwidefsky@de.ibm.com)
   *
   *  based on i386 version
   *    Copyright (C) 2001 Rusty Russell.
   */
  #include <linux/module.h>
  #include <linux/elf.h>
  #include <linux/vmalloc.h>
  #include <linux/fs.h>
  #include <linux/string.h>
  #include <linux/kernel.h>
  #include <linux/moduleloader.h>
  #include <linux/bug.h>
  #include <asm/alternative.h>
  
  #if 0
  #define DEBUGP printk
  #else
  #define DEBUGP(fmt , ...)
  #endif
  
  #define PLT_ENTRY_SIZE 20
  
  void *module_alloc(unsigned long size)
  {
  	if (PAGE_ALIGN(size) > MODULES_LEN)
  		return NULL;
  	return __vmalloc_node_range(size, 1, MODULES_VADDR, MODULES_END,
  				    GFP_KERNEL, PAGE_KERNEL_EXEC,
  				    0, NUMA_NO_NODE,
  				    __builtin_return_address(0));
  }
  
  void module_arch_freeing_init(struct module *mod)
  {
  	if (is_livepatch_module(mod) &&
  	    mod->state == MODULE_STATE_LIVE)
  		return;
  
  	vfree(mod->arch.syminfo);
  	mod->arch.syminfo = NULL;
  }
  
  static void check_rela(Elf_Rela *rela, struct module *me)
  {
  	struct mod_arch_syminfo *info;
  
  	info = me->arch.syminfo + ELF_R_SYM (rela->r_info);
  	switch (ELF_R_TYPE (rela->r_info)) {
  	case R_390_GOT12:	/* 12 bit GOT offset.  */
  	case R_390_GOT16:	/* 16 bit GOT offset.  */
  	case R_390_GOT20:	/* 20 bit GOT offset.  */
  	case R_390_GOT32:	/* 32 bit GOT offset.  */
  	case R_390_GOT64:	/* 64 bit GOT offset.  */
  	case R_390_GOTENT:	/* 32 bit PC rel. to GOT entry shifted by 1. */
  	case R_390_GOTPLT12:	/* 12 bit offset to jump slot.	*/
  	case R_390_GOTPLT16:	/* 16 bit offset to jump slot.  */
  	case R_390_GOTPLT20:	/* 20 bit offset to jump slot.  */
  	case R_390_GOTPLT32:	/* 32 bit offset to jump slot.  */
  	case R_390_GOTPLT64:	/* 64 bit offset to jump slot.	*/
  	case R_390_GOTPLTENT:	/* 32 bit rel. offset to jump slot >> 1. */
  		if (info->got_offset == -1UL) {
  			info->got_offset = me->arch.got_size;
  			me->arch.got_size += sizeof(void*);
  		}
  		break;
  	case R_390_PLT16DBL:	/* 16 bit PC rel. PLT shifted by 1.  */
  	case R_390_PLT32DBL:	/* 32 bit PC rel. PLT shifted by 1.  */
  	case R_390_PLT32:	/* 32 bit PC relative PLT address.  */
  	case R_390_PLT64:	/* 64 bit PC relative PLT address.  */
  	case R_390_PLTOFF16:	/* 16 bit offset from GOT to PLT. */
  	case R_390_PLTOFF32:	/* 32 bit offset from GOT to PLT. */
  	case R_390_PLTOFF64:	/* 16 bit offset from GOT to PLT. */
  		if (info->plt_offset == -1UL) {
  			info->plt_offset = me->arch.plt_size;
  			me->arch.plt_size += PLT_ENTRY_SIZE;
  		}
  		break;
  	case R_390_COPY:
  	case R_390_GLOB_DAT:
  	case R_390_JMP_SLOT:
  	case R_390_RELATIVE:
  		/* Only needed if we want to support loading of 
  		   modules linked with -shared. */
  		break;
  	}
  }
  
  /*
   * Account for GOT and PLT relocations. We can't add sections for
   * got and plt but we can increase the core module size.
   */
  int module_frob_arch_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs,
  			      char *secstrings, struct module *me)
  {
  	Elf_Shdr *symtab;
  	Elf_Sym *symbols;
  	Elf_Rela *rela;
  	char *strings;
  	int nrela, i, j;
  
  	/* Find symbol table and string table. */
  	symtab = NULL;
  	for (i = 0; i < hdr->e_shnum; i++)
  		switch (sechdrs[i].sh_type) {
  		case SHT_SYMTAB:
  			symtab = sechdrs + i;
  			break;
  		}
  	if (!symtab) {
  		printk(KERN_ERR "module %s: no symbol table\n", me->name);
  		return -ENOEXEC;
  	}
  
  	/* Allocate one syminfo structure per symbol. */
  	me->arch.nsyms = symtab->sh_size / sizeof(Elf_Sym);
  	me->arch.syminfo = vmalloc(me->arch.nsyms *
  				   sizeof(struct mod_arch_syminfo));
  	if (!me->arch.syminfo)
  		return -ENOMEM;
  	symbols = (void *) hdr + symtab->sh_offset;
  	strings = (void *) hdr + sechdrs[symtab->sh_link].sh_offset;
  	for (i = 0; i < me->arch.nsyms; i++) {
  		if (symbols[i].st_shndx == SHN_UNDEF &&
  		    strcmp(strings + symbols[i].st_name,
  			   "_GLOBAL_OFFSET_TABLE_") == 0)
  			/* "Define" it as absolute. */
  			symbols[i].st_shndx = SHN_ABS;
  		me->arch.syminfo[i].got_offset = -1UL;
  		me->arch.syminfo[i].plt_offset = -1UL;
  		me->arch.syminfo[i].got_initialized = 0;
  		me->arch.syminfo[i].plt_initialized = 0;
  	}
  
  	/* Search for got/plt relocations. */
  	me->arch.got_size = me->arch.plt_size = 0;
  	for (i = 0; i < hdr->e_shnum; i++) {
  		if (sechdrs[i].sh_type != SHT_RELA)
  			continue;
  		nrela = sechdrs[i].sh_size / sizeof(Elf_Rela);
  		rela = (void *) hdr + sechdrs[i].sh_offset;
  		for (j = 0; j < nrela; j++)
  			check_rela(rela + j, me);
  	}
  
  	/* Increase core size by size of got & plt and set start
  	   offsets for got and plt. */
  	me->core_layout.size = ALIGN(me->core_layout.size, 4);
  	me->arch.got_offset = me->core_layout.size;
  	me->core_layout.size += me->arch.got_size;
  	me->arch.plt_offset = me->core_layout.size;
  	me->core_layout.size += me->arch.plt_size;
  	return 0;
  }
  
  static int apply_rela_bits(Elf_Addr loc, Elf_Addr val,
  			   int sign, int bits, int shift)
  {
  	unsigned long umax;
  	long min, max;
  
  	if (val & ((1UL << shift) - 1))
  		return -ENOEXEC;
  	if (sign) {
  		val = (Elf_Addr)(((long) val) >> shift);
  		min = -(1L << (bits - 1));
  		max = (1L << (bits - 1)) - 1;
  		if ((long) val < min || (long) val > max)
  			return -ENOEXEC;
  	} else {
  		val >>= shift;
  		umax = ((1UL << (bits - 1)) << 1) - 1;
  		if ((unsigned long) val > umax)
  			return -ENOEXEC;
  	}
  
  	if (bits == 8)
  		*(unsigned char *) loc = val;
  	else if (bits == 12)
  		*(unsigned short *) loc = (val & 0xfff) |
  			(*(unsigned short *) loc & 0xf000);
  	else if (bits == 16)
  		*(unsigned short *) loc = val;
  	else if (bits == 20)
  		*(unsigned int *) loc = (val & 0xfff) << 16 |
  			(val & 0xff000) >> 4 |
  			(*(unsigned int *) loc & 0xf00000ff);
  	else if (bits == 32)
  		*(unsigned int *) loc = val;
  	else if (bits == 64)
  		*(unsigned long *) loc = val;
  	return 0;
  }
  
  static int apply_rela(Elf_Rela *rela, Elf_Addr base, Elf_Sym *symtab,
  		      const char *strtab, struct module *me)
  {
  	struct mod_arch_syminfo *info;
  	Elf_Addr loc, val;
  	int r_type, r_sym;
  	int rc = -ENOEXEC;
  
  	/* This is where to make the change */
  	loc = base + rela->r_offset;
  	/* This is the symbol it is referring to.  Note that all
  	   undefined symbols have been resolved.  */
  	r_sym = ELF_R_SYM(rela->r_info);
  	r_type = ELF_R_TYPE(rela->r_info);
  	info = me->arch.syminfo + r_sym;
  	val = symtab[r_sym].st_value;
  
  	switch (r_type) {
  	case R_390_NONE:	/* No relocation.  */
  		rc = 0;
  		break;
  	case R_390_8:		/* Direct 8 bit.   */
  	case R_390_12:		/* Direct 12 bit.  */
  	case R_390_16:		/* Direct 16 bit.  */
  	case R_390_20:		/* Direct 20 bit.  */
  	case R_390_32:		/* Direct 32 bit.  */
  	case R_390_64:		/* Direct 64 bit.  */
  		val += rela->r_addend;
  		if (r_type == R_390_8)
  			rc = apply_rela_bits(loc, val, 0, 8, 0);
  		else if (r_type == R_390_12)
  			rc = apply_rela_bits(loc, val, 0, 12, 0);
  		else if (r_type == R_390_16)
  			rc = apply_rela_bits(loc, val, 0, 16, 0);
  		else if (r_type == R_390_20)
  			rc = apply_rela_bits(loc, val, 1, 20, 0);
  		else if (r_type == R_390_32)
  			rc = apply_rela_bits(loc, val, 0, 32, 0);
  		else if (r_type == R_390_64)
  			rc = apply_rela_bits(loc, val, 0, 64, 0);
  		break;
  	case R_390_PC16:	/* PC relative 16 bit.  */
  	case R_390_PC16DBL:	/* PC relative 16 bit shifted by 1.  */
  	case R_390_PC32DBL:	/* PC relative 32 bit shifted by 1.  */
  	case R_390_PC32:	/* PC relative 32 bit.  */
  	case R_390_PC64:	/* PC relative 64 bit.	*/
  		val += rela->r_addend - loc;
  		if (r_type == R_390_PC16)
  			rc = apply_rela_bits(loc, val, 1, 16, 0);
  		else if (r_type == R_390_PC16DBL)
  			rc = apply_rela_bits(loc, val, 1, 16, 1);
  		else if (r_type == R_390_PC32DBL)
  			rc = apply_rela_bits(loc, val, 1, 32, 1);
  		else if (r_type == R_390_PC32)
  			rc = apply_rela_bits(loc, val, 1, 32, 0);
  		else if (r_type == R_390_PC64)
  			rc = apply_rela_bits(loc, val, 1, 64, 0);
  		break;
  	case R_390_GOT12:	/* 12 bit GOT offset.  */
  	case R_390_GOT16:	/* 16 bit GOT offset.  */
  	case R_390_GOT20:	/* 20 bit GOT offset.  */
  	case R_390_GOT32:	/* 32 bit GOT offset.  */
  	case R_390_GOT64:	/* 64 bit GOT offset.  */
  	case R_390_GOTENT:	/* 32 bit PC rel. to GOT entry shifted by 1. */
  	case R_390_GOTPLT12:	/* 12 bit offset to jump slot.	*/
  	case R_390_GOTPLT20:	/* 20 bit offset to jump slot.  */
  	case R_390_GOTPLT16:	/* 16 bit offset to jump slot.  */
  	case R_390_GOTPLT32:	/* 32 bit offset to jump slot.  */
  	case R_390_GOTPLT64:	/* 64 bit offset to jump slot.	*/
  	case R_390_GOTPLTENT:	/* 32 bit rel. offset to jump slot >> 1. */
  		if (info->got_initialized == 0) {
  			Elf_Addr *gotent;
  
  			gotent = me->core_layout.base + me->arch.got_offset +
  				info->got_offset;
  			*gotent = val;
  			info->got_initialized = 1;
  		}
  		val = info->got_offset + rela->r_addend;
  		if (r_type == R_390_GOT12 ||
  		    r_type == R_390_GOTPLT12)
  			rc = apply_rela_bits(loc, val, 0, 12, 0);
  		else if (r_type == R_390_GOT16 ||
  			 r_type == R_390_GOTPLT16)
  			rc = apply_rela_bits(loc, val, 0, 16, 0);
  		else if (r_type == R_390_GOT20 ||
  			 r_type == R_390_GOTPLT20)
  			rc = apply_rela_bits(loc, val, 1, 20, 0);
  		else if (r_type == R_390_GOT32 ||
  			 r_type == R_390_GOTPLT32)
  			rc = apply_rela_bits(loc, val, 0, 32, 0);
  		else if (r_type == R_390_GOT64 ||
  			 r_type == R_390_GOTPLT64)
  			rc = apply_rela_bits(loc, val, 0, 64, 0);
  		else if (r_type == R_390_GOTENT ||
  			 r_type == R_390_GOTPLTENT) {
  			val += (Elf_Addr) me->core_layout.base - loc;
  			rc = apply_rela_bits(loc, val, 1, 32, 1);
  		}
  		break;
  	case R_390_PLT16DBL:	/* 16 bit PC rel. PLT shifted by 1.  */
  	case R_390_PLT32DBL:	/* 32 bit PC rel. PLT shifted by 1.  */
  	case R_390_PLT32:	/* 32 bit PC relative PLT address.  */
  	case R_390_PLT64:	/* 64 bit PC relative PLT address.  */
  	case R_390_PLTOFF16:	/* 16 bit offset from GOT to PLT. */
  	case R_390_PLTOFF32:	/* 32 bit offset from GOT to PLT. */
  	case R_390_PLTOFF64:	/* 16 bit offset from GOT to PLT. */
  		if (info->plt_initialized == 0) {
  			unsigned int *ip;
  			ip = me->core_layout.base + me->arch.plt_offset +
  				info->plt_offset;
  			ip[0] = 0x0d10e310; /* basr 1,0; lg 1,10(1); br 1 */
  			ip[1] = 0x100a0004;
  			ip[2] = 0x07f10000;
  			ip[3] = (unsigned int) (val >> 32);
  			ip[4] = (unsigned int) val;
  			info->plt_initialized = 1;
  		}
  		if (r_type == R_390_PLTOFF16 ||
  		    r_type == R_390_PLTOFF32 ||
  		    r_type == R_390_PLTOFF64)
  			val = me->arch.plt_offset - me->arch.got_offset +
  				info->plt_offset + rela->r_addend;
  		else {
  			if (!((r_type == R_390_PLT16DBL &&
  			       val - loc + 0xffffUL < 0x1ffffeUL) ||
  			      (r_type == R_390_PLT32DBL &&
  			       val - loc + 0xffffffffULL < 0x1fffffffeULL)))
  				val = (Elf_Addr) me->core_layout.base +
  					me->arch.plt_offset +
  					info->plt_offset;
  			val += rela->r_addend - loc;
  		}
  		if (r_type == R_390_PLT16DBL)
  			rc = apply_rela_bits(loc, val, 1, 16, 1);
  		else if (r_type == R_390_PLTOFF16)
  			rc = apply_rela_bits(loc, val, 0, 16, 0);
  		else if (r_type == R_390_PLT32DBL)
  			rc = apply_rela_bits(loc, val, 1, 32, 1);
  		else if (r_type == R_390_PLT32 ||
  			 r_type == R_390_PLTOFF32)
  			rc = apply_rela_bits(loc, val, 0, 32, 0);
  		else if (r_type == R_390_PLT64 ||
  			 r_type == R_390_PLTOFF64)
  			rc = apply_rela_bits(loc, val, 0, 64, 0);
  		break;
  	case R_390_GOTOFF16:	/* 16 bit offset to GOT.  */
  	case R_390_GOTOFF32:	/* 32 bit offset to GOT.  */
  	case R_390_GOTOFF64:	/* 64 bit offset to GOT. */
  		val = val + rela->r_addend -
  			((Elf_Addr) me->core_layout.base + me->arch.got_offset);
  		if (r_type == R_390_GOTOFF16)
  			rc = apply_rela_bits(loc, val, 0, 16, 0);
  		else if (r_type == R_390_GOTOFF32)
  			rc = apply_rela_bits(loc, val, 0, 32, 0);
  		else if (r_type == R_390_GOTOFF64)
  			rc = apply_rela_bits(loc, val, 0, 64, 0);
  		break;
  	case R_390_GOTPC:	/* 32 bit PC relative offset to GOT. */
  	case R_390_GOTPCDBL:	/* 32 bit PC rel. off. to GOT shifted by 1. */
  		val = (Elf_Addr) me->core_layout.base + me->arch.got_offset +
  			rela->r_addend - loc;
  		if (r_type == R_390_GOTPC)
  			rc = apply_rela_bits(loc, val, 1, 32, 0);
  		else if (r_type == R_390_GOTPCDBL)
  			rc = apply_rela_bits(loc, val, 1, 32, 1);
  		break;
  	case R_390_COPY:
  	case R_390_GLOB_DAT:	/* Create GOT entry.  */
  	case R_390_JMP_SLOT:	/* Create PLT entry.  */
  	case R_390_RELATIVE:	/* Adjust by program base.  */
  		/* Only needed if we want to support loading of 
  		   modules linked with -shared. */
  		return -ENOEXEC;
  	default:
  		printk(KERN_ERR "module %s: unknown relocation: %u\n",
  		       me->name, r_type);
  		return -ENOEXEC;
  	}
  	if (rc) {
  		printk(KERN_ERR "module %s: relocation error for symbol %s "
  		       "(r_type %i, value 0x%lx)\n",
  		       me->name, strtab + symtab[r_sym].st_name,
  		       r_type, (unsigned long) val);
  		return rc;
  	}
  	return 0;
  }
  
  int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab,
  		       unsigned int symindex, unsigned int relsec,
  		       struct module *me)
  {
  	Elf_Addr base;
  	Elf_Sym *symtab;
  	Elf_Rela *rela;
  	unsigned long i, n;
  	int rc;
  
  	DEBUGP("Applying relocate section %u to %u\n",
  	       relsec, sechdrs[relsec].sh_info);
  	base = sechdrs[sechdrs[relsec].sh_info].sh_addr;
  	symtab = (Elf_Sym *) sechdrs[symindex].sh_addr;
  	rela = (Elf_Rela *) sechdrs[relsec].sh_addr;
  	n = sechdrs[relsec].sh_size / sizeof(Elf_Rela);
  
  	for (i = 0; i < n; i++, rela++) {
  		rc = apply_rela(rela, base, symtab, strtab, me);
  		if (rc)
  			return rc;
  	}
  	return 0;
  }
  
  int module_finalize(const Elf_Ehdr *hdr,
  		    const Elf_Shdr *sechdrs,
  		    struct module *me)
  {
  	const Elf_Shdr *s;
  	char *secstrings;
  
  	secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
  	for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) {
  		if (!strcmp(".altinstructions", secstrings + s->sh_name)) {
  			/* patch .altinstructions */
  			void *aseg = (void *)s->sh_addr;
  
  			apply_alternatives(aseg, aseg + s->sh_size);
  		}
  	}
  
  	jump_label_apply_nops(me);
  	return 0;
  }
  