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514 lines
16 KiB
514 lines
16 KiB
// SPDX-License-Identifier: GPL-2.0+ |
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/* |
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* Kernel module help for s390. |
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* |
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* S390 version |
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* Copyright IBM Corp. 2002, 2003 |
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* Author(s): Arnd Bergmann ([email protected]) |
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* Martin Schwidefsky ([email protected]) |
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* |
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* based on i386 version |
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* Copyright (C) 2001 Rusty Russell. |
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*/ |
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#include <linux/module.h> |
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#include <linux/elf.h> |
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#include <linux/vmalloc.h> |
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#include <linux/fs.h> |
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#include <linux/string.h> |
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#include <linux/kernel.h> |
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#include <linux/kasan.h> |
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#include <linux/moduleloader.h> |
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#include <linux/bug.h> |
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#include <linux/memory.h> |
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#include <asm/alternative.h> |
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#include <asm/nospec-branch.h> |
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#include <asm/facility.h> |
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|
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#if 0 |
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#define DEBUGP printk |
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#else |
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#define DEBUGP(fmt , ...) |
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#endif |
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#define PLT_ENTRY_SIZE 20 |
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|
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void *module_alloc(unsigned long size) |
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{ |
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void *p; |
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|
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if (PAGE_ALIGN(size) > MODULES_LEN) |
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return NULL; |
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p = __vmalloc_node_range(size, MODULE_ALIGN, MODULES_VADDR, MODULES_END, |
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GFP_KERNEL, PAGE_KERNEL_EXEC, 0, NUMA_NO_NODE, |
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__builtin_return_address(0)); |
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if (p && (kasan_module_alloc(p, size) < 0)) { |
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vfree(p); |
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return NULL; |
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} |
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return p; |
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} |
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|
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void module_arch_freeing_init(struct module *mod) |
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{ |
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if (is_livepatch_module(mod) && |
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mod->state == MODULE_STATE_LIVE) |
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return; |
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|
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vfree(mod->arch.syminfo); |
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mod->arch.syminfo = NULL; |
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} |
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|
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static void check_rela(Elf_Rela *rela, struct module *me) |
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{ |
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struct mod_arch_syminfo *info; |
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|
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info = me->arch.syminfo + ELF_R_SYM (rela->r_info); |
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switch (ELF_R_TYPE (rela->r_info)) { |
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case R_390_GOT12: /* 12 bit GOT offset. */ |
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case R_390_GOT16: /* 16 bit GOT offset. */ |
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case R_390_GOT20: /* 20 bit GOT offset. */ |
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case R_390_GOT32: /* 32 bit GOT offset. */ |
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case R_390_GOT64: /* 64 bit GOT offset. */ |
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case R_390_GOTENT: /* 32 bit PC rel. to GOT entry shifted by 1. */ |
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case R_390_GOTPLT12: /* 12 bit offset to jump slot. */ |
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case R_390_GOTPLT16: /* 16 bit offset to jump slot. */ |
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case R_390_GOTPLT20: /* 20 bit offset to jump slot. */ |
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case R_390_GOTPLT32: /* 32 bit offset to jump slot. */ |
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case R_390_GOTPLT64: /* 64 bit offset to jump slot. */ |
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case R_390_GOTPLTENT: /* 32 bit rel. offset to jump slot >> 1. */ |
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if (info->got_offset == -1UL) { |
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info->got_offset = me->arch.got_size; |
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me->arch.got_size += sizeof(void*); |
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} |
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break; |
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case R_390_PLT16DBL: /* 16 bit PC rel. PLT shifted by 1. */ |
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case R_390_PLT32DBL: /* 32 bit PC rel. PLT shifted by 1. */ |
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case R_390_PLT32: /* 32 bit PC relative PLT address. */ |
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case R_390_PLT64: /* 64 bit PC relative PLT address. */ |
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case R_390_PLTOFF16: /* 16 bit offset from GOT to PLT. */ |
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case R_390_PLTOFF32: /* 32 bit offset from GOT to PLT. */ |
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case R_390_PLTOFF64: /* 16 bit offset from GOT to PLT. */ |
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if (info->plt_offset == -1UL) { |
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info->plt_offset = me->arch.plt_size; |
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me->arch.plt_size += PLT_ENTRY_SIZE; |
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} |
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break; |
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case R_390_COPY: |
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case R_390_GLOB_DAT: |
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case R_390_JMP_SLOT: |
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case R_390_RELATIVE: |
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/* Only needed if we want to support loading of |
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modules linked with -shared. */ |
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break; |
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} |
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} |
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|
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/* |
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* Account for GOT and PLT relocations. We can't add sections for |
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* got and plt but we can increase the core module size. |
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*/ |
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int module_frob_arch_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs, |
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char *secstrings, struct module *me) |
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{ |
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Elf_Shdr *symtab; |
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Elf_Sym *symbols; |
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Elf_Rela *rela; |
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char *strings; |
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int nrela, i, j; |
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|
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/* Find symbol table and string table. */ |
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symtab = NULL; |
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for (i = 0; i < hdr->e_shnum; i++) |
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switch (sechdrs[i].sh_type) { |
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case SHT_SYMTAB: |
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symtab = sechdrs + i; |
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break; |
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} |
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if (!symtab) { |
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printk(KERN_ERR "module %s: no symbol table\n", me->name); |
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return -ENOEXEC; |
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} |
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/* Allocate one syminfo structure per symbol. */ |
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me->arch.nsyms = symtab->sh_size / sizeof(Elf_Sym); |
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me->arch.syminfo = vmalloc(array_size(sizeof(struct mod_arch_syminfo), |
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me->arch.nsyms)); |
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if (!me->arch.syminfo) |
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return -ENOMEM; |
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symbols = (void *) hdr + symtab->sh_offset; |
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strings = (void *) hdr + sechdrs[symtab->sh_link].sh_offset; |
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for (i = 0; i < me->arch.nsyms; i++) { |
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if (symbols[i].st_shndx == SHN_UNDEF && |
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strcmp(strings + symbols[i].st_name, |
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"_GLOBAL_OFFSET_TABLE_") == 0) |
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/* "Define" it as absolute. */ |
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symbols[i].st_shndx = SHN_ABS; |
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me->arch.syminfo[i].got_offset = -1UL; |
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me->arch.syminfo[i].plt_offset = -1UL; |
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me->arch.syminfo[i].got_initialized = 0; |
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me->arch.syminfo[i].plt_initialized = 0; |
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} |
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/* Search for got/plt relocations. */ |
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me->arch.got_size = me->arch.plt_size = 0; |
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for (i = 0; i < hdr->e_shnum; i++) { |
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if (sechdrs[i].sh_type != SHT_RELA) |
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continue; |
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nrela = sechdrs[i].sh_size / sizeof(Elf_Rela); |
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rela = (void *) hdr + sechdrs[i].sh_offset; |
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for (j = 0; j < nrela; j++) |
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check_rela(rela + j, me); |
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} |
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/* Increase core size by size of got & plt and set start |
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offsets for got and plt. */ |
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me->core_layout.size = ALIGN(me->core_layout.size, 4); |
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me->arch.got_offset = me->core_layout.size; |
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me->core_layout.size += me->arch.got_size; |
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me->arch.plt_offset = me->core_layout.size; |
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if (me->arch.plt_size) { |
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if (IS_ENABLED(CONFIG_EXPOLINE) && !nospec_disable) |
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me->arch.plt_size += PLT_ENTRY_SIZE; |
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me->core_layout.size += me->arch.plt_size; |
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} |
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return 0; |
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} |
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static int apply_rela_bits(Elf_Addr loc, Elf_Addr val, |
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int sign, int bits, int shift, |
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void *(*write)(void *dest, const void *src, size_t len)) |
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{ |
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unsigned long umax; |
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long min, max; |
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void *dest = (void *)loc; |
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if (val & ((1UL << shift) - 1)) |
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return -ENOEXEC; |
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if (sign) { |
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val = (Elf_Addr)(((long) val) >> shift); |
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min = -(1L << (bits - 1)); |
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max = (1L << (bits - 1)) - 1; |
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if ((long) val < min || (long) val > max) |
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return -ENOEXEC; |
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} else { |
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val >>= shift; |
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umax = ((1UL << (bits - 1)) << 1) - 1; |
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if ((unsigned long) val > umax) |
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return -ENOEXEC; |
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} |
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if (bits == 8) { |
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unsigned char tmp = val; |
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write(dest, &tmp, 1); |
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} else if (bits == 12) { |
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unsigned short tmp = (val & 0xfff) | |
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(*(unsigned short *) loc & 0xf000); |
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write(dest, &tmp, 2); |
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} else if (bits == 16) { |
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unsigned short tmp = val; |
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write(dest, &tmp, 2); |
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} else if (bits == 20) { |
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unsigned int tmp = (val & 0xfff) << 16 | |
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(val & 0xff000) >> 4 | (*(unsigned int *) loc & 0xf00000ff); |
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write(dest, &tmp, 4); |
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} else if (bits == 32) { |
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unsigned int tmp = val; |
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write(dest, &tmp, 4); |
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} else if (bits == 64) { |
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unsigned long tmp = val; |
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write(dest, &tmp, 8); |
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} |
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return 0; |
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} |
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static int apply_rela(Elf_Rela *rela, Elf_Addr base, Elf_Sym *symtab, |
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const char *strtab, struct module *me, |
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void *(*write)(void *dest, const void *src, size_t len)) |
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{ |
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struct mod_arch_syminfo *info; |
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Elf_Addr loc, val; |
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int r_type, r_sym; |
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int rc = -ENOEXEC; |
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/* This is where to make the change */ |
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loc = base + rela->r_offset; |
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/* This is the symbol it is referring to. Note that all |
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undefined symbols have been resolved. */ |
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r_sym = ELF_R_SYM(rela->r_info); |
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r_type = ELF_R_TYPE(rela->r_info); |
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info = me->arch.syminfo + r_sym; |
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val = symtab[r_sym].st_value; |
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switch (r_type) { |
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case R_390_NONE: /* No relocation. */ |
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rc = 0; |
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break; |
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case R_390_8: /* Direct 8 bit. */ |
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case R_390_12: /* Direct 12 bit. */ |
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case R_390_16: /* Direct 16 bit. */ |
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case R_390_20: /* Direct 20 bit. */ |
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case R_390_32: /* Direct 32 bit. */ |
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case R_390_64: /* Direct 64 bit. */ |
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val += rela->r_addend; |
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if (r_type == R_390_8) |
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rc = apply_rela_bits(loc, val, 0, 8, 0, write); |
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else if (r_type == R_390_12) |
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rc = apply_rela_bits(loc, val, 0, 12, 0, write); |
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else if (r_type == R_390_16) |
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rc = apply_rela_bits(loc, val, 0, 16, 0, write); |
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else if (r_type == R_390_20) |
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rc = apply_rela_bits(loc, val, 1, 20, 0, write); |
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else if (r_type == R_390_32) |
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rc = apply_rela_bits(loc, val, 0, 32, 0, write); |
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else if (r_type == R_390_64) |
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rc = apply_rela_bits(loc, val, 0, 64, 0, write); |
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break; |
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case R_390_PC16: /* PC relative 16 bit. */ |
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case R_390_PC16DBL: /* PC relative 16 bit shifted by 1. */ |
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case R_390_PC32DBL: /* PC relative 32 bit shifted by 1. */ |
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case R_390_PC32: /* PC relative 32 bit. */ |
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case R_390_PC64: /* PC relative 64 bit. */ |
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val += rela->r_addend - loc; |
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if (r_type == R_390_PC16) |
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rc = apply_rela_bits(loc, val, 1, 16, 0, write); |
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else if (r_type == R_390_PC16DBL) |
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rc = apply_rela_bits(loc, val, 1, 16, 1, write); |
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else if (r_type == R_390_PC32DBL) |
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rc = apply_rela_bits(loc, val, 1, 32, 1, write); |
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else if (r_type == R_390_PC32) |
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rc = apply_rela_bits(loc, val, 1, 32, 0, write); |
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else if (r_type == R_390_PC64) |
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rc = apply_rela_bits(loc, val, 1, 64, 0, write); |
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break; |
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case R_390_GOT12: /* 12 bit GOT offset. */ |
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case R_390_GOT16: /* 16 bit GOT offset. */ |
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case R_390_GOT20: /* 20 bit GOT offset. */ |
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case R_390_GOT32: /* 32 bit GOT offset. */ |
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case R_390_GOT64: /* 64 bit GOT offset. */ |
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case R_390_GOTENT: /* 32 bit PC rel. to GOT entry shifted by 1. */ |
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case R_390_GOTPLT12: /* 12 bit offset to jump slot. */ |
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case R_390_GOTPLT20: /* 20 bit offset to jump slot. */ |
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case R_390_GOTPLT16: /* 16 bit offset to jump slot. */ |
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case R_390_GOTPLT32: /* 32 bit offset to jump slot. */ |
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case R_390_GOTPLT64: /* 64 bit offset to jump slot. */ |
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case R_390_GOTPLTENT: /* 32 bit rel. offset to jump slot >> 1. */ |
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if (info->got_initialized == 0) { |
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Elf_Addr *gotent = me->core_layout.base + |
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me->arch.got_offset + |
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info->got_offset; |
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write(gotent, &val, sizeof(*gotent)); |
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info->got_initialized = 1; |
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} |
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val = info->got_offset + rela->r_addend; |
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if (r_type == R_390_GOT12 || |
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r_type == R_390_GOTPLT12) |
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rc = apply_rela_bits(loc, val, 0, 12, 0, write); |
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else if (r_type == R_390_GOT16 || |
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r_type == R_390_GOTPLT16) |
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rc = apply_rela_bits(loc, val, 0, 16, 0, write); |
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else if (r_type == R_390_GOT20 || |
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r_type == R_390_GOTPLT20) |
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rc = apply_rela_bits(loc, val, 1, 20, 0, write); |
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else if (r_type == R_390_GOT32 || |
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r_type == R_390_GOTPLT32) |
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rc = apply_rela_bits(loc, val, 0, 32, 0, write); |
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else if (r_type == R_390_GOT64 || |
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r_type == R_390_GOTPLT64) |
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rc = apply_rela_bits(loc, val, 0, 64, 0, write); |
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else if (r_type == R_390_GOTENT || |
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r_type == R_390_GOTPLTENT) { |
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val += (Elf_Addr) me->core_layout.base - loc; |
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rc = apply_rela_bits(loc, val, 1, 32, 1, write); |
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} |
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break; |
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case R_390_PLT16DBL: /* 16 bit PC rel. PLT shifted by 1. */ |
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case R_390_PLT32DBL: /* 32 bit PC rel. PLT shifted by 1. */ |
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case R_390_PLT32: /* 32 bit PC relative PLT address. */ |
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case R_390_PLT64: /* 64 bit PC relative PLT address. */ |
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case R_390_PLTOFF16: /* 16 bit offset from GOT to PLT. */ |
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case R_390_PLTOFF32: /* 32 bit offset from GOT to PLT. */ |
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case R_390_PLTOFF64: /* 16 bit offset from GOT to PLT. */ |
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if (info->plt_initialized == 0) { |
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unsigned int insn[5]; |
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unsigned int *ip = me->core_layout.base + |
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me->arch.plt_offset + |
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info->plt_offset; |
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insn[0] = 0x0d10e310; /* basr 1,0 */ |
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insn[1] = 0x100a0004; /* lg 1,10(1) */ |
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if (IS_ENABLED(CONFIG_EXPOLINE) && !nospec_disable) { |
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unsigned int *ij; |
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ij = me->core_layout.base + |
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me->arch.plt_offset + |
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me->arch.plt_size - PLT_ENTRY_SIZE; |
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insn[2] = 0xa7f40000 + /* j __jump_r1 */ |
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(unsigned int)(u16) |
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(((unsigned long) ij - 8 - |
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(unsigned long) ip) / 2); |
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} else { |
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insn[2] = 0x07f10000; /* br %r1 */ |
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} |
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insn[3] = (unsigned int) (val >> 32); |
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insn[4] = (unsigned int) val; |
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write(ip, insn, sizeof(insn)); |
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info->plt_initialized = 1; |
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} |
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if (r_type == R_390_PLTOFF16 || |
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r_type == R_390_PLTOFF32 || |
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r_type == R_390_PLTOFF64) |
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val = me->arch.plt_offset - me->arch.got_offset + |
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info->plt_offset + rela->r_addend; |
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else { |
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if (!((r_type == R_390_PLT16DBL && |
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val - loc + 0xffffUL < 0x1ffffeUL) || |
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(r_type == R_390_PLT32DBL && |
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val - loc + 0xffffffffULL < 0x1fffffffeULL))) |
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val = (Elf_Addr) me->core_layout.base + |
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me->arch.plt_offset + |
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info->plt_offset; |
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val += rela->r_addend - loc; |
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} |
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if (r_type == R_390_PLT16DBL) |
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rc = apply_rela_bits(loc, val, 1, 16, 1, write); |
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else if (r_type == R_390_PLTOFF16) |
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rc = apply_rela_bits(loc, val, 0, 16, 0, write); |
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else if (r_type == R_390_PLT32DBL) |
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rc = apply_rela_bits(loc, val, 1, 32, 1, write); |
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else if (r_type == R_390_PLT32 || |
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r_type == R_390_PLTOFF32) |
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rc = apply_rela_bits(loc, val, 0, 32, 0, write); |
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else if (r_type == R_390_PLT64 || |
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r_type == R_390_PLTOFF64) |
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rc = apply_rela_bits(loc, val, 0, 64, 0, write); |
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break; |
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case R_390_GOTOFF16: /* 16 bit offset to GOT. */ |
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case R_390_GOTOFF32: /* 32 bit offset to GOT. */ |
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case R_390_GOTOFF64: /* 64 bit offset to GOT. */ |
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val = val + rela->r_addend - |
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((Elf_Addr) me->core_layout.base + me->arch.got_offset); |
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if (r_type == R_390_GOTOFF16) |
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rc = apply_rela_bits(loc, val, 0, 16, 0, write); |
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else if (r_type == R_390_GOTOFF32) |
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rc = apply_rela_bits(loc, val, 0, 32, 0, write); |
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else if (r_type == R_390_GOTOFF64) |
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rc = apply_rela_bits(loc, val, 0, 64, 0, write); |
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break; |
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case R_390_GOTPC: /* 32 bit PC relative offset to GOT. */ |
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case R_390_GOTPCDBL: /* 32 bit PC rel. off. to GOT shifted by 1. */ |
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val = (Elf_Addr) me->core_layout.base + me->arch.got_offset + |
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rela->r_addend - loc; |
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if (r_type == R_390_GOTPC) |
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rc = apply_rela_bits(loc, val, 1, 32, 0, write); |
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else if (r_type == R_390_GOTPCDBL) |
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rc = apply_rela_bits(loc, val, 1, 32, 1, write); |
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break; |
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case R_390_COPY: |
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case R_390_GLOB_DAT: /* Create GOT entry. */ |
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case R_390_JMP_SLOT: /* Create PLT entry. */ |
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case R_390_RELATIVE: /* Adjust by program base. */ |
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/* Only needed if we want to support loading of |
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modules linked with -shared. */ |
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return -ENOEXEC; |
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default: |
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printk(KERN_ERR "module %s: unknown relocation: %u\n", |
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me->name, r_type); |
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return -ENOEXEC; |
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} |
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if (rc) { |
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printk(KERN_ERR "module %s: relocation error for symbol %s " |
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"(r_type %i, value 0x%lx)\n", |
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me->name, strtab + symtab[r_sym].st_name, |
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r_type, (unsigned long) val); |
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return rc; |
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} |
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return 0; |
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} |
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|
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static int __apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab, |
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unsigned int symindex, unsigned int relsec, |
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struct module *me, |
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void *(*write)(void *dest, const void *src, size_t len)) |
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{ |
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Elf_Addr base; |
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Elf_Sym *symtab; |
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Elf_Rela *rela; |
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unsigned long i, n; |
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int rc; |
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|
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DEBUGP("Applying relocate section %u to %u\n", |
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relsec, sechdrs[relsec].sh_info); |
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base = sechdrs[sechdrs[relsec].sh_info].sh_addr; |
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symtab = (Elf_Sym *) sechdrs[symindex].sh_addr; |
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rela = (Elf_Rela *) sechdrs[relsec].sh_addr; |
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n = sechdrs[relsec].sh_size / sizeof(Elf_Rela); |
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|
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for (i = 0; i < n; i++, rela++) { |
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rc = apply_rela(rela, base, symtab, strtab, me, write); |
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if (rc) |
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return rc; |
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} |
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return 0; |
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} |
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|
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int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab, |
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unsigned int symindex, unsigned int relsec, |
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struct module *me) |
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{ |
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bool early = me->state == MODULE_STATE_UNFORMED; |
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void *(*write)(void *, const void *, size_t) = memcpy; |
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|
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if (!early) |
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write = s390_kernel_write; |
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|
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return __apply_relocate_add(sechdrs, strtab, symindex, relsec, me, |
|
write); |
|
} |
|
|
|
int module_finalize(const Elf_Ehdr *hdr, |
|
const Elf_Shdr *sechdrs, |
|
struct module *me) |
|
{ |
|
const Elf_Shdr *s; |
|
char *secstrings, *secname; |
|
void *aseg; |
|
|
|
if (IS_ENABLED(CONFIG_EXPOLINE) && |
|
!nospec_disable && me->arch.plt_size) { |
|
unsigned int *ij; |
|
|
|
ij = me->core_layout.base + me->arch.plt_offset + |
|
me->arch.plt_size - PLT_ENTRY_SIZE; |
|
if (test_facility(35)) { |
|
ij[0] = 0xc6000000; /* exrl %r0,.+10 */ |
|
ij[1] = 0x0005a7f4; /* j . */ |
|
ij[2] = 0x000007f1; /* br %r1 */ |
|
} else { |
|
ij[0] = 0x44000000 | (unsigned int) |
|
offsetof(struct lowcore, br_r1_trampoline); |
|
ij[1] = 0xa7f40000; /* j . */ |
|
} |
|
} |
|
|
|
secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset; |
|
for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) { |
|
aseg = (void *) s->sh_addr; |
|
secname = secstrings + s->sh_name; |
|
|
|
if (!strcmp(".altinstructions", secname)) |
|
/* patch .altinstructions */ |
|
apply_alternatives(aseg, aseg + s->sh_size); |
|
|
|
if (IS_ENABLED(CONFIG_EXPOLINE) && |
|
(str_has_prefix(secname, ".s390_indirect"))) |
|
nospec_revert(aseg, aseg + s->sh_size); |
|
|
|
if (IS_ENABLED(CONFIG_EXPOLINE) && |
|
(str_has_prefix(secname, ".s390_return"))) |
|
nospec_revert(aseg, aseg + s->sh_size); |
|
} |
|
|
|
jump_label_apply_nops(me); |
|
return 0; |
|
}
|
|
|