577 lines
17 KiB
C
577 lines
17 KiB
C
// 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 (arndb@de.ibm.com)
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* Martin Schwidefsky (schwidefsky@de.ibm.com)
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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/ftrace.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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#include <asm/ftrace.lds.h>
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#include <asm/set_memory.h>
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#include <asm/setup.h>
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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 22
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static unsigned long get_module_load_offset(void)
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{
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static DEFINE_MUTEX(module_kaslr_mutex);
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static unsigned long module_load_offset;
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if (!kaslr_enabled())
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return 0;
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/*
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* Calculate the module_load_offset the first time this code
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* is called. Once calculated it stays the same until reboot.
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*/
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mutex_lock(&module_kaslr_mutex);
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if (!module_load_offset)
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module_load_offset = get_random_u32_inclusive(1, 1024) * PAGE_SIZE;
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mutex_unlock(&module_kaslr_mutex);
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return module_load_offset;
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}
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void *module_alloc(unsigned long size)
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{
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gfp_t gfp_mask = GFP_KERNEL;
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void *p;
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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,
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MODULES_VADDR + get_module_load_offset(),
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MODULES_END, gfp_mask, PAGE_KERNEL,
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VM_FLUSH_RESET_PERMS | VM_DEFER_KMEMLEAK,
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NUMA_NO_NODE, __builtin_return_address(0));
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if (p && (kasan_alloc_module_shadow(p, size, gfp_mask) < 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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#ifdef CONFIG_FUNCTION_TRACER
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void module_arch_cleanup(struct module *mod)
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{
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module_memfree(mod->arch.trampolines_start);
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}
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#endif
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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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vfree(mod->arch.syminfo);
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mod->arch.syminfo = NULL;
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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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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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* 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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struct module_memory *mod_mem;
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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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mod_mem = &me->mem[MOD_TEXT];
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mod_mem->size = ALIGN(mod_mem->size, 4);
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me->arch.got_offset = mod_mem->size;
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mod_mem->size += me->arch.got_size;
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me->arch.plt_offset = mod_mem->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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mod_mem->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->mem[MOD_TEXT].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->mem[MOD_TEXT].base +
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me->arch.got_offset - 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 char insn[PLT_ENTRY_SIZE];
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char *plt_base;
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char *ip;
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plt_base = me->mem[MOD_TEXT].base + me->arch.plt_offset;
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ip = plt_base + info->plt_offset;
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*(int *)insn = 0x0d10e310; /* basr 1,0 */
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*(int *)&insn[4] = 0x100c0004; /* lg 1,12(1) */
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if (IS_ENABLED(CONFIG_EXPOLINE) && !nospec_disable) {
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char *jump_r1;
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jump_r1 = plt_base + me->arch.plt_size -
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PLT_ENTRY_SIZE;
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/* brcl 0xf,__jump_r1 */
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*(short *)&insn[8] = 0xc0f4;
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*(int *)&insn[10] = (jump_r1 - (ip + 8)) / 2;
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} else {
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*(int *)&insn[8] = 0x07f10000; /* br %r1 */
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}
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*(long *)&insn[14] = 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->mem[MOD_TEXT].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->mem[MOD_TEXT].base + me->arch.got_offset);
|
|
if (r_type == R_390_GOTOFF16)
|
|
rc = apply_rela_bits(loc, val, 0, 16, 0, write);
|
|
else if (r_type == R_390_GOTOFF32)
|
|
rc = apply_rela_bits(loc, val, 0, 32, 0, write);
|
|
else if (r_type == R_390_GOTOFF64)
|
|
rc = apply_rela_bits(loc, val, 0, 64, 0, write);
|
|
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->mem[MOD_TEXT].base + me->arch.got_offset +
|
|
rela->r_addend - loc;
|
|
if (r_type == R_390_GOTPC)
|
|
rc = apply_rela_bits(loc, val, 1, 32, 0, write);
|
|
else if (r_type == R_390_GOTPCDBL)
|
|
rc = apply_rela_bits(loc, val, 1, 32, 1, write);
|
|
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;
|
|
}
|
|
|
|
static int __apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab,
|
|
unsigned int symindex, unsigned int relsec,
|
|
struct module *me,
|
|
void *(*write)(void *dest, const void *src, size_t len))
|
|
{
|
|
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, write);
|
|
if (rc)
|
|
return rc;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab,
|
|
unsigned int symindex, unsigned int relsec,
|
|
struct module *me)
|
|
{
|
|
bool early = me->state == MODULE_STATE_UNFORMED;
|
|
void *(*write)(void *, const void *, size_t) = memcpy;
|
|
|
|
if (!early)
|
|
write = s390_kernel_write;
|
|
|
|
return __apply_relocate_add(sechdrs, strtab, symindex, relsec, me,
|
|
write);
|
|
}
|
|
|
|
#ifdef CONFIG_FUNCTION_TRACER
|
|
static int module_alloc_ftrace_hotpatch_trampolines(struct module *me,
|
|
const Elf_Shdr *s)
|
|
{
|
|
char *start, *end;
|
|
int numpages;
|
|
size_t size;
|
|
|
|
size = FTRACE_HOTPATCH_TRAMPOLINES_SIZE(s->sh_size);
|
|
numpages = DIV_ROUND_UP(size, PAGE_SIZE);
|
|
start = module_alloc(numpages * PAGE_SIZE);
|
|
if (!start)
|
|
return -ENOMEM;
|
|
set_memory_rox((unsigned long)start, numpages);
|
|
end = start + size;
|
|
|
|
me->arch.trampolines_start = (struct ftrace_hotpatch_trampoline *)start;
|
|
me->arch.trampolines_end = (struct ftrace_hotpatch_trampoline *)end;
|
|
me->arch.next_trampoline = me->arch.trampolines_start;
|
|
|
|
return 0;
|
|
}
|
|
#endif /* CONFIG_FUNCTION_TRACER */
|
|
|
|
int module_finalize(const Elf_Ehdr *hdr,
|
|
const Elf_Shdr *sechdrs,
|
|
struct module *me)
|
|
{
|
|
const Elf_Shdr *s;
|
|
char *secstrings, *secname;
|
|
void *aseg;
|
|
#ifdef CONFIG_FUNCTION_TRACER
|
|
int ret;
|
|
#endif
|
|
|
|
if (IS_ENABLED(CONFIG_EXPOLINE) &&
|
|
!nospec_disable && me->arch.plt_size) {
|
|
unsigned int *ij;
|
|
|
|
ij = me->mem[MOD_TEXT].base + me->arch.plt_offset +
|
|
me->arch.plt_size - PLT_ENTRY_SIZE;
|
|
ij[0] = 0xc6000000; /* exrl %r0,.+10 */
|
|
ij[1] = 0x0005a7f4; /* j . */
|
|
ij[2] = 0x000007f1; /* br %r1 */
|
|
}
|
|
|
|
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);
|
|
|
|
#ifdef CONFIG_FUNCTION_TRACER
|
|
if (!strcmp(FTRACE_CALLSITE_SECTION, secname)) {
|
|
ret = module_alloc_ftrace_hotpatch_trampolines(me, s);
|
|
if (ret < 0)
|
|
return ret;
|
|
}
|
|
#endif /* CONFIG_FUNCTION_TRACER */
|
|
}
|
|
|
|
return 0;
|
|
}
|