cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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livepatch.c (1876B)

      1// SPDX-License-Identifier: GPL-2.0-or-later
      2/*
      3 * Module livepatch support
      4 *
      5 * Copyright (C) 2016 Jessica Yu <jeyu@redhat.com>
      6 */
      7
      8#include <linux/module.h>
      9#include <linux/string.h>
     10#include <linux/slab.h>
     11#include "internal.h"
     12
     13/*
     14 * Persist Elf information about a module. Copy the Elf header,
     15 * section header table, section string table, and symtab section
     16 * index from info to mod->klp_info.
     17 */
     18int copy_module_elf(struct module *mod, struct load_info *info)
     19{
     20	unsigned int size, symndx;
     21	int ret;
     22
     23	size = sizeof(*mod->klp_info);
     24	mod->klp_info = kmalloc(size, GFP_KERNEL);
     25	if (!mod->klp_info)
     26		return -ENOMEM;
     27
     28	/* Elf header */
     29	size = sizeof(mod->klp_info->hdr);
     30	memcpy(&mod->klp_info->hdr, info->hdr, size);
     31
     32	/* Elf section header table */
     33	size = sizeof(*info->sechdrs) * info->hdr->e_shnum;
     34	mod->klp_info->sechdrs = kmemdup(info->sechdrs, size, GFP_KERNEL);
     35	if (!mod->klp_info->sechdrs) {
     36		ret = -ENOMEM;
     37		goto free_info;
     38	}
     39
     40	/* Elf section name string table */
     41	size = info->sechdrs[info->hdr->e_shstrndx].sh_size;
     42	mod->klp_info->secstrings = kmemdup(info->secstrings, size, GFP_KERNEL);
     43	if (!mod->klp_info->secstrings) {
     44		ret = -ENOMEM;
     45		goto free_sechdrs;
     46	}
     47
     48	/* Elf symbol section index */
     49	symndx = info->index.sym;
     50	mod->klp_info->symndx = symndx;
     51
     52	/*
     53	 * For livepatch modules, core_kallsyms.symtab is a complete
     54	 * copy of the original symbol table. Adjust sh_addr to point
     55	 * to core_kallsyms.symtab since the copy of the symtab in module
     56	 * init memory is freed at the end of do_init_module().
     57	 */
     58	mod->klp_info->sechdrs[symndx].sh_addr = (unsigned long)mod->core_kallsyms.symtab;
     59
     60	return 0;
     61
     62free_sechdrs:
     63	kfree(mod->klp_info->sechdrs);
     64free_info:
     65	kfree(mod->klp_info);
     66	return ret;
     67}
     68
     69void free_module_elf(struct module *mod)
     70{
     71	kfree(mod->klp_info->sechdrs);
     72	kfree(mod->klp_info->secstrings);
     73	kfree(mod->klp_info);
     74}