// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Module livepatch support
 *
 * Copyright (C) 2016 Jessica Yu <jeyu@redhat.com>
 */

#include <linux/module.h>
#include <linux/string.h>
#include <linux/slab.h>
#include "internal.h"

/*
 * Persist ELF information about a module. Copy the ELF header,
 * section header table, section string table, and symtab section
 * index from info to mod->klp_info.
 */
int copy_module_elf(struct module *mod, struct load_info *info)
{
        unsigned int size, symndx;
        int ret;

        size = sizeof(*mod->klp_info);
        mod->klp_info = kmalloc(size, GFP_KERNEL);
        if (!mod->klp_info)
                return -ENOMEM;

        /* ELF header */
        size = sizeof(mod->klp_info->hdr);
        memcpy(&mod->klp_info->hdr, info->hdr, size);

        /* ELF section header table */
        size = sizeof(*info->sechdrs) * info->hdr->e_shnum;
        mod->klp_info->sechdrs = kmemdup(info->sechdrs, size, GFP_KERNEL);
        if (!mod->klp_info->sechdrs) {
                ret = -ENOMEM;
                goto free_info;
        }

        /* ELF section name string table */
        size = info->sechdrs[info->hdr->e_shstrndx].sh_size;
        mod->klp_info->secstrings = kmemdup(info->secstrings, size, GFP_KERNEL);
        if (!mod->klp_info->secstrings) {
                ret = -ENOMEM;
                goto free_sechdrs;
        }

        /* ELF symbol section index */
        symndx = info->index.sym;
        mod->klp_info->symndx = symndx;

        /*
         * For livepatch modules, core_kallsyms.symtab is a complete
         * copy of the original symbol table. Adjust sh_addr to point
         * to core_kallsyms.symtab since the copy of the symtab in module
         * init memory is freed at the end of do_init_module().
         */
        mod->klp_info->sechdrs[symndx].sh_addr = (unsigned long)mod->core_kallsyms.symtab;

        return 0;

free_sechdrs:
        kfree(mod->klp_info->sechdrs);
free_info:
        kfree(mod->klp_info);
        return ret;
}

void free_module_elf(struct module *mod)
{
        kfree(mod->klp_info->sechdrs);
        kfree(mod->klp_info->secstrings);
        kfree(mod->klp_info);
}