linux/kernel/module/livepatch.c at multikernel-riscv · multikernel/linux · GitHub

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// SPDX-License-Identifier: GPL-2.0-or-later

* Module livepatch support

#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);

}

linux/kernel/module/livepatch.c at multikernel-riscv · multikernel/linux · GitHub

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