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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kexec_file.c (2140B)

      1// SPDX-License-Identifier: GPL-2.0
      2/*
      3 * Load ELF vmlinux file for the kexec_file_load syscall.
      4 *
      5 * Copyright (c) 2019 Sven Schnelle <svens@stackframe.org>
      6 *
      7 */
      8#include <linux/elf.h>
      9#include <linux/kexec.h>
     10#include <linux/libfdt.h>
     11#include <linux/module.h>
     12#include <linux/of_fdt.h>
     13#include <linux/slab.h>
     14#include <linux/types.h>
     15
     16static void *elf_load(struct kimage *image, char *kernel_buf,
     17			unsigned long kernel_len, char *initrd,
     18			unsigned long initrd_len, char *cmdline,
     19			unsigned long cmdline_len)
     20{
     21	int ret, i;
     22	unsigned long kernel_load_addr;
     23	struct elfhdr ehdr;
     24	struct kexec_elf_info elf_info;
     25	struct kexec_buf kbuf = { .image = image, .buf_min = 0,
     26				  .buf_max = -1UL, };
     27
     28	ret = kexec_build_elf_info(kernel_buf, kernel_len, &ehdr, &elf_info);
     29	if (ret)
     30		goto out;
     31
     32	ret = kexec_elf_load(image, &ehdr, &elf_info, &kbuf, &kernel_load_addr);
     33	if (ret)
     34		goto out;
     35
     36	image->start = __pa(elf_info.ehdr->e_entry);
     37
     38	for (i = 0; i < image->nr_segments; i++)
     39		image->segment[i].mem = __pa(image->segment[i].mem);
     40
     41	pr_debug("Loaded the kernel at 0x%lx, entry at 0x%lx\n",
     42		 kernel_load_addr, image->start);
     43
     44	if (initrd != NULL) {
     45		kbuf.buffer = initrd;
     46		kbuf.bufsz = kbuf.memsz = initrd_len;
     47		kbuf.buf_align = PAGE_SIZE;
     48		kbuf.top_down = false;
     49		kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
     50		ret = kexec_add_buffer(&kbuf);
     51		if (ret)
     52			goto out;
     53
     54		pr_debug("Loaded initrd at 0x%lx\n", kbuf.mem);
     55		image->arch.initrd_start = kbuf.mem;
     56		image->arch.initrd_end = kbuf.mem + initrd_len;
     57	}
     58
     59	if (cmdline != NULL) {
     60		kbuf.buffer = cmdline;
     61		kbuf.bufsz = kbuf.memsz = ALIGN(cmdline_len, 8);
     62		kbuf.buf_align = PAGE_SIZE;
     63		kbuf.top_down = false;
     64		kbuf.buf_min = PAGE0->mem_free + PAGE_SIZE;
     65		kbuf.buf_max = kernel_load_addr;
     66		kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
     67		ret = kexec_add_buffer(&kbuf);
     68		if (ret)
     69			goto out;
     70
     71		pr_debug("Loaded cmdline at 0x%lx\n", kbuf.mem);
     72		image->arch.cmdline = kbuf.mem;
     73	}
     74out:
     75	return NULL;
     76}
     77
     78const struct kexec_file_ops kexec_elf_ops = {
     79	.probe = kexec_elf_probe,
     80	.load = elf_load,
     81};
     82
     83const struct kexec_file_ops * const kexec_file_loaders[] = {
     84	&kexec_elf_ops,
     85	NULL
     86};