LXR linux/arch/arm64/kernel/kexec

   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * Kexec image loader
   4
   5 * Copyright (C) 2018 Linaro Limited
   6 * Author: AKASHI Takahiro <takahiro.akashi@linaro.org>
   7 */
   8
   9#define pr_fmt(fmt)     "kexec_file(Image): " fmt
  10
  11#include <linux/err.h>
  12#include <linux/errno.h>
  13#include <linux/kernel.h>
  14#include <linux/kexec.h>
  15#include <linux/string.h>
  16#include <asm/byteorder.h>
  17#include <asm/cpufeature.h>
  18#include <asm/image.h>
  19#include <asm/memory.h>
  20
  21static int image_probe(const char *kernel_buf, unsigned long kernel_len)
  22{
  23        const struct arm64_image_header *h;
  24
  25        h = (const struct arm64_image_header *)(kernel_buf);
  26
  27        if (!h || (kernel_len < sizeof(*h)) ||
  28                        memcmp(&h->magic, ARM64_IMAGE_MAGIC,
  29                                sizeof(h->magic)))
  30                return -EINVAL;
  31
  32        return 0;
  33}
  34
  35static void *image_load(struct kimage *image,
  36                                char *kernel, unsigned long kernel_len,
  37                                char *initrd, unsigned long initrd_len,
  38                                char *cmdline, unsigned long cmdline_len)
  39{
  40        struct arm64_image_header *h;
  41        u64 flags, value;
  42        bool be_image, be_kernel;
  43        struct kexec_buf kbuf;
  44        unsigned long text_offset;
  45        struct kexec_segment *kernel_segment;
  46        int ret;
  47
  48        /*
  49         * We require a kernel with an unambiguous Image header. Per
  50         * Documentation/booting.rst, this is the case when image_size
  51         * is non-zero (practically speaking, since v3.17).
  52         */
  53        h = (struct arm64_image_header *)kernel;
  54        if (!h->image_size)
  55                return ERR_PTR(-EINVAL);
  56
  57        /* Check cpu features */
  58        flags = le64_to_cpu(h->flags);
  59        be_image = arm64_image_flag_field(flags, ARM64_IMAGE_FLAG_BE);
  60        be_kernel = IS_ENABLED(CONFIG_CPU_BIG_ENDIAN);
  61        if ((be_image != be_kernel) && !system_supports_mixed_endian())
  62                return ERR_PTR(-EINVAL);
  63
  64        value = arm64_image_flag_field(flags, ARM64_IMAGE_FLAG_PAGE_SIZE);
  65        if (((value == ARM64_IMAGE_FLAG_PAGE_SIZE_4K) &&
  66                        !system_supports_4kb_granule()) ||
  67            ((value == ARM64_IMAGE_FLAG_PAGE_SIZE_64K) &&
  68                        !system_supports_64kb_granule()) ||
  69            ((value == ARM64_IMAGE_FLAG_PAGE_SIZE_16K) &&
  70                        !system_supports_16kb_granule()))
  71                return ERR_PTR(-EINVAL);
  72
  73        /* Load the kernel */
  74        kbuf.image = image;
  75        kbuf.buf_min = 0;
  76        kbuf.buf_max = ULONG_MAX;
  77        kbuf.top_down = false;
  78
  79        kbuf.buffer = kernel;
  80        kbuf.bufsz = kernel_len;
  81        kbuf.mem = 0;
  82        kbuf.memsz = le64_to_cpu(h->image_size);
  83        text_offset = le64_to_cpu(h->text_offset);
  84        kbuf.buf_align = MIN_KIMG_ALIGN;
  85
  86        /* Adjust kernel segment with TEXT_OFFSET */
  87        kbuf.memsz += text_offset;
  88
  89        ret = kexec_add_buffer(&kbuf);
  90        if (ret)
  91                return ERR_PTR(ret);
  92
  93        kernel_segment = &image->segment[image->nr_segments - 1];
  94        kernel_segment->mem += text_offset;
  95        kernel_segment->memsz -= text_offset;
  96        image->start = kernel_segment->mem;
  97
  98        pr_debug("Loaded kernel at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
  99                                kernel_segment->mem, kbuf.bufsz,
 100                                kernel_segment->memsz);
 101
 102        /* Load additional data */
 103        ret = load_other_segments(image,
 104                                kernel_segment->mem, kernel_segment->memsz,
 105                                initrd, initrd_len, cmdline);
 106
 107        return ERR_PTR(ret);
 108}
 109
 110const struct kexec_file_ops kexec_image_ops = {
 111        .probe = image_probe,
 112        .load = image_load,
 113};
 114