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/pe.h>
  16#include <linux/string.h>
  17#include <linux/verification.h>
  18#include <asm/byteorder.h>
  19#include <asm/cpufeature.h>
  20#include <asm/image.h>
  21#include <asm/memory.h>
  22
  23static int image_probe(const char *kernel_buf, unsigned long kernel_len)
  24{
  25        const struct arm64_image_header *h =
  26                (const struct arm64_image_header *)(kernel_buf);
  27
  28        if (!h || (kernel_len < sizeof(*h)))
  29                return -EINVAL;
  30
  31        if (memcmp(&h->magic, ARM64_IMAGE_MAGIC, sizeof(h->magic)))
  32                return -EINVAL;
  33
  34        return 0;
  35}
  36
  37static void *image_load(struct kimage *image,
  38                                char *kernel, unsigned long kernel_len,
  39                                char *initrd, unsigned long initrd_len,
  40                                char *cmdline, unsigned long cmdline_len)
  41{
  42        struct arm64_image_header *h;
  43        u64 flags, value;
  44        bool be_image, be_kernel;
  45        struct kexec_buf kbuf;
  46        unsigned long text_offset;
  47        struct kexec_segment *kernel_segment;
  48        int ret;
  49
  50        /* We don't support crash kernels yet. */
  51        if (image->type == KEXEC_TYPE_CRASH)
  52                return ERR_PTR(-EOPNOTSUPP);
  53
  54        /*
  55         * We require a kernel with an unambiguous Image header. Per
  56         * Documentation/arm64/booting.rst, this is the case when image_size
  57         * is non-zero (practically speaking, since v3.17).
  58         */
  59        h = (struct arm64_image_header *)kernel;
  60        if (!h->image_size)
  61                return ERR_PTR(-EINVAL);
  62
  63        /* Check cpu features */
  64        flags = le64_to_cpu(h->flags);
  65        be_image = arm64_image_flag_field(flags, ARM64_IMAGE_FLAG_BE);
  66        be_kernel = IS_ENABLED(CONFIG_CPU_BIG_ENDIAN);
  67        if ((be_image != be_kernel) && !system_supports_mixed_endian())
  68                return ERR_PTR(-EINVAL);
  69
  70        value = arm64_image_flag_field(flags, ARM64_IMAGE_FLAG_PAGE_SIZE);
  71        if (((value == ARM64_IMAGE_FLAG_PAGE_SIZE_4K) &&
  72                        !system_supports_4kb_granule()) ||
  73            ((value == ARM64_IMAGE_FLAG_PAGE_SIZE_64K) &&
  74                        !system_supports_64kb_granule()) ||
  75            ((value == ARM64_IMAGE_FLAG_PAGE_SIZE_16K) &&
  76                        !system_supports_16kb_granule()))
  77                return ERR_PTR(-EINVAL);
  78
  79        /* Load the kernel */
  80        kbuf.image = image;
  81        kbuf.buf_min = 0;
  82        kbuf.buf_max = ULONG_MAX;
  83        kbuf.top_down = false;
  84
  85        kbuf.buffer = kernel;
  86        kbuf.bufsz = kernel_len;
  87        kbuf.mem = 0;
  88        kbuf.memsz = le64_to_cpu(h->image_size);
  89        text_offset = le64_to_cpu(h->text_offset);
  90        kbuf.buf_align = MIN_KIMG_ALIGN;
  91
  92        /* Adjust kernel segment with TEXT_OFFSET */
  93        kbuf.memsz += text_offset;
  94
  95        ret = kexec_add_buffer(&kbuf);
  96        if (ret)
  97                return ERR_PTR(ret);
  98
  99        kernel_segment = &image->segment[image->nr_segments - 1];
 100        kernel_segment->mem += text_offset;
 101        kernel_segment->memsz -= text_offset;
 102        image->start = kernel_segment->mem;
 103
 104        pr_debug("Loaded kernel at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
 105                                kernel_segment->mem, kbuf.bufsz,
 106                                kernel_segment->memsz);
 107
 108        /* Load additional data */
 109        ret = load_other_segments(image,
 110                                kernel_segment->mem, kernel_segment->memsz,
 111                                initrd, initrd_len, cmdline);
 112
 113        return ERR_PTR(ret);
 114}
 115
 116#ifdef CONFIG_KEXEC_IMAGE_VERIFY_SIG
 117static int image_verify_sig(const char *kernel, unsigned long kernel_len)
 118{
 119        return verify_pefile_signature(kernel, kernel_len, NULL,
 120                                       VERIFYING_KEXEC_PE_SIGNATURE);
 121}
 122#endif
 123
 124const struct kexec_file_ops kexec_image_ops = {
 125        .probe = image_probe,
 126        .load = image_load,
 127#ifdef CONFIG_KEXEC_IMAGE_VERIFY_SIG
 128        .verify_sig = image_verify_sig,
 129#endif
 130};
 131