root/arch/arm64/kernel/kexec_image.c

DEFINITIONS

1. image_probe
2. image_load
3. image_verify_sig

   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 
  23 static 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 
  37 static 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 = KEXEC_BUF_MEM_UNKNOWN;
  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
 117 static 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 
 124 const 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 };