arch/arm64/kernel/machine_kexec_file.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * kexec_file for arm64
   4  *
   5  * Copyright (C) 2018 Linaro Limited
   6  * Author: AKASHI Takahiro <takahiro.akashi@linaro.org>
   7  *
   8  * Most code is derived from arm64 port of kexec-tools
   9  */
  10
  11 #define pr_fmt(fmt) "kexec_file: " fmt
  12
  13 #include <linux/ioport.h>
  14 #include <linux/kernel.h>
  15 #include <linux/kexec.h>
  16 #include <linux/libfdt.h>
  17 #include <linux/memblock.h>
  18 #include <linux/of_fdt.h>
  19 #include <linux/random.h>
  20 #include <linux/slab.h>
  21 #include <linux/string.h>
  22 #include <linux/types.h>
  23 #include <linux/vmalloc.h>
  24 #include <asm/byteorder.h>
  25
  26 /* relevant device tree properties */
  27 #define FDT_PROP_KEXEC_ELFHDR   "linux,elfcorehdr"
  28 #define FDT_PROP_MEM_RANGE      "linux,usable-memory-range"
  29 #define FDT_PROP_INITRD_START   "linux,initrd-start"
  30 #define FDT_PROP_INITRD_END     "linux,initrd-end"
  31 #define FDT_PROP_BOOTARGS       "bootargs"
  32 #define FDT_PROP_KASLR_SEED     "kaslr-seed"
  33 #define FDT_PROP_RNG_SEED       "rng-seed"
  34 #define RNG_SEED_SIZE           128
  35
  36 const struct kexec_file_ops * const kexec_file_loaders[] = {
  37         &kexec_image_ops,
  38         NULL
  39 };
  40
  41 int arch_kimage_file_post_load_cleanup(struct kimage *image)
  42 {
  43         vfree(image->arch.dtb);
  44         image->arch.dtb = NULL;
  45
  46         vfree(image->arch.elf_headers);
  47         image->arch.elf_headers = NULL;
  48         image->arch.elf_headers_sz = 0;
  49
  50         return kexec_image_post_load_cleanup_default(image);
  51 }
  52
  53 static int setup_dtb(struct kimage *image,
  54                      unsigned long initrd_load_addr, unsigned long initrd_len,
  55                      char *cmdline, void *dtb)
  56 {
  57         int off, ret;
  58
  59         ret = fdt_path_offset(dtb, "/chosen");
  60         if (ret < 0)
  61                 goto out;
  62
  63         off = ret;
  64
  65         ret = fdt_delprop(dtb, off, FDT_PROP_KEXEC_ELFHDR);
  66         if (ret && ret != -FDT_ERR_NOTFOUND)
  67                 goto out;
  68         ret = fdt_delprop(dtb, off, FDT_PROP_MEM_RANGE);
  69         if (ret && ret != -FDT_ERR_NOTFOUND)
  70                 goto out;
  71
  72         if (image->type == KEXEC_TYPE_CRASH) {
  73                 /* add linux,elfcorehdr */
  74                 ret = fdt_appendprop_addrrange(dtb, 0, off,
  75                                 FDT_PROP_KEXEC_ELFHDR,
  76                                 image->arch.elf_headers_mem,
  77                                 image->arch.elf_headers_sz);
  78                 if (ret)
  79                         return (ret == -FDT_ERR_NOSPACE ? -ENOMEM : -EINVAL);
  80
  81                 /* add linux,usable-memory-range */
  82                 ret = fdt_appendprop_addrrange(dtb, 0, off,
  83                                 FDT_PROP_MEM_RANGE,
  84                                 crashk_res.start,
  85                                 crashk_res.end - crashk_res.start + 1);
  86                 if (ret)
  87                         return (ret == -FDT_ERR_NOSPACE ? -ENOMEM : -EINVAL);
  88         }
  89
  90         /* add bootargs */
  91         if (cmdline) {
  92                 ret = fdt_setprop_string(dtb, off, FDT_PROP_BOOTARGS, cmdline);
  93                 if (ret)
  94                         goto out;
  95         } else {
  96                 ret = fdt_delprop(dtb, off, FDT_PROP_BOOTARGS);
  97                 if (ret && (ret != -FDT_ERR_NOTFOUND))
  98                         goto out;
  99         }
 100
 101         /* add initrd-* */
 102         if (initrd_load_addr) {
 103                 ret = fdt_setprop_u64(dtb, off, FDT_PROP_INITRD_START,
 104                                       initrd_load_addr);
 105                 if (ret)
 106                         goto out;
 107
 108                 ret = fdt_setprop_u64(dtb, off, FDT_PROP_INITRD_END,
 109                                       initrd_load_addr + initrd_len);
 110                 if (ret)
 111                         goto out;
 112         } else {
 113                 ret = fdt_delprop(dtb, off, FDT_PROP_INITRD_START);
 114                 if (ret && (ret != -FDT_ERR_NOTFOUND))
 115                         goto out;
 116
 117                 ret = fdt_delprop(dtb, off, FDT_PROP_INITRD_END);
 118                 if (ret && (ret != -FDT_ERR_NOTFOUND))
 119                         goto out;
 120         }
 121
 122         /* add kaslr-seed */
 123         ret = fdt_delprop(dtb, off, FDT_PROP_KASLR_SEED);
 124         if (ret == -FDT_ERR_NOTFOUND)
 125                 ret = 0;
 126         else if (ret)
 127                 goto out;
 128
 129         if (rng_is_initialized()) {
 130                 u64 seed = get_random_u64();
 131                 ret = fdt_setprop_u64(dtb, off, FDT_PROP_KASLR_SEED, seed);
 132                 if (ret)
 133                         goto out;
 134         } else {
 135                 pr_notice("RNG is not initialised: omitting \"%s\" property\n",
 136                                 FDT_PROP_KASLR_SEED);
 137         }
 138
 139         /* add rng-seed */
 140         if (rng_is_initialized()) {
 141                 void *rng_seed;
 142                 ret = fdt_setprop_placeholder(dtb, off, FDT_PROP_RNG_SEED,
 143                                 RNG_SEED_SIZE, &rng_seed);
 144                 if (ret)
 145                         goto out;
 146                 get_random_bytes(rng_seed, RNG_SEED_SIZE);
 147         } else {
 148                 pr_notice("RNG is not initialised: omitting \"%s\" property\n",
 149                                 FDT_PROP_RNG_SEED);
 150         }
 151
 152 out:
 153         if (ret)
 154                 return (ret == -FDT_ERR_NOSPACE) ? -ENOMEM : -EINVAL;
 155
 156         return 0;
 157 }
 158
 159 /*
 160  * More space needed so that we can add initrd, bootargs, kaslr-seed,
 161  * rng-seed, userable-memory-range and elfcorehdr.
 162  */
 163 #define DTB_EXTRA_SPACE 0x1000
 164
 165 static int create_dtb(struct kimage *image,
 166                       unsigned long initrd_load_addr, unsigned long initrd_len,
 167                       char *cmdline, void **dtb)
 168 {
 169         void *buf;
 170         size_t buf_size;
 171         size_t cmdline_len;
 172         int ret;
 173
 174         cmdline_len = cmdline ? strlen(cmdline) : 0;
 175         buf_size = fdt_totalsize(initial_boot_params)
 176                         + cmdline_len + DTB_EXTRA_SPACE;
 177
 178         for (;;) {
 179                 buf = vmalloc(buf_size);
 180                 if (!buf)
 181                         return -ENOMEM;
 182
 183                 /* duplicate a device tree blob */
 184                 ret = fdt_open_into(initial_boot_params, buf, buf_size);
 185                 if (ret) {
 186                         vfree(buf);
 187                         return -EINVAL;
 188                 }
 189
 190                 ret = setup_dtb(image, initrd_load_addr, initrd_len,
 191                                 cmdline, buf);
 192                 if (ret) {
 193                         vfree(buf);
 194                         if (ret == -ENOMEM) {
 195                                 /* unlikely, but just in case */
 196                                 buf_size += DTB_EXTRA_SPACE;
 197                                 continue;
 198                         } else {
 199                                 return ret;
 200                         }
 201                 }
 202
 203                 /* trim it */
 204                 fdt_pack(buf);
 205                 *dtb = buf;
 206
 207                 return 0;
 208         }
 209 }
 210
 211 static int prepare_elf_headers(void **addr, unsigned long *sz)
 212 {
 213         struct crash_mem *cmem;
 214         unsigned int nr_ranges;
 215         int ret;
 216         u64 i;
 217         phys_addr_t start, end;
 218
 219         nr_ranges = 1; /* for exclusion of crashkernel region */
 220         for_each_mem_range(i, &start, &end)
 221                 nr_ranges++;
 222
 223         cmem = kmalloc(struct_size(cmem, ranges, nr_ranges), GFP_KERNEL);
 224         if (!cmem)
 225                 return -ENOMEM;
 226
 227         cmem->max_nr_ranges = nr_ranges;
 228         cmem->nr_ranges = 0;
 229         for_each_mem_range(i, &start, &end) {
 230                 cmem->ranges[cmem->nr_ranges].start = start;
 231                 cmem->ranges[cmem->nr_ranges].end = end - 1;
 232                 cmem->nr_ranges++;
 233         }
 234
 235         /* Exclude crashkernel region */
 236         ret = crash_exclude_mem_range(cmem, crashk_res.start, crashk_res.end);
 237
 238         if (!ret)
 239                 ret =  crash_prepare_elf64_headers(cmem, true, addr, sz);
 240
 241         kfree(cmem);
 242         return ret;
 243 }
 244
 245 /*
 246  * Tries to add the initrd and DTB to the image. If it is not possible to find
 247  * valid locations, this function will undo changes to the image and return non
 248  * zero.
 249  */
 250 int load_other_segments(struct kimage *image,
 251                         unsigned long kernel_load_addr,
 252                         unsigned long kernel_size,
 253                         char *initrd, unsigned long initrd_len,
 254                         char *cmdline)
 255 {
 256         struct kexec_buf kbuf;
 257         void *headers, *dtb = NULL;
 258         unsigned long headers_sz, initrd_load_addr = 0, dtb_len,
 259                       orig_segments = image->nr_segments;
 260         int ret = 0;
 261
 262         kbuf.image = image;
 263         /* not allocate anything below the kernel */
 264         kbuf.buf_min = kernel_load_addr + kernel_size;
 265
 266         /* load elf core header */
 267         if (image->type == KEXEC_TYPE_CRASH) {
 268                 ret = prepare_elf_headers(&headers, &headers_sz);
 269                 if (ret) {
 270                         pr_err("Preparing elf core header failed\n");
 271                         goto out_err;
 272                 }
 273
 274                 kbuf.buffer = headers;
 275                 kbuf.bufsz = headers_sz;
 276                 kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
 277                 kbuf.memsz = headers_sz;
 278                 kbuf.buf_align = SZ_64K; /* largest supported page size */
 279                 kbuf.buf_max = ULONG_MAX;
 280                 kbuf.top_down = true;
 281
 282                 ret = kexec_add_buffer(&kbuf);
 283                 if (ret) {
 284                         vfree(headers);
 285                         goto out_err;
 286                 }
 287                 image->arch.elf_headers = headers;
 288                 image->arch.elf_headers_mem = kbuf.mem;
 289                 image->arch.elf_headers_sz = headers_sz;
 290
 291                 pr_debug("Loaded elf core header at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
 292                          image->arch.elf_headers_mem, kbuf.bufsz, kbuf.memsz);
 293         }
 294
 295         /* load initrd */
 296         if (initrd) {
 297                 kbuf.buffer = initrd;
 298                 kbuf.bufsz = initrd_len;
 299                 kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
 300                 kbuf.memsz = initrd_len;
 301                 kbuf.buf_align = 0;
 302                 /* within 1GB-aligned window of up to 32GB in size */
 303                 kbuf.buf_max = round_down(kernel_load_addr, SZ_1G)
 304                                                 + (unsigned long)SZ_1G * 32;
 305                 kbuf.top_down = false;
 306
 307                 ret = kexec_add_buffer(&kbuf);
 308                 if (ret)
 309                         goto out_err;
 310                 initrd_load_addr = kbuf.mem;
 311
 312                 pr_debug("Loaded initrd at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
 313                                 initrd_load_addr, kbuf.bufsz, kbuf.memsz);
 314         }
 315
 316         /* load dtb */
 317         ret = create_dtb(image, initrd_load_addr, initrd_len, cmdline, &dtb);
 318         if (ret) {
 319                 pr_err("Preparing for new dtb failed\n");
 320                 goto out_err;
 321         }
 322
 323         dtb_len = fdt_totalsize(dtb);
 324         kbuf.buffer = dtb;
 325         kbuf.bufsz = dtb_len;
 326         kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
 327         kbuf.memsz = dtb_len;
 328         /* not across 2MB boundary */
 329         kbuf.buf_align = SZ_2M;
 330         kbuf.buf_max = ULONG_MAX;
 331         kbuf.top_down = true;
 332
 333         ret = kexec_add_buffer(&kbuf);
 334         if (ret)
 335                 goto out_err;
 336         image->arch.dtb = dtb;
 337         image->arch.dtb_mem = kbuf.mem;
 338
 339         pr_debug("Loaded dtb at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
 340                         kbuf.mem, kbuf.bufsz, kbuf.memsz);
 341
 342         return 0;
 343
 344 out_err:
 345         image->nr_segments = orig_segments;
 346         vfree(dtb);
 347         return ret;
 348 }