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 } 349