arch/powerpc/kernel/machine_kexec_file_64.c

   1 /*
   2  * ppc64 code to implement the kexec_file_load syscall
   3  *
   4  * Copyright (C) 2004  Adam Litke (agl@us.ibm.com)
   5  * Copyright (C) 2004  IBM Corp.
   6  * Copyright (C) 2004,2005  Milton D Miller II, IBM Corporation
   7  * Copyright (C) 2005  R Sharada (sharada@in.ibm.com)
   8  * Copyright (C) 2006  Mohan Kumar M (mohan@in.ibm.com)
   9  * Copyright (C) 2016  IBM Corporation
  10  *
  11  * Based on kexec-tools' kexec-elf-ppc64.c, fs2dt.c.
  12  * Heavily modified for the kernel by
  13  * Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>.
  14  *
  15  * This program is free software; you can redistribute it and/or modify
  16  * it under the terms of the GNU General Public License as published by
  17  * the Free Software Foundation (version 2 of the License).
  18  *
  19  * This program is distributed in the hope that it will be useful,
  20  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22  * GNU General Public License for more details.
  23  */
  24
  25 #include <linux/slab.h>
  26 #include <linux/kexec.h>
  27 #include <linux/memblock.h>
  28 #include <linux/of_fdt.h>
  29 #include <linux/libfdt.h>
  30 #include <asm/ima.h>
  31
  32 #define SLAVE_CODE_SIZE         256
  33
  34 const struct kexec_file_ops * const kexec_file_loaders[] = {
  35         &kexec_elf64_ops,
  36         NULL
  37 };
  38
  39 int arch_kexec_kernel_image_probe(struct kimage *image, void *buf,
  40                                   unsigned long buf_len)
  41 {
  42         /* We don't support crash kernels yet. */
  43         if (image->type == KEXEC_TYPE_CRASH)
  44                 return -EOPNOTSUPP;
  45
  46         return kexec_image_probe_default(image, buf, buf_len);
  47 }
  48
  49 /**
  50  * arch_kexec_walk_mem - call func(data) for each unreserved memory block
  51  * @kbuf:       Context info for the search. Also passed to @func.
  52  * @func:       Function to call for each memory block.
  53  *
  54  * This function is used by kexec_add_buffer and kexec_locate_mem_hole
  55  * to find unreserved memory to load kexec segments into.
  56  *
  57  * Return: The memory walk will stop when func returns a non-zero value
  58  * and that value will be returned. If all free regions are visited without
  59  * func returning non-zero, then zero will be returned.
  60  */
  61 int arch_kexec_walk_mem(struct kexec_buf *kbuf,
  62                         int (*func)(struct resource *, void *))
  63 {
  64         int ret = 0;
  65         u64 i;
  66         phys_addr_t mstart, mend;
  67         struct resource res = { };
  68
  69         if (kbuf->top_down) {
  70                 for_each_free_mem_range_reverse(i, NUMA_NO_NODE, 0,
  71                                                 &mstart, &mend, NULL) {
  72                         /*
  73                          * In memblock, end points to the first byte after the
  74                          * range while in kexec, end points to the last byte
  75                          * in the range.
  76                          */
  77                         res.start = mstart;
  78                         res.end = mend - 1;
  79                         ret = func(&res, kbuf);
  80                         if (ret)
  81                                 break;
  82                 }
  83         } else {
  84                 for_each_free_mem_range(i, NUMA_NO_NODE, 0, &mstart, &mend,
  85                                         NULL) {
  86                         /*
  87                          * In memblock, end points to the first byte after the
  88                          * range while in kexec, end points to the last byte
  89                          * in the range.
  90                          */
  91                         res.start = mstart;
  92                         res.end = mend - 1;
  93                         ret = func(&res, kbuf);
  94                         if (ret)
  95                                 break;
  96                 }
  97         }
  98
  99         return ret;
 100 }
 101
 102 /**
 103  * setup_purgatory - initialize the purgatory's global variables
 104  * @image:              kexec image.
 105  * @slave_code:         Slave code for the purgatory.
 106  * @fdt:                Flattened device tree for the next kernel.
 107  * @kernel_load_addr:   Address where the kernel is loaded.
 108  * @fdt_load_addr:      Address where the flattened device tree is loaded.
 109  *
 110  * Return: 0 on success, or negative errno on error.
 111  */
 112 int setup_purgatory(struct kimage *image, const void *slave_code,
 113                     const void *fdt, unsigned long kernel_load_addr,
 114                     unsigned long fdt_load_addr)
 115 {
 116         unsigned int *slave_code_buf, master_entry;
 117         int ret;
 118
 119         slave_code_buf = kmalloc(SLAVE_CODE_SIZE, GFP_KERNEL);
 120         if (!slave_code_buf)
 121                 return -ENOMEM;
 122
 123         /* Get the slave code from the new kernel and put it in purgatory. */
 124         ret = kexec_purgatory_get_set_symbol(image, "purgatory_start",
 125                                              slave_code_buf, SLAVE_CODE_SIZE,
 126                                              true);
 127         if (ret) {
 128                 kfree(slave_code_buf);
 129                 return ret;
 130         }
 131
 132         master_entry = slave_code_buf[0];
 133         memcpy(slave_code_buf, slave_code, SLAVE_CODE_SIZE);
 134         slave_code_buf[0] = master_entry;
 135         ret = kexec_purgatory_get_set_symbol(image, "purgatory_start",
 136                                              slave_code_buf, SLAVE_CODE_SIZE,
 137                                              false);
 138         kfree(slave_code_buf);
 139
 140         ret = kexec_purgatory_get_set_symbol(image, "kernel", &kernel_load_addr,
 141                                              sizeof(kernel_load_addr), false);
 142         if (ret)
 143                 return ret;
 144         ret = kexec_purgatory_get_set_symbol(image, "dt_offset", &fdt_load_addr,
 145                                              sizeof(fdt_load_addr), false);
 146         if (ret)
 147                 return ret;
 148
 149         return 0;
 150 }
 151
 152 /**
 153  * delete_fdt_mem_rsv - delete memory reservation with given address and size
 154  *
 155  * Return: 0 on success, or negative errno on error.
 156  */
 157 int delete_fdt_mem_rsv(void *fdt, unsigned long start, unsigned long size)
 158 {
 159         int i, ret, num_rsvs = fdt_num_mem_rsv(fdt);
 160
 161         for (i = 0; i < num_rsvs; i++) {
 162                 uint64_t rsv_start, rsv_size;
 163
 164                 ret = fdt_get_mem_rsv(fdt, i, &rsv_start, &rsv_size);
 165                 if (ret) {
 166                         pr_err("Malformed device tree.\n");
 167                         return -EINVAL;
 168                 }
 169
 170                 if (rsv_start == start && rsv_size == size) {
 171                         ret = fdt_del_mem_rsv(fdt, i);
 172                         if (ret) {
 173                                 pr_err("Error deleting device tree reservation.\n");
 174                                 return -EINVAL;
 175                         }
 176
 177                         return 0;
 178                 }
 179         }
 180
 181         return -ENOENT;
 182 }
 183
 184 /*
 185  * setup_new_fdt - modify /chosen and memory reservation for the next kernel
 186  * @image:              kexec image being loaded.
 187  * @fdt:                Flattened device tree for the next kernel.
 188  * @initrd_load_addr:   Address where the next initrd will be loaded.
 189  * @initrd_len:         Size of the next initrd, or 0 if there will be none.
 190  * @cmdline:            Command line for the next kernel, or NULL if there will
 191  *                      be none.
 192  *
 193  * Return: 0 on success, or negative errno on error.
 194  */
 195 int setup_new_fdt(const struct kimage *image, void *fdt,
 196                   unsigned long initrd_load_addr, unsigned long initrd_len,
 197                   const char *cmdline)
 198 {
 199         int ret, chosen_node;
 200         const void *prop;
 201
 202         /* Remove memory reservation for the current device tree. */
 203         ret = delete_fdt_mem_rsv(fdt, __pa(initial_boot_params),
 204                                  fdt_totalsize(initial_boot_params));
 205         if (ret == 0)
 206                 pr_debug("Removed old device tree reservation.\n");
 207         else if (ret != -ENOENT)
 208                 return ret;
 209
 210         chosen_node = fdt_path_offset(fdt, "/chosen");
 211         if (chosen_node == -FDT_ERR_NOTFOUND) {
 212                 chosen_node = fdt_add_subnode(fdt, fdt_path_offset(fdt, "/"),
 213                                               "chosen");
 214                 if (chosen_node < 0) {
 215                         pr_err("Error creating /chosen.\n");
 216                         return -EINVAL;
 217                 }
 218         } else if (chosen_node < 0) {
 219                 pr_err("Malformed device tree: error reading /chosen.\n");
 220                 return -EINVAL;
 221         }
 222
 223         /* Did we boot using an initrd? */
 224         prop = fdt_getprop(fdt, chosen_node, "linux,initrd-start", NULL);
 225         if (prop) {
 226                 uint64_t tmp_start, tmp_end, tmp_size;
 227
 228                 tmp_start = fdt64_to_cpu(*((const fdt64_t *) prop));
 229
 230                 prop = fdt_getprop(fdt, chosen_node, "linux,initrd-end", NULL);
 231                 if (!prop) {
 232                         pr_err("Malformed device tree.\n");
 233                         return -EINVAL;
 234                 }
 235                 tmp_end = fdt64_to_cpu(*((const fdt64_t *) prop));
 236
 237                 /*
 238                  * kexec reserves exact initrd size, while firmware may
 239                  * reserve a multiple of PAGE_SIZE, so check for both.
 240                  */
 241                 tmp_size = tmp_end - tmp_start;
 242                 ret = delete_fdt_mem_rsv(fdt, tmp_start, tmp_size);
 243                 if (ret == -ENOENT)
 244                         ret = delete_fdt_mem_rsv(fdt, tmp_start,
 245                                                  round_up(tmp_size, PAGE_SIZE));
 246                 if (ret == 0)
 247                         pr_debug("Removed old initrd reservation.\n");
 248                 else if (ret != -ENOENT)
 249                         return ret;
 250
 251                 /* If there's no new initrd, delete the old initrd's info. */
 252                 if (initrd_len == 0) {
 253                         ret = fdt_delprop(fdt, chosen_node,
 254                                           "linux,initrd-start");
 255                         if (ret) {
 256                                 pr_err("Error deleting linux,initrd-start.\n");
 257                                 return -EINVAL;
 258                         }
 259
 260                         ret = fdt_delprop(fdt, chosen_node, "linux,initrd-end");
 261                         if (ret) {
 262                                 pr_err("Error deleting linux,initrd-end.\n");
 263                                 return -EINVAL;
 264                         }
 265                 }
 266         }
 267
 268         if (initrd_len) {
 269                 ret = fdt_setprop_u64(fdt, chosen_node,
 270                                       "linux,initrd-start",
 271                                       initrd_load_addr);
 272                 if (ret < 0)
 273                         goto err;
 274
 275                 /* initrd-end is the first address after the initrd image. */
 276                 ret = fdt_setprop_u64(fdt, chosen_node, "linux,initrd-end",
 277                                       initrd_load_addr + initrd_len);
 278                 if (ret < 0)
 279                         goto err;
 280
 281                 ret = fdt_add_mem_rsv(fdt, initrd_load_addr, initrd_len);
 282                 if (ret) {
 283                         pr_err("Error reserving initrd memory: %s\n",
 284                                fdt_strerror(ret));
 285                         return -EINVAL;
 286                 }
 287         }
 288
 289         if (cmdline != NULL) {
 290                 ret = fdt_setprop_string(fdt, chosen_node, "bootargs", cmdline);
 291                 if (ret < 0)
 292                         goto err;
 293         } else {
 294                 ret = fdt_delprop(fdt, chosen_node, "bootargs");
 295                 if (ret && ret != -FDT_ERR_NOTFOUND) {
 296                         pr_err("Error deleting bootargs.\n");
 297                         return -EINVAL;
 298                 }
 299         }
 300
 301         ret = setup_ima_buffer(image, fdt, chosen_node);
 302         if (ret) {
 303                 pr_err("Error setting up the new device tree.\n");
 304                 return ret;
 305         }
 306
 307         ret = fdt_setprop(fdt, chosen_node, "linux,booted-from-kexec", NULL, 0);
 308         if (ret)
 309                 goto err;
 310
 311         return 0;
 312
 313 err:
 314         pr_err("Error setting up the new device tree.\n");
 315         return -EINVAL;
 316 }