arch/powerpc/kexec/file_load.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * powerpc code to implement the kexec_file_load syscall
   4  *
   5  * Copyright (C) 2004  Adam Litke (agl@us.ibm.com)
   6  * Copyright (C) 2004  IBM Corp.
   7  * Copyright (C) 2004,2005  Milton D Miller II, IBM Corporation
   8  * Copyright (C) 2005  R Sharada (sharada@in.ibm.com)
   9  * Copyright (C) 2006  Mohan Kumar M (mohan@in.ibm.com)
  10  * Copyright (C) 2016  IBM Corporation
  11  *
  12  * Based on kexec-tools' kexec-elf-ppc64.c, fs2dt.c.
  13  * Heavily modified for the kernel by
  14  * Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>.
  15  */
  16
  17 #include <linux/slab.h>
  18 #include <linux/kexec.h>
  19 #include <linux/of_fdt.h>
  20 #include <linux/libfdt.h>
  21 #include <asm/setup.h>
  22 #include <asm/ima.h>
  23
  24 #define SLAVE_CODE_SIZE         256     /* First 0x100 bytes */
  25
  26 /**
  27  * setup_kdump_cmdline - Prepend "elfcorehdr=<addr> " to command line
  28  *                       of kdump kernel for exporting the core.
  29  * @image:               Kexec image
  30  * @cmdline:             Command line parameters to update.
  31  * @cmdline_len:         Length of the cmdline parameters.
  32  *
  33  * kdump segment must be setup before calling this function.
  34  *
  35  * Returns new cmdline buffer for kdump kernel on success, NULL otherwise.
  36  */
  37 char *setup_kdump_cmdline(struct kimage *image, char *cmdline,
  38                           unsigned long cmdline_len)
  39 {
  40         int elfcorehdr_strlen;
  41         char *cmdline_ptr;
  42
  43         cmdline_ptr = kzalloc(COMMAND_LINE_SIZE, GFP_KERNEL);
  44         if (!cmdline_ptr)
  45                 return NULL;
  46
  47         elfcorehdr_strlen = sprintf(cmdline_ptr, "elfcorehdr=0x%lx ",
  48                                     image->arch.elfcorehdr_addr);
  49
  50         if (elfcorehdr_strlen + cmdline_len > COMMAND_LINE_SIZE) {
  51                 pr_err("Appending elfcorehdr=<addr> exceeds cmdline size\n");
  52                 kfree(cmdline_ptr);
  53                 return NULL;
  54         }
  55
  56         memcpy(cmdline_ptr + elfcorehdr_strlen, cmdline, cmdline_len);
  57         // Ensure it's nul terminated
  58         cmdline_ptr[COMMAND_LINE_SIZE - 1] = '\0';
  59         return cmdline_ptr;
  60 }
  61
  62 /**
  63  * setup_purgatory - initialize the purgatory's global variables
  64  * @image:              kexec image.
  65  * @slave_code:         Slave code for the purgatory.
  66  * @fdt:                Flattened device tree for the next kernel.
  67  * @kernel_load_addr:   Address where the kernel is loaded.
  68  * @fdt_load_addr:      Address where the flattened device tree is loaded.
  69  *
  70  * Return: 0 on success, or negative errno on error.
  71  */
  72 int setup_purgatory(struct kimage *image, const void *slave_code,
  73                     const void *fdt, unsigned long kernel_load_addr,
  74                     unsigned long fdt_load_addr)
  75 {
  76         unsigned int *slave_code_buf, master_entry;
  77         int ret;
  78
  79         slave_code_buf = kmalloc(SLAVE_CODE_SIZE, GFP_KERNEL);
  80         if (!slave_code_buf)
  81                 return -ENOMEM;
  82
  83         /* Get the slave code from the new kernel and put it in purgatory. */
  84         ret = kexec_purgatory_get_set_symbol(image, "purgatory_start",
  85                                              slave_code_buf, SLAVE_CODE_SIZE,
  86                                              true);
  87         if (ret) {
  88                 kfree(slave_code_buf);
  89                 return ret;
  90         }
  91
  92         master_entry = slave_code_buf[0];
  93         memcpy(slave_code_buf, slave_code, SLAVE_CODE_SIZE);
  94         slave_code_buf[0] = master_entry;
  95         ret = kexec_purgatory_get_set_symbol(image, "purgatory_start",
  96                                              slave_code_buf, SLAVE_CODE_SIZE,
  97                                              false);
  98         kfree(slave_code_buf);
  99
 100         ret = kexec_purgatory_get_set_symbol(image, "kernel", &kernel_load_addr,
 101                                              sizeof(kernel_load_addr), false);
 102         if (ret)
 103                 return ret;
 104         ret = kexec_purgatory_get_set_symbol(image, "dt_offset", &fdt_load_addr,
 105                                              sizeof(fdt_load_addr), false);
 106         if (ret)
 107                 return ret;
 108
 109         return 0;
 110 }
 111
 112 /**
 113  * delete_fdt_mem_rsv - delete memory reservation with given address and size
 114  *
 115  * Return: 0 on success, or negative errno on error.
 116  */
 117 int delete_fdt_mem_rsv(void *fdt, unsigned long start, unsigned long size)
 118 {
 119         int i, ret, num_rsvs = fdt_num_mem_rsv(fdt);
 120
 121         for (i = 0; i < num_rsvs; i++) {
 122                 uint64_t rsv_start, rsv_size;
 123
 124                 ret = fdt_get_mem_rsv(fdt, i, &rsv_start, &rsv_size);
 125                 if (ret) {
 126                         pr_err("Malformed device tree.\n");
 127                         return -EINVAL;
 128                 }
 129
 130                 if (rsv_start == start && rsv_size == size) {
 131                         ret = fdt_del_mem_rsv(fdt, i);
 132                         if (ret) {
 133                                 pr_err("Error deleting device tree reservation.\n");
 134                                 return -EINVAL;
 135                         }
 136
 137                         return 0;
 138                 }
 139         }
 140
 141         return -ENOENT;
 142 }
 143
 144 /*
 145  * setup_new_fdt - modify /chosen and memory reservation for the next kernel
 146  * @image:              kexec image being loaded.
 147  * @fdt:                Flattened device tree for the next kernel.
 148  * @initrd_load_addr:   Address where the next initrd will be loaded.
 149  * @initrd_len:         Size of the next initrd, or 0 if there will be none.
 150  * @cmdline:            Command line for the next kernel, or NULL if there will
 151  *                      be none.
 152  *
 153  * Return: 0 on success, or negative errno on error.
 154  */
 155 int setup_new_fdt(const struct kimage *image, void *fdt,
 156                   unsigned long initrd_load_addr, unsigned long initrd_len,
 157                   const char *cmdline)
 158 {
 159         int ret, chosen_node;
 160         const void *prop;
 161
 162         /* Remove memory reservation for the current device tree. */
 163         ret = delete_fdt_mem_rsv(fdt, __pa(initial_boot_params),
 164                                  fdt_totalsize(initial_boot_params));
 165         if (ret == 0)
 166                 pr_debug("Removed old device tree reservation.\n");
 167         else if (ret != -ENOENT)
 168                 return ret;
 169
 170         chosen_node = fdt_path_offset(fdt, "/chosen");
 171         if (chosen_node == -FDT_ERR_NOTFOUND) {
 172                 chosen_node = fdt_add_subnode(fdt, fdt_path_offset(fdt, "/"),
 173                                               "chosen");
 174                 if (chosen_node < 0) {
 175                         pr_err("Error creating /chosen.\n");
 176                         return -EINVAL;
 177                 }
 178         } else if (chosen_node < 0) {
 179                 pr_err("Malformed device tree: error reading /chosen.\n");
 180                 return -EINVAL;
 181         }
 182
 183         /* Did we boot using an initrd? */
 184         prop = fdt_getprop(fdt, chosen_node, "linux,initrd-start", NULL);
 185         if (prop) {
 186                 uint64_t tmp_start, tmp_end, tmp_size;
 187
 188                 tmp_start = fdt64_to_cpu(*((const fdt64_t *) prop));
 189
 190                 prop = fdt_getprop(fdt, chosen_node, "linux,initrd-end", NULL);
 191                 if (!prop) {
 192                         pr_err("Malformed device tree.\n");
 193                         return -EINVAL;
 194                 }
 195                 tmp_end = fdt64_to_cpu(*((const fdt64_t *) prop));
 196
 197                 /*
 198                  * kexec reserves exact initrd size, while firmware may
 199                  * reserve a multiple of PAGE_SIZE, so check for both.
 200                  */
 201                 tmp_size = tmp_end - tmp_start;
 202                 ret = delete_fdt_mem_rsv(fdt, tmp_start, tmp_size);
 203                 if (ret == -ENOENT)
 204                         ret = delete_fdt_mem_rsv(fdt, tmp_start,
 205                                                  round_up(tmp_size, PAGE_SIZE));
 206                 if (ret == 0)
 207                         pr_debug("Removed old initrd reservation.\n");
 208                 else if (ret != -ENOENT)
 209                         return ret;
 210
 211                 /* If there's no new initrd, delete the old initrd's info. */
 212                 if (initrd_len == 0) {
 213                         ret = fdt_delprop(fdt, chosen_node,
 214                                           "linux,initrd-start");
 215                         if (ret) {
 216                                 pr_err("Error deleting linux,initrd-start.\n");
 217                                 return -EINVAL;
 218                         }
 219
 220                         ret = fdt_delprop(fdt, chosen_node, "linux,initrd-end");
 221                         if (ret) {
 222                                 pr_err("Error deleting linux,initrd-end.\n");
 223                                 return -EINVAL;
 224                         }
 225                 }
 226         }
 227
 228         if (initrd_len) {
 229                 ret = fdt_setprop_u64(fdt, chosen_node,
 230                                       "linux,initrd-start",
 231                                       initrd_load_addr);
 232                 if (ret < 0)
 233                         goto err;
 234
 235                 /* initrd-end is the first address after the initrd image. */
 236                 ret = fdt_setprop_u64(fdt, chosen_node, "linux,initrd-end",
 237                                       initrd_load_addr + initrd_len);
 238                 if (ret < 0)
 239                         goto err;
 240
 241                 ret = fdt_add_mem_rsv(fdt, initrd_load_addr, initrd_len);
 242                 if (ret) {
 243                         pr_err("Error reserving initrd memory: %s\n",
 244                                fdt_strerror(ret));
 245                         return -EINVAL;
 246                 }
 247         }
 248
 249         if (cmdline != NULL) {
 250                 ret = fdt_setprop_string(fdt, chosen_node, "bootargs", cmdline);
 251                 if (ret < 0)
 252                         goto err;
 253         } else {
 254                 ret = fdt_delprop(fdt, chosen_node, "bootargs");
 255                 if (ret && ret != -FDT_ERR_NOTFOUND) {
 256                         pr_err("Error deleting bootargs.\n");
 257                         return -EINVAL;
 258                 }
 259         }
 260
 261         if (image->type == KEXEC_TYPE_CRASH) {
 262                 /*
 263                  * Avoid elfcorehdr from being stomped on in kdump kernel by
 264                  * setting up memory reserve map.
 265                  */
 266                 ret = fdt_add_mem_rsv(fdt, image->arch.elfcorehdr_addr,
 267                                       image->arch.elf_headers_sz);
 268                 if (ret) {
 269                         pr_err("Error reserving elfcorehdr memory: %s\n",
 270                                fdt_strerror(ret));
 271                         goto err;
 272                 }
 273         }
 274
 275         ret = setup_ima_buffer(image, fdt, chosen_node);
 276         if (ret) {
 277                 pr_err("Error setting up the new device tree.\n");
 278                 return ret;
 279         }
 280
 281         ret = fdt_setprop(fdt, chosen_node, "linux,booted-from-kexec", NULL, 0);
 282         if (ret)
 283                 goto err;
 284
 285         return 0;
 286
 287 err:
 288         pr_err("Error setting up the new device tree.\n");
 289         return -EINVAL;
 290 }