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/of_fdt.h>
  28 #include <linux/libfdt.h>
  29 #include <asm/ima.h>
  30
  31 #define SLAVE_CODE_SIZE         256
  32
  33 const struct kexec_file_ops * const kexec_file_loaders[] = {
  34         &kexec_elf64_ops,
  35         NULL
  36 };
  37
  38 int arch_kexec_kernel_image_probe(struct kimage *image, void *buf,
  39                                   unsigned long buf_len)
  40 {
  41         /* We don't support crash kernels yet. */
  42         if (image->type == KEXEC_TYPE_CRASH)
  43                 return -EOPNOTSUPP;
  44
  45         return kexec_image_probe_default(image, buf, buf_len);
  46 }
  47
  48 /**
  49  * setup_purgatory - initialize the purgatory's global variables
  50  * @image:              kexec image.
  51  * @slave_code:         Slave code for the purgatory.
  52  * @fdt:                Flattened device tree for the next kernel.
  53  * @kernel_load_addr:   Address where the kernel is loaded.
  54  * @fdt_load_addr:      Address where the flattened device tree is loaded.
  55  *
  56  * Return: 0 on success, or negative errno on error.
  57  */
  58 int setup_purgatory(struct kimage *image, const void *slave_code,
  59                     const void *fdt, unsigned long kernel_load_addr,
  60                     unsigned long fdt_load_addr)
  61 {
  62         unsigned int *slave_code_buf, master_entry;
  63         int ret;
  64
  65         slave_code_buf = kmalloc(SLAVE_CODE_SIZE, GFP_KERNEL);
  66         if (!slave_code_buf)
  67                 return -ENOMEM;
  68
  69         /* Get the slave code from the new kernel and put it in purgatory. */
  70         ret = kexec_purgatory_get_set_symbol(image, "purgatory_start",
  71                                              slave_code_buf, SLAVE_CODE_SIZE,
  72                                              true);
  73         if (ret) {
  74                 kfree(slave_code_buf);
  75                 return ret;
  76         }
  77
  78         master_entry = slave_code_buf[0];
  79         memcpy(slave_code_buf, slave_code, SLAVE_CODE_SIZE);
  80         slave_code_buf[0] = master_entry;
  81         ret = kexec_purgatory_get_set_symbol(image, "purgatory_start",
  82                                              slave_code_buf, SLAVE_CODE_SIZE,
  83                                              false);
  84         kfree(slave_code_buf);
  85
  86         ret = kexec_purgatory_get_set_symbol(image, "kernel", &kernel_load_addr,
  87                                              sizeof(kernel_load_addr), false);
  88         if (ret)
  89                 return ret;
  90         ret = kexec_purgatory_get_set_symbol(image, "dt_offset", &fdt_load_addr,
  91                                              sizeof(fdt_load_addr), false);
  92         if (ret)
  93                 return ret;
  94
  95         return 0;
  96 }
  97
  98 /**
  99  * delete_fdt_mem_rsv - delete memory reservation with given address and size
 100  *
 101  * Return: 0 on success, or negative errno on error.
 102  */
 103 int delete_fdt_mem_rsv(void *fdt, unsigned long start, unsigned long size)
 104 {
 105         int i, ret, num_rsvs = fdt_num_mem_rsv(fdt);
 106
 107         for (i = 0; i < num_rsvs; i++) {
 108                 uint64_t rsv_start, rsv_size;
 109
 110                 ret = fdt_get_mem_rsv(fdt, i, &rsv_start, &rsv_size);
 111                 if (ret) {
 112                         pr_err("Malformed device tree.\n");
 113                         return -EINVAL;
 114                 }
 115
 116                 if (rsv_start == start && rsv_size == size) {
 117                         ret = fdt_del_mem_rsv(fdt, i);
 118                         if (ret) {
 119                                 pr_err("Error deleting device tree reservation.\n");
 120                                 return -EINVAL;
 121                         }
 122
 123                         return 0;
 124                 }
 125         }
 126
 127         return -ENOENT;
 128 }
 129
 130 /*
 131  * setup_new_fdt - modify /chosen and memory reservation for the next kernel
 132  * @image:              kexec image being loaded.
 133  * @fdt:                Flattened device tree for the next kernel.
 134  * @initrd_load_addr:   Address where the next initrd will be loaded.
 135  * @initrd_len:         Size of the next initrd, or 0 if there will be none.
 136  * @cmdline:            Command line for the next kernel, or NULL if there will
 137  *                      be none.
 138  *
 139  * Return: 0 on success, or negative errno on error.
 140  */
 141 int setup_new_fdt(const struct kimage *image, void *fdt,
 142                   unsigned long initrd_load_addr, unsigned long initrd_len,
 143                   const char *cmdline)
 144 {
 145         int ret, chosen_node;
 146         const void *prop;
 147
 148         /* Remove memory reservation for the current device tree. */
 149         ret = delete_fdt_mem_rsv(fdt, __pa(initial_boot_params),
 150                                  fdt_totalsize(initial_boot_params));
 151         if (ret == 0)
 152                 pr_debug("Removed old device tree reservation.\n");
 153         else if (ret != -ENOENT)
 154                 return ret;
 155
 156         chosen_node = fdt_path_offset(fdt, "/chosen");
 157         if (chosen_node == -FDT_ERR_NOTFOUND) {
 158                 chosen_node = fdt_add_subnode(fdt, fdt_path_offset(fdt, "/"),
 159                                               "chosen");
 160                 if (chosen_node < 0) {
 161                         pr_err("Error creating /chosen.\n");
 162                         return -EINVAL;
 163                 }
 164         } else if (chosen_node < 0) {
 165                 pr_err("Malformed device tree: error reading /chosen.\n");
 166                 return -EINVAL;
 167         }
 168
 169         /* Did we boot using an initrd? */
 170         prop = fdt_getprop(fdt, chosen_node, "linux,initrd-start", NULL);
 171         if (prop) {
 172                 uint64_t tmp_start, tmp_end, tmp_size;
 173
 174                 tmp_start = fdt64_to_cpu(*((const fdt64_t *) prop));
 175
 176                 prop = fdt_getprop(fdt, chosen_node, "linux,initrd-end", NULL);
 177                 if (!prop) {
 178                         pr_err("Malformed device tree.\n");
 179                         return -EINVAL;
 180                 }
 181                 tmp_end = fdt64_to_cpu(*((const fdt64_t *) prop));
 182
 183                 /*
 184                  * kexec reserves exact initrd size, while firmware may
 185                  * reserve a multiple of PAGE_SIZE, so check for both.
 186                  */
 187                 tmp_size = tmp_end - tmp_start;
 188                 ret = delete_fdt_mem_rsv(fdt, tmp_start, tmp_size);
 189                 if (ret == -ENOENT)
 190                         ret = delete_fdt_mem_rsv(fdt, tmp_start,
 191                                                  round_up(tmp_size, PAGE_SIZE));
 192                 if (ret == 0)
 193                         pr_debug("Removed old initrd reservation.\n");
 194                 else if (ret != -ENOENT)
 195                         return ret;
 196
 197                 /* If there's no new initrd, delete the old initrd's info. */
 198                 if (initrd_len == 0) {
 199                         ret = fdt_delprop(fdt, chosen_node,
 200                                           "linux,initrd-start");
 201                         if (ret) {
 202                                 pr_err("Error deleting linux,initrd-start.\n");
 203                                 return -EINVAL;
 204                         }
 205
 206                         ret = fdt_delprop(fdt, chosen_node, "linux,initrd-end");
 207                         if (ret) {
 208                                 pr_err("Error deleting linux,initrd-end.\n");
 209                                 return -EINVAL;
 210                         }
 211                 }
 212         }
 213
 214         if (initrd_len) {
 215                 ret = fdt_setprop_u64(fdt, chosen_node,
 216                                       "linux,initrd-start",
 217                                       initrd_load_addr);
 218                 if (ret < 0)
 219                         goto err;
 220
 221                 /* initrd-end is the first address after the initrd image. */
 222                 ret = fdt_setprop_u64(fdt, chosen_node, "linux,initrd-end",
 223                                       initrd_load_addr + initrd_len);
 224                 if (ret < 0)
 225                         goto err;
 226
 227                 ret = fdt_add_mem_rsv(fdt, initrd_load_addr, initrd_len);
 228                 if (ret) {
 229                         pr_err("Error reserving initrd memory: %s\n",
 230                                fdt_strerror(ret));
 231                         return -EINVAL;
 232                 }
 233         }
 234
 235         if (cmdline != NULL) {
 236                 ret = fdt_setprop_string(fdt, chosen_node, "bootargs", cmdline);
 237                 if (ret < 0)
 238                         goto err;
 239         } else {
 240                 ret = fdt_delprop(fdt, chosen_node, "bootargs");
 241                 if (ret && ret != -FDT_ERR_NOTFOUND) {
 242                         pr_err("Error deleting bootargs.\n");
 243                         return -EINVAL;
 244                 }
 245         }
 246
 247         ret = setup_ima_buffer(image, fdt, chosen_node);
 248         if (ret) {
 249                 pr_err("Error setting up the new device tree.\n");
 250                 return ret;
 251         }
 252
 253         ret = fdt_setprop(fdt, chosen_node, "linux,booted-from-kexec", NULL, 0);
 254         if (ret)
 255                 goto err;
 256
 257         return 0;
 258
 259 err:
 260         pr_err("Error setting up the new device tree.\n");
 261         return -EINVAL;
 262 }