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 } 291