1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * ppc64 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/ima.h> 22 23 #define SLAVE_CODE_SIZE 256 24 25 const struct kexec_file_ops * const kexec_file_loaders[] = { 26 &kexec_elf64_ops, 27 NULL 28 }; 29 30 int arch_kexec_kernel_image_probe(struct kimage *image, void *buf, 31 unsigned long buf_len) 32 { 33 /* We don't support crash kernels yet. */ 34 if (image->type == KEXEC_TYPE_CRASH) 35 return -EOPNOTSUPP; 36 37 return kexec_image_probe_default(image, buf, buf_len); 38 } 39 40 /** 41 * setup_purgatory - initialize the purgatory's global variables 42 * @image: kexec image. 43 * @slave_code: Slave code for the purgatory. 44 * @fdt: Flattened device tree for the next kernel. 45 * @kernel_load_addr: Address where the kernel is loaded. 46 * @fdt_load_addr: Address where the flattened device tree is loaded. 47 * 48 * Return: 0 on success, or negative errno on error. 49 */ 50 int setup_purgatory(struct kimage *image, const void *slave_code, 51 const void *fdt, unsigned long kernel_load_addr, 52 unsigned long fdt_load_addr) 53 { 54 unsigned int *slave_code_buf, master_entry; 55 int ret; 56 57 slave_code_buf = kmalloc(SLAVE_CODE_SIZE, GFP_KERNEL); 58 if (!slave_code_buf) 59 return -ENOMEM; 60 61 /* Get the slave code from the new kernel and put it in purgatory. */ 62 ret = kexec_purgatory_get_set_symbol(image, "purgatory_start", 63 slave_code_buf, SLAVE_CODE_SIZE, 64 true); 65 if (ret) { 66 kfree(slave_code_buf); 67 return ret; 68 } 69 70 master_entry = slave_code_buf[0]; 71 memcpy(slave_code_buf, slave_code, SLAVE_CODE_SIZE); 72 slave_code_buf[0] = master_entry; 73 ret = kexec_purgatory_get_set_symbol(image, "purgatory_start", 74 slave_code_buf, SLAVE_CODE_SIZE, 75 false); 76 kfree(slave_code_buf); 77 78 ret = kexec_purgatory_get_set_symbol(image, "kernel", &kernel_load_addr, 79 sizeof(kernel_load_addr), false); 80 if (ret) 81 return ret; 82 ret = kexec_purgatory_get_set_symbol(image, "dt_offset", &fdt_load_addr, 83 sizeof(fdt_load_addr), false); 84 if (ret) 85 return ret; 86 87 return 0; 88 } 89 90 /** 91 * delete_fdt_mem_rsv - delete memory reservation with given address and size 92 * 93 * Return: 0 on success, or negative errno on error. 94 */ 95 int delete_fdt_mem_rsv(void *fdt, unsigned long start, unsigned long size) 96 { 97 int i, ret, num_rsvs = fdt_num_mem_rsv(fdt); 98 99 for (i = 0; i < num_rsvs; i++) { 100 uint64_t rsv_start, rsv_size; 101 102 ret = fdt_get_mem_rsv(fdt, i, &rsv_start, &rsv_size); 103 if (ret) { 104 pr_err("Malformed device tree.\n"); 105 return -EINVAL; 106 } 107 108 if (rsv_start == start && rsv_size == size) { 109 ret = fdt_del_mem_rsv(fdt, i); 110 if (ret) { 111 pr_err("Error deleting device tree reservation.\n"); 112 return -EINVAL; 113 } 114 115 return 0; 116 } 117 } 118 119 return -ENOENT; 120 } 121 122 /* 123 * setup_new_fdt - modify /chosen and memory reservation for the next kernel 124 * @image: kexec image being loaded. 125 * @fdt: Flattened device tree for the next kernel. 126 * @initrd_load_addr: Address where the next initrd will be loaded. 127 * @initrd_len: Size of the next initrd, or 0 if there will be none. 128 * @cmdline: Command line for the next kernel, or NULL if there will 129 * be none. 130 * 131 * Return: 0 on success, or negative errno on error. 132 */ 133 int setup_new_fdt(const struct kimage *image, void *fdt, 134 unsigned long initrd_load_addr, unsigned long initrd_len, 135 const char *cmdline) 136 { 137 int ret, chosen_node; 138 const void *prop; 139 140 /* Remove memory reservation for the current device tree. */ 141 ret = delete_fdt_mem_rsv(fdt, __pa(initial_boot_params), 142 fdt_totalsize(initial_boot_params)); 143 if (ret == 0) 144 pr_debug("Removed old device tree reservation.\n"); 145 else if (ret != -ENOENT) 146 return ret; 147 148 chosen_node = fdt_path_offset(fdt, "/chosen"); 149 if (chosen_node == -FDT_ERR_NOTFOUND) { 150 chosen_node = fdt_add_subnode(fdt, fdt_path_offset(fdt, "/"), 151 "chosen"); 152 if (chosen_node < 0) { 153 pr_err("Error creating /chosen.\n"); 154 return -EINVAL; 155 } 156 } else if (chosen_node < 0) { 157 pr_err("Malformed device tree: error reading /chosen.\n"); 158 return -EINVAL; 159 } 160 161 /* Did we boot using an initrd? */ 162 prop = fdt_getprop(fdt, chosen_node, "linux,initrd-start", NULL); 163 if (prop) { 164 uint64_t tmp_start, tmp_end, tmp_size; 165 166 tmp_start = fdt64_to_cpu(*((const fdt64_t *) prop)); 167 168 prop = fdt_getprop(fdt, chosen_node, "linux,initrd-end", NULL); 169 if (!prop) { 170 pr_err("Malformed device tree.\n"); 171 return -EINVAL; 172 } 173 tmp_end = fdt64_to_cpu(*((const fdt64_t *) prop)); 174 175 /* 176 * kexec reserves exact initrd size, while firmware may 177 * reserve a multiple of PAGE_SIZE, so check for both. 178 */ 179 tmp_size = tmp_end - tmp_start; 180 ret = delete_fdt_mem_rsv(fdt, tmp_start, tmp_size); 181 if (ret == -ENOENT) 182 ret = delete_fdt_mem_rsv(fdt, tmp_start, 183 round_up(tmp_size, PAGE_SIZE)); 184 if (ret == 0) 185 pr_debug("Removed old initrd reservation.\n"); 186 else if (ret != -ENOENT) 187 return ret; 188 189 /* If there's no new initrd, delete the old initrd's info. */ 190 if (initrd_len == 0) { 191 ret = fdt_delprop(fdt, chosen_node, 192 "linux,initrd-start"); 193 if (ret) { 194 pr_err("Error deleting linux,initrd-start.\n"); 195 return -EINVAL; 196 } 197 198 ret = fdt_delprop(fdt, chosen_node, "linux,initrd-end"); 199 if (ret) { 200 pr_err("Error deleting linux,initrd-end.\n"); 201 return -EINVAL; 202 } 203 } 204 } 205 206 if (initrd_len) { 207 ret = fdt_setprop_u64(fdt, chosen_node, 208 "linux,initrd-start", 209 initrd_load_addr); 210 if (ret < 0) 211 goto err; 212 213 /* initrd-end is the first address after the initrd image. */ 214 ret = fdt_setprop_u64(fdt, chosen_node, "linux,initrd-end", 215 initrd_load_addr + initrd_len); 216 if (ret < 0) 217 goto err; 218 219 ret = fdt_add_mem_rsv(fdt, initrd_load_addr, initrd_len); 220 if (ret) { 221 pr_err("Error reserving initrd memory: %s\n", 222 fdt_strerror(ret)); 223 return -EINVAL; 224 } 225 } 226 227 if (cmdline != NULL) { 228 ret = fdt_setprop_string(fdt, chosen_node, "bootargs", cmdline); 229 if (ret < 0) 230 goto err; 231 } else { 232 ret = fdt_delprop(fdt, chosen_node, "bootargs"); 233 if (ret && ret != -FDT_ERR_NOTFOUND) { 234 pr_err("Error deleting bootargs.\n"); 235 return -EINVAL; 236 } 237 } 238 239 ret = setup_ima_buffer(image, fdt, chosen_node); 240 if (ret) { 241 pr_err("Error setting up the new device tree.\n"); 242 return ret; 243 } 244 245 ret = fdt_setprop(fdt, chosen_node, "linux,booted-from-kexec", NULL, 0); 246 if (ret) 247 goto err; 248 249 return 0; 250 251 err: 252 pr_err("Error setting up the new device tree.\n"); 253 return -EINVAL; 254 } 255