1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * kexec_file for arm64 4 * 5 * Copyright (C) 2018 Linaro Limited 6 * Author: AKASHI Takahiro <takahiro.akashi@linaro.org> 7 * 8 * Most code is derived from arm64 port of kexec-tools 9 */ 10 11 #define pr_fmt(fmt) "kexec_file: " fmt 12 13 #include <linux/ioport.h> 14 #include <linux/kernel.h> 15 #include <linux/kexec.h> 16 #include <linux/libfdt.h> 17 #include <linux/memblock.h> 18 #include <linux/of_fdt.h> 19 #include <linux/random.h> 20 #include <linux/string.h> 21 #include <linux/types.h> 22 #include <linux/vmalloc.h> 23 #include <asm/byteorder.h> 24 25 /* relevant device tree properties */ 26 #define FDT_PROP_INITRD_START "linux,initrd-start" 27 #define FDT_PROP_INITRD_END "linux,initrd-end" 28 #define FDT_PROP_BOOTARGS "bootargs" 29 #define FDT_PROP_KASLR_SEED "kaslr-seed" 30 31 const struct kexec_file_ops * const kexec_file_loaders[] = { 32 &kexec_image_ops, 33 NULL 34 }; 35 36 int arch_kimage_file_post_load_cleanup(struct kimage *image) 37 { 38 vfree(image->arch.dtb); 39 image->arch.dtb = NULL; 40 41 return kexec_image_post_load_cleanup_default(image); 42 } 43 44 static int setup_dtb(struct kimage *image, 45 unsigned long initrd_load_addr, unsigned long initrd_len, 46 char *cmdline, void *dtb) 47 { 48 int off, ret; 49 50 ret = fdt_path_offset(dtb, "/chosen"); 51 if (ret < 0) 52 goto out; 53 54 off = ret; 55 56 /* add bootargs */ 57 if (cmdline) { 58 ret = fdt_setprop_string(dtb, off, FDT_PROP_BOOTARGS, cmdline); 59 if (ret) 60 goto out; 61 } else { 62 ret = fdt_delprop(dtb, off, FDT_PROP_BOOTARGS); 63 if (ret && (ret != -FDT_ERR_NOTFOUND)) 64 goto out; 65 } 66 67 /* add initrd-* */ 68 if (initrd_load_addr) { 69 ret = fdt_setprop_u64(dtb, off, FDT_PROP_INITRD_START, 70 initrd_load_addr); 71 if (ret) 72 goto out; 73 74 ret = fdt_setprop_u64(dtb, off, FDT_PROP_INITRD_END, 75 initrd_load_addr + initrd_len); 76 if (ret) 77 goto out; 78 } else { 79 ret = fdt_delprop(dtb, off, FDT_PROP_INITRD_START); 80 if (ret && (ret != -FDT_ERR_NOTFOUND)) 81 goto out; 82 83 ret = fdt_delprop(dtb, off, FDT_PROP_INITRD_END); 84 if (ret && (ret != -FDT_ERR_NOTFOUND)) 85 goto out; 86 } 87 88 /* add kaslr-seed */ 89 ret = fdt_delprop(dtb, off, FDT_PROP_KASLR_SEED); 90 if (ret == -FDT_ERR_NOTFOUND) 91 ret = 0; 92 else if (ret) 93 goto out; 94 95 if (rng_is_initialized()) { 96 u64 seed = get_random_u64(); 97 ret = fdt_setprop_u64(dtb, off, FDT_PROP_KASLR_SEED, seed); 98 if (ret) 99 goto out; 100 } else { 101 pr_notice("RNG is not initialised: omitting \"%s\" property\n", 102 FDT_PROP_KASLR_SEED); 103 } 104 105 out: 106 if (ret) 107 return (ret == -FDT_ERR_NOSPACE) ? -ENOMEM : -EINVAL; 108 109 return 0; 110 } 111 112 /* 113 * More space needed so that we can add initrd, bootargs and kaslr-seed. 114 */ 115 #define DTB_EXTRA_SPACE 0x1000 116 117 static int create_dtb(struct kimage *image, 118 unsigned long initrd_load_addr, unsigned long initrd_len, 119 char *cmdline, void **dtb) 120 { 121 void *buf; 122 size_t buf_size; 123 size_t cmdline_len; 124 int ret; 125 126 cmdline_len = cmdline ? strlen(cmdline) : 0; 127 buf_size = fdt_totalsize(initial_boot_params) 128 + cmdline_len + DTB_EXTRA_SPACE; 129 130 for (;;) { 131 buf = vmalloc(buf_size); 132 if (!buf) 133 return -ENOMEM; 134 135 /* duplicate a device tree blob */ 136 ret = fdt_open_into(initial_boot_params, buf, buf_size); 137 if (ret) 138 return -EINVAL; 139 140 ret = setup_dtb(image, initrd_load_addr, initrd_len, 141 cmdline, buf); 142 if (ret) { 143 vfree(buf); 144 if (ret == -ENOMEM) { 145 /* unlikely, but just in case */ 146 buf_size += DTB_EXTRA_SPACE; 147 continue; 148 } else { 149 return ret; 150 } 151 } 152 153 /* trim it */ 154 fdt_pack(buf); 155 *dtb = buf; 156 157 return 0; 158 } 159 } 160 161 int load_other_segments(struct kimage *image, 162 unsigned long kernel_load_addr, 163 unsigned long kernel_size, 164 char *initrd, unsigned long initrd_len, 165 char *cmdline) 166 { 167 struct kexec_buf kbuf; 168 void *dtb = NULL; 169 unsigned long initrd_load_addr = 0, dtb_len; 170 int ret = 0; 171 172 kbuf.image = image; 173 /* not allocate anything below the kernel */ 174 kbuf.buf_min = kernel_load_addr + kernel_size; 175 176 /* load initrd */ 177 if (initrd) { 178 kbuf.buffer = initrd; 179 kbuf.bufsz = initrd_len; 180 kbuf.mem = 0; 181 kbuf.memsz = initrd_len; 182 kbuf.buf_align = 0; 183 /* within 1GB-aligned window of up to 32GB in size */ 184 kbuf.buf_max = round_down(kernel_load_addr, SZ_1G) 185 + (unsigned long)SZ_1G * 32; 186 kbuf.top_down = false; 187 188 ret = kexec_add_buffer(&kbuf); 189 if (ret) 190 goto out_err; 191 initrd_load_addr = kbuf.mem; 192 193 pr_debug("Loaded initrd at 0x%lx bufsz=0x%lx memsz=0x%lx\n", 194 initrd_load_addr, initrd_len, initrd_len); 195 } 196 197 /* load dtb */ 198 ret = create_dtb(image, initrd_load_addr, initrd_len, cmdline, &dtb); 199 if (ret) { 200 pr_err("Preparing for new dtb failed\n"); 201 goto out_err; 202 } 203 204 dtb_len = fdt_totalsize(dtb); 205 kbuf.buffer = dtb; 206 kbuf.bufsz = dtb_len; 207 kbuf.mem = 0; 208 kbuf.memsz = dtb_len; 209 /* not across 2MB boundary */ 210 kbuf.buf_align = SZ_2M; 211 kbuf.buf_max = ULONG_MAX; 212 kbuf.top_down = true; 213 214 ret = kexec_add_buffer(&kbuf); 215 if (ret) 216 goto out_err; 217 image->arch.dtb = dtb; 218 image->arch.dtb_mem = kbuf.mem; 219 220 pr_debug("Loaded dtb at 0x%lx bufsz=0x%lx memsz=0x%lx\n", 221 kbuf.mem, dtb_len, dtb_len); 222 223 return 0; 224 225 out_err: 226 vfree(dtb); 227 return ret; 228 } 229