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 && (ret != -FDT_ERR_NOTFOUND)) 91 goto out; 92 93 if (rng_is_initialized()) { 94 u64 seed = get_random_u64(); 95 ret = fdt_setprop_u64(dtb, off, FDT_PROP_KASLR_SEED, seed); 96 if (ret) 97 goto out; 98 } else { 99 pr_notice("RNG is not initialised: omitting \"%s\" property\n", 100 FDT_PROP_KASLR_SEED); 101 } 102 103 out: 104 if (ret) 105 return (ret == -FDT_ERR_NOSPACE) ? -ENOMEM : -EINVAL; 106 107 return 0; 108 } 109 110 /* 111 * More space needed so that we can add initrd, bootargs and kaslr-seed. 112 */ 113 #define DTB_EXTRA_SPACE 0x1000 114 115 static int create_dtb(struct kimage *image, 116 unsigned long initrd_load_addr, unsigned long initrd_len, 117 char *cmdline, void **dtb) 118 { 119 void *buf; 120 size_t buf_size; 121 int ret; 122 123 buf_size = fdt_totalsize(initial_boot_params) 124 + strlen(cmdline) + DTB_EXTRA_SPACE; 125 126 for (;;) { 127 buf = vmalloc(buf_size); 128 if (!buf) 129 return -ENOMEM; 130 131 /* duplicate a device tree blob */ 132 ret = fdt_open_into(initial_boot_params, buf, buf_size); 133 if (ret) 134 return -EINVAL; 135 136 ret = setup_dtb(image, initrd_load_addr, initrd_len, 137 cmdline, buf); 138 if (ret) { 139 vfree(buf); 140 if (ret == -ENOMEM) { 141 /* unlikely, but just in case */ 142 buf_size += DTB_EXTRA_SPACE; 143 continue; 144 } else { 145 return ret; 146 } 147 } 148 149 /* trim it */ 150 fdt_pack(buf); 151 *dtb = buf; 152 153 return 0; 154 } 155 } 156 157 int load_other_segments(struct kimage *image, 158 unsigned long kernel_load_addr, 159 unsigned long kernel_size, 160 char *initrd, unsigned long initrd_len, 161 char *cmdline) 162 { 163 struct kexec_buf kbuf; 164 void *dtb = NULL; 165 unsigned long initrd_load_addr = 0, dtb_len; 166 int ret = 0; 167 168 kbuf.image = image; 169 /* not allocate anything below the kernel */ 170 kbuf.buf_min = kernel_load_addr + kernel_size; 171 172 /* load initrd */ 173 if (initrd) { 174 kbuf.buffer = initrd; 175 kbuf.bufsz = initrd_len; 176 kbuf.mem = 0; 177 kbuf.memsz = initrd_len; 178 kbuf.buf_align = 0; 179 /* within 1GB-aligned window of up to 32GB in size */ 180 kbuf.buf_max = round_down(kernel_load_addr, SZ_1G) 181 + (unsigned long)SZ_1G * 32; 182 kbuf.top_down = false; 183 184 ret = kexec_add_buffer(&kbuf); 185 if (ret) 186 goto out_err; 187 initrd_load_addr = kbuf.mem; 188 189 pr_debug("Loaded initrd at 0x%lx bufsz=0x%lx memsz=0x%lx\n", 190 initrd_load_addr, initrd_len, initrd_len); 191 } 192 193 /* load dtb */ 194 ret = create_dtb(image, initrd_load_addr, initrd_len, cmdline, &dtb); 195 if (ret) { 196 pr_err("Preparing for new dtb failed\n"); 197 goto out_err; 198 } 199 200 dtb_len = fdt_totalsize(dtb); 201 kbuf.buffer = dtb; 202 kbuf.bufsz = dtb_len; 203 kbuf.mem = 0; 204 kbuf.memsz = dtb_len; 205 /* not across 2MB boundary */ 206 kbuf.buf_align = SZ_2M; 207 kbuf.buf_max = ULONG_MAX; 208 kbuf.top_down = true; 209 210 ret = kexec_add_buffer(&kbuf); 211 if (ret) 212 goto out_err; 213 image->arch.dtb = dtb; 214 image->arch.dtb_mem = kbuf.mem; 215 216 pr_debug("Loaded dtb at 0x%lx bufsz=0x%lx memsz=0x%lx\n", 217 kbuf.mem, dtb_len, dtb_len); 218 219 return 0; 220 221 out_err: 222 vfree(dtb); 223 return ret; 224 } 225