1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * kexec for arm64 4 * 5 * Copyright (C) Linaro. 6 * Copyright (C) Huawei Futurewei Technologies. 7 */ 8 9 #include <linux/interrupt.h> 10 #include <linux/irq.h> 11 #include <linux/kernel.h> 12 #include <linux/kexec.h> 13 #include <linux/page-flags.h> 14 #include <linux/set_memory.h> 15 #include <linux/smp.h> 16 17 #include <asm/cacheflush.h> 18 #include <asm/cpu_ops.h> 19 #include <asm/daifflags.h> 20 #include <asm/memory.h> 21 #include <asm/mmu.h> 22 #include <asm/mmu_context.h> 23 #include <asm/page.h> 24 25 #include "cpu-reset.h" 26 27 /* Global variables for the arm64_relocate_new_kernel routine. */ 28 extern const unsigned char arm64_relocate_new_kernel[]; 29 extern const unsigned long arm64_relocate_new_kernel_size; 30 31 /** 32 * kexec_image_info - For debugging output. 33 */ 34 #define kexec_image_info(_i) _kexec_image_info(__func__, __LINE__, _i) 35 static void _kexec_image_info(const char *func, int line, 36 const struct kimage *kimage) 37 { 38 unsigned long i; 39 40 pr_debug("%s:%d:\n", func, line); 41 pr_debug(" kexec kimage info:\n"); 42 pr_debug(" type: %d\n", kimage->type); 43 pr_debug(" start: %lx\n", kimage->start); 44 pr_debug(" head: %lx\n", kimage->head); 45 pr_debug(" nr_segments: %lu\n", kimage->nr_segments); 46 pr_debug(" kern_reloc: %pa\n", &kimage->arch.kern_reloc); 47 48 for (i = 0; i < kimage->nr_segments; i++) { 49 pr_debug(" segment[%lu]: %016lx - %016lx, 0x%lx bytes, %lu pages\n", 50 i, 51 kimage->segment[i].mem, 52 kimage->segment[i].mem + kimage->segment[i].memsz, 53 kimage->segment[i].memsz, 54 kimage->segment[i].memsz / PAGE_SIZE); 55 } 56 } 57 58 void machine_kexec_cleanup(struct kimage *kimage) 59 { 60 /* Empty routine needed to avoid build errors. */ 61 } 62 63 int machine_kexec_post_load(struct kimage *kimage) 64 { 65 void *reloc_code = page_to_virt(kimage->control_code_page); 66 67 memcpy(reloc_code, arm64_relocate_new_kernel, 68 arm64_relocate_new_kernel_size); 69 kimage->arch.kern_reloc = __pa(reloc_code); 70 kexec_image_info(kimage); 71 72 /* 73 * For execution with the MMU off, reloc_code needs to be cleaned to the 74 * PoC and invalidated from the I-cache. 75 */ 76 dcache_clean_inval_poc((unsigned long)reloc_code, 77 (unsigned long)reloc_code + 78 arm64_relocate_new_kernel_size); 79 icache_inval_pou((uintptr_t)reloc_code, 80 (uintptr_t)reloc_code + 81 arm64_relocate_new_kernel_size); 82 83 return 0; 84 } 85 86 /** 87 * machine_kexec_prepare - Prepare for a kexec reboot. 88 * 89 * Called from the core kexec code when a kernel image is loaded. 90 * Forbid loading a kexec kernel if we have no way of hotplugging cpus or cpus 91 * are stuck in the kernel. This avoids a panic once we hit machine_kexec(). 92 */ 93 int machine_kexec_prepare(struct kimage *kimage) 94 { 95 if (kimage->type != KEXEC_TYPE_CRASH && cpus_are_stuck_in_kernel()) { 96 pr_err("Can't kexec: CPUs are stuck in the kernel.\n"); 97 return -EBUSY; 98 } 99 100 return 0; 101 } 102 103 /** 104 * kexec_list_flush - Helper to flush the kimage list and source pages to PoC. 105 */ 106 static void kexec_list_flush(struct kimage *kimage) 107 { 108 kimage_entry_t *entry; 109 110 for (entry = &kimage->head; ; entry++) { 111 unsigned int flag; 112 unsigned long addr; 113 114 /* flush the list entries. */ 115 dcache_clean_inval_poc((unsigned long)entry, 116 (unsigned long)entry + 117 sizeof(kimage_entry_t)); 118 119 flag = *entry & IND_FLAGS; 120 if (flag == IND_DONE) 121 break; 122 123 addr = (unsigned long)phys_to_virt(*entry & PAGE_MASK); 124 125 switch (flag) { 126 case IND_INDIRECTION: 127 /* Set entry point just before the new list page. */ 128 entry = (kimage_entry_t *)addr - 1; 129 break; 130 case IND_SOURCE: 131 /* flush the source pages. */ 132 dcache_clean_inval_poc(addr, addr + PAGE_SIZE); 133 break; 134 case IND_DESTINATION: 135 break; 136 default: 137 BUG(); 138 } 139 } 140 } 141 142 /** 143 * kexec_segment_flush - Helper to flush the kimage segments to PoC. 144 */ 145 static void kexec_segment_flush(const struct kimage *kimage) 146 { 147 unsigned long i; 148 149 pr_debug("%s:\n", __func__); 150 151 for (i = 0; i < kimage->nr_segments; i++) { 152 pr_debug(" segment[%lu]: %016lx - %016lx, 0x%lx bytes, %lu pages\n", 153 i, 154 kimage->segment[i].mem, 155 kimage->segment[i].mem + kimage->segment[i].memsz, 156 kimage->segment[i].memsz, 157 kimage->segment[i].memsz / PAGE_SIZE); 158 159 dcache_clean_inval_poc( 160 (unsigned long)phys_to_virt(kimage->segment[i].mem), 161 (unsigned long)phys_to_virt(kimage->segment[i].mem) + 162 kimage->segment[i].memsz); 163 } 164 } 165 166 /** 167 * machine_kexec - Do the kexec reboot. 168 * 169 * Called from the core kexec code for a sys_reboot with LINUX_REBOOT_CMD_KEXEC. 170 */ 171 void machine_kexec(struct kimage *kimage) 172 { 173 bool in_kexec_crash = (kimage == kexec_crash_image); 174 bool stuck_cpus = cpus_are_stuck_in_kernel(); 175 176 /* 177 * New cpus may have become stuck_in_kernel after we loaded the image. 178 */ 179 BUG_ON(!in_kexec_crash && (stuck_cpus || (num_online_cpus() > 1))); 180 WARN(in_kexec_crash && (stuck_cpus || smp_crash_stop_failed()), 181 "Some CPUs may be stale, kdump will be unreliable.\n"); 182 183 /* Flush the kimage list and its buffers. */ 184 kexec_list_flush(kimage); 185 186 /* Flush the new image if already in place. */ 187 if ((kimage != kexec_crash_image) && (kimage->head & IND_DONE)) 188 kexec_segment_flush(kimage); 189 190 pr_info("Bye!\n"); 191 192 local_daif_mask(); 193 194 /* 195 * cpu_soft_restart will shutdown the MMU, disable data caches, then 196 * transfer control to the kern_reloc which contains a copy of 197 * the arm64_relocate_new_kernel routine. arm64_relocate_new_kernel 198 * uses physical addressing to relocate the new image to its final 199 * position and transfers control to the image entry point when the 200 * relocation is complete. 201 * In kexec case, kimage->start points to purgatory assuming that 202 * kernel entry and dtb address are embedded in purgatory by 203 * userspace (kexec-tools). 204 * In kexec_file case, the kernel starts directly without purgatory. 205 */ 206 cpu_soft_restart(kimage->arch.kern_reloc, kimage->head, kimage->start, 207 kimage->arch.dtb_mem); 208 209 BUG(); /* Should never get here. */ 210 } 211 212 static void machine_kexec_mask_interrupts(void) 213 { 214 unsigned int i; 215 struct irq_desc *desc; 216 217 for_each_irq_desc(i, desc) { 218 struct irq_chip *chip; 219 int ret; 220 221 chip = irq_desc_get_chip(desc); 222 if (!chip) 223 continue; 224 225 /* 226 * First try to remove the active state. If this 227 * fails, try to EOI the interrupt. 228 */ 229 ret = irq_set_irqchip_state(i, IRQCHIP_STATE_ACTIVE, false); 230 231 if (ret && irqd_irq_inprogress(&desc->irq_data) && 232 chip->irq_eoi) 233 chip->irq_eoi(&desc->irq_data); 234 235 if (chip->irq_mask) 236 chip->irq_mask(&desc->irq_data); 237 238 if (chip->irq_disable && !irqd_irq_disabled(&desc->irq_data)) 239 chip->irq_disable(&desc->irq_data); 240 } 241 } 242 243 /** 244 * machine_crash_shutdown - shutdown non-crashing cpus and save registers 245 */ 246 void machine_crash_shutdown(struct pt_regs *regs) 247 { 248 local_irq_disable(); 249 250 /* shutdown non-crashing cpus */ 251 crash_smp_send_stop(); 252 253 /* for crashing cpu */ 254 crash_save_cpu(regs, smp_processor_id()); 255 machine_kexec_mask_interrupts(); 256 257 pr_info("Starting crashdump kernel...\n"); 258 } 259 260 void arch_kexec_protect_crashkres(void) 261 { 262 int i; 263 264 kexec_segment_flush(kexec_crash_image); 265 266 for (i = 0; i < kexec_crash_image->nr_segments; i++) 267 set_memory_valid( 268 __phys_to_virt(kexec_crash_image->segment[i].mem), 269 kexec_crash_image->segment[i].memsz >> PAGE_SHIFT, 0); 270 } 271 272 void arch_kexec_unprotect_crashkres(void) 273 { 274 int i; 275 276 for (i = 0; i < kexec_crash_image->nr_segments; i++) 277 set_memory_valid( 278 __phys_to_virt(kexec_crash_image->segment[i].mem), 279 kexec_crash_image->segment[i].memsz >> PAGE_SHIFT, 1); 280 } 281 282 #ifdef CONFIG_HIBERNATION 283 /* 284 * To preserve the crash dump kernel image, the relevant memory segments 285 * should be mapped again around the hibernation. 286 */ 287 void crash_prepare_suspend(void) 288 { 289 if (kexec_crash_image) 290 arch_kexec_unprotect_crashkres(); 291 } 292 293 void crash_post_resume(void) 294 { 295 if (kexec_crash_image) 296 arch_kexec_protect_crashkres(); 297 } 298 299 /* 300 * crash_is_nosave 301 * 302 * Return true only if a page is part of reserved memory for crash dump kernel, 303 * but does not hold any data of loaded kernel image. 304 * 305 * Note that all the pages in crash dump kernel memory have been initially 306 * marked as Reserved as memory was allocated via memblock_reserve(). 307 * 308 * In hibernation, the pages which are Reserved and yet "nosave" are excluded 309 * from the hibernation iamge. crash_is_nosave() does thich check for crash 310 * dump kernel and will reduce the total size of hibernation image. 311 */ 312 313 bool crash_is_nosave(unsigned long pfn) 314 { 315 int i; 316 phys_addr_t addr; 317 318 if (!crashk_res.end) 319 return false; 320 321 /* in reserved memory? */ 322 addr = __pfn_to_phys(pfn); 323 if ((addr < crashk_res.start) || (crashk_res.end < addr)) 324 return false; 325 326 if (!kexec_crash_image) 327 return true; 328 329 /* not part of loaded kernel image? */ 330 for (i = 0; i < kexec_crash_image->nr_segments; i++) 331 if (addr >= kexec_crash_image->segment[i].mem && 332 addr < (kexec_crash_image->segment[i].mem + 333 kexec_crash_image->segment[i].memsz)) 334 return false; 335 336 return true; 337 } 338 339 void crash_free_reserved_phys_range(unsigned long begin, unsigned long end) 340 { 341 unsigned long addr; 342 struct page *page; 343 344 for (addr = begin; addr < end; addr += PAGE_SIZE) { 345 page = phys_to_page(addr); 346 free_reserved_page(page); 347 } 348 } 349 #endif /* CONFIG_HIBERNATION */ 350