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/smp.h> 15 16 #include <asm/cacheflush.h> 17 #include <asm/cpu_ops.h> 18 #include <asm/daifflags.h> 19 #include <asm/memory.h> 20 #include <asm/mmu.h> 21 #include <asm/mmu_context.h> 22 #include <asm/page.h> 23 24 #include "cpu-reset.h" 25 26 /* Global variables for the arm64_relocate_new_kernel routine. */ 27 extern const unsigned char arm64_relocate_new_kernel[]; 28 extern const unsigned long arm64_relocate_new_kernel_size; 29 30 /** 31 * kexec_image_info - For debugging output. 32 */ 33 #define kexec_image_info(_i) _kexec_image_info(__func__, __LINE__, _i) 34 static void _kexec_image_info(const char *func, int line, 35 const struct kimage *kimage) 36 { 37 unsigned long i; 38 39 pr_debug("%s:%d:\n", func, line); 40 pr_debug(" kexec kimage info:\n"); 41 pr_debug(" type: %d\n", kimage->type); 42 pr_debug(" start: %lx\n", kimage->start); 43 pr_debug(" head: %lx\n", kimage->head); 44 pr_debug(" nr_segments: %lu\n", kimage->nr_segments); 45 46 for (i = 0; i < kimage->nr_segments; i++) { 47 pr_debug(" segment[%lu]: %016lx - %016lx, 0x%lx bytes, %lu pages\n", 48 i, 49 kimage->segment[i].mem, 50 kimage->segment[i].mem + kimage->segment[i].memsz, 51 kimage->segment[i].memsz, 52 kimage->segment[i].memsz / PAGE_SIZE); 53 } 54 } 55 56 void machine_kexec_cleanup(struct kimage *kimage) 57 { 58 /* Empty routine needed to avoid build errors. */ 59 } 60 61 /** 62 * machine_kexec_prepare - Prepare for a kexec reboot. 63 * 64 * Called from the core kexec code when a kernel image is loaded. 65 * Forbid loading a kexec kernel if we have no way of hotplugging cpus or cpus 66 * are stuck in the kernel. This avoids a panic once we hit machine_kexec(). 67 */ 68 int machine_kexec_prepare(struct kimage *kimage) 69 { 70 kexec_image_info(kimage); 71 72 if (kimage->type != KEXEC_TYPE_CRASH && cpus_are_stuck_in_kernel()) { 73 pr_err("Can't kexec: CPUs are stuck in the kernel.\n"); 74 return -EBUSY; 75 } 76 77 return 0; 78 } 79 80 /** 81 * kexec_list_flush - Helper to flush the kimage list and source pages to PoC. 82 */ 83 static void kexec_list_flush(struct kimage *kimage) 84 { 85 kimage_entry_t *entry; 86 87 for (entry = &kimage->head; ; entry++) { 88 unsigned int flag; 89 void *addr; 90 91 /* flush the list entries. */ 92 __flush_dcache_area(entry, sizeof(kimage_entry_t)); 93 94 flag = *entry & IND_FLAGS; 95 if (flag == IND_DONE) 96 break; 97 98 addr = phys_to_virt(*entry & PAGE_MASK); 99 100 switch (flag) { 101 case IND_INDIRECTION: 102 /* Set entry point just before the new list page. */ 103 entry = (kimage_entry_t *)addr - 1; 104 break; 105 case IND_SOURCE: 106 /* flush the source pages. */ 107 __flush_dcache_area(addr, PAGE_SIZE); 108 break; 109 case IND_DESTINATION: 110 break; 111 default: 112 BUG(); 113 } 114 } 115 } 116 117 /** 118 * kexec_segment_flush - Helper to flush the kimage segments to PoC. 119 */ 120 static void kexec_segment_flush(const struct kimage *kimage) 121 { 122 unsigned long i; 123 124 pr_debug("%s:\n", __func__); 125 126 for (i = 0; i < kimage->nr_segments; i++) { 127 pr_debug(" segment[%lu]: %016lx - %016lx, 0x%lx bytes, %lu pages\n", 128 i, 129 kimage->segment[i].mem, 130 kimage->segment[i].mem + kimage->segment[i].memsz, 131 kimage->segment[i].memsz, 132 kimage->segment[i].memsz / PAGE_SIZE); 133 134 __flush_dcache_area(phys_to_virt(kimage->segment[i].mem), 135 kimage->segment[i].memsz); 136 } 137 } 138 139 /** 140 * machine_kexec - Do the kexec reboot. 141 * 142 * Called from the core kexec code for a sys_reboot with LINUX_REBOOT_CMD_KEXEC. 143 */ 144 void machine_kexec(struct kimage *kimage) 145 { 146 phys_addr_t reboot_code_buffer_phys; 147 void *reboot_code_buffer; 148 bool in_kexec_crash = (kimage == kexec_crash_image); 149 bool stuck_cpus = cpus_are_stuck_in_kernel(); 150 151 /* 152 * New cpus may have become stuck_in_kernel after we loaded the image. 153 */ 154 BUG_ON(!in_kexec_crash && (stuck_cpus || (num_online_cpus() > 1))); 155 WARN(in_kexec_crash && (stuck_cpus || smp_crash_stop_failed()), 156 "Some CPUs may be stale, kdump will be unreliable.\n"); 157 158 reboot_code_buffer_phys = page_to_phys(kimage->control_code_page); 159 reboot_code_buffer = phys_to_virt(reboot_code_buffer_phys); 160 161 kexec_image_info(kimage); 162 163 /* 164 * Copy arm64_relocate_new_kernel to the reboot_code_buffer for use 165 * after the kernel is shut down. 166 */ 167 memcpy(reboot_code_buffer, arm64_relocate_new_kernel, 168 arm64_relocate_new_kernel_size); 169 170 /* Flush the reboot_code_buffer in preparation for its execution. */ 171 __flush_dcache_area(reboot_code_buffer, arm64_relocate_new_kernel_size); 172 173 /* 174 * Although we've killed off the secondary CPUs, we don't update 175 * the online mask if we're handling a crash kernel and consequently 176 * need to avoid flush_icache_range(), which will attempt to IPI 177 * the offline CPUs. Therefore, we must use the __* variant here. 178 */ 179 __flush_icache_range((uintptr_t)reboot_code_buffer, 180 (uintptr_t)reboot_code_buffer + 181 arm64_relocate_new_kernel_size); 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 reboot_code_buffer 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(reboot_code_buffer_phys, kimage->head, kimage->start, 207 #ifdef CONFIG_KEXEC_FILE 208 kimage->arch.dtb_mem); 209 #else 210 0); 211 #endif 212 213 BUG(); /* Should never get here. */ 214 } 215 216 static void machine_kexec_mask_interrupts(void) 217 { 218 unsigned int i; 219 struct irq_desc *desc; 220 221 for_each_irq_desc(i, desc) { 222 struct irq_chip *chip; 223 int ret; 224 225 chip = irq_desc_get_chip(desc); 226 if (!chip) 227 continue; 228 229 /* 230 * First try to remove the active state. If this 231 * fails, try to EOI the interrupt. 232 */ 233 ret = irq_set_irqchip_state(i, IRQCHIP_STATE_ACTIVE, false); 234 235 if (ret && irqd_irq_inprogress(&desc->irq_data) && 236 chip->irq_eoi) 237 chip->irq_eoi(&desc->irq_data); 238 239 if (chip->irq_mask) 240 chip->irq_mask(&desc->irq_data); 241 242 if (chip->irq_disable && !irqd_irq_disabled(&desc->irq_data)) 243 chip->irq_disable(&desc->irq_data); 244 } 245 } 246 247 /** 248 * machine_crash_shutdown - shutdown non-crashing cpus and save registers 249 */ 250 void machine_crash_shutdown(struct pt_regs *regs) 251 { 252 local_irq_disable(); 253 254 /* shutdown non-crashing cpus */ 255 crash_smp_send_stop(); 256 257 /* for crashing cpu */ 258 crash_save_cpu(regs, smp_processor_id()); 259 machine_kexec_mask_interrupts(); 260 261 pr_info("Starting crashdump kernel...\n"); 262 } 263 264 void arch_kexec_protect_crashkres(void) 265 { 266 int i; 267 268 kexec_segment_flush(kexec_crash_image); 269 270 for (i = 0; i < kexec_crash_image->nr_segments; i++) 271 set_memory_valid( 272 __phys_to_virt(kexec_crash_image->segment[i].mem), 273 kexec_crash_image->segment[i].memsz >> PAGE_SHIFT, 0); 274 } 275 276 void arch_kexec_unprotect_crashkres(void) 277 { 278 int i; 279 280 for (i = 0; i < kexec_crash_image->nr_segments; i++) 281 set_memory_valid( 282 __phys_to_virt(kexec_crash_image->segment[i].mem), 283 kexec_crash_image->segment[i].memsz >> PAGE_SHIFT, 1); 284 } 285 286 #ifdef CONFIG_HIBERNATION 287 /* 288 * To preserve the crash dump kernel image, the relevant memory segments 289 * should be mapped again around the hibernation. 290 */ 291 void crash_prepare_suspend(void) 292 { 293 if (kexec_crash_image) 294 arch_kexec_unprotect_crashkres(); 295 } 296 297 void crash_post_resume(void) 298 { 299 if (kexec_crash_image) 300 arch_kexec_protect_crashkres(); 301 } 302 303 /* 304 * crash_is_nosave 305 * 306 * Return true only if a page is part of reserved memory for crash dump kernel, 307 * but does not hold any data of loaded kernel image. 308 * 309 * Note that all the pages in crash dump kernel memory have been initially 310 * marked as Reserved as memory was allocated via memblock_reserve(). 311 * 312 * In hibernation, the pages which are Reserved and yet "nosave" are excluded 313 * from the hibernation iamge. crash_is_nosave() does thich check for crash 314 * dump kernel and will reduce the total size of hibernation image. 315 */ 316 317 bool crash_is_nosave(unsigned long pfn) 318 { 319 int i; 320 phys_addr_t addr; 321 322 if (!crashk_res.end) 323 return false; 324 325 /* in reserved memory? */ 326 addr = __pfn_to_phys(pfn); 327 if ((addr < crashk_res.start) || (crashk_res.end < addr)) 328 return false; 329 330 if (!kexec_crash_image) 331 return true; 332 333 /* not part of loaded kernel image? */ 334 for (i = 0; i < kexec_crash_image->nr_segments; i++) 335 if (addr >= kexec_crash_image->segment[i].mem && 336 addr < (kexec_crash_image->segment[i].mem + 337 kexec_crash_image->segment[i].memsz)) 338 return false; 339 340 return true; 341 } 342 343 void crash_free_reserved_phys_range(unsigned long begin, unsigned long end) 344 { 345 unsigned long addr; 346 struct page *page; 347 348 for (addr = begin; addr < end; addr += PAGE_SIZE) { 349 page = phys_to_page(addr); 350 free_reserved_page(page); 351 } 352 } 353 #endif /* CONFIG_HIBERNATION */ 354