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/reboot.h> 15 #include <linux/set_memory.h> 16 #include <linux/smp.h> 17 18 #include <asm/cacheflush.h> 19 #include <asm/cpu_ops.h> 20 #include <asm/daifflags.h> 21 #include <asm/memory.h> 22 #include <asm/mmu.h> 23 #include <asm/mmu_context.h> 24 #include <asm/page.h> 25 #include <asm/sections.h> 26 #include <asm/trans_pgd.h> 27 28 /** 29 * kexec_image_info - For debugging output. 30 */ 31 #define kexec_image_info(_i) _kexec_image_info(__func__, __LINE__, _i) 32 static void _kexec_image_info(const char *func, int line, 33 const struct kimage *kimage) 34 { 35 unsigned long i; 36 37 pr_debug("%s:%d:\n", func, line); 38 pr_debug(" kexec kimage info:\n"); 39 pr_debug(" type: %d\n", kimage->type); 40 pr_debug(" start: %lx\n", kimage->start); 41 pr_debug(" head: %lx\n", kimage->head); 42 pr_debug(" nr_segments: %lu\n", kimage->nr_segments); 43 pr_debug(" dtb_mem: %pa\n", &kimage->arch.dtb_mem); 44 pr_debug(" kern_reloc: %pa\n", &kimage->arch.kern_reloc); 45 pr_debug(" el2_vectors: %pa\n", &kimage->arch.el2_vectors); 46 47 for (i = 0; i < kimage->nr_segments; i++) { 48 pr_debug(" segment[%lu]: %016lx - %016lx, 0x%lx bytes, %lu pages\n", 49 i, 50 kimage->segment[i].mem, 51 kimage->segment[i].mem + kimage->segment[i].memsz, 52 kimage->segment[i].memsz, 53 kimage->segment[i].memsz / PAGE_SIZE); 54 } 55 } 56 57 void machine_kexec_cleanup(struct kimage *kimage) 58 { 59 /* Empty routine needed to avoid build errors. */ 60 } 61 62 /** 63 * machine_kexec_prepare - Prepare for a kexec reboot. 64 * 65 * Called from the core kexec code when a kernel image is loaded. 66 * Forbid loading a kexec kernel if we have no way of hotplugging cpus or cpus 67 * are stuck in the kernel. This avoids a panic once we hit machine_kexec(). 68 */ 69 int machine_kexec_prepare(struct kimage *kimage) 70 { 71 if (kimage->type != KEXEC_TYPE_CRASH && cpus_are_stuck_in_kernel()) { 72 pr_err("Can't kexec: CPUs are stuck in the kernel.\n"); 73 return -EBUSY; 74 } 75 76 return 0; 77 } 78 79 /** 80 * kexec_segment_flush - Helper to flush the kimage segments to PoC. 81 */ 82 static void kexec_segment_flush(const struct kimage *kimage) 83 { 84 unsigned long i; 85 86 pr_debug("%s:\n", __func__); 87 88 for (i = 0; i < kimage->nr_segments; i++) { 89 pr_debug(" segment[%lu]: %016lx - %016lx, 0x%lx bytes, %lu pages\n", 90 i, 91 kimage->segment[i].mem, 92 kimage->segment[i].mem + kimage->segment[i].memsz, 93 kimage->segment[i].memsz, 94 kimage->segment[i].memsz / PAGE_SIZE); 95 96 dcache_clean_inval_poc( 97 (unsigned long)phys_to_virt(kimage->segment[i].mem), 98 (unsigned long)phys_to_virt(kimage->segment[i].mem) + 99 kimage->segment[i].memsz); 100 } 101 } 102 103 /* Allocates pages for kexec page table */ 104 static void *kexec_page_alloc(void *arg) 105 { 106 struct kimage *kimage = arg; 107 struct page *page = kimage_alloc_control_pages(kimage, 0); 108 void *vaddr = NULL; 109 110 if (!page) 111 return NULL; 112 113 vaddr = page_address(page); 114 memset(vaddr, 0, PAGE_SIZE); 115 116 return vaddr; 117 } 118 119 int machine_kexec_post_load(struct kimage *kimage) 120 { 121 int rc; 122 pgd_t *trans_pgd; 123 void *reloc_code = page_to_virt(kimage->control_code_page); 124 long reloc_size; 125 struct trans_pgd_info info = { 126 .trans_alloc_page = kexec_page_alloc, 127 .trans_alloc_arg = kimage, 128 }; 129 130 /* If in place, relocation is not used, only flush next kernel */ 131 if (kimage->head & IND_DONE) { 132 kexec_segment_flush(kimage); 133 kexec_image_info(kimage); 134 return 0; 135 } 136 137 kimage->arch.el2_vectors = 0; 138 if (is_hyp_nvhe()) { 139 rc = trans_pgd_copy_el2_vectors(&info, 140 &kimage->arch.el2_vectors); 141 if (rc) 142 return rc; 143 } 144 145 /* Create a copy of the linear map */ 146 trans_pgd = kexec_page_alloc(kimage); 147 if (!trans_pgd) 148 return -ENOMEM; 149 rc = trans_pgd_create_copy(&info, &trans_pgd, PAGE_OFFSET, PAGE_END); 150 if (rc) 151 return rc; 152 kimage->arch.ttbr1 = __pa(trans_pgd); 153 kimage->arch.zero_page = __pa_symbol(empty_zero_page); 154 155 reloc_size = __relocate_new_kernel_end - __relocate_new_kernel_start; 156 memcpy(reloc_code, __relocate_new_kernel_start, reloc_size); 157 kimage->arch.kern_reloc = __pa(reloc_code); 158 rc = trans_pgd_idmap_page(&info, &kimage->arch.ttbr0, 159 &kimage->arch.t0sz, reloc_code); 160 if (rc) 161 return rc; 162 kimage->arch.phys_offset = virt_to_phys(kimage) - (long)kimage; 163 164 /* Flush the reloc_code in preparation for its execution. */ 165 dcache_clean_inval_poc((unsigned long)reloc_code, 166 (unsigned long)reloc_code + reloc_size); 167 icache_inval_pou((uintptr_t)reloc_code, 168 (uintptr_t)reloc_code + reloc_size); 169 kexec_image_info(kimage); 170 171 return 0; 172 } 173 174 /** 175 * machine_kexec - Do the kexec reboot. 176 * 177 * Called from the core kexec code for a sys_reboot with LINUX_REBOOT_CMD_KEXEC. 178 */ 179 void machine_kexec(struct kimage *kimage) 180 { 181 bool in_kexec_crash = (kimage == kexec_crash_image); 182 bool stuck_cpus = cpus_are_stuck_in_kernel(); 183 184 /* 185 * New cpus may have become stuck_in_kernel after we loaded the image. 186 */ 187 BUG_ON(!in_kexec_crash && (stuck_cpus || (num_online_cpus() > 1))); 188 WARN(in_kexec_crash && (stuck_cpus || smp_crash_stop_failed()), 189 "Some CPUs may be stale, kdump will be unreliable.\n"); 190 191 pr_info("Bye!\n"); 192 193 local_daif_mask(); 194 195 /* 196 * Both restart and kernel_reloc will shutdown the MMU, disable data 197 * caches. However, restart will start new kernel or purgatory directly, 198 * kernel_reloc contains the body of arm64_relocate_new_kernel 199 * In kexec case, kimage->start points to purgatory assuming that 200 * kernel entry and dtb address are embedded in purgatory by 201 * userspace (kexec-tools). 202 * In kexec_file case, the kernel starts directly without purgatory. 203 */ 204 if (kimage->head & IND_DONE) { 205 typeof(cpu_soft_restart) *restart; 206 207 cpu_install_idmap(); 208 restart = (void *)__pa_symbol(cpu_soft_restart); 209 restart(is_hyp_nvhe(), kimage->start, kimage->arch.dtb_mem, 210 0, 0); 211 } else { 212 void (*kernel_reloc)(struct kimage *kimage); 213 214 if (is_hyp_nvhe()) 215 __hyp_set_vectors(kimage->arch.el2_vectors); 216 cpu_install_ttbr0(kimage->arch.ttbr0, kimage->arch.t0sz); 217 kernel_reloc = (void *)kimage->arch.kern_reloc; 218 kernel_reloc(kimage); 219 } 220 221 BUG(); /* Should never get here. */ 222 } 223 224 static void machine_kexec_mask_interrupts(void) 225 { 226 unsigned int i; 227 struct irq_desc *desc; 228 229 for_each_irq_desc(i, desc) { 230 struct irq_chip *chip; 231 int ret; 232 233 chip = irq_desc_get_chip(desc); 234 if (!chip) 235 continue; 236 237 /* 238 * First try to remove the active state. If this 239 * fails, try to EOI the interrupt. 240 */ 241 ret = irq_set_irqchip_state(i, IRQCHIP_STATE_ACTIVE, false); 242 243 if (ret && irqd_irq_inprogress(&desc->irq_data) && 244 chip->irq_eoi) 245 chip->irq_eoi(&desc->irq_data); 246 247 if (chip->irq_mask) 248 chip->irq_mask(&desc->irq_data); 249 250 if (chip->irq_disable && !irqd_irq_disabled(&desc->irq_data)) 251 chip->irq_disable(&desc->irq_data); 252 } 253 } 254 255 /** 256 * machine_crash_shutdown - shutdown non-crashing cpus and save registers 257 */ 258 void machine_crash_shutdown(struct pt_regs *regs) 259 { 260 local_irq_disable(); 261 262 /* shutdown non-crashing cpus */ 263 crash_smp_send_stop(); 264 265 /* for crashing cpu */ 266 crash_save_cpu(regs, smp_processor_id()); 267 machine_kexec_mask_interrupts(); 268 269 pr_info("Starting crashdump kernel...\n"); 270 } 271 272 #ifdef CONFIG_HIBERNATION 273 /* 274 * To preserve the crash dump kernel image, the relevant memory segments 275 * should be mapped again around the hibernation. 276 */ 277 void crash_prepare_suspend(void) 278 { 279 if (kexec_crash_image) 280 arch_kexec_unprotect_crashkres(); 281 } 282 283 void crash_post_resume(void) 284 { 285 if (kexec_crash_image) 286 arch_kexec_protect_crashkres(); 287 } 288 289 /* 290 * crash_is_nosave 291 * 292 * Return true only if a page is part of reserved memory for crash dump kernel, 293 * but does not hold any data of loaded kernel image. 294 * 295 * Note that all the pages in crash dump kernel memory have been initially 296 * marked as Reserved as memory was allocated via memblock_reserve(). 297 * 298 * In hibernation, the pages which are Reserved and yet "nosave" are excluded 299 * from the hibernation iamge. crash_is_nosave() does thich check for crash 300 * dump kernel and will reduce the total size of hibernation image. 301 */ 302 303 bool crash_is_nosave(unsigned long pfn) 304 { 305 int i; 306 phys_addr_t addr; 307 308 if (!crashk_res.end) 309 return false; 310 311 /* in reserved memory? */ 312 addr = __pfn_to_phys(pfn); 313 if ((addr < crashk_res.start) || (crashk_res.end < addr)) { 314 if (!crashk_low_res.end) 315 return false; 316 317 if ((addr < crashk_low_res.start) || (crashk_low_res.end < addr)) 318 return false; 319 } 320 321 if (!kexec_crash_image) 322 return true; 323 324 /* not part of loaded kernel image? */ 325 for (i = 0; i < kexec_crash_image->nr_segments; i++) 326 if (addr >= kexec_crash_image->segment[i].mem && 327 addr < (kexec_crash_image->segment[i].mem + 328 kexec_crash_image->segment[i].memsz)) 329 return false; 330 331 return true; 332 } 333 334 void crash_free_reserved_phys_range(unsigned long begin, unsigned long end) 335 { 336 unsigned long addr; 337 struct page *page; 338 339 for (addr = begin; addr < end; addr += PAGE_SIZE) { 340 page = phys_to_page(addr); 341 free_reserved_page(page); 342 } 343 } 344 #endif /* CONFIG_HIBERNATION */ 345