arch/arm64/kernel/machine_kexec.c

   1 /*
   2  * kexec for arm64
   3  *
   4  * Copyright (C) Linaro.
   5  * Copyright (C) Huawei Futurewei Technologies.
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  */
  11
  12 #include <linux/interrupt.h>
  13 #include <linux/irq.h>
  14 #include <linux/kernel.h>
  15 #include <linux/kexec.h>
  16 #include <linux/page-flags.h>
  17 #include <linux/smp.h>
  18
  19 #include <asm/cacheflush.h>
  20 #include <asm/cpu_ops.h>
  21 #include <asm/memory.h>
  22 #include <asm/mmu.h>
  23 #include <asm/mmu_context.h>
  24 #include <asm/page.h>
  25
  26 #include "cpu-reset.h"
  27
  28 /* Global variables for the arm64_relocate_new_kernel routine. */
  29 extern const unsigned char arm64_relocate_new_kernel[];
  30 extern const unsigned long arm64_relocate_new_kernel_size;
  31
  32 /**
  33  * kexec_image_info - For debugging output.
  34  */
  35 #define kexec_image_info(_i) _kexec_image_info(__func__, __LINE__, _i)
  36 static void _kexec_image_info(const char *func, int line,
  37         const struct kimage *kimage)
  38 {
  39         unsigned long i;
  40
  41         pr_debug("%s:%d:\n", func, line);
  42         pr_debug("  kexec kimage info:\n");
  43         pr_debug("    type:        %d\n", kimage->type);
  44         pr_debug("    start:       %lx\n", kimage->start);
  45         pr_debug("    head:        %lx\n", kimage->head);
  46         pr_debug("    nr_segments: %lu\n", kimage->nr_segments);
  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 /**
  64  * machine_kexec_prepare - Prepare for a kexec reboot.
  65  *
  66  * Called from the core kexec code when a kernel image is loaded.
  67  * Forbid loading a kexec kernel if we have no way of hotplugging cpus or cpus
  68  * are stuck in the kernel. This avoids a panic once we hit machine_kexec().
  69  */
  70 int machine_kexec_prepare(struct kimage *kimage)
  71 {
  72         kexec_image_info(kimage);
  73
  74         if (kimage->type != KEXEC_TYPE_CRASH && cpus_are_stuck_in_kernel()) {
  75                 pr_err("Can't kexec: CPUs are stuck in the kernel.\n");
  76                 return -EBUSY;
  77         }
  78
  79         return 0;
  80 }
  81
  82 /**
  83  * kexec_list_flush - Helper to flush the kimage list and source pages to PoC.
  84  */
  85 static void kexec_list_flush(struct kimage *kimage)
  86 {
  87         kimage_entry_t *entry;
  88
  89         for (entry = &kimage->head; ; entry++) {
  90                 unsigned int flag;
  91                 void *addr;
  92
  93                 /* flush the list entries. */
  94                 __flush_dcache_area(entry, sizeof(kimage_entry_t));
  95
  96                 flag = *entry & IND_FLAGS;
  97                 if (flag == IND_DONE)
  98                         break;
  99
 100                 addr = phys_to_virt(*entry & PAGE_MASK);
 101
 102                 switch (flag) {
 103                 case IND_INDIRECTION:
 104                         /* Set entry point just before the new list page. */
 105                         entry = (kimage_entry_t *)addr - 1;
 106                         break;
 107                 case IND_SOURCE:
 108                         /* flush the source pages. */
 109                         __flush_dcache_area(addr, PAGE_SIZE);
 110                         break;
 111                 case IND_DESTINATION:
 112                         break;
 113                 default:
 114                         BUG();
 115                 }
 116         }
 117 }
 118
 119 /**
 120  * kexec_segment_flush - Helper to flush the kimage segments to PoC.
 121  */
 122 static void kexec_segment_flush(const struct kimage *kimage)
 123 {
 124         unsigned long i;
 125
 126         pr_debug("%s:\n", __func__);
 127
 128         for (i = 0; i < kimage->nr_segments; i++) {
 129                 pr_debug("  segment[%lu]: %016lx - %016lx, 0x%lx bytes, %lu pages\n",
 130                         i,
 131                         kimage->segment[i].mem,
 132                         kimage->segment[i].mem + kimage->segment[i].memsz,
 133                         kimage->segment[i].memsz,
 134                         kimage->segment[i].memsz /  PAGE_SIZE);
 135
 136                 __flush_dcache_area(phys_to_virt(kimage->segment[i].mem),
 137                         kimage->segment[i].memsz);
 138         }
 139 }
 140
 141 /**
 142  * machine_kexec - Do the kexec reboot.
 143  *
 144  * Called from the core kexec code for a sys_reboot with LINUX_REBOOT_CMD_KEXEC.
 145  */
 146 void machine_kexec(struct kimage *kimage)
 147 {
 148         phys_addr_t reboot_code_buffer_phys;
 149         void *reboot_code_buffer;
 150         bool in_kexec_crash = (kimage == kexec_crash_image);
 151         bool stuck_cpus = cpus_are_stuck_in_kernel();
 152
 153         /*
 154          * New cpus may have become stuck_in_kernel after we loaded the image.
 155          */
 156         BUG_ON(!in_kexec_crash && (stuck_cpus || (num_online_cpus() > 1)));
 157         WARN(in_kexec_crash && (stuck_cpus || smp_crash_stop_failed()),
 158                 "Some CPUs may be stale, kdump will be unreliable.\n");
 159
 160         reboot_code_buffer_phys = page_to_phys(kimage->control_code_page);
 161         reboot_code_buffer = phys_to_virt(reboot_code_buffer_phys);
 162
 163         kexec_image_info(kimage);
 164
 165         pr_debug("%s:%d: control_code_page:        %p\n", __func__, __LINE__,
 166                 kimage->control_code_page);
 167         pr_debug("%s:%d: reboot_code_buffer_phys:  %pa\n", __func__, __LINE__,
 168                 &reboot_code_buffer_phys);
 169         pr_debug("%s:%d: reboot_code_buffer:       %p\n", __func__, __LINE__,
 170                 reboot_code_buffer);
 171         pr_debug("%s:%d: relocate_new_kernel:      %p\n", __func__, __LINE__,
 172                 arm64_relocate_new_kernel);
 173         pr_debug("%s:%d: relocate_new_kernel_size: 0x%lx(%lu) bytes\n",
 174                 __func__, __LINE__, arm64_relocate_new_kernel_size,
 175                 arm64_relocate_new_kernel_size);
 176
 177         /*
 178          * Copy arm64_relocate_new_kernel to the reboot_code_buffer for use
 179          * after the kernel is shut down.
 180          */
 181         memcpy(reboot_code_buffer, arm64_relocate_new_kernel,
 182                 arm64_relocate_new_kernel_size);
 183
 184         /* Flush the reboot_code_buffer in preparation for its execution. */
 185         __flush_dcache_area(reboot_code_buffer, arm64_relocate_new_kernel_size);
 186         flush_icache_range((uintptr_t)reboot_code_buffer,
 187                 arm64_relocate_new_kernel_size);
 188
 189         /* Flush the kimage list and its buffers. */
 190         kexec_list_flush(kimage);
 191
 192         /* Flush the new image if already in place. */
 193         if ((kimage != kexec_crash_image) && (kimage->head & IND_DONE))
 194                 kexec_segment_flush(kimage);
 195
 196         pr_info("Bye!\n");
 197
 198         /* Disable all DAIF exceptions. */
 199         asm volatile ("msr daifset, #0xf" : : : "memory");
 200
 201         /*
 202          * cpu_soft_restart will shutdown the MMU, disable data caches, then
 203          * transfer control to the reboot_code_buffer which contains a copy of
 204          * the arm64_relocate_new_kernel routine.  arm64_relocate_new_kernel
 205          * uses physical addressing to relocate the new image to its final
 206          * position and transfers control to the image entry point when the
 207          * relocation is complete.
 208          */
 209
 210         cpu_soft_restart(kimage != kexec_crash_image,
 211                 reboot_code_buffer_phys, kimage->head, kimage->start, 0);
 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 in kexec_reserve_crashkres_pages().
 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                 ClearPageReserved(page);
 351                 free_reserved_page(page);
 352         }
 353 }
 354 #endif /* CONFIG_HIBERNATION */
 355
 356 void arch_crash_save_vmcoreinfo(void)
 357 {
 358         VMCOREINFO_NUMBER(VA_BITS);
 359         /* Please note VMCOREINFO_NUMBER() uses "%d", not "%x" */
 360         vmcoreinfo_append_str("NUMBER(kimage_voffset)=0x%llx\n",
 361                                                 kimage_voffset);
 362         vmcoreinfo_append_str("NUMBER(PHYS_OFFSET)=0x%llx\n",
 363                                                 PHYS_OFFSET);
 364 }