arch/arm64/kernel/machine_kexec.c

   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 #include <asm/sections.h>
  25 #include <asm/trans_pgd.h>
  26
  27 /**
  28  * kexec_image_info - For debugging output.
  29  */
  30 #define kexec_image_info(_i) _kexec_image_info(__func__, __LINE__, _i)
  31 static void _kexec_image_info(const char *func, int line,
  32         const struct kimage *kimage)
  33 {
  34         unsigned long i;
  35
  36         pr_debug("%s:%d:\n", func, line);
  37         pr_debug("  kexec kimage info:\n");
  38         pr_debug("    type:        %d\n", kimage->type);
  39         pr_debug("    start:       %lx\n", kimage->start);
  40         pr_debug("    head:        %lx\n", kimage->head);
  41         pr_debug("    nr_segments: %lu\n", kimage->nr_segments);
  42         pr_debug("    dtb_mem: %pa\n", &kimage->arch.dtb_mem);
  43         pr_debug("    kern_reloc: %pa\n", &kimage->arch.kern_reloc);
  44         pr_debug("    el2_vectors: %pa\n", &kimage->arch.el2_vectors);
  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         if (kimage->type != KEXEC_TYPE_CRASH && cpus_are_stuck_in_kernel()) {
  71                 pr_err("Can't kexec: CPUs are stuck in the kernel.\n");
  72                 return -EBUSY;
  73         }
  74
  75         return 0;
  76 }
  77
  78 /**
  79  * kexec_segment_flush - Helper to flush the kimage segments to PoC.
  80  */
  81 static void kexec_segment_flush(const struct kimage *kimage)
  82 {
  83         unsigned long i;
  84
  85         pr_debug("%s:\n", __func__);
  86
  87         for (i = 0; i < kimage->nr_segments; i++) {
  88                 pr_debug("  segment[%lu]: %016lx - %016lx, 0x%lx bytes, %lu pages\n",
  89                         i,
  90                         kimage->segment[i].mem,
  91                         kimage->segment[i].mem + kimage->segment[i].memsz,
  92                         kimage->segment[i].memsz,
  93                         kimage->segment[i].memsz /  PAGE_SIZE);
  94
  95                 dcache_clean_inval_poc(
  96                         (unsigned long)phys_to_virt(kimage->segment[i].mem),
  97                         (unsigned long)phys_to_virt(kimage->segment[i].mem) +
  98                                 kimage->segment[i].memsz);
  99         }
 100 }
 101
 102 /* Allocates pages for kexec page table */
 103 static void *kexec_page_alloc(void *arg)
 104 {
 105         struct kimage *kimage = (struct kimage *)arg;
 106         struct page *page = kimage_alloc_control_pages(kimage, 0);
 107         void *vaddr = NULL;
 108
 109         if (!page)
 110                 return NULL;
 111
 112         vaddr = page_address(page);
 113         memset(vaddr, 0, PAGE_SIZE);
 114
 115         return vaddr;
 116 }
 117
 118 int machine_kexec_post_load(struct kimage *kimage)
 119 {
 120         int rc;
 121         pgd_t *trans_pgd;
 122         void *reloc_code = page_to_virt(kimage->control_code_page);
 123         long reloc_size;
 124         struct trans_pgd_info info = {
 125                 .trans_alloc_page       = kexec_page_alloc,
 126                 .trans_alloc_arg        = kimage,
 127         };
 128
 129         /* If in place, relocation is not used, only flush next kernel */
 130         if (kimage->head & IND_DONE) {
 131                 kexec_segment_flush(kimage);
 132                 kexec_image_info(kimage);
 133                 return 0;
 134         }
 135
 136         kimage->arch.el2_vectors = 0;
 137         if (is_hyp_nvhe()) {
 138                 rc = trans_pgd_copy_el2_vectors(&info,
 139                                                 &kimage->arch.el2_vectors);
 140                 if (rc)
 141                         return rc;
 142         }
 143
 144         /* Create a copy of the linear map */
 145         trans_pgd = kexec_page_alloc(kimage);
 146         if (!trans_pgd)
 147                 return -ENOMEM;
 148         rc = trans_pgd_create_copy(&info, &trans_pgd, PAGE_OFFSET, PAGE_END);
 149         if (rc)
 150                 return rc;
 151         kimage->arch.ttbr1 = __pa(trans_pgd);
 152         kimage->arch.zero_page = __pa_symbol(empty_zero_page);
 153
 154         reloc_size = __relocate_new_kernel_end - __relocate_new_kernel_start;
 155         memcpy(reloc_code, __relocate_new_kernel_start, reloc_size);
 156         kimage->arch.kern_reloc = __pa(reloc_code);
 157         rc = trans_pgd_idmap_page(&info, &kimage->arch.ttbr0,
 158                                   &kimage->arch.t0sz, reloc_code);
 159         if (rc)
 160                 return rc;
 161         kimage->arch.phys_offset = virt_to_phys(kimage) - (long)kimage;
 162
 163         /* Flush the reloc_code in preparation for its execution. */
 164         dcache_clean_inval_poc((unsigned long)reloc_code,
 165                                (unsigned long)reloc_code + reloc_size);
 166         icache_inval_pou((uintptr_t)reloc_code,
 167                          (uintptr_t)reloc_code + reloc_size);
 168         kexec_image_info(kimage);
 169
 170         return 0;
 171 }
 172
 173 /**
 174  * machine_kexec - Do the kexec reboot.
 175  *
 176  * Called from the core kexec code for a sys_reboot with LINUX_REBOOT_CMD_KEXEC.
 177  */
 178 void machine_kexec(struct kimage *kimage)
 179 {
 180         bool in_kexec_crash = (kimage == kexec_crash_image);
 181         bool stuck_cpus = cpus_are_stuck_in_kernel();
 182
 183         /*
 184          * New cpus may have become stuck_in_kernel after we loaded the image.
 185          */
 186         BUG_ON(!in_kexec_crash && (stuck_cpus || (num_online_cpus() > 1)));
 187         WARN(in_kexec_crash && (stuck_cpus || smp_crash_stop_failed()),
 188                 "Some CPUs may be stale, kdump will be unreliable.\n");
 189
 190         pr_info("Bye!\n");
 191
 192         local_daif_mask();
 193
 194         /*
 195          * Both restart and kernel_reloc will shutdown the MMU, disable data
 196          * caches. However, restart will start new kernel or purgatory directly,
 197          * kernel_reloc contains the body of arm64_relocate_new_kernel
 198          * In kexec case, kimage->start points to purgatory assuming that
 199          * kernel entry and dtb address are embedded in purgatory by
 200          * userspace (kexec-tools).
 201          * In kexec_file case, the kernel starts directly without purgatory.
 202          */
 203         if (kimage->head & IND_DONE) {
 204                 typeof(cpu_soft_restart) *restart;
 205
 206                 cpu_install_idmap();
 207                 restart = (void *)__pa_symbol(function_nocfi(cpu_soft_restart));
 208                 restart(is_hyp_nvhe(), kimage->start, kimage->arch.dtb_mem,
 209                         0, 0);
 210         } else {
 211                 void (*kernel_reloc)(struct kimage *kimage);
 212
 213                 if (is_hyp_nvhe())
 214                         __hyp_set_vectors(kimage->arch.el2_vectors);
 215                 cpu_install_ttbr0(kimage->arch.ttbr0, kimage->arch.t0sz);
 216                 kernel_reloc = (void *)kimage->arch.kern_reloc;
 217                 kernel_reloc(kimage);
 218         }
 219
 220         BUG(); /* Should never get here. */
 221 }
 222
 223 static void machine_kexec_mask_interrupts(void)
 224 {
 225         unsigned int i;
 226         struct irq_desc *desc;
 227
 228         for_each_irq_desc(i, desc) {
 229                 struct irq_chip *chip;
 230                 int ret;
 231
 232                 chip = irq_desc_get_chip(desc);
 233                 if (!chip)
 234                         continue;
 235
 236                 /*
 237                  * First try to remove the active state. If this
 238                  * fails, try to EOI the interrupt.
 239                  */
 240                 ret = irq_set_irqchip_state(i, IRQCHIP_STATE_ACTIVE, false);
 241
 242                 if (ret && irqd_irq_inprogress(&desc->irq_data) &&
 243                     chip->irq_eoi)
 244                         chip->irq_eoi(&desc->irq_data);
 245
 246                 if (chip->irq_mask)
 247                         chip->irq_mask(&desc->irq_data);
 248
 249                 if (chip->irq_disable && !irqd_irq_disabled(&desc->irq_data))
 250                         chip->irq_disable(&desc->irq_data);
 251         }
 252 }
 253
 254 /**
 255  * machine_crash_shutdown - shutdown non-crashing cpus and save registers
 256  */
 257 void machine_crash_shutdown(struct pt_regs *regs)
 258 {
 259         local_irq_disable();
 260
 261         /* shutdown non-crashing cpus */
 262         crash_smp_send_stop();
 263
 264         /* for crashing cpu */
 265         crash_save_cpu(regs, smp_processor_id());
 266         machine_kexec_mask_interrupts();
 267
 268         pr_info("Starting crashdump kernel...\n");
 269 }
 270
 271 void arch_kexec_protect_crashkres(void)
 272 {
 273         int i;
 274
 275         for (i = 0; i < kexec_crash_image->nr_segments; i++)
 276                 set_memory_valid(
 277                         __phys_to_virt(kexec_crash_image->segment[i].mem),
 278                         kexec_crash_image->segment[i].memsz >> PAGE_SHIFT, 0);
 279 }
 280
 281 void arch_kexec_unprotect_crashkres(void)
 282 {
 283         int i;
 284
 285         for (i = 0; i < kexec_crash_image->nr_segments; i++)
 286                 set_memory_valid(
 287                         __phys_to_virt(kexec_crash_image->segment[i].mem),
 288                         kexec_crash_image->segment[i].memsz >> PAGE_SHIFT, 1);
 289 }
 290
 291 #ifdef CONFIG_HIBERNATION
 292 /*
 293  * To preserve the crash dump kernel image, the relevant memory segments
 294  * should be mapped again around the hibernation.
 295  */
 296 void crash_prepare_suspend(void)
 297 {
 298         if (kexec_crash_image)
 299                 arch_kexec_unprotect_crashkres();
 300 }
 301
 302 void crash_post_resume(void)
 303 {
 304         if (kexec_crash_image)
 305                 arch_kexec_protect_crashkres();
 306 }
 307
 308 /*
 309  * crash_is_nosave
 310  *
 311  * Return true only if a page is part of reserved memory for crash dump kernel,
 312  * but does not hold any data of loaded kernel image.
 313  *
 314  * Note that all the pages in crash dump kernel memory have been initially
 315  * marked as Reserved as memory was allocated via memblock_reserve().
 316  *
 317  * In hibernation, the pages which are Reserved and yet "nosave" are excluded
 318  * from the hibernation iamge. crash_is_nosave() does thich check for crash
 319  * dump kernel and will reduce the total size of hibernation image.
 320  */
 321
 322 bool crash_is_nosave(unsigned long pfn)
 323 {
 324         int i;
 325         phys_addr_t addr;
 326
 327         if (!crashk_res.end)
 328                 return false;
 329
 330         /* in reserved memory? */
 331         addr = __pfn_to_phys(pfn);
 332         if ((addr < crashk_res.start) || (crashk_res.end < addr))
 333                 return false;
 334
 335         if (!kexec_crash_image)
 336                 return true;
 337
 338         /* not part of loaded kernel image? */
 339         for (i = 0; i < kexec_crash_image->nr_segments; i++)
 340                 if (addr >= kexec_crash_image->segment[i].mem &&
 341                                 addr < (kexec_crash_image->segment[i].mem +
 342                                         kexec_crash_image->segment[i].memsz))
 343                         return false;
 344
 345         return true;
 346 }
 347
 348 void crash_free_reserved_phys_range(unsigned long begin, unsigned long end)
 349 {
 350         unsigned long addr;
 351         struct page *page;
 352
 353         for (addr = begin; addr < end; addr += PAGE_SIZE) {
 354                 page = phys_to_page(addr);
 355                 free_reserved_page(page);
 356         }
 357 }
 358 #endif /* CONFIG_HIBERNATION */