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/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 */