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