text: /*
   * kexec for arm64
   *
   * Copyright (C) Linaro.
   * Copyright (C) Huawei Futurewei Technologies.
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License version 2 as
   * published by the Free Software Foundation.
   */
  
  #include <linux/interrupt.h>
  #include <linux/irq.h>
  #include <linux/kernel.h>
  #include <linux/kexec.h>
  #include <linux/page-flags.h>
  #include <linux/smp.h>
  
  #include <asm/cacheflush.h>
  #include <asm/cpu_ops.h>
  #include <asm/daifflags.h>
  #include <asm/memory.h>
  #include <asm/mmu.h>
  #include <asm/mmu_context.h>
  #include <asm/page.h>
  
  #include "cpu-reset.h"
  
  /* Global variables for the arm64_relocate_new_kernel routine. */
  extern const unsigned char arm64_relocate_new_kernel[];
  extern const unsigned long arm64_relocate_new_kernel_size;
  
  /**
   * kexec_image_info - For debugging output.
   */
  #define kexec_image_info(_i) _kexec_image_info(__func__, __LINE__, _i)
  static void _kexec_image_info(const char *func, int line,
  	const struct kimage *kimage)
  {
  	unsigned long i;
  
  	pr_debug("%s:%d:\n", func, line);
  	pr_debug("  kexec kimage info:\n");
  	pr_debug("    type:        %d\n", kimage->type);
  	pr_debug("    start:       %lx\n", kimage->start);
  	pr_debug("    head:        %lx\n", kimage->head);
  	pr_debug("    nr_segments: %lu\n", kimage->nr_segments);
  
  	for (i = 0; i < kimage->nr_segments; i++) {
  		pr_debug("      segment[%lu]: %016lx - %016lx, 0x%lx bytes, %lu pages\n",
  			i,
  			kimage->segment[i].mem,
  			kimage->segment[i].mem + kimage->segment[i].memsz,
  			kimage->segment[i].memsz,
  			kimage->segment[i].memsz /  PAGE_SIZE);
  	}
  }
  
  void machine_kexec_cleanup(struct kimage *kimage)
  {
  	/* Empty routine needed to avoid build errors. */
  }
  
  /**
   * machine_kexec_prepare - Prepare for a kexec reboot.
   *
   * Called from the core kexec code when a kernel image is loaded.
   * Forbid loading a kexec kernel if we have no way of hotplugging cpus or cpus
   * are stuck in the kernel. This avoids a panic once we hit machine_kexec().
   */
  int machine_kexec_prepare(struct kimage *kimage)
  {
  	kexec_image_info(kimage);
  
  	if (kimage->type != KEXEC_TYPE_CRASH && cpus_are_stuck_in_kernel()) {
  		pr_err("Can't kexec: CPUs are stuck in the kernel.\n");
  		return -EBUSY;
  	}
  
  	return 0;
  }
  
  /**
   * kexec_list_flush - Helper to flush the kimage list and source pages to PoC.
   */
  static void kexec_list_flush(struct kimage *kimage)
  {
  	kimage_entry_t *entry;
  
  	for (entry = &kimage->head; ; entry++) {
  		unsigned int flag;
  		void *addr;
  
  		/* flush the list entries. */
  		__flush_dcache_area(entry, sizeof(kimage_entry_t));
  
  		flag = *entry & IND_FLAGS;
  		if (flag == IND_DONE)
  			break;
  
  		addr = phys_to_virt(*entry & PAGE_MASK);
  
  		switch (flag) {
  		case IND_INDIRECTION:
  			/* Set entry point just before the new list page. */
  			entry = (kimage_entry_t *)addr - 1;
  			break;
  		case IND_SOURCE:
  			/* flush the source pages. */
  			__flush_dcache_area(addr, PAGE_SIZE);
  			break;
  		case IND_DESTINATION:
  			break;
  		default:
  			BUG();
  		}
  	}
  }
  
  /**
   * kexec_segment_flush - Helper to flush the kimage segments to PoC.
   */
  static void kexec_segment_flush(const struct kimage *kimage)
  {
  	unsigned long i;
  
  	pr_debug("%s:\n", __func__);
  
  	for (i = 0; i < kimage->nr_segments; i++) {
  		pr_debug("  segment[%lu]: %016lx - %016lx, 0x%lx bytes, %lu pages\n",
  			i,
  			kimage->segment[i].mem,
  			kimage->segment[i].mem + kimage->segment[i].memsz,
  			kimage->segment[i].memsz,
  			kimage->segment[i].memsz /  PAGE_SIZE);
  
  		__flush_dcache_area(phys_to_virt(kimage->segment[i].mem),
  			kimage->segment[i].memsz);
  	}
  }
  
  /**
   * machine_kexec - Do the kexec reboot.
   *
   * Called from the core kexec code for a sys_reboot with LINUX_REBOOT_CMD_KEXEC.
   */
  void machine_kexec(struct kimage *kimage)
  {
  	phys_addr_t reboot_code_buffer_phys;
  	void *reboot_code_buffer;
  	bool in_kexec_crash = (kimage == kexec_crash_image);
  	bool stuck_cpus = cpus_are_stuck_in_kernel();
  
  	/*
  	 * New cpus may have become stuck_in_kernel after we loaded the image.
  	 */
  	BUG_ON(!in_kexec_crash && (stuck_cpus || (num_online_cpus() > 1)));
  	WARN(in_kexec_crash && (stuck_cpus || smp_crash_stop_failed()),
  		"Some CPUs may be stale, kdump will be unreliable.\n");
  
  	reboot_code_buffer_phys = page_to_phys(kimage->control_code_page);
  	reboot_code_buffer = phys_to_virt(reboot_code_buffer_phys);
  
  	kexec_image_info(kimage);
  
  	pr_debug("%s:%d: control_code_page:        %p\n", __func__, __LINE__,
  		kimage->control_code_page);
  	pr_debug("%s:%d: reboot_code_buffer_phys:  %pa\n", __func__, __LINE__,
  		&reboot_code_buffer_phys);
  	pr_debug("%s:%d: reboot_code_buffer:       %p\n", __func__, __LINE__,
  		reboot_code_buffer);
  	pr_debug("%s:%d: relocate_new_kernel:      %p\n", __func__, __LINE__,
  		arm64_relocate_new_kernel);
  	pr_debug("%s:%d: relocate_new_kernel_size: 0x%lx(%lu) bytes\n",
  		__func__, __LINE__, arm64_relocate_new_kernel_size,
  		arm64_relocate_new_kernel_size);
  
  	/*
  	 * Copy arm64_relocate_new_kernel to the reboot_code_buffer for use
  	 * after the kernel is shut down.
  	 */
  	memcpy(reboot_code_buffer, arm64_relocate_new_kernel,
  		arm64_relocate_new_kernel_size);
  
  	/* Flush the reboot_code_buffer in preparation for its execution. */
  	__flush_dcache_area(reboot_code_buffer, arm64_relocate_new_kernel_size);
  
  	/*
  	 * Although we've killed off the secondary CPUs, we don't update
  	 * the online mask if we're handling a crash kernel and consequently
  	 * need to avoid flush_icache_range(), which will attempt to IPI
  	 * the offline CPUs. Therefore, we must use the __* variant here.
  	 */
  	__flush_icache_range((uintptr_t)reboot_code_buffer,
  			     arm64_relocate_new_kernel_size);
  
  	/* Flush the kimage list and its buffers. */
  	kexec_list_flush(kimage);
  
  	/* Flush the new image if already in place. */
  	if ((kimage != kexec_crash_image) && (kimage->head & IND_DONE))
  		kexec_segment_flush(kimage);
  
  	pr_info("Bye!\n");
  
  	local_daif_mask();
  
  	/*
  	 * cpu_soft_restart will shutdown the MMU, disable data caches, then
  	 * transfer control to the reboot_code_buffer which contains a copy of
  	 * the arm64_relocate_new_kernel routine.  arm64_relocate_new_kernel
  	 * uses physical addressing to relocate the new image to its final
  	 * position and transfers control to the image entry point when the
  	 * relocation is complete.
  	 * In kexec case, kimage->start points to purgatory assuming that
  	 * kernel entry and dtb address are embedded in purgatory by
  	 * userspace (kexec-tools).
  	 * In kexec_file case, the kernel starts directly without purgatory.
  	 */
  	cpu_soft_restart(reboot_code_buffer_phys, kimage->head, kimage->start,
  #ifdef CONFIG_KEXEC_FILE
  						kimage->arch.dtb_mem);
  #else
  						0);
  #endif
  
  	BUG(); /* Should never get here. */
  }
  
  static void machine_kexec_mask_interrupts(void)
  {
  	unsigned int i;
  	struct irq_desc *desc;
  
  	for_each_irq_desc(i, desc) {
  		struct irq_chip *chip;
  		int ret;
  
  		chip = irq_desc_get_chip(desc);
  		if (!chip)
  			continue;
  
  		/*
  		 * First try to remove the active state. If this
  		 * fails, try to EOI the interrupt.
  		 */
  		ret = irq_set_irqchip_state(i, IRQCHIP_STATE_ACTIVE, false);
  
  		if (ret && irqd_irq_inprogress(&desc->irq_data) &&
  		    chip->irq_eoi)
  			chip->irq_eoi(&desc->irq_data);
  
  		if (chip->irq_mask)
  			chip->irq_mask(&desc->irq_data);
  
  		if (chip->irq_disable && !irqd_irq_disabled(&desc->irq_data))
  			chip->irq_disable(&desc->irq_data);
  	}
  }
  
  /**
   * machine_crash_shutdown - shutdown non-crashing cpus and save registers
   */
  void machine_crash_shutdown(struct pt_regs *regs)
  {
  	local_irq_disable();
  
  	/* shutdown non-crashing cpus */
  	crash_smp_send_stop();
  
  	/* for crashing cpu */
  	crash_save_cpu(regs, smp_processor_id());
  	machine_kexec_mask_interrupts();
  
  	pr_info("Starting crashdump kernel...\n");
  }
  
  void arch_kexec_protect_crashkres(void)
  {
  	int i;
  
  	kexec_segment_flush(kexec_crash_image);
  
  	for (i = 0; i < kexec_crash_image->nr_segments; i++)
  		set_memory_valid(
  			__phys_to_virt(kexec_crash_image->segment[i].mem),
  			kexec_crash_image->segment[i].memsz >> PAGE_SHIFT, 0);
  }
  
  void arch_kexec_unprotect_crashkres(void)
  {
  	int i;
  
  	for (i = 0; i < kexec_crash_image->nr_segments; i++)
  		set_memory_valid(
  			__phys_to_virt(kexec_crash_image->segment[i].mem),
  			kexec_crash_image->segment[i].memsz >> PAGE_SHIFT, 1);
  }
  
  #ifdef CONFIG_HIBERNATION
  /*
   * To preserve the crash dump kernel image, the relevant memory segments
   * should be mapped again around the hibernation.
   */
  void crash_prepare_suspend(void)
  {
  	if (kexec_crash_image)
  		arch_kexec_unprotect_crashkres();
  }
  
  void crash_post_resume(void)
  {
  	if (kexec_crash_image)
  		arch_kexec_protect_crashkres();
  }
  
  /*
   * crash_is_nosave
   *
   * Return true only if a page is part of reserved memory for crash dump kernel,
   * but does not hold any data of loaded kernel image.
   *
   * Note that all the pages in crash dump kernel memory have been initially
   * marked as Reserved as memory was allocated via memblock_reserve().
   *
   * In hibernation, the pages which are Reserved and yet "nosave" are excluded
   * from the hibernation iamge. crash_is_nosave() does thich check for crash
   * dump kernel and will reduce the total size of hibernation image.
   */
  
  bool crash_is_nosave(unsigned long pfn)
  {
  	int i;
  	phys_addr_t addr;
  
  	if (!crashk_res.end)
  		return false;
  
  	/* in reserved memory? */
  	addr = __pfn_to_phys(pfn);
  	if ((addr < crashk_res.start) || (crashk_res.end < addr))
  		return false;
  
  	if (!kexec_crash_image)
  		return true;
  
  	/* not part of loaded kernel image? */
  	for (i = 0; i < kexec_crash_image->nr_segments; i++)
  		if (addr >= kexec_crash_image->segment[i].mem &&
  				addr < (kexec_crash_image->segment[i].mem +
  					kexec_crash_image->segment[i].memsz))
  			return false;
  
  	return true;
  }
  
  void crash_free_reserved_phys_range(unsigned long begin, unsigned long end)
  {
  	unsigned long addr;
  	struct page *page;
  
  	for (addr = begin; addr < end; addr += PAGE_SIZE) {
  		page = phys_to_page(addr);
  		free_reserved_page(page);
  	}
  }
  #endif /* CONFIG_HIBERNATION */
  