arch/arm64/kernel/machine_kexec.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * kexec for arm64
  *
  * Copyright (C) Linaro.
  * Copyright (C) Huawei Futurewei Technologies.
  */

 #include <linux/interrupt.h>
 #include <linux/irq.h>
 #include <linux/kernel.h>
 #include <linux/kexec.h>
 #include <linux/page-flags.h>
 #include <linux/set_memory.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);
 	pr_debug("    kern_reloc: %pa\n", &kimage->arch.kern_reloc);

 	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. */
 }

 int machine_kexec_post_load(struct kimage *kimage)
 {
 	void *reloc_code = page_to_virt(kimage->control_code_page);

 	memcpy(reloc_code, arm64_relocate_new_kernel,
 	       arm64_relocate_new_kernel_size);
 	kimage->arch.kern_reloc = __pa(reloc_code);
 	kexec_image_info(kimage);

 	/*
 	 * For execution with the MMU off, reloc_code needs to be cleaned to the
 	 * PoC and invalidated from the I-cache.
 	 */
 	dcache_clean_inval_poc((unsigned long)reloc_code,
 			    (unsigned long)reloc_code +
 				    arm64_relocate_new_kernel_size);
 	icache_inval_pou((uintptr_t)reloc_code,
 				(uintptr_t)reloc_code +
 					arm64_relocate_new_kernel_size);

 	return 0;
 }

 /**
  * 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)
 {
 	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;
 		unsigned long addr;

 		/* flush the list entries. */
 		dcache_clean_inval_poc((unsigned long)entry,
 				    (unsigned long)entry +
 					    sizeof(kimage_entry_t));

 		flag = *entry & IND_FLAGS;
 		if (flag == IND_DONE)
 			break;

 		addr = (unsigned long)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. */
 			dcache_clean_inval_poc(addr, 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);

 		dcache_clean_inval_poc(
 			(unsigned long)phys_to_virt(kimage->segment[i].mem),
 			(unsigned long)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)
 {
 	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");

 	/* 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 kern_reloc 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(kimage->arch.kern_reloc, kimage->head, kimage->start,
 			 kimage->arch.dtb_mem);

 	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 */
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* kexec for arm64
	*
	* Copyright (C) Linaro.
	* Copyright (C) Huawei Futurewei Technologies.
	*/

	#include <linux/interrupt.h>
	#include <linux/irq.h>
	#include <linux/kernel.h>
	#include <linux/kexec.h>
	#include <linux/page-flags.h>
	#include <linux/set_memory.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);
	pr_debug(" kern_reloc: %pa\n", &kimage->arch.kern_reloc);

	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. */
	}

	int machine_kexec_post_load(struct kimage *kimage)
	{
	void *reloc_code = page_to_virt(kimage->control_code_page);

	memcpy(reloc_code, arm64_relocate_new_kernel,
	arm64_relocate_new_kernel_size);
	kimage->arch.kern_reloc = __pa(reloc_code);
	kexec_image_info(kimage);

	/*
	* For execution with the MMU off, reloc_code needs to be cleaned to the
	* PoC and invalidated from the I-cache.
	*/
	dcache_clean_inval_poc((unsigned long)reloc_code,
	(unsigned long)reloc_code +
	arm64_relocate_new_kernel_size);
	icache_inval_pou((uintptr_t)reloc_code,
	(uintptr_t)reloc_code +
	arm64_relocate_new_kernel_size);

	return 0;
	}

	/**
	* 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)
	{
	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;
	unsigned long addr;

	/* flush the list entries. */
	dcache_clean_inval_poc((unsigned long)entry,
	(unsigned long)entry +
	sizeof(kimage_entry_t));

	flag = *entry & IND_FLAGS;
	if (flag == IND_DONE)
	break;

	addr = (unsigned long)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. */
	dcache_clean_inval_poc(addr, 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);

	dcache_clean_inval_poc(
	(unsigned long)phys_to_virt(kimage->segment[i].mem),
	(unsigned long)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)
	{
	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");

	/* 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 kern_reloc 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(kimage->arch.kern_reloc, kimage->head, kimage->start,
	kimage->arch.dtb_mem);

	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 */