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/reboot.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 <asm/sections.h>
 #include <asm/trans_pgd.h>

 /**
  * 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)
 {
 	kexec_dprintk("%s:%d:\n", func, line);
 	kexec_dprintk("  kexec kimage info:\n");
 	kexec_dprintk("    type:        %d\n", kimage->type);
 	kexec_dprintk("    head:        %lx\n", kimage->head);
 	kexec_dprintk("    kern_reloc: %pa\n", &kimage->arch.kern_reloc);
 	kexec_dprintk("    el2_vectors: %pa\n", &kimage->arch.el2_vectors);
 }

 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)
 {
 	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_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);
 	}
 }

 /* Allocates pages for kexec page table */
 static void *kexec_page_alloc(void *arg)
 {
 	struct kimage *kimage = arg;
 	struct page *page = kimage_alloc_control_pages(kimage, 0);
 	void *vaddr = NULL;

 	if (!page)
 		return NULL;

 	vaddr = page_address(page);
 	memset(vaddr, 0, PAGE_SIZE);

 	return vaddr;
 }

 int machine_kexec_post_load(struct kimage *kimage)
 {
 	int rc;
 	pgd_t *trans_pgd;
 	void *reloc_code = page_to_virt(kimage->control_code_page);
 	long reloc_size;
 	struct trans_pgd_info info = {
 		.trans_alloc_page	= kexec_page_alloc,
 		.trans_alloc_arg	= kimage,
 	};

 	/* If in place, relocation is not used, only flush next kernel */
 	if (kimage->head & IND_DONE) {
 		kexec_segment_flush(kimage);
 		kexec_image_info(kimage);
 		return 0;
 	}

 	kimage->arch.el2_vectors = 0;
 	if (is_hyp_nvhe()) {
 		rc = trans_pgd_copy_el2_vectors(&info,
 						&kimage->arch.el2_vectors);
 		if (rc)
 			return rc;
 	}

 	/* Create a copy of the linear map */
 	trans_pgd = kexec_page_alloc(kimage);
 	if (!trans_pgd)
 		return -ENOMEM;
 	rc = trans_pgd_create_copy(&info, &trans_pgd, PAGE_OFFSET, PAGE_END);
 	if (rc)
 		return rc;
 	kimage->arch.ttbr1 = __pa(trans_pgd);
 	kimage->arch.zero_page = __pa_symbol(empty_zero_page);

 	reloc_size = __relocate_new_kernel_end - __relocate_new_kernel_start;
 	memcpy(reloc_code, __relocate_new_kernel_start, reloc_size);
 	kimage->arch.kern_reloc = __pa(reloc_code);
 	rc = trans_pgd_idmap_page(&info, &kimage->arch.ttbr0,
 				  &kimage->arch.t0sz, reloc_code);
 	if (rc)
 		return rc;
 	kimage->arch.phys_offset = virt_to_phys(kimage) - (long)kimage;

 	/* Flush the reloc_code in preparation for its execution. */
 	dcache_clean_inval_poc((unsigned long)reloc_code,
 			       (unsigned long)reloc_code + reloc_size);
 	icache_inval_pou((uintptr_t)reloc_code,
 			 (uintptr_t)reloc_code + reloc_size);
 	kexec_image_info(kimage);

 	return 0;
 }

 /**
  * 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");

 	pr_info("Bye!\n");

 	local_daif_mask();

 	/*
 	 * Both restart and kernel_reloc will shutdown the MMU, disable data
 	 * caches. However, restart will start new kernel or purgatory directly,
 	 * kernel_reloc contains the body of arm64_relocate_new_kernel
 	 * 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.
 	 */
 	if (kimage->head & IND_DONE) {
 		typeof(cpu_soft_restart) *restart;

 		cpu_install_idmap();
 		restart = (void *)__pa_symbol(cpu_soft_restart);
 		restart(is_hyp_nvhe(), kimage->start, kimage->arch.dtb_mem,
 			0, 0);
 	} else {
 		void (*kernel_reloc)(struct kimage *kimage);

 		if (is_hyp_nvhe())
 			__hyp_set_vectors(kimage->arch.el2_vectors);
 		cpu_install_ttbr0(kimage->arch.ttbr0, kimage->arch.t0sz);
 		kernel_reloc = (void *)kimage->arch.kern_reloc;
 		kernel_reloc(kimage);
 	}

 	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");
 }

 #if defined(CONFIG_CRASH_DUMP) && defined(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)) {
 		if (!crashk_low_res.end)
 			return false;

 		if ((addr < crashk_low_res.start) || (crashk_low_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/reboot.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 <asm/sections.h>
	#include <asm/trans_pgd.h>

	/**
	* 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)
	{
	kexec_dprintk("%s:%d:\n", func, line);
	kexec_dprintk(" kexec kimage info:\n");
	kexec_dprintk(" type: %d\n", kimage->type);
	kexec_dprintk(" head: %lx\n", kimage->head);
	kexec_dprintk(" kern_reloc: %pa\n", &kimage->arch.kern_reloc);
	kexec_dprintk(" el2_vectors: %pa\n", &kimage->arch.el2_vectors);
	}

	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)
	{
	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_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);
	}
	}

	/* Allocates pages for kexec page table */
	static void kexec_page_alloc(void arg)
	{
	struct kimage *kimage = arg;
	struct page *page = kimage_alloc_control_pages(kimage, 0);
	void *vaddr = NULL;

	if (!page)
	return NULL;

	vaddr = page_address(page);
	memset(vaddr, 0, PAGE_SIZE);

	return vaddr;
	}

	int machine_kexec_post_load(struct kimage *kimage)
	{
	int rc;
	pgd_t *trans_pgd;
	void *reloc_code = page_to_virt(kimage->control_code_page);
	long reloc_size;
	struct trans_pgd_info info = {
	.trans_alloc_page = kexec_page_alloc,
	.trans_alloc_arg = kimage,
	};

	/* If in place, relocation is not used, only flush next kernel */
	if (kimage->head & IND_DONE) {
	kexec_segment_flush(kimage);
	kexec_image_info(kimage);
	return 0;
	}

	kimage->arch.el2_vectors = 0;
	if (is_hyp_nvhe()) {
	rc = trans_pgd_copy_el2_vectors(&info,
	&kimage->arch.el2_vectors);
	if (rc)
	return rc;
	}

	/* Create a copy of the linear map */
	trans_pgd = kexec_page_alloc(kimage);
	if (!trans_pgd)
	return -ENOMEM;
	rc = trans_pgd_create_copy(&info, &trans_pgd, PAGE_OFFSET, PAGE_END);
	if (rc)
	return rc;
	kimage->arch.ttbr1 = __pa(trans_pgd);
	kimage->arch.zero_page = __pa_symbol(empty_zero_page);

	reloc_size = __relocate_new_kernel_end - __relocate_new_kernel_start;
	memcpy(reloc_code, __relocate_new_kernel_start, reloc_size);
	kimage->arch.kern_reloc = __pa(reloc_code);
	rc = trans_pgd_idmap_page(&info, &kimage->arch.ttbr0,
	&kimage->arch.t0sz, reloc_code);
	if (rc)
	return rc;
	kimage->arch.phys_offset = virt_to_phys(kimage) - (long)kimage;

	/* Flush the reloc_code in preparation for its execution. */
	dcache_clean_inval_poc((unsigned long)reloc_code,
	(unsigned long)reloc_code + reloc_size);
	icache_inval_pou((uintptr_t)reloc_code,
	(uintptr_t)reloc_code + reloc_size);
	kexec_image_info(kimage);

	return 0;
	}

	/**
	* 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");

	pr_info("Bye!\n");

	local_daif_mask();

	/*
	* Both restart and kernel_reloc will shutdown the MMU, disable data
	* caches. However, restart will start new kernel or purgatory directly,
	* kernel_reloc contains the body of arm64_relocate_new_kernel
	* 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.
	*/
	if (kimage->head & IND_DONE) {
	typeof(cpu_soft_restart) *restart;

	cpu_install_idmap();
	restart = (void *)__pa_symbol(cpu_soft_restart);
	restart(is_hyp_nvhe(), kimage->start, kimage->arch.dtb_mem,
	0, 0);
	} else {
	void (kernel_reloc)(struct kimage kimage);

	if (is_hyp_nvhe())
	__hyp_set_vectors(kimage->arch.el2_vectors);
	cpu_install_ttbr0(kimage->arch.ttbr0, kimage->arch.t0sz);
	kernel_reloc = (void *)kimage->arch.kern_reloc;
	kernel_reloc(kimage);
	}

	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");
	}

	#if defined(CONFIG_CRASH_DUMP) && defined(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)) {
	if (!crashk_low_res.end)
	return false;

	if ((addr < crashk_low_res.start) \|\| (crashk_low_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 */