1 files changed, 353 insertions, 0 deletions
diff --git a/arch/arm64/kernel/machine_kexec.c b/arch/arm64/kernel/machine_kexec.c
new file mode 100644
index 000000000..a0b144cfa
--- /dev/null
+++ b/arch/arm64/kernel/machine_kexec.c
@@ -0,0 +1,353 @@
+// 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/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);
+
+	/*
+	 * 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,
+			     (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 */