1 files changed, 239 insertions, 0 deletions
diff --git a/arch/riscv/kernel/machine_kexec.c b/arch/riscv/kernel/machine_kexec.c
new file mode 100644
index 000000000..2d139b724
--- /dev/null
+++ b/arch/riscv/kernel/machine_kexec.c
@@ -0,0 +1,239 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019 FORTH-ICS/CARV
+ *  Nick Kossifidis <mick@ics.forth.gr>
+ */
+
+#include <linux/kexec.h>
+#include <asm/kexec.h>		/* For riscv_kexec_* symbol defines */
+#include <linux/smp.h>		/* For smp_send_stop () */
+#include <asm/cacheflush.h>	/* For local_flush_icache_all() */
+#include <asm/barrier.h>	/* For smp_wmb() */
+#include <asm/page.h>		/* For PAGE_MASK */
+#include <linux/libfdt.h>	/* For fdt_check_header() */
+#include <asm/set_memory.h>	/* For set_memory_x() */
+#include <linux/compiler.h>	/* For unreachable() */
+#include <linux/cpu.h>		/* For cpu_down() */
+#include <linux/reboot.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+
+/*
+ * kexec_image_info - Print received image details
+ */
+static void
+kexec_image_info(const struct kimage *image)
+{
+	unsigned long i;
+
+	pr_debug("Kexec image info:\n");
+	pr_debug("\ttype:        %d\n", image->type);
+	pr_debug("\tstart:       %lx\n", image->start);
+	pr_debug("\thead:        %lx\n", image->head);
+	pr_debug("\tnr_segments: %lu\n", image->nr_segments);
+
+	for (i = 0; i < image->nr_segments; i++) {
+		pr_debug("\t    segment[%lu]: %016lx - %016lx", i,
+			image->segment[i].mem,
+			image->segment[i].mem + image->segment[i].memsz);
+		pr_debug("\t\t0x%lx bytes, %lu pages\n",
+			(unsigned long) image->segment[i].memsz,
+			(unsigned long) image->segment[i].memsz /  PAGE_SIZE);
+	}
+}
+
+/*
+ * machine_kexec_prepare - Initialize kexec
+ *
+ * This function is called from do_kexec_load, when the user has
+ * provided us with an image to be loaded. Its goal is to validate
+ * the image and prepare the control code buffer as needed.
+ * Note that kimage_alloc_init has already been called and the
+ * control buffer has already been allocated.
+ */
+int
+machine_kexec_prepare(struct kimage *image)
+{
+	struct kimage_arch *internal = &image->arch;
+	struct fdt_header fdt = {0};
+	void *control_code_buffer = NULL;
+	unsigned int control_code_buffer_sz = 0;
+	int i = 0;
+
+	kexec_image_info(image);
+
+	/* Find the Flattened Device Tree and save its physical address */
+	for (i = 0; i < image->nr_segments; i++) {
+		if (image->segment[i].memsz <= sizeof(fdt))
+			continue;
+
+		if (image->file_mode)
+			memcpy(&fdt, image->segment[i].buf, sizeof(fdt));
+		else if (copy_from_user(&fdt, image->segment[i].buf, sizeof(fdt)))
+			continue;
+
+		if (fdt_check_header(&fdt))
+			continue;
+
+		internal->fdt_addr = (unsigned long) image->segment[i].mem;
+		break;
+	}
+
+	if (!internal->fdt_addr) {
+		pr_err("Device tree not included in the provided image\n");
+		return -EINVAL;
+	}
+
+	/* Copy the assembler code for relocation to the control page */
+	if (image->type != KEXEC_TYPE_CRASH) {
+		control_code_buffer = page_address(image->control_code_page);
+		control_code_buffer_sz = page_size(image->control_code_page);
+
+		if (unlikely(riscv_kexec_relocate_size > control_code_buffer_sz)) {
+			pr_err("Relocation code doesn't fit within a control page\n");
+			return -EINVAL;
+		}
+
+		memcpy(control_code_buffer, riscv_kexec_relocate,
+			riscv_kexec_relocate_size);
+
+		/* Mark the control page executable */
+		set_memory_x((unsigned long) control_code_buffer, 1);
+	}
+
+	return 0;
+}
+
+
+/*
+ * machine_kexec_cleanup - Cleanup any leftovers from
+ *			   machine_kexec_prepare
+ *
+ * This function is called by kimage_free to handle any arch-specific
+ * allocations done on machine_kexec_prepare. Since we didn't do any
+ * allocations there, this is just an empty function. Note that the
+ * control buffer is freed by kimage_free.
+ */
+void
+machine_kexec_cleanup(struct kimage *image)
+{
+}
+
+
+/*
+ * machine_shutdown - Prepare for a kexec reboot
+ *
+ * This function is called by kernel_kexec just before machine_kexec
+ * below. Its goal is to prepare the rest of the system (the other
+ * harts and possibly devices etc) for a kexec reboot.
+ */
+void machine_shutdown(void)
+{
+	/*
+	 * No more interrupts on this hart
+	 * until we are back up.
+	 */
+	local_irq_disable();
+
+#if defined(CONFIG_HOTPLUG_CPU)
+	smp_shutdown_nonboot_cpus(smp_processor_id());
+#endif
+}
+
+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 - Prepare to kexec after a kernel crash
+ *
+ * This function is called by crash_kexec just before machine_kexec
+ * and its goal is to 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();
+
+	crash_save_cpu(regs, smp_processor_id());
+	machine_kexec_mask_interrupts();
+
+	pr_info("Starting crashdump kernel...\n");
+}
+
+/*
+ * machine_kexec - Jump to the loaded kimage
+ *
+ * This function is called by kernel_kexec which is called by the
+ * reboot system call when the reboot cmd is LINUX_REBOOT_CMD_KEXEC,
+ * or by crash_kernel which is called by the kernel's arch-specific
+ * trap handler in case of a kernel panic. It's the final stage of
+ * the kexec process where the pre-loaded kimage is ready to be
+ * executed. We assume at this point that all other harts are
+ * suspended and this hart will be the new boot hart.
+ */
+void __noreturn
+machine_kexec(struct kimage *image)
+{
+	struct kimage_arch *internal = &image->arch;
+	unsigned long jump_addr = (unsigned long) image->start;
+	unsigned long first_ind_entry = (unsigned long) &image->head;
+	unsigned long this_cpu_id = __smp_processor_id();
+	unsigned long this_hart_id = cpuid_to_hartid_map(this_cpu_id);
+	unsigned long fdt_addr = internal->fdt_addr;
+	void *control_code_buffer = page_address(image->control_code_page);
+	riscv_kexec_method kexec_method = NULL;
+
+#ifdef CONFIG_SMP
+	WARN(smp_crash_stop_failed(),
+		"Some CPUs may be stale, kdump will be unreliable.\n");
+#endif
+
+	if (image->type != KEXEC_TYPE_CRASH)
+		kexec_method = control_code_buffer;
+	else
+		kexec_method = (riscv_kexec_method) &riscv_kexec_norelocate;
+
+	pr_notice("Will call new kernel at %08lx from hart id %lx\n",
+		  jump_addr, this_hart_id);
+	pr_notice("FDT image at %08lx\n", fdt_addr);
+
+	/* Make sure the relocation code is visible to the hart */
+	local_flush_icache_all();
+
+	/* Jump to the relocation code */
+	pr_notice("Bye...\n");
+	kexec_method(first_ind_entry, jump_addr, fdt_addr,
+		     this_hart_id, kernel_map.va_pa_offset);
+	unreachable();
+}