1 files changed, 287 insertions, 0 deletions
diff --git a/arch/s390/kernel/machine_kexec.c b/arch/s390/kernel/machine_kexec.c
new file mode 100644
index 000000000..d91989c7b
--- /dev/null
+++ b/arch/s390/kernel/machine_kexec.c
@@ -0,0 +1,287 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright IBM Corp. 2005, 2011
+ *
+ * Author(s): Rolf Adelsberger,
+ *	      Heiko Carstens <heiko.carstens@de.ibm.com>
+ *	      Michael Holzheu <holzheu@linux.vnet.ibm.com>
+ */
+
+#include <linux/device.h>
+#include <linux/mm.h>
+#include <linux/kexec.h>
+#include <linux/delay.h>
+#include <linux/reboot.h>
+#include <linux/ftrace.h>
+#include <linux/debug_locks.h>
+#include <asm/cio.h>
+#include <asm/setup.h>
+#include <asm/smp.h>
+#include <asm/ipl.h>
+#include <asm/diag.h>
+#include <asm/elf.h>
+#include <asm/asm-offsets.h>
+#include <asm/cacheflush.h>
+#include <asm/os_info.h>
+#include <asm/set_memory.h>
+#include <asm/stacktrace.h>
+#include <asm/switch_to.h>
+#include <asm/nmi.h>
+
+typedef void (*relocate_kernel_t)(kimage_entry_t *, unsigned long);
+
+extern const unsigned char relocate_kernel[];
+extern const unsigned long long relocate_kernel_len;
+
+#ifdef CONFIG_CRASH_DUMP
+
+/*
+ * Reset the system, copy boot CPU registers to absolute zero,
+ * and jump to the kdump image
+ */
+static void __do_machine_kdump(void *image)
+{
+	int (*start_kdump)(int);
+	unsigned long prefix;
+
+	/* store_status() saved the prefix register to lowcore */
+	prefix = (unsigned long) S390_lowcore.prefixreg_save_area;
+
+	/* Now do the reset  */
+	s390_reset_system();
+
+	/*
+	 * Copy dump CPU store status info to absolute zero.
+	 * This need to be done *after* s390_reset_system set the
+	 * prefix register of this CPU to zero
+	 */
+	memcpy((void *) __LC_FPREGS_SAVE_AREA,
+	       (void *)(prefix + __LC_FPREGS_SAVE_AREA), 512);
+
+	__load_psw_mask(PSW_MASK_BASE | PSW_DEFAULT_KEY | PSW_MASK_EA | PSW_MASK_BA);
+	start_kdump = (void *)((struct kimage *) image)->start;
+	start_kdump(1);
+
+	/* Die if start_kdump returns */
+	disabled_wait();
+}
+
+/*
+ * Start kdump: create a LGR log entry, store status of all CPUs and
+ * branch to __do_machine_kdump.
+ */
+static noinline void __machine_kdump(void *image)
+{
+	struct mcesa *mcesa;
+	union ctlreg2 cr2_old, cr2_new;
+	int this_cpu, cpu;
+
+	lgr_info_log();
+	/* Get status of the other CPUs */
+	this_cpu = smp_find_processor_id(stap());
+	for_each_online_cpu(cpu) {
+		if (cpu == this_cpu)
+			continue;
+		if (smp_store_status(cpu))
+			continue;
+	}
+	/* Store status of the boot CPU */
+	mcesa = (struct mcesa *)(S390_lowcore.mcesad & MCESA_ORIGIN_MASK);
+	if (MACHINE_HAS_VX)
+		save_vx_regs((__vector128 *) mcesa->vector_save_area);
+	if (MACHINE_HAS_GS) {
+		__ctl_store(cr2_old.val, 2, 2);
+		cr2_new = cr2_old;
+		cr2_new.gse = 1;
+		__ctl_load(cr2_new.val, 2, 2);
+		save_gs_cb((struct gs_cb *) mcesa->guarded_storage_save_area);
+		__ctl_load(cr2_old.val, 2, 2);
+	}
+	/*
+	 * To create a good backchain for this CPU in the dump store_status
+	 * is passed the address of a function. The address is saved into
+	 * the PSW save area of the boot CPU and the function is invoked as
+	 * a tail call of store_status. The backchain in the dump will look
+	 * like this:
+	 *   restart_int_handler ->  __machine_kexec -> __do_machine_kdump
+	 * The call to store_status() will not return.
+	 */
+	store_status(__do_machine_kdump, image);
+}
+
+static unsigned long do_start_kdump(unsigned long addr)
+{
+	struct kimage *image = (struct kimage *) addr;
+	int (*start_kdump)(int) = (void *)image->start;
+	int rc;
+
+	__arch_local_irq_stnsm(0xfb); /* disable DAT */
+	rc = start_kdump(0);
+	__arch_local_irq_stosm(0x04); /* enable DAT */
+	return rc;
+}
+
+#endif /* CONFIG_CRASH_DUMP */
+
+/*
+ * Check if kdump checksums are valid: We call purgatory with parameter "0"
+ */
+static bool kdump_csum_valid(struct kimage *image)
+{
+#ifdef CONFIG_CRASH_DUMP
+	int rc;
+
+	preempt_disable();
+	rc = CALL_ON_STACK(do_start_kdump, S390_lowcore.nodat_stack, 1, image);
+	preempt_enable();
+	return rc == 0;
+#else
+	return false;
+#endif
+}
+
+#ifdef CONFIG_CRASH_DUMP
+
+void crash_free_reserved_phys_range(unsigned long begin, unsigned long end)
+{
+	unsigned long addr, size;
+
+	for (addr = begin; addr < end; addr += PAGE_SIZE)
+		free_reserved_page(pfn_to_page(addr >> PAGE_SHIFT));
+	size = begin - crashk_res.start;
+	if (size)
+		os_info_crashkernel_add(crashk_res.start, size);
+	else
+		os_info_crashkernel_add(0, 0);
+}
+
+static void crash_protect_pages(int protect)
+{
+	unsigned long size;
+
+	if (!crashk_res.end)
+		return;
+	size = resource_size(&crashk_res);
+	if (protect)
+		set_memory_ro(crashk_res.start, size >> PAGE_SHIFT);
+	else
+		set_memory_rw(crashk_res.start, size >> PAGE_SHIFT);
+}
+
+void arch_kexec_protect_crashkres(void)
+{
+	crash_protect_pages(1);
+}
+
+void arch_kexec_unprotect_crashkres(void)
+{
+	crash_protect_pages(0);
+}
+
+#endif
+
+/*
+ * Give back memory to hypervisor before new kdump is loaded
+ */
+static int machine_kexec_prepare_kdump(void)
+{
+#ifdef CONFIG_CRASH_DUMP
+	if (MACHINE_IS_VM)
+		diag10_range(PFN_DOWN(crashk_res.start),
+			     PFN_DOWN(crashk_res.end - crashk_res.start + 1));
+	return 0;
+#else
+	return -EINVAL;
+#endif
+}
+
+int machine_kexec_prepare(struct kimage *image)
+{
+	void *reboot_code_buffer;
+
+	if (image->type == KEXEC_TYPE_CRASH)
+		return machine_kexec_prepare_kdump();
+
+	/* We don't support anything but the default image type for now. */
+	if (image->type != KEXEC_TYPE_DEFAULT)
+		return -EINVAL;
+
+	/* Get the destination where the assembler code should be copied to.*/
+	reboot_code_buffer = (void *) page_to_phys(image->control_code_page);
+
+	/* Then copy it */
+	memcpy(reboot_code_buffer, relocate_kernel, relocate_kernel_len);
+	return 0;
+}
+
+void machine_kexec_cleanup(struct kimage *image)
+{
+}
+
+void arch_crash_save_vmcoreinfo(void)
+{
+	VMCOREINFO_SYMBOL(lowcore_ptr);
+	VMCOREINFO_SYMBOL(high_memory);
+	VMCOREINFO_LENGTH(lowcore_ptr, NR_CPUS);
+	vmcoreinfo_append_str("SDMA=%lx\n", __sdma);
+	vmcoreinfo_append_str("EDMA=%lx\n", __edma);
+	vmcoreinfo_append_str("KERNELOFFSET=%lx\n", kaslr_offset());
+	mem_assign_absolute(S390_lowcore.vmcore_info, paddr_vmcoreinfo_note());
+}
+
+void machine_shutdown(void)
+{
+}
+
+void machine_crash_shutdown(struct pt_regs *regs)
+{
+	set_os_info_reipl_block();
+}
+
+/*
+ * Do normal kexec
+ */
+static void __do_machine_kexec(void *data)
+{
+	relocate_kernel_t data_mover;
+	struct kimage *image = data;
+
+	s390_reset_system();
+	data_mover = (relocate_kernel_t) page_to_phys(image->control_code_page);
+
+	__arch_local_irq_stnsm(0xfb); /* disable DAT - avoid no-execute */
+	/* Call the moving routine */
+	(*data_mover)(&image->head, image->start);
+
+	/* Die if kexec returns */
+	disabled_wait();
+}
+
+/*
+ * Reset system and call either kdump or normal kexec
+ */
+static void __machine_kexec(void *data)
+{
+	__arch_local_irq_stosm(0x04); /* enable DAT */
+	pfault_fini();
+	tracing_off();
+	debug_locks_off();
+#ifdef CONFIG_CRASH_DUMP
+	if (((struct kimage *) data)->type == KEXEC_TYPE_CRASH)
+		__machine_kdump(data);
+#endif
+	__do_machine_kexec(data);
+}
+
+/*
+ * Do either kdump or normal kexec. In case of kdump we first ask
+ * purgatory, if kdump checksums are valid.
+ */
+void machine_kexec(struct kimage *image)
+{
+	if (image->type == KEXEC_TYPE_CRASH && !kdump_csum_valid(image))
+		return;
+	tracer_disable();
+	smp_send_stop();
+	smp_call_ipl_cpu(__machine_kexec, image);
+}