v4.19.13 snapshot.
diff --git a/arch/s390/kernel/machine_kexec.c b/arch/s390/kernel/machine_kexec.c
new file mode 100644
index 0000000..b7020e7
--- /dev/null
+++ b/arch/s390/kernel/machine_kexec.c
@@ -0,0 +1,304 @@
+// 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 <linux/suspend.h>
+#include <asm/cio.h>
+#include <asm/setup.h>
+#include <asm/pgtable.h>
+#include <asm/pgalloc.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/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
+
+/*
+ * PM notifier callback for kdump
+ */
+static int machine_kdump_pm_cb(struct notifier_block *nb, unsigned long action,
+ void *ptr)
+{
+ switch (action) {
+ case PM_SUSPEND_PREPARE:
+ case PM_HIBERNATION_PREPARE:
+ if (kexec_crash_image)
+ arch_kexec_unprotect_crashkres();
+ break;
+ case PM_POST_SUSPEND:
+ case PM_POST_HIBERNATION:
+ if (kexec_crash_image)
+ arch_kexec_protect_crashkres();
+ break;
+ default:
+ return NOTIFY_DONE;
+ }
+ return NOTIFY_OK;
+}
+
+static int __init machine_kdump_pm_init(void)
+{
+ pm_notifier(machine_kdump_pm_cb, 0);
+ return 0;
+}
+arch_initcall(machine_kdump_pm_init);
+
+/*
+ * 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((unsigned long) __builtin_return_address(0));
+}
+
+/*
+ * 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);
+}
+#endif
+
+/*
+ * 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 (*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 == 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);
+ 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((unsigned long) __builtin_return_address(0));
+}
+
+/*
+ * 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);
+}