text: /*
   * arch/s390/kernel/machine_kexec.c
   *
   * 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/pgtable.h>
  #include <asm/pgalloc.h>
  #include <asm/smp.h>
  #include <asm/reset.h>
  #include <asm/ipl.h>
  #include <asm/diag.h>
  #include <asm/asm-offsets.h>
  #include <asm/os_info.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
  
  void *fill_cpu_elf_notes(void *ptr, struct save_area *sa);
  
  /*
   * Create ELF notes for one CPU
   */
  static void add_elf_notes(int cpu)
  {
  	struct save_area *sa = (void *) 4608 + store_prefix();
  	void *ptr;
  
  	memcpy((void *) (4608UL + sa->pref_reg), sa, sizeof(*sa));
  	ptr = (u64 *) per_cpu_ptr(crash_notes, cpu);
  	ptr = fill_cpu_elf_notes(ptr, sa);
  	memset(ptr, 0, sizeof(struct elf_note));
  }
  
  /*
   * Initialize CPU ELF notes
   */
  void setup_regs(void)
  {
  	unsigned long sa = S390_lowcore.prefixreg_save_area + SAVE_AREA_BASE;
  	int cpu, this_cpu;
  
  	this_cpu = smp_find_processor_id(stap());
  	add_elf_notes(this_cpu);
  	for_each_online_cpu(cpu) {
  		if (cpu == this_cpu)
  			continue;
  		if (smp_store_status(cpu))
  			continue;
  		add_elf_notes(cpu);
  	}
  	/* Copy dump CPU store status info to absolute zero */
  	memcpy((void *) SAVE_AREA_BASE, (void *) sa, sizeof(struct save_area));
  }
  
  #endif
  
  /*
   * Start kdump: We expect here that a store status has been done on our CPU
   */
  static void __do_machine_kdump(void *image)
  {
  #ifdef CONFIG_CRASH_DUMP
  	int (*start_kdump)(int) = (void *)((struct kimage *) image)->start;
  
  	setup_regs();
  	__load_psw_mask(PSW_MASK_BASE | PSW_DEFAULT_KEY | PSW_MASK_EA | PSW_MASK_BA);
  	start_kdump(1);
  #endif
  }
  
  /*
   * Check if kdump checksums are valid: We call purgatory with parameter "0"
   */
  static int 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 : -EINVAL;
  #else
  	return -EINVAL;
  #endif
  }
  
  /*
   * Map or unmap crashkernel memory
   */
  static void crash_map_pages(int enable)
  {
  	unsigned long size = resource_size(&crashk_res);
  
  	BUG_ON(crashk_res.start % KEXEC_CRASH_MEM_ALIGN ||
  	       size % KEXEC_CRASH_MEM_ALIGN);
  	if (enable)
  		vmem_add_mapping(crashk_res.start, size);
  	else {
  		vmem_remove_mapping(crashk_res.start, size);
  		if (size)
  			os_info_crashkernel_add(crashk_res.start, size);
  		else
  			os_info_crashkernel_add(0, 0);
  	}
  }
  
  /*
   * Map crashkernel memory
   */
  void crash_map_reserved_pages(void)
  {
  	crash_map_pages(1);
  }
  
  /*
   * Unmap crashkernel memory
   */
  void crash_unmap_reserved_pages(void)
  {
  	crash_map_pages(0);
  }
  
  /*
   * 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;
  
  	/* Can't replace kernel image since it is read-only. */
  	if (ipl_flags & IPL_NSS_VALID)
  		return -ENOSYS;
  
  	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);
  }
  
  void machine_shutdown(void)
  {
  }
  
  /*
   * Do normal kexec
   */
  static void __do_machine_kexec(void *data)
  {
  	relocate_kernel_t data_mover;
  	struct kimage *image = data;
  
  	data_mover = (relocate_kernel_t) page_to_phys(image->control_code_page);
  
  	/* Call the moving routine */
  	(*data_mover)(&image->head, image->start);
  }
  
  /*
   * Reset system and call either kdump or normal kexec
   */
  static void __machine_kexec(void *data)
  {
  	struct kimage *image = data;
  
  	__arch_local_irq_stosm(0x04); /* enable DAT */
  	pfault_fini();
  	tracing_off();
  	debug_locks_off();
  	if (image->type == KEXEC_TYPE_CRASH) {
  		lgr_info_log();
  		s390_reset_system(__do_machine_kdump, data);
  	} else {
  		s390_reset_system(__do_machine_kexec, data);
  	}
  	disabled_wait((unsigned long) __builtin_return_address(0));
  }
  
  /*
   * 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);
  }
  