text: /*
   * Copyright 2004 James Cleverdon, IBM.
   * Subject to the GNU Public License, v.2
   *
   * Flat APIC subarch code.
   *
   * Hacked for x86-64 by James Cleverdon from i386 architecture code by
   * Martin Bligh, Andi Kleen, James Bottomley, John Stultz, and
   * James Cleverdon.
   */
  #include <linux/errno.h>
  #include <linux/threads.h>
  #include <linux/cpumask.h>
  #include <linux/string.h>
  #include <linux/kernel.h>
  #include <linux/ctype.h>
  #include <linux/init.h>
  #include <linux/hardirq.h>
  #include <linux/module.h>
  #include <asm/smp.h>
  #include <asm/apic.h>
  #include <asm/ipi.h>
  
  #ifdef CONFIG_ACPI
  #include <acpi/acpi_bus.h>
  #endif
  
  static struct apic apic_physflat;
  static struct apic apic_flat;
  
  struct apic __read_mostly *apic = &apic_flat;
  EXPORT_SYMBOL_GPL(apic);
  
  static int flat_acpi_madt_oem_check(char *oem_id, char *oem_table_id)
  {
  	return 1;
  }
  
  static const struct cpumask *flat_target_cpus(void)
  {
  	return cpu_online_mask;
  }
  
  static void flat_vector_allocation_domain(int cpu, struct cpumask *retmask)
  {
  	/* Careful. Some cpus do not strictly honor the set of cpus
  	 * specified in the interrupt destination when using lowest
  	 * priority interrupt delivery mode.
  	 *
  	 * In particular there was a hyperthreading cpu observed to
  	 * deliver interrupts to the wrong hyperthread when only one
  	 * hyperthread was specified in the interrupt desitination.
  	 */
  	cpumask_clear(retmask);
  	cpumask_bits(retmask)[0] = APIC_ALL_CPUS;
  }
  
  /*
   * Set up the logical destination ID.
   *
   * Intel recommends to set DFR, LDR and TPR before enabling
   * an APIC.  See e.g. "AP-388 82489DX User's Manual" (Intel
   * document number 292116).  So here it goes...
   */
  void flat_init_apic_ldr(void)
  {
  	unsigned long val;
  	unsigned long num, id;
  
  	num = smp_processor_id();
  	id = 1UL << num;
  	apic_write(APIC_DFR, APIC_DFR_FLAT);
  	val = apic_read(APIC_LDR) & ~APIC_LDR_MASK;
  	val |= SET_APIC_LOGICAL_ID(id);
  	apic_write(APIC_LDR, val);
  }
  
  static inline void _flat_send_IPI_mask(unsigned long mask, int vector)
  {
  	unsigned long flags;
  
  	local_irq_save(flags);
  	__default_send_IPI_dest_field(mask, vector, apic->dest_logical);
  	local_irq_restore(flags);
  }
  
  static void flat_send_IPI_mask(const struct cpumask *cpumask, int vector)
  {
  	unsigned long mask = cpumask_bits(cpumask)[0];
  
  	_flat_send_IPI_mask(mask, vector);
  }
  
  static void
   flat_send_IPI_mask_allbutself(const struct cpumask *cpumask, int vector)
  {
  	unsigned long mask = cpumask_bits(cpumask)[0];
  	int cpu = smp_processor_id();
  
  	if (cpu < BITS_PER_LONG)
  		clear_bit(cpu, &mask);
  
  	_flat_send_IPI_mask(mask, vector);
  }
  
  static void flat_send_IPI_allbutself(int vector)
  {
  	int cpu = smp_processor_id();
  #ifdef	CONFIG_HOTPLUG_CPU
  	int hotplug = 1;
  #else
  	int hotplug = 0;
  #endif
  	if (hotplug || vector == NMI_VECTOR) {
  		if (!cpumask_equal(cpu_online_mask, cpumask_of(cpu))) {
  			unsigned long mask = cpumask_bits(cpu_online_mask)[0];
  
  			if (cpu < BITS_PER_LONG)
  				clear_bit(cpu, &mask);
  
  			_flat_send_IPI_mask(mask, vector);
  		}
  	} else if (num_online_cpus() > 1) {
  		__default_send_IPI_shortcut(APIC_DEST_ALLBUT,
  					    vector, apic->dest_logical);
  	}
  }
  
  static void flat_send_IPI_all(int vector)
  {
  	if (vector == NMI_VECTOR) {
  		flat_send_IPI_mask(cpu_online_mask, vector);
  	} else {
  		__default_send_IPI_shortcut(APIC_DEST_ALLINC,
  					    vector, apic->dest_logical);
  	}
  }
  
  static unsigned int flat_get_apic_id(unsigned long x)
  {
  	unsigned int id;
  
  	id = (((x)>>24) & 0xFFu);
  
  	return id;
  }
  
  static unsigned long set_apic_id(unsigned int id)
  {
  	unsigned long x;
  
  	x = ((id & 0xFFu)<<24);
  	return x;
  }
  
  static unsigned int read_xapic_id(void)
  {
  	unsigned int id;
  
  	id = flat_get_apic_id(apic_read(APIC_ID));
  	return id;
  }
  
  static int flat_apic_id_registered(void)
  {
  	return physid_isset(read_xapic_id(), phys_cpu_present_map);
  }
  
  static int flat_phys_pkg_id(int initial_apic_id, int index_msb)
  {
  	return initial_apic_id >> index_msb;
  }
  
  static int flat_probe(void)
  {
  	return 1;
  }
  
  static struct apic apic_flat =  {
  	.name				= "flat",
  	.probe				= flat_probe,
  	.acpi_madt_oem_check		= flat_acpi_madt_oem_check,
  	.apic_id_valid			= default_apic_id_valid,
  	.apic_id_registered		= flat_apic_id_registered,
  
  	.irq_delivery_mode		= dest_LowestPrio,
  	.irq_dest_mode			= 1, /* logical */
  
  	.target_cpus			= flat_target_cpus,
  	.disable_esr			= 0,
  	.dest_logical			= APIC_DEST_LOGICAL,
  	.check_apicid_used		= NULL,
  	.check_apicid_present		= NULL,
  
  	.vector_allocation_domain	= flat_vector_allocation_domain,
  	.init_apic_ldr			= flat_init_apic_ldr,
  
  	.ioapic_phys_id_map		= NULL,
  	.setup_apic_routing		= NULL,
  	.multi_timer_check		= NULL,
  	.cpu_present_to_apicid		= default_cpu_present_to_apicid,
  	.apicid_to_cpu_present		= NULL,
  	.setup_portio_remap		= NULL,
  	.check_phys_apicid_present	= default_check_phys_apicid_present,
  	.enable_apic_mode		= NULL,
  	.phys_pkg_id			= flat_phys_pkg_id,
  	.mps_oem_check			= NULL,
  
  	.get_apic_id			= flat_get_apic_id,
  	.set_apic_id			= set_apic_id,
  	.apic_id_mask			= 0xFFu << 24,
  
  	.cpu_mask_to_apicid		= default_cpu_mask_to_apicid,
  	.cpu_mask_to_apicid_and		= default_cpu_mask_to_apicid_and,
  
  	.send_IPI_mask			= flat_send_IPI_mask,
  	.send_IPI_mask_allbutself	= flat_send_IPI_mask_allbutself,
  	.send_IPI_allbutself		= flat_send_IPI_allbutself,
  	.send_IPI_all			= flat_send_IPI_all,
  	.send_IPI_self			= apic_send_IPI_self,
  
  	.trampoline_phys_low		= DEFAULT_TRAMPOLINE_PHYS_LOW,
  	.trampoline_phys_high		= DEFAULT_TRAMPOLINE_PHYS_HIGH,
  	.wait_for_init_deassert		= NULL,
  	.smp_callin_clear_local_apic	= NULL,
  	.inquire_remote_apic		= default_inquire_remote_apic,
  
  	.read				= native_apic_mem_read,
  	.write				= native_apic_mem_write,
  	.icr_read			= native_apic_icr_read,
  	.icr_write			= native_apic_icr_write,
  	.wait_icr_idle			= native_apic_wait_icr_idle,
  	.safe_wait_icr_idle		= native_safe_apic_wait_icr_idle,
  };
  
  /*
   * Physflat mode is used when there are more than 8 CPUs on a system.
   * We cannot use logical delivery in this case because the mask
   * overflows, so use physical mode.
   */
  static int physflat_acpi_madt_oem_check(char *oem_id, char *oem_table_id)
  {
  #ifdef CONFIG_ACPI
  	/*
  	 * Quirk: some x86_64 machines can only use physical APIC mode
  	 * regardless of how many processors are present (x86_64 ES7000
  	 * is an example).
  	 */
  	if (acpi_gbl_FADT.header.revision >= FADT2_REVISION_ID &&
  		(acpi_gbl_FADT.flags & ACPI_FADT_APIC_PHYSICAL)) {
  		printk(KERN_DEBUG "system APIC only can use physical flat");
  		return 1;
  	}
  
  	if (!strncmp(oem_id, "IBM", 3) && !strncmp(oem_table_id, "EXA", 3)) {
  		printk(KERN_DEBUG "IBM Summit detected, will use apic physical");
  		return 1;
  	}
  #endif
  
  	return 0;
  }
  
  static const struct cpumask *physflat_target_cpus(void)
  {
  	return cpu_online_mask;
  }
  
  static void physflat_vector_allocation_domain(int cpu, struct cpumask *retmask)
  {
  	cpumask_clear(retmask);
  	cpumask_set_cpu(cpu, retmask);
  }
  
  static void physflat_send_IPI_mask(const struct cpumask *cpumask, int vector)
  {
  	default_send_IPI_mask_sequence_phys(cpumask, vector);
  }
  
  static void physflat_send_IPI_mask_allbutself(const struct cpumask *cpumask,
  					      int vector)
  {
  	default_send_IPI_mask_allbutself_phys(cpumask, vector);
  }
  
  static void physflat_send_IPI_allbutself(int vector)
  {
  	default_send_IPI_mask_allbutself_phys(cpu_online_mask, vector);
  }
  
  static void physflat_send_IPI_all(int vector)
  {
  	physflat_send_IPI_mask(cpu_online_mask, vector);
  }
  
  static unsigned int physflat_cpu_mask_to_apicid(const struct cpumask *cpumask)
  {
  	int cpu;
  
  	/*
  	 * We're using fixed IRQ delivery, can only return one phys APIC ID.
  	 * May as well be the first.
  	 */
  	cpu = cpumask_first(cpumask);
  	if ((unsigned)cpu < nr_cpu_ids)
  		return per_cpu(x86_cpu_to_apicid, cpu);
  	else
  		return BAD_APICID;
  }
  
  static unsigned int
  physflat_cpu_mask_to_apicid_and(const struct cpumask *cpumask,
  				const struct cpumask *andmask)
  {
  	int cpu;
  
  	/*
  	 * We're using fixed IRQ delivery, can only return one phys APIC ID.
  	 * May as well be the first.
  	 */
  	for_each_cpu_and(cpu, cpumask, andmask) {
  		if (cpumask_test_cpu(cpu, cpu_online_mask))
  			break;
  	}
  	return per_cpu(x86_cpu_to_apicid, cpu);
  }
  
  static int physflat_probe(void)
  {
  	if (apic == &apic_physflat || num_possible_cpus() > 8)
  		return 1;
  
  	return 0;
  }
  
  static struct apic apic_physflat =  {
  
  	.name				= "physical flat",
  	.probe				= physflat_probe,
  	.acpi_madt_oem_check		= physflat_acpi_madt_oem_check,
  	.apic_id_valid			= default_apic_id_valid,
  	.apic_id_registered		= flat_apic_id_registered,
  
  	.irq_delivery_mode		= dest_Fixed,
  	.irq_dest_mode			= 0, /* physical */
  
  	.target_cpus			= physflat_target_cpus,
  	.disable_esr			= 0,
  	.dest_logical			= 0,
  	.check_apicid_used		= NULL,
  	.check_apicid_present		= NULL,
  
  	.vector_allocation_domain	= physflat_vector_allocation_domain,
  	/* not needed, but shouldn't hurt: */
  	.init_apic_ldr			= flat_init_apic_ldr,
  
  	.ioapic_phys_id_map		= NULL,
  	.setup_apic_routing		= NULL,
  	.multi_timer_check		= NULL,
  	.cpu_present_to_apicid		= default_cpu_present_to_apicid,
  	.apicid_to_cpu_present		= NULL,
  	.setup_portio_remap		= NULL,
  	.check_phys_apicid_present	= default_check_phys_apicid_present,
  	.enable_apic_mode		= NULL,
  	.phys_pkg_id			= flat_phys_pkg_id,
  	.mps_oem_check			= NULL,
  
  	.get_apic_id			= flat_get_apic_id,
  	.set_apic_id			= set_apic_id,
  	.apic_id_mask			= 0xFFu << 24,
  
  	.cpu_mask_to_apicid		= physflat_cpu_mask_to_apicid,
  	.cpu_mask_to_apicid_and		= physflat_cpu_mask_to_apicid_and,
  
  	.send_IPI_mask			= physflat_send_IPI_mask,
  	.send_IPI_mask_allbutself	= physflat_send_IPI_mask_allbutself,
  	.send_IPI_allbutself		= physflat_send_IPI_allbutself,
  	.send_IPI_all			= physflat_send_IPI_all,
  	.send_IPI_self			= apic_send_IPI_self,
  
  	.trampoline_phys_low		= DEFAULT_TRAMPOLINE_PHYS_LOW,
  	.trampoline_phys_high		= DEFAULT_TRAMPOLINE_PHYS_HIGH,
  	.wait_for_init_deassert		= NULL,
  	.smp_callin_clear_local_apic	= NULL,
  	.inquire_remote_apic		= default_inquire_remote_apic,
  
  	.read				= native_apic_mem_read,
  	.write				= native_apic_mem_write,
  	.icr_read			= native_apic_icr_read,
  	.icr_write			= native_apic_icr_write,
  	.wait_icr_idle			= native_apic_wait_icr_idle,
  	.safe_wait_icr_idle		= native_safe_apic_wait_icr_idle,
  };
  
  /*
   * We need to check for physflat first, so this order is important.
   */
  apic_drivers(apic_physflat, apic_flat);
  