OSCL-LXR linux-6.0.1/​arch/​x86/​kernel/​apic/​io_apic.c	Source navigation Diff markup Identifier search General search
	Version: linux-6.0.1 spark-3.0.0 hadoop-3.2.0-src hadoop-3.3.0-src spark-2.4.7 linux-4.15.13 hadoop-2.7.4-src Revert   Change

 // SPDX-License-Identifier: GPL-2.0
 /*
  *  Intel IO-APIC support for multi-Pentium hosts.
  *
  *  Copyright (C) 1997, 1998, 1999, 2000, 2009 Ingo Molnar, Hajnalka Szabo
  *
  *  Many thanks to Stig Venaas for trying out countless experimental
  *  patches and reporting/debugging problems patiently!
  *
  *  (c) 1999, Multiple IO-APIC support, developed by
  *  Ken-ichi Yaku <yaku@css1.kbnes.nec.co.jp> and
  *      Hidemi Kishimoto <kisimoto@css1.kbnes.nec.co.jp>,
  *  further tested and cleaned up by Zach Brown <zab@redhat.com>
  *  and Ingo Molnar <mingo@redhat.com>
  *
  *  Fixes
  *  Maciej W. Rozycki   :   Bits for genuine 82489DX APICs;
  *                  thanks to Eric Gilmore
  *                  and Rolf G. Tews
  *                  for testing these extensively
  *  Paul Diefenbaugh    :   Added full ACPI support
  *
  * Historical information which is worth to be preserved:
  *
  * - SiS APIC rmw bug:
  *
  *  We used to have a workaround for a bug in SiS chips which
  *  required to rewrite the index register for a read-modify-write
  *  operation as the chip lost the index information which was
  *  setup for the read already. We cache the data now, so that
  *  workaround has been removed.
  */
 
 #include <linux/mm.h>
 #include <linux/interrupt.h>
 #include <linux/irq.h>
 #include <linux/init.h>
 #include <linux/delay.h>
 #include <linux/sched.h>
 #include <linux/pci.h>
 #include <linux/mc146818rtc.h>
 #include <linux/compiler.h>
 #include <linux/acpi.h>
 #include <linux/export.h>
 #include <linux/syscore_ops.h>
 #include <linux/freezer.h>
 #include <linux/kthread.h>
 #include <linux/jiffies.h>  /* time_after() */
 #include <linux/slab.h>
 #include <linux/memblock.h>
 #include <linux/msi.h>
 
 #include <asm/irqdomain.h>
 #include <asm/io.h>
 #include <asm/smp.h>
 #include <asm/cpu.h>
 #include <asm/desc.h>
 #include <asm/proto.h>
 #include <asm/acpi.h>
 #include <asm/dma.h>
 #include <asm/timer.h>
 #include <asm/time.h>
 #include <asm/i8259.h>
 #include <asm/setup.h>
 #include <asm/irq_remapping.h>
 #include <asm/hw_irq.h>
 #include <asm/apic.h>
 #include <asm/pgtable.h>
 
 #define for_each_ioapic(idx)        \
     for ((idx) = 0; (idx) < nr_ioapics; (idx)++)
 #define for_each_ioapic_reverse(idx)    \
     for ((idx) = nr_ioapics - 1; (idx) >= 0; (idx)--)
 #define for_each_pin(idx, pin)      \
     for ((pin) = 0; (pin) < ioapics[(idx)].nr_registers; (pin)++)
 #define for_each_ioapic_pin(idx, pin)   \
     for_each_ioapic((idx))      \
         for_each_pin((idx), (pin))
 #define for_each_irq_pin(entry, head) \
     list_for_each_entry(entry, &head, list)
 
 static DEFINE_RAW_SPINLOCK(ioapic_lock);
 static DEFINE_MUTEX(ioapic_mutex);
 static unsigned int ioapic_dynirq_base;
 static int ioapic_initialized;
 
 struct irq_pin_list {
     struct list_head list;
     int apic, pin;
 };
 
 struct mp_chip_data {
     struct list_head        irq_2_pin;
     struct IO_APIC_route_entry  entry;
     bool                is_level;
     bool                active_low;
     bool                isa_irq;
     u32 count;
 };
 
 struct mp_ioapic_gsi {
     u32 gsi_base;
     u32 gsi_end;
 };
 
 static struct ioapic {
     /*
      * # of IRQ routing registers
      */
     int nr_registers;
     /*
      * Saved state during suspend/resume, or while enabling intr-remap.
      */
     struct IO_APIC_route_entry *saved_registers;
     /* I/O APIC config */
     struct mpc_ioapic mp_config;
     /* IO APIC gsi routing info */
     struct mp_ioapic_gsi  gsi_config;
     struct ioapic_domain_cfg irqdomain_cfg;
     struct irq_domain *irqdomain;
     struct resource *iomem_res;
 } ioapics[MAX_IO_APICS];
 
 #define mpc_ioapic_ver(ioapic_idx)  ioapics[ioapic_idx].mp_config.apicver
 
 int mpc_ioapic_id(int ioapic_idx)
 {
     return ioapics[ioapic_idx].mp_config.apicid;
 }
 
 unsigned int mpc_ioapic_addr(int ioapic_idx)
 {
     return ioapics[ioapic_idx].mp_config.apicaddr;
 }
 
 static inline struct mp_ioapic_gsi *mp_ioapic_gsi_routing(int ioapic_idx)
 {
     return &ioapics[ioapic_idx].gsi_config;
 }
 
 static inline int mp_ioapic_pin_count(int ioapic)
 {
     struct mp_ioapic_gsi *gsi_cfg = mp_ioapic_gsi_routing(ioapic);
 
     return gsi_cfg->gsi_end - gsi_cfg->gsi_base + 1;
 }
 
 static inline u32 mp_pin_to_gsi(int ioapic, int pin)
 {
     return mp_ioapic_gsi_routing(ioapic)->gsi_base + pin;
 }
 
 static inline bool mp_is_legacy_irq(int irq)
 {
     return irq >= 0 && irq < nr_legacy_irqs();
 }
 
 static inline struct irq_domain *mp_ioapic_irqdomain(int ioapic)
 {
     return ioapics[ioapic].irqdomain;
 }
 
 int nr_ioapics;
 
 /* The one past the highest gsi number used */
 u32 gsi_top;
 
 /* MP IRQ source entries */
 struct mpc_intsrc mp_irqs[MAX_IRQ_SOURCES];
 
 /* # of MP IRQ source entries */
 int mp_irq_entries;
 
 #ifdef CONFIG_EISA
 int mp_bus_id_to_type[MAX_MP_BUSSES];
 #endif
 
 DECLARE_BITMAP(mp_bus_not_pci, MAX_MP_BUSSES);
 
 int skip_ioapic_setup;
 
 /**
  * disable_ioapic_support() - disables ioapic support at runtime
  */
 void disable_ioapic_support(void)
 {
 #ifdef CONFIG_PCI
     noioapicquirk = 1;
     noioapicreroute = -1;
 #endif
     skip_ioapic_setup = 1;
 }
 
 static int __init parse_noapic(char *str)
 {
     /* disable IO-APIC */
     disable_ioapic_support();
     return 0;
 }
 early_param("noapic", parse_noapic);
 
 /* Will be called in mpparse/ACPI codes for saving IRQ info */
 void mp_save_irq(struct mpc_intsrc *m)
 {
     int i;
 
     apic_printk(APIC_VERBOSE, "Int: type %d, pol %d, trig %d, bus %02x,"
         " IRQ %02x, APIC ID %x, APIC INT %02x\n",
         m->irqtype, m->irqflag & 3, (m->irqflag >> 2) & 3, m->srcbus,
         m->srcbusirq, m->dstapic, m->dstirq);
 
     for (i = 0; i < mp_irq_entries; i++) {
         if (!memcmp(&mp_irqs[i], m, sizeof(*m)))
             return;
     }
 
     memcpy(&mp_irqs[mp_irq_entries], m, sizeof(*m));
     if (++mp_irq_entries == MAX_IRQ_SOURCES)
         panic("Max # of irq sources exceeded!!\n");
 }
 
 static void alloc_ioapic_saved_registers(int idx)
 {
     size_t size;
 
     if (ioapics[idx].saved_registers)
         return;
 
     size = sizeof(struct IO_APIC_route_entry) * ioapics[idx].nr_registers;
     ioapics[idx].saved_registers = kzalloc(size, GFP_KERNEL);
     if (!ioapics[idx].saved_registers)
         pr_err("IOAPIC %d: suspend/resume impossible!\n", idx);
 }
 
 static void free_ioapic_saved_registers(int idx)
 {
     kfree(ioapics[idx].saved_registers);
     ioapics[idx].saved_registers = NULL;
 }
 
 int __init arch_early_ioapic_init(void)
 {
     int i;
 
     if (!nr_legacy_irqs())
         io_apic_irqs = ~0UL;
 
     for_each_ioapic(i)
         alloc_ioapic_saved_registers(i);
 
     return 0;
 }
 
 struct io_apic {
     unsigned int index;
     unsigned int unused[3];
     unsigned int data;
     unsigned int unused2[11];
     unsigned int eoi;
 };
 
 static __attribute_const__ struct io_apic __iomem *io_apic_base(int idx)
 {
     return (void __iomem *) __fix_to_virt(FIX_IO_APIC_BASE_0 + idx)
         + (mpc_ioapic_addr(idx) & ~PAGE_MASK);
 }
 
 static inline void io_apic_eoi(unsigned int apic, unsigned int vector)
 {
     struct io_apic __iomem *io_apic = io_apic_base(apic);
     writel(vector, &io_apic->eoi);
 }
 
 unsigned int native_io_apic_read(unsigned int apic, unsigned int reg)
 {
     struct io_apic __iomem *io_apic = io_apic_base(apic);
     writel(reg, &io_apic->index);
     return readl(&io_apic->data);
 }
 
 static void io_apic_write(unsigned int apic, unsigned int reg,
               unsigned int value)
 {
     struct io_apic __iomem *io_apic = io_apic_base(apic);
 
     writel(reg, &io_apic->index);
     writel(value, &io_apic->data);
 }
 
 static struct IO_APIC_route_entry __ioapic_read_entry(int apic, int pin)
 {
     struct IO_APIC_route_entry entry;
 
     entry.w1 = io_apic_read(apic, 0x10 + 2 * pin);
     entry.w2 = io_apic_read(apic, 0x11 + 2 * pin);
 
     return entry;
 }
 
 static struct IO_APIC_route_entry ioapic_read_entry(int apic, int pin)
 {
     struct IO_APIC_route_entry entry;
     unsigned long flags;
 
     raw_spin_lock_irqsave(&ioapic_lock, flags);
     entry = __ioapic_read_entry(apic, pin);
     raw_spin_unlock_irqrestore(&ioapic_lock, flags);
 
     return entry;
 }
 
 /*
  * When we write a new IO APIC routing entry, we need to write the high
  * word first! If the mask bit in the low word is clear, we will enable
  * the interrupt, and we need to make sure the entry is fully populated
  * before that happens.
  */
 static void __ioapic_write_entry(int apic, int pin, struct IO_APIC_route_entry e)
 {
     io_apic_write(apic, 0x11 + 2*pin, e.w2);
     io_apic_write(apic, 0x10 + 2*pin, e.w1);
 }
 
 static void ioapic_write_entry(int apic, int pin, struct IO_APIC_route_entry e)
 {
     unsigned long flags;
 
     raw_spin_lock_irqsave(&ioapic_lock, flags);
     __ioapic_write_entry(apic, pin, e);
     raw_spin_unlock_irqrestore(&ioapic_lock, flags);
 }
 
 /*
  * When we mask an IO APIC routing entry, we need to write the low
  * word first, in order to set the mask bit before we change the
  * high bits!
  */
 static void ioapic_mask_entry(int apic, int pin)
 {
     struct IO_APIC_route_entry e = { .masked = true };
     unsigned long flags;
 
     raw_spin_lock_irqsave(&ioapic_lock, flags);
     io_apic_write(apic, 0x10 + 2*pin, e.w1);
     io_apic_write(apic, 0x11 + 2*pin, e.w2);
     raw_spin_unlock_irqrestore(&ioapic_lock, flags);
 }
 
 /*
  * The common case is 1:1 IRQ<->pin mappings. Sometimes there are
  * shared ISA-space IRQs, so we have to support them. We are super
  * fast in the common case, and fast for shared ISA-space IRQs.
  */
 static int __add_pin_to_irq_node(struct mp_chip_data *data,
                  int node, int apic, int pin)
 {
     struct irq_pin_list *entry;
 
     /* don't allow duplicates */
     for_each_irq_pin(entry, data->irq_2_pin)
         if (entry->apic == apic && entry->pin == pin)
             return 0;
 
     entry = kzalloc_node(sizeof(struct irq_pin_list), GFP_ATOMIC, node);
     if (!entry) {
         pr_err("can not alloc irq_pin_list (%d,%d,%d)\n",
                node, apic, pin);
         return -ENOMEM;
     }
     entry->apic = apic;
     entry->pin = pin;
     list_add_tail(&entry->list, &data->irq_2_pin);
 
     return 0;
 }
 
 static void __remove_pin_from_irq(struct mp_chip_data *data, int apic, int pin)
 {
     struct irq_pin_list *tmp, *entry;
 
     list_for_each_entry_safe(entry, tmp, &data->irq_2_pin, list)
         if (entry->apic == apic && entry->pin == pin) {
             list_del(&entry->list);
             kfree(entry);
             return;
         }
 }
 
 static void add_pin_to_irq_node(struct mp_chip_data *data,
                 int node, int apic, int pin)
 {
     if (__add_pin_to_irq_node(data, node, apic, pin))
         panic("IO-APIC: failed to add irq-pin. Can not proceed\n");
 }
 
 /*
  * Reroute an IRQ to a different pin.
  */
 static void __init replace_pin_at_irq_node(struct mp_chip_data *data, int node,
                        int oldapic, int oldpin,
                        int newapic, int newpin)
 {
     struct irq_pin_list *entry;
 
     for_each_irq_pin(entry, data->irq_2_pin) {
         if (entry->apic == oldapic && entry->pin == oldpin) {
             entry->apic = newapic;
             entry->pin = newpin;
             /* every one is different, right? */
             return;
         }
     }
 
     /* old apic/pin didn't exist, so just add new ones */
     add_pin_to_irq_node(data, node, newapic, newpin);
 }
 
 static void io_apic_modify_irq(struct mp_chip_data *data, bool masked,
                    void (*final)(struct irq_pin_list *entry))
 {
     struct irq_pin_list *entry;
 
     data->entry.masked = masked;
 
     for_each_irq_pin(entry, data->irq_2_pin) {
         io_apic_write(entry->apic, 0x10 + 2 * entry->pin, data->entry.w1);
         if (final)
             final(entry);
     }
 }
 
 static void io_apic_sync(struct irq_pin_list *entry)
 {
     /*
      * Synchronize the IO-APIC and the CPU by doing
      * a dummy read from the IO-APIC
      */
     struct io_apic __iomem *io_apic;
 
     io_apic = io_apic_base(entry->apic);
     readl(&io_apic->data);
 }
 
 static void mask_ioapic_irq(struct irq_data *irq_data)
 {
     struct mp_chip_data *data = irq_data->chip_data;
     unsigned long flags;
 
     raw_spin_lock_irqsave(&ioapic_lock, flags);
     io_apic_modify_irq(data, true, &io_apic_sync);
     raw_spin_unlock_irqrestore(&ioapic_lock, flags);
 }
 
 static void __unmask_ioapic(struct mp_chip_data *data)
 {
     io_apic_modify_irq(data, false, NULL);
 }
 
 static void unmask_ioapic_irq(struct irq_data *irq_data)
 {
     struct mp_chip_data *data = irq_data->chip_data;
     unsigned long flags;
 
     raw_spin_lock_irqsave(&ioapic_lock, flags);
     __unmask_ioapic(data);
     raw_spin_unlock_irqrestore(&ioapic_lock, flags);
 }
 
 /*
  * IO-APIC versions below 0x20 don't support EOI register.
  * For the record, here is the information about various versions:
  *     0Xh     82489DX
  *     1Xh     I/OAPIC or I/O(x)APIC which are not PCI 2.2 Compliant
  *     2Xh     I/O(x)APIC which is PCI 2.2 Compliant
  *     30h-FFh Reserved
  *
  * Some of the Intel ICH Specs (ICH2 to ICH5) documents the io-apic
  * version as 0x2. This is an error with documentation and these ICH chips
  * use io-apic's of version 0x20.
  *
  * For IO-APIC's with EOI register, we use that to do an explicit EOI.
  * Otherwise, we simulate the EOI message manually by changing the trigger
  * mode to edge and then back to level, with RTE being masked during this.
  */
 static void __eoi_ioapic_pin(int apic, int pin, int vector)
 {
     if (mpc_ioapic_ver(apic) >= 0x20) {
         io_apic_eoi(apic, vector);
     } else {
         struct IO_APIC_route_entry entry, entry1;
 
         entry = entry1 = __ioapic_read_entry(apic, pin);
 
         /*
          * Mask the entry and change the trigger mode to edge.
          */
         entry1.masked = true;
         entry1.is_level = false;
 
         __ioapic_write_entry(apic, pin, entry1);
 
         /*
          * Restore the previous level triggered entry.
          */
         __ioapic_write_entry(apic, pin, entry);
     }
 }
 
 static void eoi_ioapic_pin(int vector, struct mp_chip_data *data)
 {
     unsigned long flags;
     struct irq_pin_list *entry;
 
     raw_spin_lock_irqsave(&ioapic_lock, flags);
     for_each_irq_pin(entry, data->irq_2_pin)
         __eoi_ioapic_pin(entry->apic, entry->pin, vector);
     raw_spin_unlock_irqrestore(&ioapic_lock, flags);
 }
 
 static void clear_IO_APIC_pin(unsigned int apic, unsigned int pin)
 {
     struct IO_APIC_route_entry entry;
 
     /* Check delivery_mode to be sure we're not clearing an SMI pin */
     entry = ioapic_read_entry(apic, pin);
     if (entry.delivery_mode == APIC_DELIVERY_MODE_SMI)
         return;
 
     /*
      * Make sure the entry is masked and re-read the contents to check
      * if it is a level triggered pin and if the remote-IRR is set.
      */
     if (!entry.masked) {
         entry.masked = true;
         ioapic_write_entry(apic, pin, entry);
         entry = ioapic_read_entry(apic, pin);
     }
 
     if (entry.irr) {
         unsigned long flags;
 
         /*
          * Make sure the trigger mode is set to level. Explicit EOI
          * doesn't clear the remote-IRR if the trigger mode is not
          * set to level.
          */
         if (!entry.is_level) {
             entry.is_level = true;
             ioapic_write_entry(apic, pin, entry);
         }
         raw_spin_lock_irqsave(&ioapic_lock, flags);
         __eoi_ioapic_pin(apic, pin, entry.vector);
         raw_spin_unlock_irqrestore(&ioapic_lock, flags);
     }
 
     /*
      * Clear the rest of the bits in the IO-APIC RTE except for the mask
      * bit.
      */
     ioapic_mask_entry(apic, pin);
     entry = ioapic_read_entry(apic, pin);
     if (entry.irr)
         pr_err("Unable to reset IRR for apic: %d, pin :%d\n",
                mpc_ioapic_id(apic), pin);
 }
 
 void clear_IO_APIC (void)
 {
     int apic, pin;
 
     for_each_ioapic_pin(apic, pin)
         clear_IO_APIC_pin(apic, pin);
 }
 
 #ifdef CONFIG_X86_32
 /*
  * support for broken MP BIOSs, enables hand-redirection of PIRQ0-7 to
  * specific CPU-side IRQs.
  */
 
 #define MAX_PIRQS 8
 static int pirq_entries[MAX_PIRQS] = {
     [0 ... MAX_PIRQS - 1] = -1
 };
 
 static int __init ioapic_pirq_setup(char *str)
 {
     int i, max;
     int ints[MAX_PIRQS+1];
 
     get_options(str, ARRAY_SIZE(ints), ints);
 
     apic_printk(APIC_VERBOSE, KERN_INFO
             "PIRQ redirection, working around broken MP-BIOS.\n");
     max = MAX_PIRQS;
     if (ints[0] < MAX_PIRQS)
         max = ints[0];
 
     for (i = 0; i < max; i++) {
         apic_printk(APIC_VERBOSE, KERN_DEBUG
                 "... PIRQ%d -> IRQ %d\n", i, ints[i+1]);
         /*
          * PIRQs are mapped upside down, usually.
          */
         pirq_entries[MAX_PIRQS-i-1] = ints[i+1];
     }
     return 1;
 }
 
 __setup("pirq=", ioapic_pirq_setup);
 #endif /* CONFIG_X86_32 */
 
 /*
  * Saves all the IO-APIC RTE's
  */
 int save_ioapic_entries(void)
 {
     int apic, pin;
     int err = 0;
 
     for_each_ioapic(apic) {
         if (!ioapics[apic].saved_registers) {
             err = -ENOMEM;
             continue;
         }
 
         for_each_pin(apic, pin)
             ioapics[apic].saved_registers[pin] =
                 ioapic_read_entry(apic, pin);
     }
 
     return err;
 }
 
 /*
  * Mask all IO APIC entries.
  */
 void mask_ioapic_entries(void)
 {
     int apic, pin;
 
     for_each_ioapic(apic) {
         if (!ioapics[apic].saved_registers)
             continue;
 
         for_each_pin(apic, pin) {
             struct IO_APIC_route_entry entry;
 
             entry = ioapics[apic].saved_registers[pin];
             if (!entry.masked) {
                 entry.masked = true;
                 ioapic_write_entry(apic, pin, entry);
             }
         }
     }
 }
 
 /*
  * Restore IO APIC entries which was saved in the ioapic structure.
  */
 int restore_ioapic_entries(void)
 {
     int apic, pin;
 
     for_each_ioapic(apic) {
         if (!ioapics[apic].saved_registers)
             continue;
 
         for_each_pin(apic, pin)
             ioapic_write_entry(apic, pin,
                        ioapics[apic].saved_registers[pin]);
     }
     return 0;
 }
 
 /*
  * Find the IRQ entry number of a certain pin.
  */
 static int find_irq_entry(int ioapic_idx, int pin, int type)
 {
     int i;
 
     for (i = 0; i < mp_irq_entries; i++)
         if (mp_irqs[i].irqtype == type &&
             (mp_irqs[i].dstapic == mpc_ioapic_id(ioapic_idx) ||
              mp_irqs[i].dstapic == MP_APIC_ALL) &&
             mp_irqs[i].dstirq == pin)
             return i;
 
     return -1;
 }
 
 /*
  * Find the pin to which IRQ[irq] (ISA) is connected
  */
 static int __init find_isa_irq_pin(int irq, int type)
 {
     int i;
 
     for (i = 0; i < mp_irq_entries; i++) {
         int lbus = mp_irqs[i].srcbus;
 
         if (test_bit(lbus, mp_bus_not_pci) &&
             (mp_irqs[i].irqtype == type) &&
             (mp_irqs[i].srcbusirq == irq))
 
             return mp_irqs[i].dstirq;
     }
     return -1;
 }
 
 static int __init find_isa_irq_apic(int irq, int type)
 {
     int i;
 
     for (i = 0; i < mp_irq_entries; i++) {
         int lbus = mp_irqs[i].srcbus;
 
         if (test_bit(lbus, mp_bus_not_pci) &&
             (mp_irqs[i].irqtype == type) &&
             (mp_irqs[i].srcbusirq == irq))
             break;
     }
 
     if (i < mp_irq_entries) {
         int ioapic_idx;
 
         for_each_ioapic(ioapic_idx)
             if (mpc_ioapic_id(ioapic_idx) == mp_irqs[i].dstapic)
                 return ioapic_idx;
     }
 
     return -1;
 }
 
 static bool irq_active_low(int idx)
 {
     int bus = mp_irqs[idx].srcbus;
 
     /*
      * Determine IRQ line polarity (high active or low active):
      */
     switch (mp_irqs[idx].irqflag & MP_IRQPOL_MASK) {
     case MP_IRQPOL_DEFAULT:
         /*
          * Conforms to spec, ie. bus-type dependent polarity.  PCI
          * defaults to low active. [E]ISA defaults to high active.
          */
         return !test_bit(bus, mp_bus_not_pci);
     case MP_IRQPOL_ACTIVE_HIGH:
         return false;
     case MP_IRQPOL_RESERVED:
         pr_warn("IOAPIC: Invalid polarity: 2, defaulting to low\n");
         fallthrough;
     case MP_IRQPOL_ACTIVE_LOW:
     default: /* Pointless default required due to do gcc stupidity */
         return true;
     }
 }
 
 #ifdef CONFIG_EISA
 /*
  * EISA Edge/Level control register, ELCR
  */
 static bool EISA_ELCR(unsigned int irq)
 {
     if (irq < nr_legacy_irqs()) {
         unsigned int port = PIC_ELCR1 + (irq >> 3);
         return (inb(port) >> (irq & 7)) & 1;
     }
     apic_printk(APIC_VERBOSE, KERN_INFO
             "Broken MPtable reports ISA irq %d\n", irq);
     return false;
 }
 
 /*
  * EISA interrupts are always active high and can be edge or level
  * triggered depending on the ELCR value.  If an interrupt is listed as
  * EISA conforming in the MP table, that means its trigger type must be
  * read in from the ELCR.
  */
 static bool eisa_irq_is_level(int idx, int bus, bool level)
 {
     switch (mp_bus_id_to_type[bus]) {
     case MP_BUS_PCI:
     case MP_BUS_ISA:
         return level;
     case MP_BUS_EISA:
         return EISA_ELCR(mp_irqs[idx].srcbusirq);
     }
     pr_warn("IOAPIC: Invalid srcbus: %d defaulting to level\n", bus);
     return true;
 }
 #else
 static inline int eisa_irq_is_level(int idx, int bus, bool level)
 {
     return level;
 }
 #endif
 
 static bool irq_is_level(int idx)
 {
     int bus = mp_irqs[idx].srcbus;
     bool level;
 
     /*
      * Determine IRQ trigger mode (edge or level sensitive):
      */
     switch (mp_irqs[idx].irqflag & MP_IRQTRIG_MASK) {
     case MP_IRQTRIG_DEFAULT:
         /*
          * Conforms to spec, ie. bus-type dependent trigger
          * mode. PCI defaults to level, ISA to edge.
          */
         level = !test_bit(bus, mp_bus_not_pci);
         /* Take EISA into account */
         return eisa_irq_is_level(idx, bus, level);
     case MP_IRQTRIG_EDGE:
         return false;
     case MP_IRQTRIG_RESERVED:
         pr_warn("IOAPIC: Invalid trigger mode 2 defaulting to level\n");
         fallthrough;
     case MP_IRQTRIG_LEVEL:
     default: /* Pointless default required due to do gcc stupidity */
         return true;
     }
 }
 
 static int __acpi_get_override_irq(u32 gsi, bool *trigger, bool *polarity)
 {
     int ioapic, pin, idx;
 
     if (skip_ioapic_setup)
         return -1;
 
     ioapic = mp_find_ioapic(gsi);
     if (ioapic < 0)
         return -1;
 
     pin = mp_find_ioapic_pin(ioapic, gsi);
     if (pin < 0)
         return -1;
 
     idx = find_irq_entry(ioapic, pin, mp_INT);
     if (idx < 0)
         return -1;
 
     *trigger = irq_is_level(idx);
     *polarity = irq_active_low(idx);
     return 0;
 }
 
 #ifdef CONFIG_ACPI
 int acpi_get_override_irq(u32 gsi, int *is_level, int *active_low)
 {
     *is_level = *active_low = 0;
     return __acpi_get_override_irq(gsi, (bool *)is_level,
                        (bool *)active_low);
 }
 #endif
 
 void ioapic_set_alloc_attr(struct irq_alloc_info *info, int node,
                int trigger, int polarity)
 {
     init_irq_alloc_info(info, NULL);
     info->type = X86_IRQ_ALLOC_TYPE_IOAPIC;
     info->ioapic.node = node;
     info->ioapic.is_level = trigger;
     info->ioapic.active_low = polarity;
     info->ioapic.valid = 1;
 }
 
 static void ioapic_copy_alloc_attr(struct irq_alloc_info *dst,
                    struct irq_alloc_info *src,
                    u32 gsi, int ioapic_idx, int pin)
 {
     bool level, pol_low;
 
     copy_irq_alloc_info(dst, src);
     dst->type = X86_IRQ_ALLOC_TYPE_IOAPIC;
     dst->devid = mpc_ioapic_id(ioapic_idx);
     dst->ioapic.pin = pin;
     dst->ioapic.valid = 1;
     if (src && src->ioapic.valid) {
         dst->ioapic.node = src->ioapic.node;
         dst->ioapic.is_level = src->ioapic.is_level;
         dst->ioapic.active_low = src->ioapic.active_low;
     } else {
         dst->ioapic.node = NUMA_NO_NODE;
         if (__acpi_get_override_irq(gsi, &level, &pol_low) >= 0) {
             dst->ioapic.is_level = level;
             dst->ioapic.active_low = pol_low;
         } else {
             /*
              * PCI interrupts are always active low level
              * triggered.
              */
             dst->ioapic.is_level = true;
             dst->ioapic.active_low = true;
         }
     }
 }
 
 static int ioapic_alloc_attr_node(struct irq_alloc_info *info)
 {
     return (info && info->ioapic.valid) ? info->ioapic.node : NUMA_NO_NODE;
 }
 
 static void mp_register_handler(unsigned int irq, bool level)
 {
     irq_flow_handler_t hdl;
     bool fasteoi;
 
     if (level) {
         irq_set_status_flags(irq, IRQ_LEVEL);
         fasteoi = true;
     } else {
         irq_clear_status_flags(irq, IRQ_LEVEL);
         fasteoi = false;
     }
 
     hdl = fasteoi ? handle_fasteoi_irq : handle_edge_irq;
     __irq_set_handler(irq, hdl, 0, fasteoi ? "fasteoi" : "edge");
 }
 
 static bool mp_check_pin_attr(int irq, struct irq_alloc_info *info)
 {
     struct mp_chip_data *data = irq_get_chip_data(irq);
 
     /*
      * setup_IO_APIC_irqs() programs all legacy IRQs with default trigger
      * and polarity attributes. So allow the first user to reprogram the
      * pin with real trigger and polarity attributes.
      */
     if (irq < nr_legacy_irqs() && data->count == 1) {
         if (info->ioapic.is_level != data->is_level)
             mp_register_handler(irq, info->ioapic.is_level);
         data->entry.is_level = data->is_level = info->ioapic.is_level;
         data->entry.active_low = data->active_low = info->ioapic.active_low;
     }
 
     return data->is_level == info->ioapic.is_level &&
            data->active_low == info->ioapic.active_low;
 }
 
 static int alloc_irq_from_domain(struct irq_domain *domain, int ioapic, u32 gsi,
                  struct irq_alloc_info *info)
 {
     bool legacy = false;
     int irq = -1;
     int type = ioapics[ioapic].irqdomain_cfg.type;
 
     switch (type) {
     case IOAPIC_DOMAIN_LEGACY:
         /*
          * Dynamically allocate IRQ number for non-ISA IRQs in the first
          * 16 GSIs on some weird platforms.
          */
         if (!ioapic_initialized || gsi >= nr_legacy_irqs())
             irq = gsi;
         legacy = mp_is_legacy_irq(irq);
         break;
     case IOAPIC_DOMAIN_STRICT:
         irq = gsi;
         break;
     case IOAPIC_DOMAIN_DYNAMIC:
         break;
     default:
         WARN(1, "ioapic: unknown irqdomain type %d\n", type);
         return -1;
     }
 
     return __irq_domain_alloc_irqs(domain, irq, 1,
                        ioapic_alloc_attr_node(info),
                        info, legacy, NULL);
 }
 
 /*
  * Need special handling for ISA IRQs because there may be multiple IOAPIC pins
  * sharing the same ISA IRQ number and irqdomain only supports 1:1 mapping
  * between IOAPIC pin and IRQ number. A typical IOAPIC has 24 pins, pin 0-15 are
  * used for legacy IRQs and pin 16-23 are used for PCI IRQs (PIRQ A-H).
  * When ACPI is disabled, only legacy IRQ numbers (IRQ0-15) are available, and
  * some BIOSes may use MP Interrupt Source records to override IRQ numbers for
  * PIRQs instead of reprogramming the interrupt routing logic. Thus there may be
  * multiple pins sharing the same legacy IRQ number when ACPI is disabled.
  */
 static int alloc_isa_irq_from_domain(struct irq_domain *domain,
                      int irq, int ioapic, int pin,
                      struct irq_alloc_info *info)
 {
     struct mp_chip_data *data;
     struct irq_data *irq_data = irq_get_irq_data(irq);
     int node = ioapic_alloc_attr_node(info);
 
     /*
      * Legacy ISA IRQ has already been allocated, just add pin to
      * the pin list associated with this IRQ and program the IOAPIC
      * entry. The IOAPIC entry
      */
     if (irq_data && irq_data->parent_data) {
         if (!mp_check_pin_attr(irq, info))
             return -EBUSY;
         if (__add_pin_to_irq_node(irq_data->chip_data, node, ioapic,
                       info->ioapic.pin))
             return -ENOMEM;
     } else {
         info->flags |= X86_IRQ_ALLOC_LEGACY;
         irq = __irq_domain_alloc_irqs(domain, irq, 1, node, info, true,
                           NULL);
         if (irq >= 0) {
             irq_data = irq_domain_get_irq_data(domain, irq);
             data = irq_data->chip_data;
             data->isa_irq = true;
         }
     }
 
     return irq;
 }
 
 static int mp_map_pin_to_irq(u32 gsi, int idx, int ioapic, int pin,
                  unsigned int flags, struct irq_alloc_info *info)
 {
     int irq;
     bool legacy = false;
     struct irq_alloc_info tmp;
     struct mp_chip_data *data;
     struct irq_domain *domain = mp_ioapic_irqdomain(ioapic);
 
     if (!domain)
         return -ENOSYS;
 
     if (idx >= 0 && test_bit(mp_irqs[idx].srcbus, mp_bus_not_pci)) {
         irq = mp_irqs[idx].srcbusirq;
         legacy = mp_is_legacy_irq(irq);
         /*
          * IRQ2 is unusable for historical reasons on systems which
          * have a legacy PIC. See the comment vs. IRQ2 further down.
          *
          * If this gets removed at some point then the related code
          * in lapic_assign_system_vectors() needs to be adjusted as
          * well.
          */
         if (legacy && irq == PIC_CASCADE_IR)
             return -EINVAL;
     }
 
     mutex_lock(&ioapic_mutex);
     if (!(flags & IOAPIC_MAP_ALLOC)) {
         if (!legacy) {
             irq = irq_find_mapping(domain, pin);
             if (irq == 0)
                 irq = -ENOENT;
         }
     } else {
         ioapic_copy_alloc_attr(&tmp, info, gsi, ioapic, pin);
         if (legacy)
             irq = alloc_isa_irq_from_domain(domain, irq,
                             ioapic, pin, &tmp);
         else if ((irq = irq_find_mapping(domain, pin)) == 0)
             irq = alloc_irq_from_domain(domain, ioapic, gsi, &tmp);
         else if (!mp_check_pin_attr(irq, &tmp))
             irq = -EBUSY;
         if (irq >= 0) {
             data = irq_get_chip_data(irq);
             data->count++;
         }
     }
     mutex_unlock(&ioapic_mutex);
 
     return irq;
 }
 
 static int pin_2_irq(int idx, int ioapic, int pin, unsigned int flags)
 {
     u32 gsi = mp_pin_to_gsi(ioapic, pin);
 
     /*
      * Debugging check, we are in big trouble if this message pops up!
      */
     if (mp_irqs[idx].dstirq != pin)
         pr_err("broken BIOS or MPTABLE parser, ayiee!!\n");
 
 #ifdef CONFIG_X86_32
     /*
      * PCI IRQ command line redirection. Yes, limits are hardcoded.
      */
     if ((pin >= 16) && (pin <= 23)) {
         if (pirq_entries[pin-16] != -1) {
             if (!pirq_entries[pin-16]) {
                 apic_printk(APIC_VERBOSE, KERN_DEBUG
                         "disabling PIRQ%d\n", pin-16);
             } else {
                 int irq = pirq_entries[pin-16];
                 apic_printk(APIC_VERBOSE, KERN_DEBUG
                         "using PIRQ%d -> IRQ %d\n",
                         pin-16, irq);
                 return irq;
             }
         }
     }
 #endif
 
     return  mp_map_pin_to_irq(gsi, idx, ioapic, pin, flags, NULL);
 }
 
 int mp_map_gsi_to_irq(u32 gsi, unsigned int flags, struct irq_alloc_info *info)
 {
     int ioapic, pin, idx;
 
     ioapic = mp_find_ioapic(gsi);
     if (ioapic < 0)
         return -ENODEV;
 
     pin = mp_find_ioapic_pin(ioapic, gsi);
     idx = find_irq_entry(ioapic, pin, mp_INT);
     if ((flags & IOAPIC_MAP_CHECK) && idx < 0)
         return -ENODEV;
 
     return mp_map_pin_to_irq(gsi, idx, ioapic, pin, flags, info);
 }
 
 void mp_unmap_irq(int irq)
 {
     struct irq_data *irq_data = irq_get_irq_data(irq);
     struct mp_chip_data *data;
 
     if (!irq_data || !irq_data->domain)
         return;
 
     data = irq_data->chip_data;
     if (!data || data->isa_irq)
         return;
 
     mutex_lock(&ioapic_mutex);
     if (--data->count == 0)
         irq_domain_free_irqs(irq, 1);
     mutex_unlock(&ioapic_mutex);
 }
 
 /*
  * Find a specific PCI IRQ entry.
  * Not an __init, possibly needed by modules
  */
 int IO_APIC_get_PCI_irq_vector(int bus, int slot, int pin)
 {
     int irq, i, best_ioapic = -1, best_idx = -1;
 
     apic_printk(APIC_DEBUG,
             "querying PCI -> IRQ mapping bus:%d, slot:%d, pin:%d.\n",
             bus, slot, pin);
     if (test_bit(bus, mp_bus_not_pci)) {
         apic_printk(APIC_VERBOSE,
                 "PCI BIOS passed nonexistent PCI bus %d!\n", bus);
         return -1;
     }
 
     for (i = 0; i < mp_irq_entries; i++) {
         int lbus = mp_irqs[i].srcbus;
         int ioapic_idx, found = 0;
 
         if (bus != lbus || mp_irqs[i].irqtype != mp_INT ||
             slot != ((mp_irqs[i].srcbusirq >> 2) & 0x1f))
             continue;
 
         for_each_ioapic(ioapic_idx)
             if (mpc_ioapic_id(ioapic_idx) == mp_irqs[i].dstapic ||
                 mp_irqs[i].dstapic == MP_APIC_ALL) {
                 found = 1;
                 break;
             }
         if (!found)
             continue;
 
         /* Skip ISA IRQs */
         irq = pin_2_irq(i, ioapic_idx, mp_irqs[i].dstirq, 0);
         if (irq > 0 && !IO_APIC_IRQ(irq))
             continue;
 
         if (pin == (mp_irqs[i].srcbusirq & 3)) {
             best_idx = i;
             best_ioapic = ioapic_idx;
             goto out;
         }
 
         /*
          * Use the first all-but-pin matching entry as a
          * best-guess fuzzy result for broken mptables.
          */
         if (best_idx < 0) {
             best_idx = i;
             best_ioapic = ioapic_idx;
         }
     }
     if (best_idx < 0)
         return -1;
 
 out:
     return pin_2_irq(best_idx, best_ioapic, mp_irqs[best_idx].dstirq,
              IOAPIC_MAP_ALLOC);
 }
 EXPORT_SYMBOL(IO_APIC_get_PCI_irq_vector);
 
 static struct irq_chip ioapic_chip, ioapic_ir_chip;
 
 static void __init setup_IO_APIC_irqs(void)
 {
     unsigned int ioapic, pin;
     int idx;
 
     apic_printk(APIC_VERBOSE, KERN_DEBUG "init IO_APIC IRQs\n");
 
     for_each_ioapic_pin(ioapic, pin) {
         idx = find_irq_entry(ioapic, pin, mp_INT);
         if (idx < 0)
             apic_printk(APIC_VERBOSE,
                     KERN_DEBUG " apic %d pin %d not connected\n",
                     mpc_ioapic_id(ioapic), pin);
         else
             pin_2_irq(idx, ioapic, pin,
                   ioapic ? 0 : IOAPIC_MAP_ALLOC);
     }
 }
 
 void ioapic_zap_locks(void)
 {
     raw_spin_lock_init(&ioapic_lock);
 }
 
 static void io_apic_print_entries(unsigned int apic, unsigned int nr_entries)
 {
     struct IO_APIC_route_entry entry;
     char buf[256];
     int i;
 
     printk(KERN_DEBUG "IOAPIC %d:\n", apic);
     for (i = 0; i <= nr_entries; i++) {
         entry = ioapic_read_entry(apic, i);
         snprintf(buf, sizeof(buf),
              " pin%02x, %s, %s, %s, V(%02X), IRR(%1d), S(%1d)",
              i,
              entry.masked ? "disabled" : "enabled ",
              entry.is_level ? "level" : "edge ",
              entry.active_low ? "low " : "high",
              entry.vector, entry.irr, entry.delivery_status);
         if (entry.ir_format) {
             printk(KERN_DEBUG "%s, remapped, I(%04X),  Z(%X)\n",
                    buf,
                    (entry.ir_index_15 << 15) | entry.ir_index_0_14,
                 entry.ir_zero);
         } else {
             printk(KERN_DEBUG "%s, %s, D(%02X%02X), M(%1d)\n", buf,
                    entry.dest_mode_logical ? "logical " : "physical",
                    entry.virt_destid_8_14, entry.destid_0_7,
                    entry.delivery_mode);
         }
     }
 }
 
 static void __init print_IO_APIC(int ioapic_idx)
 {
     union IO_APIC_reg_00 reg_00;
     union IO_APIC_reg_01 reg_01;
     union IO_APIC_reg_02 reg_02;
     union IO_APIC_reg_03 reg_03;
     unsigned long flags;
 
     raw_spin_lock_irqsave(&ioapic_lock, flags);
     reg_00.raw = io_apic_read(ioapic_idx, 0);
     reg_01.raw = io_apic_read(ioapic_idx, 1);
     if (reg_01.bits.version >= 0x10)
         reg_02.raw = io_apic_read(ioapic_idx, 2);
     if (reg_01.bits.version >= 0x20)
         reg_03.raw = io_apic_read(ioapic_idx, 3);
     raw_spin_unlock_irqrestore(&ioapic_lock, flags);
 
     printk(KERN_DEBUG "IO APIC #%d......\n", mpc_ioapic_id(ioapic_idx));
     printk(KERN_DEBUG ".... register #00: %08X\n", reg_00.raw);
     printk(KERN_DEBUG ".......    : physical APIC id: %02X\n", reg_00.bits.ID);
     printk(KERN_DEBUG ".......    : Delivery Type: %X\n", reg_00.bits.delivery_type);
     printk(KERN_DEBUG ".......    : LTS          : %X\n", reg_00.bits.LTS);
 
     printk(KERN_DEBUG ".... register #01: %08X\n", *(int *)&reg_01);
     printk(KERN_DEBUG ".......     : max redirection entries: %02X\n",
         reg_01.bits.entries);
 
     printk(KERN_DEBUG ".......     : PRQ implemented: %X\n", reg_01.bits.PRQ);
     printk(KERN_DEBUG ".......     : IO APIC version: %02X\n",
         reg_01.bits.version);
 
     /*
      * Some Intel chipsets with IO APIC VERSION of 0x1? don't have reg_02,
      * but the value of reg_02 is read as the previous read register
      * value, so ignore it if reg_02 == reg_01.
      */
     if (reg_01.bits.version >= 0x10 && reg_02.raw != reg_01.raw) {
         printk(KERN_DEBUG ".... register #02: %08X\n", reg_02.raw);
         printk(KERN_DEBUG ".......     : arbitration: %02X\n", reg_02.bits.arbitration);
     }
 
     /*
      * Some Intel chipsets with IO APIC VERSION of 0x2? don't have reg_02
      * or reg_03, but the value of reg_0[23] is read as the previous read
      * register value, so ignore it if reg_03 == reg_0[12].
      */
     if (reg_01.bits.version >= 0x20 && reg_03.raw != reg_02.raw &&
         reg_03.raw != reg_01.raw) {
         printk(KERN_DEBUG ".... register #03: %08X\n", reg_03.raw);
         printk(KERN_DEBUG ".......     : Boot DT    : %X\n", reg_03.bits.boot_DT);
     }
 
     printk(KERN_DEBUG ".... IRQ redirection table:\n");
     io_apic_print_entries(ioapic_idx, reg_01.bits.entries);
 }
 
 void __init print_IO_APICs(void)
 {
     int ioapic_idx;
     unsigned int irq;
 
     printk(KERN_DEBUG "number of MP IRQ sources: %d.\n", mp_irq_entries);
     for_each_ioapic(ioapic_idx)
         printk(KERN_DEBUG "number of IO-APIC #%d registers: %d.\n",
                mpc_ioapic_id(ioapic_idx),
                ioapics[ioapic_idx].nr_registers);
 
     /*
      * We are a bit conservative about what we expect.  We have to
      * know about every hardware change ASAP.
      */
     printk(KERN_INFO "testing the IO APIC.......................\n");
 
     for_each_ioapic(ioapic_idx)
         print_IO_APIC(ioapic_idx);
 
     printk(KERN_DEBUG "IRQ to pin mappings:\n");
     for_each_active_irq(irq) {
         struct irq_pin_list *entry;
         struct irq_chip *chip;
         struct mp_chip_data *data;
 
         chip = irq_get_chip(irq);
         if (chip != &ioapic_chip && chip != &ioapic_ir_chip)
             continue;
         data = irq_get_chip_data(irq);
         if (!data)
             continue;
         if (list_empty(&data->irq_2_pin))
             continue;
 
         printk(KERN_DEBUG "IRQ%d ", irq);
         for_each_irq_pin(entry, data->irq_2_pin)
             pr_cont("-> %d:%d", entry->apic, entry->pin);
         pr_cont("\n");
     }
 
     printk(KERN_INFO ".................................... done.\n");
 }
 
 /* Where if anywhere is the i8259 connect in external int mode */
 static struct { int pin, apic; } ioapic_i8259 = { -1, -1 };
 
 void __init enable_IO_APIC(void)
 {
     int i8259_apic, i8259_pin;
     int apic, pin;
 
     if (skip_ioapic_setup)
         nr_ioapics = 0;
 
     if (!nr_legacy_irqs() || !nr_ioapics)
         return;
 
     for_each_ioapic_pin(apic, pin) {
         /* See if any of the pins is in ExtINT mode */
         struct IO_APIC_route_entry entry = ioapic_read_entry(apic, pin);
 
         /* If the interrupt line is enabled and in ExtInt mode
          * I have found the pin where the i8259 is connected.
          */
         if (!entry.masked &&
             entry.delivery_mode == APIC_DELIVERY_MODE_EXTINT) {
             ioapic_i8259.apic = apic;
             ioapic_i8259.pin  = pin;
             goto found_i8259;
         }
     }
  found_i8259:
     /* Look to see what if the MP table has reported the ExtINT */
     /* If we could not find the appropriate pin by looking at the ioapic
      * the i8259 probably is not connected the ioapic but give the
      * mptable a chance anyway.
      */
     i8259_pin  = find_isa_irq_pin(0, mp_ExtINT);
     i8259_apic = find_isa_irq_apic(0, mp_ExtINT);
     /* Trust the MP table if nothing is setup in the hardware */
     if ((ioapic_i8259.pin == -1) && (i8259_pin >= 0)) {
         printk(KERN_WARNING "ExtINT not setup in hardware but reported by MP table\n");
         ioapic_i8259.pin  = i8259_pin;
         ioapic_i8259.apic = i8259_apic;
     }
     /* Complain if the MP table and the hardware disagree */
     if (((ioapic_i8259.apic != i8259_apic) || (ioapic_i8259.pin != i8259_pin)) &&
         (i8259_pin >= 0) && (ioapic_i8259.pin >= 0))
     {
         printk(KERN_WARNING "ExtINT in hardware and MP table differ\n");
     }
 
     /*
      * Do not trust the IO-APIC being empty at bootup
      */
     clear_IO_APIC();
 }
 
 void native_restore_boot_irq_mode(void)
 {
     /*
      * If the i8259 is routed through an IOAPIC
      * Put that IOAPIC in virtual wire mode
      * so legacy interrupts can be delivered.
      */
     if (ioapic_i8259.pin != -1) {
         struct IO_APIC_route_entry entry;
         u32 apic_id = read_apic_id();
 
         memset(&entry, 0, sizeof(entry));
         entry.masked        = false;
         entry.is_level      = false;
         entry.active_low    = false;
         entry.dest_mode_logical = false;
         entry.delivery_mode = APIC_DELIVERY_MODE_EXTINT;
         entry.destid_0_7    = apic_id & 0xFF;
         entry.virt_destid_8_14  = apic_id >> 8;
 
         /*
          * Add it to the IO-APIC irq-routing table:
          */
         ioapic_write_entry(ioapic_i8259.apic, ioapic_i8259.pin, entry);
     }
 
     if (boot_cpu_has(X86_FEATURE_APIC) || apic_from_smp_config())
         disconnect_bsp_APIC(ioapic_i8259.pin != -1);
 }
 
 void restore_boot_irq_mode(void)
 {
     if (!nr_legacy_irqs())
         return;
 
     x86_apic_ops.restore();
 }
 
 #ifdef CONFIG_X86_32
 /*
  * function to set the IO-APIC physical IDs based on the
  * values stored in the MPC table.
  *
  * by Matt Domsch <Matt_Domsch@dell.com>  Tue Dec 21 12:25:05 CST 1999
  */
 void __init setup_ioapic_ids_from_mpc_nocheck(void)
 {
     union IO_APIC_reg_00 reg_00;
     physid_mask_t phys_id_present_map;
     int ioapic_idx;
     int i;
     unsigned char old_id;
     unsigned long flags;
 
     /*
      * This is broken; anything with a real cpu count has to
      * circumvent this idiocy regardless.
      */
     apic->ioapic_phys_id_map(&phys_cpu_present_map, &phys_id_present_map);
 
     /*
      * Set the IOAPIC ID to the value stored in the MPC table.
      */
     for_each_ioapic(ioapic_idx) {
         /* Read the register 0 value */
         raw_spin_lock_irqsave(&ioapic_lock, flags);
         reg_00.raw = io_apic_read(ioapic_idx, 0);
         raw_spin_unlock_irqrestore(&ioapic_lock, flags);
 
         old_id = mpc_ioapic_id(ioapic_idx);
 
         if (mpc_ioapic_id(ioapic_idx) >= get_physical_broadcast()) {
             printk(KERN_ERR "BIOS bug, IO-APIC#%d ID is %d in the MPC table!...\n",
                 ioapic_idx, mpc_ioapic_id(ioapic_idx));
             printk(KERN_ERR "... fixing up to %d. (tell your hw vendor)\n",
                 reg_00.bits.ID);
             ioapics[ioapic_idx].mp_config.apicid = reg_00.bits.ID;
         }
 
         /*
          * Sanity check, is the ID really free? Every APIC in a
          * system must have a unique ID or we get lots of nice
          * 'stuck on smp_invalidate_needed IPI wait' messages.
          */
         if (apic->check_apicid_used(&phys_id_present_map,
                         mpc_ioapic_id(ioapic_idx))) {
             printk(KERN_ERR "BIOS bug, IO-APIC#%d ID %d is already used!...\n",
                 ioapic_idx, mpc_ioapic_id(ioapic_idx));
             for (i = 0; i < get_physical_broadcast(); i++)
                 if (!physid_isset(i, phys_id_present_map))
                     break;
             if (i >= get_physical_broadcast())
                 panic("Max APIC ID exceeded!\n");
             printk(KERN_ERR "... fixing up to %d. (tell your hw vendor)\n",
                 i);
             physid_set(i, phys_id_present_map);
             ioapics[ioapic_idx].mp_config.apicid = i;
         } else {
             physid_mask_t tmp;
             apic->apicid_to_cpu_present(mpc_ioapic_id(ioapic_idx),
                             &tmp);
             apic_printk(APIC_VERBOSE, "Setting %d in the "
                     "phys_id_present_map\n",
                     mpc_ioapic_id(ioapic_idx));
             physids_or(phys_id_present_map, phys_id_present_map, tmp);
         }
 
         /*
          * We need to adjust the IRQ routing table
          * if the ID changed.
          */
         if (old_id != mpc_ioapic_id(ioapic_idx))
             for (i = 0; i < mp_irq_entries; i++)
                 if (mp_irqs[i].dstapic == old_id)
                     mp_irqs[i].dstapic
                         = mpc_ioapic_id(ioapic_idx);
 
         /*
          * Update the ID register according to the right value
          * from the MPC table if they are different.
          */
         if (mpc_ioapic_id(ioapic_idx) == reg_00.bits.ID)
             continue;
 
         apic_printk(APIC_VERBOSE, KERN_INFO
             "...changing IO-APIC physical APIC ID to %d ...",
             mpc_ioapic_id(ioapic_idx));
 
         reg_00.bits.ID = mpc_ioapic_id(ioapic_idx);
         raw_spin_lock_irqsave(&ioapic_lock, flags);
         io_apic_write(ioapic_idx, 0, reg_00.raw);
         raw_spin_unlock_irqrestore(&ioapic_lock, flags);
 
         /*
          * Sanity check
          */
         raw_spin_lock_irqsave(&ioapic_lock, flags);
         reg_00.raw = io_apic_read(ioapic_idx, 0);
         raw_spin_unlock_irqrestore(&ioapic_lock, flags);
         if (reg_00.bits.ID != mpc_ioapic_id(ioapic_idx))
             pr_cont("could not set ID!\n");
         else
             apic_printk(APIC_VERBOSE, " ok.\n");
     }
 }
 
 void __init setup_ioapic_ids_from_mpc(void)
 {
 
     if (acpi_ioapic)
         return;
     /*
      * Don't check I/O APIC IDs for xAPIC systems.  They have
      * no meaning without the serial APIC bus.
      */
     if (!(boot_cpu_data.x86_vendor == X86_VENDOR_INTEL)
         || APIC_XAPIC(boot_cpu_apic_version))
         return;
     setup_ioapic_ids_from_mpc_nocheck();
 }
 #endif
 
 int no_timer_check __initdata;
 
 static int __init notimercheck(char *s)
 {
     no_timer_check = 1;
     return 1;
 }
 __setup("no_timer_check", notimercheck);
 
 static void __init delay_with_tsc(void)
 {
     unsigned long long start, now;
     unsigned long end = jiffies + 4;
 
     start = rdtsc();
 
     /*
      * We don't know the TSC frequency yet, but waiting for
      * 40000000000/HZ TSC cycles is safe:
      * 4 GHz == 10 jiffies
      * 1 GHz == 40 jiffies
      */
     do {
         rep_nop();
         now = rdtsc();
     } while ((now - start) < 40000000000ULL / HZ &&
         time_before_eq(jiffies, end));
 }
 
 static void __init delay_without_tsc(void)
 {
     unsigned long end = jiffies + 4;
     int band = 1;
 
     /*
      * We don't know any frequency yet, but waiting for
      * 40940000000/HZ cycles is safe:
      * 4 GHz == 10 jiffies
      * 1 GHz == 40 jiffies
      * 1 << 1 + 1 << 2 +...+ 1 << 11 = 4094
      */
     do {
         __delay(((1U << band++) * 10000000UL) / HZ);
     } while (band < 12 && time_before_eq(jiffies, end));
 }
 
 /*
  * There is a nasty bug in some older SMP boards, their mptable lies
  * about the timer IRQ. We do the following to work around the situation:
  *
  *  - timer IRQ defaults to IO-APIC IRQ
  *  - if this function detects that timer IRQs are defunct, then we fall
  *    back to ISA timer IRQs
  */
 static int __init timer_irq_works(void)
 {
     unsigned long t1 = jiffies;
 
     if (no_timer_check)
         return 1;
 
     local_irq_enable();
     if (boot_cpu_has(X86_FEATURE_TSC))
         delay_with_tsc();
     else
         delay_without_tsc();
 
     /*
      * Expect a few ticks at least, to be sure some possible
      * glue logic does not lock up after one or two first
      * ticks in a non-ExtINT mode.  Also the local APIC
      * might have cached one ExtINT interrupt.  Finally, at
      * least one tick may be lost due to delays.
      */
 
     local_irq_disable();
 
     /* Did jiffies advance? */
     return time_after(jiffies, t1 + 4);
 }
 
 /*
  * In the SMP+IOAPIC case it might happen that there are an unspecified
  * number of pending IRQ events unhandled. These cases are very rare,
  * so we 'resend' these IRQs via IPIs, to the same CPU. It's much
  * better to do it this way as thus we do not have to be aware of
  * 'pending' interrupts in the IRQ path, except at this point.
  */
 /*
  * Edge triggered needs to resend any interrupt
  * that was delayed but this is now handled in the device
  * independent code.
  */
 
 /*
  * Starting up a edge-triggered IO-APIC interrupt is
  * nasty - we need to make sure that we get the edge.
  * If it is already asserted for some reason, we need
  * return 1 to indicate that is was pending.
  *
  * This is not complete - we should be able to fake
  * an edge even if it isn't on the 8259A...
  */
 static unsigned int startup_ioapic_irq(struct irq_data *data)
 {
     int was_pending = 0, irq = data->irq;
     unsigned long flags;
 
     raw_spin_lock_irqsave(&ioapic_lock, flags);
     if (irq < nr_legacy_irqs()) {
         legacy_pic->mask(irq);
         if (legacy_pic->irq_pending(irq))
             was_pending = 1;
     }
     __unmask_ioapic(data->chip_data);
     raw_spin_unlock_irqrestore(&ioapic_lock, flags);
 
     return was_pending;
 }
 
 atomic_t irq_mis_count;
 
 #ifdef CONFIG_GENERIC_PENDING_IRQ
 static bool io_apic_level_ack_pending(struct mp_chip_data *data)
 {
     struct irq_pin_list *entry;
     unsigned long flags;
 
     raw_spin_lock_irqsave(&ioapic_lock, flags);
     for_each_irq_pin(entry, data->irq_2_pin) {
         struct IO_APIC_route_entry e;
         int pin;
 
         pin = entry->pin;
         e.w1 = io_apic_read(entry->apic, 0x10 + pin*2);
         /* Is the remote IRR bit set? */
         if (e.irr) {
             raw_spin_unlock_irqrestore(&ioapic_lock, flags);
             return true;
         }
     }
     raw_spin_unlock_irqrestore(&ioapic_lock, flags);
 
     return false;
 }
 
 static inline bool ioapic_prepare_move(struct irq_data *data)
 {
     /* If we are moving the IRQ we need to mask it */
     if (unlikely(irqd_is_setaffinity_pending(data))) {
         if (!irqd_irq_masked(data))
             mask_ioapic_irq(data);
         return true;
     }
     return false;
 }
 
 static inline void ioapic_finish_move(struct irq_data *data, bool moveit)
 {
     if (unlikely(moveit)) {
         /* Only migrate the irq if the ack has been received.
          *
          * On rare occasions the broadcast level triggered ack gets
          * delayed going to ioapics, and if we reprogram the
          * vector while Remote IRR is still set the irq will never
          * fire again.
          *
          * To prevent this scenario we read the Remote IRR bit
          * of the ioapic.  This has two effects.
          * - On any sane system the read of the ioapic will
          *   flush writes (and acks) going to the ioapic from
          *   this cpu.
          * - We get to see if the ACK has actually been delivered.
          *
          * Based on failed experiments of reprogramming the
          * ioapic entry from outside of irq context starting
          * with masking the ioapic entry and then polling until
          * Remote IRR was clear before reprogramming the
          * ioapic I don't trust the Remote IRR bit to be
          * completely accurate.
          *
          * However there appears to be no other way to plug
          * this race, so if the Remote IRR bit is not
          * accurate and is causing problems then it is a hardware bug
          * and you can go talk to the chipset vendor about it.
          */
         if (!io_apic_level_ack_pending(data->chip_data))
             irq_move_masked_irq(data);
         /* If the IRQ is masked in the core, leave it: */
         if (!irqd_irq_masked(data))
             unmask_ioapic_irq(data);
     }
 }
 #else
 static inline bool ioapic_prepare_move(struct irq_data *data)
 {
     return false;
 }
 static inline void ioapic_finish_move(struct irq_data *data, bool moveit)
 {
 }
 #endif
 
 static void ioapic_ack_level(struct irq_data *irq_data)
 {
     struct irq_cfg *cfg = irqd_cfg(irq_data);
     unsigned long v;
     bool moveit;
     int i;
 
     irq_complete_move(cfg);
     moveit = ioapic_prepare_move(irq_data);
 
     /*
      * It appears there is an erratum which affects at least version 0x11
      * of I/O APIC (that's the 82093AA and cores integrated into various
      * chipsets).  Under certain conditions a level-triggered interrupt is
      * erroneously delivered as edge-triggered one but the respective IRR
      * bit gets set nevertheless.  As a result the I/O unit expects an EOI
      * message but it will never arrive and further interrupts are blocked
      * from the source.  The exact reason is so far unknown, but the
      * phenomenon was observed when two consecutive interrupt requests
      * from a given source get delivered to the same CPU and the source is
      * temporarily disabled in between.
      *
      * A workaround is to simulate an EOI message manually.  We achieve it
      * by setting the trigger mode to edge and then to level when the edge
      * trigger mode gets detected in the TMR of a local APIC for a
      * level-triggered interrupt.  We mask the source for the time of the
      * operation to prevent an edge-triggered interrupt escaping meanwhile.
      * The idea is from Manfred Spraul.  --macro
      *
      * Also in the case when cpu goes offline, fixup_irqs() will forward
      * any unhandled interrupt on the offlined cpu to the new cpu
      * destination that is handling the corresponding interrupt. This
      * interrupt forwarding is done via IPI's. Hence, in this case also
      * level-triggered io-apic interrupt will be seen as an edge
      * interrupt in the IRR. And we can't rely on the cpu's EOI
      * to be broadcasted to the IO-APIC's which will clear the remoteIRR
      * corresponding to the level-triggered interrupt. Hence on IO-APIC's
      * supporting EOI register, we do an explicit EOI to clear the
      * remote IRR and on IO-APIC's which don't have an EOI register,
      * we use the above logic (mask+edge followed by unmask+level) from
      * Manfred Spraul to clear the remote IRR.
      */
     i = cfg->vector;
     v = apic_read(APIC_TMR + ((i & ~0x1f) >> 1));
 
     /*
      * We must acknowledge the irq before we move it or the acknowledge will
      * not propagate properly.
      */
     ack_APIC_irq();
 
     /*
      * Tail end of clearing remote IRR bit (either by delivering the EOI
      * message via io-apic EOI register write or simulating it using
      * mask+edge followed by unmask+level logic) manually when the
      * level triggered interrupt is seen as the edge triggered interrupt
      * at the cpu.
      */
     if (!(v & (1 << (i & 0x1f)))) {
         atomic_inc(&irq_mis_count);
         eoi_ioapic_pin(cfg->vector, irq_data->chip_data);
     }
 
     ioapic_finish_move(irq_data, moveit);
 }
 
 static void ioapic_ir_ack_level(struct irq_data *irq_data)
 {
     struct mp_chip_data *data = irq_data->chip_data;
 
     /*
      * Intr-remapping uses pin number as the virtual vector
      * in the RTE. Actual vector is programmed in
      * intr-remapping table entry. Hence for the io-apic
      * EOI we use the pin number.
      */
     apic_ack_irq(irq_data);
     eoi_ioapic_pin(data->entry.vector, data);
 }
 
 /*
  * The I/OAPIC is just a device for generating MSI messages from legacy
  * interrupt pins. Various fields of the RTE translate into bits of the
  * resulting MSI which had a historical meaning.
  *
  * With interrupt remapping, many of those bits have different meanings
  * in the underlying MSI, but the way that the I/OAPIC transforms them
  * from its RTE to the MSI message is the same. This function allows
  * the parent IRQ domain to compose the MSI message, then takes the
  * relevant bits to put them in the appropriate places in the RTE in
  * order to generate that message when the IRQ happens.
  *
  * The setup here relies on a preconfigured route entry (is_level,
  * active_low, masked) because the parent domain is merely composing the
  * generic message routing information which is used for the MSI.
  */
 static void ioapic_setup_msg_from_msi(struct irq_data *irq_data,
                       struct IO_APIC_route_entry *entry)
 {
     struct msi_msg msg;
 
     /* Let the parent domain compose the MSI message */
     irq_chip_compose_msi_msg(irq_data, &msg);
 
     /*
      * - Real vector
      * - DMAR/IR: 8bit subhandle (ioapic.pin)
      * - AMD/IR:  8bit IRTE index
      */
     entry->vector           = msg.arch_data.vector;
     /* Delivery mode (for DMAR/IR all 0) */
     entry->delivery_mode        = msg.arch_data.delivery_mode;
     /* Destination mode or DMAR/IR index bit 15 */
     entry->dest_mode_logical    = msg.arch_addr_lo.dest_mode_logical;
     /* DMAR/IR: 1, 0 for all other modes */
     entry->ir_format        = msg.arch_addr_lo.dmar_format;
     /*
      * - DMAR/IR: index bit 0-14.
      *
      * - Virt: If the host supports x2apic without a virtualized IR
      *     unit then bit 0-6 of dmar_index_0_14 are providing bit
      *     8-14 of the destination id.
      *
      * All other modes have bit 0-6 of dmar_index_0_14 cleared and the
      * topmost 8 bits are destination id bit 0-7 (entry::destid_0_7).
      */
     entry->ir_index_0_14        = msg.arch_addr_lo.dmar_index_0_14;
 }
 
 static void ioapic_configure_entry(struct irq_data *irqd)
 {
     struct mp_chip_data *mpd = irqd->chip_data;
     struct irq_pin_list *entry;
 
     ioapic_setup_msg_from_msi(irqd, &mpd->entry);
 
     for_each_irq_pin(entry, mpd->irq_2_pin)
         __ioapic_write_entry(entry->apic, entry->pin, mpd->entry);
 }
 
 static int ioapic_set_affinity(struct irq_data *irq_data,
                    const struct cpumask *mask, bool force)
 {
     struct irq_data *parent = irq_data->parent_data;
     unsigned long flags;
     int ret;
 
     ret = parent->chip->irq_set_affinity(parent, mask, force);
     raw_spin_lock_irqsave(&ioapic_lock, flags);
     if (ret >= 0 && ret != IRQ_SET_MASK_OK_DONE)
         ioapic_configure_entry(irq_data);
     raw_spin_unlock_irqrestore(&ioapic_lock, flags);
 
     return ret;
 }
 
 /*
  * Interrupt shutdown masks the ioapic pin, but the interrupt might already
  * be in flight, but not yet serviced by the target CPU. That means
  * __synchronize_hardirq() would return and claim that everything is calmed
  * down. So free_irq() would proceed and deactivate the interrupt and free
  * resources.
  *
  * Once the target CPU comes around to service it it will find a cleared
  * vector and complain. While the spurious interrupt is harmless, the full
  * release of resources might prevent the interrupt from being acknowledged
  * which keeps the hardware in a weird state.
  *
  * Verify that the corresponding Remote-IRR bits are clear.
  */
 static int ioapic_irq_get_chip_state(struct irq_data *irqd,
                    enum irqchip_irq_state which,
                    bool *state)
 {
     struct mp_chip_data *mcd = irqd->chip_data;
     struct IO_APIC_route_entry rentry;
     struct irq_pin_list *p;
 
     if (which != IRQCHIP_STATE_ACTIVE)
         return -EINVAL;
 
     *state = false;
     raw_spin_lock(&ioapic_lock);
     for_each_irq_pin(p, mcd->irq_2_pin) {
         rentry = __ioapic_read_entry(p->apic, p->pin);
         /*
          * The remote IRR is only valid in level trigger mode. It's
          * meaning is undefined for edge triggered interrupts and
          * irrelevant because the IO-APIC treats them as fire and
          * forget.
          */
         if (rentry.irr && rentry.is_level) {
             *state = true;
             break;
         }
     }
     raw_spin_unlock(&ioapic_lock);
     return 0;
 }
 
 static struct irq_chip ioapic_chip __read_mostly = {
     .name           = "IO-APIC",
     .irq_startup        = startup_ioapic_irq,
     .irq_mask       = mask_ioapic_irq,
     .irq_unmask     = unmask_ioapic_irq,
     .irq_ack        = irq_chip_ack_parent,
     .irq_eoi        = ioapic_ack_level,
     .irq_set_affinity   = ioapic_set_affinity,
     .irq_retrigger      = irq_chip_retrigger_hierarchy,
     .irq_get_irqchip_state  = ioapic_irq_get_chip_state,
     .flags          = IRQCHIP_SKIP_SET_WAKE |
                   IRQCHIP_AFFINITY_PRE_STARTUP,
 };
 
 static struct irq_chip ioapic_ir_chip __read_mostly = {
     .name           = "IR-IO-APIC",
     .irq_startup        = startup_ioapic_irq,
     .irq_mask       = mask_ioapic_irq,
     .irq_unmask     = unmask_ioapic_irq,
     .irq_ack        = irq_chip_ack_parent,
     .irq_eoi        = ioapic_ir_ack_level,
     .irq_set_affinity   = ioapic_set_affinity,
     .irq_retrigger      = irq_chip_retrigger_hierarchy,
     .irq_get_irqchip_state  = ioapic_irq_get_chip_state,
     .flags          = IRQCHIP_SKIP_SET_WAKE |
                   IRQCHIP_AFFINITY_PRE_STARTUP,
 };
 
 static inline void init_IO_APIC_traps(void)
 {
     struct irq_cfg *cfg;
     unsigned int irq;
 
     for_each_active_irq(irq) {
         cfg = irq_cfg(irq);
         if (IO_APIC_IRQ(irq) && cfg && !cfg->vector) {
             /*
              * Hmm.. We don't have an entry for this,
              * so default to an old-fashioned 8259
              * interrupt if we can..
              */
             if (irq < nr_legacy_irqs())
                 legacy_pic->make_irq(irq);
             else
                 /* Strange. Oh, well.. */
                 irq_set_chip(irq, &no_irq_chip);
         }
     }
 }
 
 /*
  * The local APIC irq-chip implementation:
  */
 
 static void mask_lapic_irq(struct irq_data *data)
 {
     unsigned long v;
 
     v = apic_read(APIC_LVT0);
     apic_write(APIC_LVT0, v | APIC_LVT_MASKED);
 }
 
 static void unmask_lapic_irq(struct irq_data *data)
 {
     unsigned long v;
 
     v = apic_read(APIC_LVT0);
     apic_write(APIC_LVT0, v & ~APIC_LVT_MASKED);
 }
 
 static void ack_lapic_irq(struct irq_data *data)
 {
     ack_APIC_irq();
 }
 
 static struct irq_chip lapic_chip __read_mostly = {
     .name       = "local-APIC",
     .irq_mask   = mask_lapic_irq,
     .irq_unmask = unmask_lapic_irq,
     .irq_ack    = ack_lapic_irq,
 };
 
 static void lapic_register_intr(int irq)
 {
     irq_clear_status_flags(irq, IRQ_LEVEL);
     irq_set_chip_and_handler_name(irq, &lapic_chip, handle_edge_irq,
                       "edge");
 }
 
 /*
  * This looks a bit hackish but it's about the only one way of sending
  * a few INTA cycles to 8259As and any associated glue logic.  ICR does
  * not support the ExtINT mode, unfortunately.  We need to send these
  * cycles as some i82489DX-based boards have glue logic that keeps the
  * 8259A interrupt line asserted until INTA.  --macro
  */
 static inline void __init unlock_ExtINT_logic(void)
 {
     int apic, pin, i;
     struct IO_APIC_route_entry entry0, entry1;
     unsigned char save_control, save_freq_select;
     u32 apic_id;
 
     pin  = find_isa_irq_pin(8, mp_INT);
     if (pin == -1) {
         WARN_ON_ONCE(1);
         return;
     }
     apic = find_isa_irq_apic(8, mp_INT);
     if (apic == -1) {
         WARN_ON_ONCE(1);
         return;
     }
 
     entry0 = ioapic_read_entry(apic, pin);
     clear_IO_APIC_pin(apic, pin);
 
     apic_id = hard_smp_processor_id();
     memset(&entry1, 0, sizeof(entry1));
 
     entry1.dest_mode_logical    = true;
     entry1.masked           = false;
     entry1.destid_0_7       = apic_id & 0xFF;
     entry1.virt_destid_8_14     = apic_id >> 8;
     entry1.delivery_mode        = APIC_DELIVERY_MODE_EXTINT;
     entry1.active_low       = entry0.active_low;
     entry1.is_level         = false;
     entry1.vector = 0;
 
     ioapic_write_entry(apic, pin, entry1);
 
     save_control = CMOS_READ(RTC_CONTROL);
     save_freq_select = CMOS_READ(RTC_FREQ_SELECT);
     CMOS_WRITE((save_freq_select & ~RTC_RATE_SELECT) | 0x6,
            RTC_FREQ_SELECT);
     CMOS_WRITE(save_control | RTC_PIE, RTC_CONTROL);
 
     i = 100;
     while (i-- > 0) {
         mdelay(10);
         if ((CMOS_READ(RTC_INTR_FLAGS) & RTC_PF) == RTC_PF)
             i -= 10;
     }
 
     CMOS_WRITE(save_control, RTC_CONTROL);
     CMOS_WRITE(save_freq_select, RTC_FREQ_SELECT);
     clear_IO_APIC_pin(apic, pin);
 
     ioapic_write_entry(apic, pin, entry0);
 }
 
 static int disable_timer_pin_1 __initdata;
 /* Actually the next is obsolete, but keep it for paranoid reasons -AK */
 static int __init disable_timer_pin_setup(char *arg)
 {
     disable_timer_pin_1 = 1;
     return 0;
 }
 early_param("disable_timer_pin_1", disable_timer_pin_setup);
 
 static int mp_alloc_timer_irq(int ioapic, int pin)
 {
     int irq = -1;
     struct irq_domain *domain = mp_ioapic_irqdomain(ioapic);
 
     if (domain) {
         struct irq_alloc_info info;
 
         ioapic_set_alloc_attr(&info, NUMA_NO_NODE, 0, 0);
         info.devid = mpc_ioapic_id(ioapic);
         info.ioapic.pin = pin;
         mutex_lock(&ioapic_mutex);
         irq = alloc_isa_irq_from_domain(domain, 0, ioapic, pin, &info);
         mutex_unlock(&ioapic_mutex);
     }
 
     return irq;
 }
 
 /*
  * This code may look a bit paranoid, but it's supposed to cooperate with
  * a wide range of boards and BIOS bugs.  Fortunately only the timer IRQ
  * is so screwy.  Thanks to Brian Perkins for testing/hacking this beast
  * fanatically on his truly buggy board.
  *
  * FIXME: really need to revamp this for all platforms.
  */
 static inline void __init check_timer(void)
 {
     struct irq_data *irq_data = irq_get_irq_data(0);
     struct mp_chip_data *data = irq_data->chip_data;
     struct irq_cfg *cfg = irqd_cfg(irq_data);
     int node = cpu_to_node(0);
     int apic1, pin1, apic2, pin2;
     int no_pin1 = 0;
 
     if (!global_clock_event)
         return;
 
     local_irq_disable();
 
     /*
      * get/set the timer IRQ vector:
      */
     legacy_pic->mask(0);
 
     /*
      * As IRQ0 is to be enabled in the 8259A, the virtual
      * wire has to be disabled in the local APIC.  Also
      * timer interrupts need to be acknowledged manually in
      * the 8259A for the i82489DX when using the NMI
      * watchdog as that APIC treats NMIs as level-triggered.
      * The AEOI mode will finish them in the 8259A
      * automatically.
      */
     apic_write(APIC_LVT0, APIC_LVT_MASKED | APIC_DM_EXTINT);
     legacy_pic->init(1);
 
     pin1  = find_isa_irq_pin(0, mp_INT);
     apic1 = find_isa_irq_apic(0, mp_INT);
     pin2  = ioapic_i8259.pin;
     apic2 = ioapic_i8259.apic;
 
     apic_printk(APIC_QUIET, KERN_INFO "..TIMER: vector=0x%02X "
             "apic1=%d pin1=%d apic2=%d pin2=%d\n",
             cfg->vector, apic1, pin1, apic2, pin2);
 
     /*
      * Some BIOS writers are clueless and report the ExtINTA
      * I/O APIC input from the cascaded 8259A as the timer
      * interrupt input.  So just in case, if only one pin
      * was found above, try it both directly and through the
      * 8259A.
      */
     if (pin1 == -1) {
         panic_if_irq_remap("BIOS bug: timer not connected to IO-APIC");
         pin1 = pin2;
         apic1 = apic2;
         no_pin1 = 1;
     } else if (pin2 == -1) {
         pin2 = pin1;
         apic2 = apic1;
     }
 
     if (pin1 != -1) {
         /* Ok, does IRQ0 through the IOAPIC work? */
         if (no_pin1) {
             mp_alloc_timer_irq(apic1, pin1);
         } else {
             /*
              * for edge trigger, it's already unmasked,
              * so only need to unmask if it is level-trigger
              * do we really have level trigger timer?
              */
             int idx = find_irq_entry(apic1, pin1, mp_INT);
 
             if (idx != -1 && irq_is_level(idx))
                 unmask_ioapic_irq(irq_get_irq_data(0));
         }
         irq_domain_deactivate_irq(irq_data);
         irq_domain_activate_irq(irq_data, false);
         if (timer_irq_works()) {
             if (disable_timer_pin_1 > 0)
                 clear_IO_APIC_pin(0, pin1);
             goto out;
         }
         panic_if_irq_remap("timer doesn't work through Interrupt-remapped IO-APIC");
         clear_IO_APIC_pin(apic1, pin1);
         if (!no_pin1)
             apic_printk(APIC_QUIET, KERN_ERR "..MP-BIOS bug: "
                     "8254 timer not connected to IO-APIC\n");
 
         apic_printk(APIC_QUIET, KERN_INFO "...trying to set up timer "
                 "(IRQ0) through the 8259A ...\n");
         apic_printk(APIC_QUIET, KERN_INFO
                 "..... (found apic %d pin %d) ...\n", apic2, pin2);
         /*
          * legacy devices should be connected to IO APIC #0
          */
         replace_pin_at_irq_node(data, node, apic1, pin1, apic2, pin2);
         irq_domain_deactivate_irq(irq_data);
         irq_domain_activate_irq(irq_data, false);
         legacy_pic->unmask(0);
         if (timer_irq_works()) {
             apic_printk(APIC_QUIET, KERN_INFO "....... works.\n");
             goto out;
         }
         /*
          * Cleanup, just in case ...
          */
         legacy_pic->mask(0);
         clear_IO_APIC_pin(apic2, pin2);
         apic_printk(APIC_QUIET, KERN_INFO "....... failed.\n");
     }
 
     apic_printk(APIC_QUIET, KERN_INFO
             "...trying to set up timer as Virtual Wire IRQ...\n");
 
     lapic_register_intr(0);
     apic_write(APIC_LVT0, APIC_DM_FIXED | cfg->vector); /* Fixed mode */
     legacy_pic->unmask(0);
 
     if (timer_irq_works()) {
         apic_printk(APIC_QUIET, KERN_INFO "..... works.\n");
         goto out;
     }
     legacy_pic->mask(0);
     apic_write(APIC_LVT0, APIC_LVT_MASKED | APIC_DM_FIXED | cfg->vector);
     apic_printk(APIC_QUIET, KERN_INFO "..... failed.\n");
 
     apic_printk(APIC_QUIET, KERN_INFO
             "...trying to set up timer as ExtINT IRQ...\n");
 
     legacy_pic->init(0);
     legacy_pic->make_irq(0);
     apic_write(APIC_LVT0, APIC_DM_EXTINT);
     legacy_pic->unmask(0);
 
     unlock_ExtINT_logic();
 
     if (timer_irq_works()) {
         apic_printk(APIC_QUIET, KERN_INFO "..... works.\n");
         goto out;
     }
     apic_printk(APIC_QUIET, KERN_INFO "..... failed :(.\n");
     if (apic_is_x2apic_enabled())
         apic_printk(APIC_QUIET, KERN_INFO
                 "Perhaps problem with the pre-enabled x2apic mode\n"
                 "Try booting with x2apic and interrupt-remapping disabled in the bios.\n");
     panic("IO-APIC + timer doesn't work!  Boot with apic=debug and send a "
         "report.  Then try booting with the 'noapic' option.\n");
 out:
     local_irq_enable();
 }
 
 /*
  * Traditionally ISA IRQ2 is the cascade IRQ, and is not available
  * to devices.  However there may be an I/O APIC pin available for
  * this interrupt regardless.  The pin may be left unconnected, but
  * typically it will be reused as an ExtINT cascade interrupt for
  * the master 8259A.  In the MPS case such a pin will normally be
  * reported as an ExtINT interrupt in the MP table.  With ACPI
  * there is no provision for ExtINT interrupts, and in the absence
  * of an override it would be treated as an ordinary ISA I/O APIC
  * interrupt, that is edge-triggered and unmasked by default.  We
  * used to do this, but it caused problems on some systems because
  * of the NMI watchdog and sometimes IRQ0 of the 8254 timer using
  * the same ExtINT cascade interrupt to drive the local APIC of the
  * bootstrap processor.  Therefore we refrain from routing IRQ2 to
  * the I/O APIC in all cases now.  No actual device should request
  * it anyway.  --macro
  */
 #define PIC_IRQS    (1UL << PIC_CASCADE_IR)
 
 static int mp_irqdomain_create(int ioapic)
 {
     struct irq_domain *parent;
     int hwirqs = mp_ioapic_pin_count(ioapic);
     struct ioapic *ip = &ioapics[ioapic];
     struct ioapic_domain_cfg *cfg = &ip->irqdomain_cfg;
     struct mp_ioapic_gsi *gsi_cfg = mp_ioapic_gsi_routing(ioapic);
     struct fwnode_handle *fn;
     struct irq_fwspec fwspec;
 
     if (cfg->type == IOAPIC_DOMAIN_INVALID)
         return 0;
 
     /* Handle device tree enumerated APICs proper */
     if (cfg->dev) {
         fn = of_node_to_fwnode(cfg->dev);
     } else {
         fn = irq_domain_alloc_named_id_fwnode("IO-APIC", mpc_ioapic_id(ioapic));
         if (!fn)
             return -ENOMEM;
     }
 
     fwspec.fwnode = fn;
     fwspec.param_count = 1;
     fwspec.param[0] = mpc_ioapic_id(ioapic);
 
     parent = irq_find_matching_fwspec(&fwspec, DOMAIN_BUS_ANY);
     if (!parent) {
         if (!cfg->dev)
             irq_domain_free_fwnode(fn);
         return -ENODEV;
     }
 
     ip->irqdomain = irq_domain_create_linear(fn, hwirqs, cfg->ops,
                          (void *)(long)ioapic);
 
     if (!ip->irqdomain) {
         /* Release fw handle if it was allocated above */
         if (!cfg->dev)
             irq_domain_free_fwnode(fn);
         return -ENOMEM;
     }
 
     ip->irqdomain->parent = parent;
 
     if (cfg->type == IOAPIC_DOMAIN_LEGACY ||
         cfg->type == IOAPIC_DOMAIN_STRICT)
         ioapic_dynirq_base = max(ioapic_dynirq_base,
                      gsi_cfg->gsi_end + 1);
 
     return 0;
 }
 
 static void ioapic_destroy_irqdomain(int idx)
 {
     struct ioapic_domain_cfg *cfg = &ioapics[idx].irqdomain_cfg;
     struct fwnode_handle *fn = ioapics[idx].irqdomain->fwnode;
 
     if (ioapics[idx].irqdomain) {
         irq_domain_remove(ioapics[idx].irqdomain);
         if (!cfg->dev)
             irq_domain_free_fwnode(fn);
         ioapics[idx].irqdomain = NULL;
     }
 }
 
 void __init setup_IO_APIC(void)
 {
     int ioapic;
 
     if (skip_ioapic_setup || !nr_ioapics)
         return;
 
     io_apic_irqs = nr_legacy_irqs() ? ~PIC_IRQS : ~0UL;
 
     apic_printk(APIC_VERBOSE, "ENABLING IO-APIC IRQs\n");
     for_each_ioapic(ioapic)
         BUG_ON(mp_irqdomain_create(ioapic));
 
     /*
          * Set up IO-APIC IRQ routing.
          */
     x86_init.mpparse.setup_ioapic_ids();
 
     sync_Arb_IDs();
     setup_IO_APIC_irqs();
     init_IO_APIC_traps();
     if (nr_legacy_irqs())
         check_timer();
 
     ioapic_initialized = 1;
 }
 
 static void resume_ioapic_id(int ioapic_idx)
 {
     unsigned long flags;
     union IO_APIC_reg_00 reg_00;
 
     raw_spin_lock_irqsave(&ioapic_lock, flags);
     reg_00.raw = io_apic_read(ioapic_idx, 0);
     if (reg_00.bits.ID != mpc_ioapic_id(ioapic_idx)) {
         reg_00.bits.ID = mpc_ioapic_id(ioapic_idx);
         io_apic_write(ioapic_idx, 0, reg_00.raw);
     }
     raw_spin_unlock_irqrestore(&ioapic_lock, flags);
 }
 
 static void ioapic_resume(void)
 {
     int ioapic_idx;
 
     for_each_ioapic_reverse(ioapic_idx)
         resume_ioapic_id(ioapic_idx);
 
     restore_ioapic_entries();
 }
 
 static struct syscore_ops ioapic_syscore_ops = {
     .suspend = save_ioapic_entries,
     .resume = ioapic_resume,
 };
 
 static int __init ioapic_init_ops(void)
 {
     register_syscore_ops(&ioapic_syscore_ops);
 
     return 0;
 }
 
 device_initcall(ioapic_init_ops);
 
 static int io_apic_get_redir_entries(int ioapic)
 {
     union IO_APIC_reg_01    reg_01;
     unsigned long flags;
 
     raw_spin_lock_irqsave(&ioapic_lock, flags);
     reg_01.raw = io_apic_read(ioapic, 1);
     raw_spin_unlock_irqrestore(&ioapic_lock, flags);
 
     /* The register returns the maximum index redir index
      * supported, which is one less than the total number of redir
      * entries.
      */
     return reg_01.bits.entries + 1;
 }
 
 unsigned int arch_dynirq_lower_bound(unsigned int from)
 {
     /*
      * dmar_alloc_hwirq() may be called before setup_IO_APIC(), so use
      * gsi_top if ioapic_dynirq_base hasn't been initialized yet.
      */
     if (!ioapic_initialized)
         return gsi_top;
     /*
      * For DT enabled machines ioapic_dynirq_base is irrelevant and not
      * updated. So simply return @from if ioapic_dynirq_base == 0.
      */
     return ioapic_dynirq_base ? : from;
 }
 
 #ifdef CONFIG_X86_32
 static int io_apic_get_unique_id(int ioapic, int apic_id)
 {
     union IO_APIC_reg_00 reg_00;
     static physid_mask_t apic_id_map = PHYSID_MASK_NONE;
     physid_mask_t tmp;
     unsigned long flags;
     int i = 0;
 
     /*
      * The P4 platform supports up to 256 APIC IDs on two separate APIC
      * buses (one for LAPICs, one for IOAPICs), where predecessors only
      * supports up to 16 on one shared APIC bus.
      *
      * TBD: Expand LAPIC/IOAPIC support on P4-class systems to take full
      *      advantage of new APIC bus architecture.
      */
 
     if (physids_empty(apic_id_map))
         apic->ioapic_phys_id_map(&phys_cpu_present_map, &apic_id_map);
 
     raw_spin_lock_irqsave(&ioapic_lock, flags);
     reg_00.raw = io_apic_read(ioapic, 0);
     raw_spin_unlock_irqrestore(&ioapic_lock, flags);
 
     if (apic_id >= get_physical_broadcast()) {
         printk(KERN_WARNING "IOAPIC[%d]: Invalid apic_id %d, trying "
             "%d\n", ioapic, apic_id, reg_00.bits.ID);
         apic_id = reg_00.bits.ID;
     }
 
     /*
      * Every APIC in a system must have a unique ID or we get lots of nice
      * 'stuck on smp_invalidate_needed IPI wait' messages.
      */
     if (apic->check_apicid_used(&apic_id_map, apic_id)) {
 
         for (i = 0; i < get_physical_broadcast(); i++) {
             if (!apic->check_apicid_used(&apic_id_map, i))
                 break;
         }
 
         if (i == get_physical_broadcast())
             panic("Max apic_id exceeded!\n");
 
         printk(KERN_WARNING "IOAPIC[%d]: apic_id %d already used, "
             "trying %d\n", ioapic, apic_id, i);
 
         apic_id = i;
     }
 
     apic->apicid_to_cpu_present(apic_id, &tmp);
     physids_or(apic_id_map, apic_id_map, tmp);
 
     if (reg_00.bits.ID != apic_id) {
         reg_00.bits.ID = apic_id;
 
         raw_spin_lock_irqsave(&ioapic_lock, flags);
         io_apic_write(ioapic, 0, reg_00.raw);
         reg_00.raw = io_apic_read(ioapic, 0);
         raw_spin_unlock_irqrestore(&ioapic_lock, flags);
 
         /* Sanity check */
         if (reg_00.bits.ID != apic_id) {
             pr_err("IOAPIC[%d]: Unable to change apic_id!\n",
                    ioapic);
             return -1;
         }
     }
 
     apic_printk(APIC_VERBOSE, KERN_INFO
             "IOAPIC[%d]: Assigned apic_id %d\n", ioapic, apic_id);
 
     return apic_id;
 }
 
 static u8 io_apic_unique_id(int idx, u8 id)
 {
     if ((boot_cpu_data.x86_vendor == X86_VENDOR_INTEL) &&
         !APIC_XAPIC(boot_cpu_apic_version))
         return io_apic_get_unique_id(idx, id);
     else
         return id;
 }
 #else
 static u8 io_apic_unique_id(int idx, u8 id)
 {
     union IO_APIC_reg_00 reg_00;
     DECLARE_BITMAP(used, 256);
     unsigned long flags;
     u8 new_id;
     int i;
 
     bitmap_zero(used, 256);
     for_each_ioapic(i)
         __set_bit(mpc_ioapic_id(i), used);
 
     /* Hand out the requested id if available */
     if (!test_bit(id, used))
         return id;
 
     /*
      * Read the current id from the ioapic and keep it if
      * available.
      */
     raw_spin_lock_irqsave(&ioapic_lock, flags);
     reg_00.raw = io_apic_read(idx, 0);
     raw_spin_unlock_irqrestore(&ioapic_lock, flags);
     new_id = reg_00.bits.ID;
     if (!test_bit(new_id, used)) {
         apic_printk(APIC_VERBOSE, KERN_INFO
             "IOAPIC[%d]: Using reg apic_id %d instead of %d\n",
              idx, new_id, id);
         return new_id;
     }
 
     /*
      * Get the next free id and write it to the ioapic.
      */
     new_id = find_first_zero_bit(used, 256);
     reg_00.bits.ID = new_id;
     raw_spin_lock_irqsave(&ioapic_lock, flags);
     io_apic_write(idx, 0, reg_00.raw);
     reg_00.raw = io_apic_read(idx, 0);
     raw_spin_unlock_irqrestore(&ioapic_lock, flags);
     /* Sanity check */
     BUG_ON(reg_00.bits.ID != new_id);
 
     return new_id;
 }
 #endif
 
 static int io_apic_get_version(int ioapic)
 {
     union IO_APIC_reg_01    reg_01;
     unsigned long flags;
 
     raw_spin_lock_irqsave(&ioapic_lock, flags);
     reg_01.raw = io_apic_read(ioapic, 1);
     raw_spin_unlock_irqrestore(&ioapic_lock, flags);
 
     return reg_01.bits.version;
 }
 
 /*
  * This function updates target affinity of IOAPIC interrupts to include
  * the CPUs which came online during SMP bringup.
  */
 #define IOAPIC_RESOURCE_NAME_SIZE 11
 
 static struct resource *ioapic_resources;
 
 static struct resource * __init ioapic_setup_resources(void)
 {
     unsigned long n;
     struct resource *res;
     char *mem;
     int i;
 
     if (nr_ioapics == 0)
         return NULL;
 
     n = IOAPIC_RESOURCE_NAME_SIZE + sizeof(struct resource);
     n *= nr_ioapics;
 
     mem = memblock_alloc(n, SMP_CACHE_BYTES);
     if (!mem)
         panic("%s: Failed to allocate %lu bytes\n", __func__, n);
     res = (void *)mem;
 
     mem += sizeof(struct resource) * nr_ioapics;
 
     for_each_ioapic(i) {
         res[i].name = mem;
         res[i].flags = IORESOURCE_MEM | IORESOURCE_BUSY;
         snprintf(mem, IOAPIC_RESOURCE_NAME_SIZE, "IOAPIC %u", i);
         mem += IOAPIC_RESOURCE_NAME_SIZE;
         ioapics[i].iomem_res = &res[i];
     }
 
     ioapic_resources = res;
 
     return res;
 }
 
 static void io_apic_set_fixmap(enum fixed_addresses idx, phys_addr_t phys)
 {
     pgprot_t flags = FIXMAP_PAGE_NOCACHE;
 
     /*
      * Ensure fixmaps for IOAPIC MMIO respect memory encryption pgprot
      * bits, just like normal ioremap():
      */
     flags = pgprot_decrypted(flags);
 
     __set_fixmap(idx, phys, flags);
 }
 
 void __init io_apic_init_mappings(void)
 {
     unsigned long ioapic_phys, idx = FIX_IO_APIC_BASE_0;
     struct resource *ioapic_res;
     int i;
 
     ioapic_res = ioapic_setup_resources();
     for_each_ioapic(i) {
         if (smp_found_config) {
             ioapic_phys = mpc_ioapic_addr(i);
 #ifdef CONFIG_X86_32
             if (!ioapic_phys) {
                 printk(KERN_ERR
                        "WARNING: bogus zero IO-APIC "
                        "address found in MPTABLE, "
                        "disabling IO/APIC support!\n");
                 smp_found_config = 0;
                 skip_ioapic_setup = 1;
                 goto fake_ioapic_page;
             }
 #endif
         } else {
 #ifdef CONFIG_X86_32
 fake_ioapic_page:
 #endif
             ioapic_phys = (unsigned long)memblock_alloc(PAGE_SIZE,
                                     PAGE_SIZE);
             if (!ioapic_phys)
                 panic("%s: Failed to allocate %lu bytes align=0x%lx\n",
                       __func__, PAGE_SIZE, PAGE_SIZE);
             ioapic_phys = __pa(ioapic_phys);
         }
         io_apic_set_fixmap(idx, ioapic_phys);
         apic_printk(APIC_VERBOSE, "mapped IOAPIC to %08lx (%08lx)\n",
             __fix_to_virt(idx) + (ioapic_phys & ~PAGE_MASK),
             ioapic_phys);
         idx++;
 
         ioapic_res->start = ioapic_phys;
         ioapic_res->end = ioapic_phys + IO_APIC_SLOT_SIZE - 1;
         ioapic_res++;
     }
 }
 
 void __init ioapic_insert_resources(void)
 {
     int i;
     struct resource *r = ioapic_resources;
 
     if (!r) {
         if (nr_ioapics > 0)
             printk(KERN_ERR
                 "IO APIC resources couldn't be allocated.\n");
         return;
     }
 
     for_each_ioapic(i) {
         insert_resource(&iomem_resource, r);
         r++;
     }
 }
 
 int mp_find_ioapic(u32 gsi)
 {
     int i;
 
     if (nr_ioapics == 0)
         return -1;
 
     /* Find the IOAPIC that manages this GSI. */
     for_each_ioapic(i) {
         struct mp_ioapic_gsi *gsi_cfg = mp_ioapic_gsi_routing(i);
         if (gsi >= gsi_cfg->gsi_base && gsi <= gsi_cfg->gsi_end)
             return i;
     }
 
     printk(KERN_ERR "ERROR: Unable to locate IOAPIC for GSI %d\n", gsi);
     return -1;
 }
 
 int mp_find_ioapic_pin(int ioapic, u32 gsi)
 {
     struct mp_ioapic_gsi *gsi_cfg;
 
     if (WARN_ON(ioapic < 0))
         return -1;
 
     gsi_cfg = mp_ioapic_gsi_routing(ioapic);
     if (WARN_ON(gsi > gsi_cfg->gsi_end))
         return -1;
 
     return gsi - gsi_cfg->gsi_base;
 }
 
 static int bad_ioapic_register(int idx)
 {
     union IO_APIC_reg_00 reg_00;
     union IO_APIC_reg_01 reg_01;
     union IO_APIC_reg_02 reg_02;
 
     reg_00.raw = io_apic_read(idx, 0);
     reg_01.raw = io_apic_read(idx, 1);
     reg_02.raw = io_apic_read(idx, 2);
 
     if (reg_00.raw == -1 && reg_01.raw == -1 && reg_02.raw == -1) {
         pr_warn("I/O APIC 0x%x registers return all ones, skipping!\n",
             mpc_ioapic_addr(idx));
         return 1;
     }
 
     return 0;
 }
 
 static int find_free_ioapic_entry(void)
 {
     int idx;
 
     for (idx = 0; idx < MAX_IO_APICS; idx++)
         if (ioapics[idx].nr_registers == 0)
             return idx;
 
     return MAX_IO_APICS;
 }
 
 /**
  * mp_register_ioapic - Register an IOAPIC device
  * @id:     hardware IOAPIC ID
  * @address:    physical address of IOAPIC register area
  * @gsi_base:   base of GSI associated with the IOAPIC
  * @cfg:    configuration information for the IOAPIC
  */
 int mp_register_ioapic(int id, u32 address, u32 gsi_base,
                struct ioapic_domain_cfg *cfg)
 {
     bool hotplug = !!ioapic_initialized;
     struct mp_ioapic_gsi *gsi_cfg;
     int idx, ioapic, entries;
     u32 gsi_end;
 
     if (!address) {
         pr_warn("Bogus (zero) I/O APIC address found, skipping!\n");
         return -EINVAL;
     }
     for_each_ioapic(ioapic)
         if (ioapics[ioapic].mp_config.apicaddr == address) {
             pr_warn("address 0x%x conflicts with IOAPIC%d\n",
                 address, ioapic);
             return -EEXIST;
         }
 
     idx = find_free_ioapic_entry();
     if (idx >= MAX_IO_APICS) {
         pr_warn("Max # of I/O APICs (%d) exceeded (found %d), skipping\n",
             MAX_IO_APICS, idx);
         return -ENOSPC;
     }
 
     ioapics[idx].mp_config.type = MP_IOAPIC;
     ioapics[idx].mp_config.flags = MPC_APIC_USABLE;
     ioapics[idx].mp_config.apicaddr = address;
 
     io_apic_set_fixmap(FIX_IO_APIC_BASE_0 + idx, address);
     if (bad_ioapic_register(idx)) {
         clear_fixmap(FIX_IO_APIC_BASE_0 + idx);
         return -ENODEV;
     }
 
     ioapics[idx].mp_config.apicid = io_apic_unique_id(idx, id);
     ioapics[idx].mp_config.apicver = io_apic_get_version(idx);
 
     /*
      * Build basic GSI lookup table to facilitate gsi->io_apic lookups
      * and to prevent reprogramming of IOAPIC pins (PCI GSIs).
      */
     entries = io_apic_get_redir_entries(idx);
     gsi_end = gsi_base + entries - 1;
     for_each_ioapic(ioapic) {
         gsi_cfg = mp_ioapic_gsi_routing(ioapic);
         if ((gsi_base >= gsi_cfg->gsi_base &&
              gsi_base <= gsi_cfg->gsi_end) ||
             (gsi_end >= gsi_cfg->gsi_base &&
              gsi_end <= gsi_cfg->gsi_end)) {
             pr_warn("GSI range [%u-%u] for new IOAPIC conflicts with GSI[%u-%u]\n",
                 gsi_base, gsi_end,
                 gsi_cfg->gsi_base, gsi_cfg->gsi_end);
             clear_fixmap(FIX_IO_APIC_BASE_0 + idx);
             return -ENOSPC;
         }
     }
     gsi_cfg = mp_ioapic_gsi_routing(idx);
     gsi_cfg->gsi_base = gsi_base;
     gsi_cfg->gsi_end = gsi_end;
 
     ioapics[idx].irqdomain = NULL;
     ioapics[idx].irqdomain_cfg = *cfg;
 
     /*
      * If mp_register_ioapic() is called during early boot stage when
      * walking ACPI/DT tables, it's too early to create irqdomain,
      * we are still using bootmem allocator. So delay it to setup_IO_APIC().
      */
     if (hotplug) {
         if (mp_irqdomain_create(idx)) {
             clear_fixmap(FIX_IO_APIC_BASE_0 + idx);
             return -ENOMEM;
         }
         alloc_ioapic_saved_registers(idx);
     }
 
     if (gsi_cfg->gsi_end >= gsi_top)
         gsi_top = gsi_cfg->gsi_end + 1;
     if (nr_ioapics <= idx)
         nr_ioapics = idx + 1;
 
     /* Set nr_registers to mark entry present */
     ioapics[idx].nr_registers = entries;
 
     pr_info("IOAPIC[%d]: apic_id %d, version %d, address 0x%x, GSI %d-%d\n",
         idx, mpc_ioapic_id(idx),
         mpc_ioapic_ver(idx), mpc_ioapic_addr(idx),
         gsi_cfg->gsi_base, gsi_cfg->gsi_end);
 
     return 0;
 }
 
 int mp_unregister_ioapic(u32 gsi_base)
 {
     int ioapic, pin;
     int found = 0;
 
     for_each_ioapic(ioapic)
         if (ioapics[ioapic].gsi_config.gsi_base == gsi_base) {
             found = 1;
             break;
         }
     if (!found) {
         pr_warn("can't find IOAPIC for GSI %d\n", gsi_base);
         return -ENODEV;
     }
 
     for_each_pin(ioapic, pin) {
         u32 gsi = mp_pin_to_gsi(ioapic, pin);
         int irq = mp_map_gsi_to_irq(gsi, 0, NULL);
         struct mp_chip_data *data;
 
         if (irq >= 0) {
             data = irq_get_chip_data(irq);
             if (data && data->count) {
                 pr_warn("pin%d on IOAPIC%d is still in use.\n",
                     pin, ioapic);
                 return -EBUSY;
             }
         }
     }
 
     /* Mark entry not present */
     ioapics[ioapic].nr_registers  = 0;
     ioapic_destroy_irqdomain(ioapic);
     free_ioapic_saved_registers(ioapic);
     if (ioapics[ioapic].iomem_res)
         release_resource(ioapics[ioapic].iomem_res);
     clear_fixmap(FIX_IO_APIC_BASE_0 + ioapic);
     memset(&ioapics[ioapic], 0, sizeof(ioapics[ioapic]));
 
     return 0;
 }
 
 int mp_ioapic_registered(u32 gsi_base)
 {
     int ioapic;
 
     for_each_ioapic(ioapic)
         if (ioapics[ioapic].gsi_config.gsi_base == gsi_base)
             return 1;
 
     return 0;
 }
 
 static void mp_irqdomain_get_attr(u32 gsi, struct mp_chip_data *data,
                   struct irq_alloc_info *info)
 {
     if (info && info->ioapic.valid) {
         data->is_level = info->ioapic.is_level;
         data->active_low = info->ioapic.active_low;
     } else if (__acpi_get_override_irq(gsi, &data->is_level,
                        &data->active_low) < 0) {
         /* PCI interrupts are always active low level triggered. */
         data->is_level = true;
         data->active_low = true;
     }
 }
 
 /*
  * Configure the I/O-APIC specific fields in the routing entry.
  *
  * This is important to setup the I/O-APIC specific bits (is_level,
  * active_low, masked) because the underlying parent domain will only
  * provide the routing information and is oblivious of the I/O-APIC
  * specific bits.
  *
  * The entry is just preconfigured at this point and not written into the
  * RTE. This happens later during activation which will fill in the actual
  * routing information.
  */
 static void mp_preconfigure_entry(struct mp_chip_data *data)
 {
     struct IO_APIC_route_entry *entry = &data->entry;
 
     memset(entry, 0, sizeof(*entry));
     entry->is_level      = data->is_level;
     entry->active_low    = data->active_low;
     /*
      * Mask level triggered irqs. Edge triggered irqs are masked
      * by the irq core code in case they fire.
      */
     entry->masked       = data->is_level;
 }
 
 int mp_irqdomain_alloc(struct irq_domain *domain, unsigned int virq,
                unsigned int nr_irqs, void *arg)
 {
     struct irq_alloc_info *info = arg;
     struct mp_chip_data *data;
     struct irq_data *irq_data;
     int ret, ioapic, pin;
     unsigned long flags;
 
     if (!info || nr_irqs > 1)
         return -EINVAL;
     irq_data = irq_domain_get_irq_data(domain, virq);
     if (!irq_data)
         return -EINVAL;
 
     ioapic = mp_irqdomain_ioapic_idx(domain);
     pin = info->ioapic.pin;
     if (irq_find_mapping(domain, (irq_hw_number_t)pin) > 0)
         return -EEXIST;
 
     data = kzalloc(sizeof(*data), GFP_KERNEL);
     if (!data)
         return -ENOMEM;
 
     ret = irq_domain_alloc_irqs_parent(domain, virq, nr_irqs, info);
     if (ret < 0) {
         kfree(data);
         return ret;
     }
 
     INIT_LIST_HEAD(&data->irq_2_pin);
     irq_data->hwirq = info->ioapic.pin;
     irq_data->chip = (domain->parent == x86_vector_domain) ?
               &ioapic_chip : &ioapic_ir_chip;
     irq_data->chip_data = data;
     mp_irqdomain_get_attr(mp_pin_to_gsi(ioapic, pin), data, info);
 
     add_pin_to_irq_node(data, ioapic_alloc_attr_node(info), ioapic, pin);
 
     mp_preconfigure_entry(data);
     mp_register_handler(virq, data->is_level);
 
     local_irq_save(flags);
     if (virq < nr_legacy_irqs())
         legacy_pic->mask(virq);
     local_irq_restore(flags);
 
     apic_printk(APIC_VERBOSE, KERN_DEBUG
             "IOAPIC[%d]: Preconfigured routing entry (%d-%d -> IRQ %d Level:%i ActiveLow:%i)\n",
             ioapic, mpc_ioapic_id(ioapic), pin, virq,
             data->is_level, data->active_low);
     return 0;
 }
 
 void mp_irqdomain_free(struct irq_domain *domain, unsigned int virq,
                unsigned int nr_irqs)
 {
     struct irq_data *irq_data;
     struct mp_chip_data *data;
 
     BUG_ON(nr_irqs != 1);
     irq_data = irq_domain_get_irq_data(domain, virq);
     if (irq_data && irq_data->chip_data) {
         data = irq_data->chip_data;
         __remove_pin_from_irq(data, mp_irqdomain_ioapic_idx(domain),
                       (int)irq_data->hwirq);
         WARN_ON(!list_empty(&data->irq_2_pin));
         kfree(irq_data->chip_data);
     }
     irq_domain_free_irqs_top(domain, virq, nr_irqs);
 }
 
 int mp_irqdomain_activate(struct irq_domain *domain,
               struct irq_data *irq_data, bool reserve)
 {
     unsigned long flags;
 
     raw_spin_lock_irqsave(&ioapic_lock, flags);
     ioapic_configure_entry(irq_data);
     raw_spin_unlock_irqrestore(&ioapic_lock, flags);
     return 0;
 }
 
 void mp_irqdomain_deactivate(struct irq_domain *domain,
                  struct irq_data *irq_data)
 {
     /* It won't be called for IRQ with multiple IOAPIC pins associated */
     ioapic_mask_entry(mp_irqdomain_ioapic_idx(domain),
               (int)irq_data->hwirq);
 }
 
 int mp_irqdomain_ioapic_idx(struct irq_domain *domain)
 {
     return (int)(long)domain->host_data;
 }
 
 const struct irq_domain_ops mp_ioapic_irqdomain_ops = {
     .alloc      = mp_irqdomain_alloc,
     .free       = mp_irqdomain_free,
     .activate   = mp_irqdomain_activate,
     .deactivate = mp_irqdomain_deactivate,
 };