linux/arch/s390/kernel/irq.c
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   1/*
   2 *    Copyright IBM Corp. 2004, 2011
   3 *    Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>,
   4 *               Holger Smolinski <Holger.Smolinski@de.ibm.com>,
   5 *               Thomas Spatzier <tspat@de.ibm.com>,
   6 *
   7 * This file contains interrupt related functions.
   8 */
   9
  10#include <linux/kernel_stat.h>
  11#include <linux/interrupt.h>
  12#include <linux/seq_file.h>
  13#include <linux/proc_fs.h>
  14#include <linux/profile.h>
  15#include <linux/module.h>
  16#include <linux/kernel.h>
  17#include <linux/ftrace.h>
  18#include <linux/errno.h>
  19#include <linux/slab.h>
  20#include <linux/cpu.h>
  21#include <linux/irq.h>
  22#include <asm/irq_regs.h>
  23#include <asm/cputime.h>
  24#include <asm/lowcore.h>
  25#include <asm/irq.h>
  26#include <asm/hw_irq.h>
  27#include "entry.h"
  28
  29DEFINE_PER_CPU_SHARED_ALIGNED(struct irq_stat, irq_stat);
  30EXPORT_PER_CPU_SYMBOL_GPL(irq_stat);
  31
  32struct irq_class {
  33        int irq;
  34        char *name;
  35        char *desc;
  36};
  37
  38/*
  39 * The list of "main" irq classes on s390. This is the list of interrupts
  40 * that appear both in /proc/stat ("intr" line) and /proc/interrupts.
  41 * Historically only external and I/O interrupts have been part of /proc/stat.
  42 * We can't add the split external and I/O sub classes since the first field
  43 * in the "intr" line in /proc/stat is supposed to be the sum of all other
  44 * fields.
  45 * Since the external and I/O interrupt fields are already sums we would end
  46 * up with having a sum which accounts each interrupt twice.
  47 */
  48static const struct irq_class irqclass_main_desc[NR_IRQS_BASE] = {
  49        {.irq = EXT_INTERRUPT,  .name = "EXT"},
  50        {.irq = IO_INTERRUPT,   .name = "I/O"},
  51        {.irq = THIN_INTERRUPT, .name = "AIO"},
  52};
  53
  54/*
  55 * The list of split external and I/O interrupts that appear only in
  56 * /proc/interrupts.
  57 * In addition this list contains non external / I/O events like NMIs.
  58 */
  59static const struct irq_class irqclass_sub_desc[] = {
  60        {.irq = IRQEXT_CLK, .name = "CLK", .desc = "[EXT] Clock Comparator"},
  61        {.irq = IRQEXT_EXC, .name = "EXC", .desc = "[EXT] External Call"},
  62        {.irq = IRQEXT_EMS, .name = "EMS", .desc = "[EXT] Emergency Signal"},
  63        {.irq = IRQEXT_TMR, .name = "TMR", .desc = "[EXT] CPU Timer"},
  64        {.irq = IRQEXT_TLA, .name = "TAL", .desc = "[EXT] Timing Alert"},
  65        {.irq = IRQEXT_PFL, .name = "PFL", .desc = "[EXT] Pseudo Page Fault"},
  66        {.irq = IRQEXT_DSD, .name = "DSD", .desc = "[EXT] DASD Diag"},
  67        {.irq = IRQEXT_VRT, .name = "VRT", .desc = "[EXT] Virtio"},
  68        {.irq = IRQEXT_SCP, .name = "SCP", .desc = "[EXT] Service Call"},
  69        {.irq = IRQEXT_IUC, .name = "IUC", .desc = "[EXT] IUCV"},
  70        {.irq = IRQEXT_CMS, .name = "CMS", .desc = "[EXT] CPU-Measurement: Sampling"},
  71        {.irq = IRQEXT_CMC, .name = "CMC", .desc = "[EXT] CPU-Measurement: Counter"},
  72        {.irq = IRQEXT_FTP, .name = "FTP", .desc = "[EXT] HMC FTP Service"},
  73        {.irq = IRQIO_CIO,  .name = "CIO", .desc = "[I/O] Common I/O Layer Interrupt"},
  74        {.irq = IRQIO_QAI,  .name = "QAI", .desc = "[I/O] QDIO Adapter Interrupt"},
  75        {.irq = IRQIO_DAS,  .name = "DAS", .desc = "[I/O] DASD"},
  76        {.irq = IRQIO_C15,  .name = "C15", .desc = "[I/O] 3215"},
  77        {.irq = IRQIO_C70,  .name = "C70", .desc = "[I/O] 3270"},
  78        {.irq = IRQIO_TAP,  .name = "TAP", .desc = "[I/O] Tape"},
  79        {.irq = IRQIO_VMR,  .name = "VMR", .desc = "[I/O] Unit Record Devices"},
  80        {.irq = IRQIO_LCS,  .name = "LCS", .desc = "[I/O] LCS"},
  81        {.irq = IRQIO_CTC,  .name = "CTC", .desc = "[I/O] CTC"},
  82        {.irq = IRQIO_APB,  .name = "APB", .desc = "[I/O] AP Bus"},
  83        {.irq = IRQIO_ADM,  .name = "ADM", .desc = "[I/O] EADM Subchannel"},
  84        {.irq = IRQIO_CSC,  .name = "CSC", .desc = "[I/O] CHSC Subchannel"},
  85        {.irq = IRQIO_PCI,  .name = "PCI", .desc = "[I/O] PCI Interrupt" },
  86        {.irq = IRQIO_MSI,  .name = "MSI", .desc = "[I/O] MSI Interrupt" },
  87        {.irq = IRQIO_VIR,  .name = "VIR", .desc = "[I/O] Virtual I/O Devices"},
  88        {.irq = IRQIO_VAI,  .name = "VAI", .desc = "[I/O] Virtual I/O Devices AI"},
  89        {.irq = NMI_NMI,    .name = "NMI", .desc = "[NMI] Machine Check"},
  90        {.irq = CPU_RST,    .name = "RST", .desc = "[CPU] CPU Restart"},
  91};
  92
  93void __init init_IRQ(void)
  94{
  95        BUILD_BUG_ON(ARRAY_SIZE(irqclass_sub_desc) != NR_ARCH_IRQS);
  96        init_cio_interrupts();
  97        init_airq_interrupts();
  98        init_ext_interrupts();
  99}
 100
 101void do_IRQ(struct pt_regs *regs, int irq)
 102{
 103        struct pt_regs *old_regs;
 104
 105        old_regs = set_irq_regs(regs);
 106        irq_enter();
 107        if (S390_lowcore.int_clock >= S390_lowcore.clock_comparator)
 108                /* Serve timer interrupts first. */
 109                clock_comparator_work();
 110        generic_handle_irq(irq);
 111        irq_exit();
 112        set_irq_regs(old_regs);
 113}
 114
 115/*
 116 * show_interrupts is needed by /proc/interrupts.
 117 */
 118int show_interrupts(struct seq_file *p, void *v)
 119{
 120        int index = *(loff_t *) v;
 121        int cpu, irq;
 122
 123        get_online_cpus();
 124        if (index == 0) {
 125                seq_puts(p, "           ");
 126                for_each_online_cpu(cpu)
 127                        seq_printf(p, "CPU%d       ", cpu);
 128                seq_putc(p, '\n');
 129        }
 130        if (index < NR_IRQS_BASE) {
 131                seq_printf(p, "%s: ", irqclass_main_desc[index].name);
 132                irq = irqclass_main_desc[index].irq;
 133                for_each_online_cpu(cpu)
 134                        seq_printf(p, "%10u ", kstat_irqs_cpu(irq, cpu));
 135                seq_putc(p, '\n');
 136                goto out;
 137        }
 138        if (index > NR_IRQS_BASE)
 139                goto out;
 140
 141        for (index = 0; index < NR_ARCH_IRQS; index++) {
 142                seq_printf(p, "%s: ", irqclass_sub_desc[index].name);
 143                irq = irqclass_sub_desc[index].irq;
 144                for_each_online_cpu(cpu)
 145                        seq_printf(p, "%10u ",
 146                                   per_cpu(irq_stat, cpu).irqs[irq]);
 147                if (irqclass_sub_desc[index].desc)
 148                        seq_printf(p, "  %s", irqclass_sub_desc[index].desc);
 149                seq_putc(p, '\n');
 150        }
 151out:
 152        put_online_cpus();
 153        return 0;
 154}
 155
 156unsigned int arch_dynirq_lower_bound(unsigned int from)
 157{
 158        return from < NR_IRQS_BASE ? NR_IRQS_BASE : from;
 159}
 160
 161/*
 162 * Switch to the asynchronous interrupt stack for softirq execution.
 163 */
 164void do_softirq_own_stack(void)
 165{
 166        unsigned long old, new;
 167
 168        old = current_stack_pointer();
 169        /* Check against async. stack address range. */
 170        new = S390_lowcore.async_stack;
 171        if (((new - old) >> (PAGE_SHIFT + THREAD_ORDER)) != 0) {
 172                /* Need to switch to the async. stack. */
 173                new -= STACK_FRAME_OVERHEAD;
 174                ((struct stack_frame *) new)->back_chain = old;
 175                asm volatile("   la    15,0(%0)\n"
 176                             "   basr  14,%2\n"
 177                             "   la    15,0(%1)\n"
 178                             : : "a" (new), "a" (old),
 179                                 "a" (__do_softirq)
 180                             : "0", "1", "2", "3", "4", "5", "14",
 181                               "cc", "memory" );
 182        } else {
 183                /* We are already on the async stack. */
 184                __do_softirq();
 185        }
 186}
 187
 188/*
 189 * ext_int_hash[index] is the list head for all external interrupts that hash
 190 * to this index.
 191 */
 192static struct hlist_head ext_int_hash[32] ____cacheline_aligned;
 193
 194struct ext_int_info {
 195        ext_int_handler_t handler;
 196        struct hlist_node entry;
 197        struct rcu_head rcu;
 198        u16 code;
 199};
 200
 201/* ext_int_hash_lock protects the handler lists for external interrupts */
 202static DEFINE_SPINLOCK(ext_int_hash_lock);
 203
 204static inline int ext_hash(u16 code)
 205{
 206        BUILD_BUG_ON(!is_power_of_2(ARRAY_SIZE(ext_int_hash)));
 207
 208        return (code + (code >> 9)) & (ARRAY_SIZE(ext_int_hash) - 1);
 209}
 210
 211int register_external_irq(u16 code, ext_int_handler_t handler)
 212{
 213        struct ext_int_info *p;
 214        unsigned long flags;
 215        int index;
 216
 217        p = kmalloc(sizeof(*p), GFP_ATOMIC);
 218        if (!p)
 219                return -ENOMEM;
 220        p->code = code;
 221        p->handler = handler;
 222        index = ext_hash(code);
 223
 224        spin_lock_irqsave(&ext_int_hash_lock, flags);
 225        hlist_add_head_rcu(&p->entry, &ext_int_hash[index]);
 226        spin_unlock_irqrestore(&ext_int_hash_lock, flags);
 227        return 0;
 228}
 229EXPORT_SYMBOL(register_external_irq);
 230
 231int unregister_external_irq(u16 code, ext_int_handler_t handler)
 232{
 233        struct ext_int_info *p;
 234        unsigned long flags;
 235        int index = ext_hash(code);
 236
 237        spin_lock_irqsave(&ext_int_hash_lock, flags);
 238        hlist_for_each_entry_rcu(p, &ext_int_hash[index], entry) {
 239                if (p->code == code && p->handler == handler) {
 240                        hlist_del_rcu(&p->entry);
 241                        kfree_rcu(p, rcu);
 242                }
 243        }
 244        spin_unlock_irqrestore(&ext_int_hash_lock, flags);
 245        return 0;
 246}
 247EXPORT_SYMBOL(unregister_external_irq);
 248
 249static irqreturn_t do_ext_interrupt(int irq, void *dummy)
 250{
 251        struct pt_regs *regs = get_irq_regs();
 252        struct ext_code ext_code;
 253        struct ext_int_info *p;
 254        int index;
 255
 256        ext_code = *(struct ext_code *) &regs->int_code;
 257        if (ext_code.code != EXT_IRQ_CLK_COMP)
 258                set_cpu_flag(CIF_NOHZ_DELAY);
 259
 260        index = ext_hash(ext_code.code);
 261        rcu_read_lock();
 262        hlist_for_each_entry_rcu(p, &ext_int_hash[index], entry) {
 263                if (unlikely(p->code != ext_code.code))
 264                        continue;
 265                p->handler(ext_code, regs->int_parm, regs->int_parm_long);
 266        }
 267        rcu_read_unlock();
 268        return IRQ_HANDLED;
 269}
 270
 271static struct irqaction external_interrupt = {
 272        .name    = "EXT",
 273        .handler = do_ext_interrupt,
 274};
 275
 276void __init init_ext_interrupts(void)
 277{
 278        int idx;
 279
 280        for (idx = 0; idx < ARRAY_SIZE(ext_int_hash); idx++)
 281                INIT_HLIST_HEAD(&ext_int_hash[idx]);
 282
 283        irq_set_chip_and_handler(EXT_INTERRUPT,
 284                                 &dummy_irq_chip, handle_percpu_irq);
 285        setup_irq(EXT_INTERRUPT, &external_interrupt);
 286}
 287
 288static DEFINE_SPINLOCK(irq_subclass_lock);
 289static unsigned char irq_subclass_refcount[64];
 290
 291void irq_subclass_register(enum irq_subclass subclass)
 292{
 293        spin_lock(&irq_subclass_lock);
 294        if (!irq_subclass_refcount[subclass])
 295                ctl_set_bit(0, subclass);
 296        irq_subclass_refcount[subclass]++;
 297        spin_unlock(&irq_subclass_lock);
 298}
 299EXPORT_SYMBOL(irq_subclass_register);
 300
 301void irq_subclass_unregister(enum irq_subclass subclass)
 302{
 303        spin_lock(&irq_subclass_lock);
 304        irq_subclass_refcount[subclass]--;
 305        if (!irq_subclass_refcount[subclass])
 306                ctl_clear_bit(0, subclass);
 307        spin_unlock(&irq_subclass_lock);
 308}
 309EXPORT_SYMBOL(irq_subclass_unregister);
 310