linux/arch/s390/kernel/irq.c
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   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 *    Copyright IBM Corp. 2004, 2011
   4 *    Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>,
   5 *               Holger Smolinski <Holger.Smolinski@de.ibm.com>,
   6 *               Thomas Spatzier <tspat@de.ibm.com>,
   7 *
   8 * This file contains interrupt related functions.
   9 */
  10
  11#include <linux/kernel_stat.h>
  12#include <linux/interrupt.h>
  13#include <linux/seq_file.h>
  14#include <linux/proc_fs.h>
  15#include <linux/profile.h>
  16#include <linux/export.h>
  17#include <linux/kernel.h>
  18#include <linux/ftrace.h>
  19#include <linux/errno.h>
  20#include <linux/slab.h>
  21#include <linux/init.h>
  22#include <linux/cpu.h>
  23#include <linux/irq.h>
  24#include <asm/irq_regs.h>
  25#include <asm/cputime.h>
  26#include <asm/lowcore.h>
  27#include <asm/irq.h>
  28#include <asm/hw_irq.h>
  29#include <asm/stacktrace.h>
  30#include "entry.h"
  31
  32DEFINE_PER_CPU_SHARED_ALIGNED(struct irq_stat, irq_stat);
  33EXPORT_PER_CPU_SYMBOL_GPL(irq_stat);
  34
  35struct irq_class {
  36        int irq;
  37        char *name;
  38        char *desc;
  39};
  40
  41/*
  42 * The list of "main" irq classes on s390. This is the list of interrupts
  43 * that appear both in /proc/stat ("intr" line) and /proc/interrupts.
  44 * Historically only external and I/O interrupts have been part of /proc/stat.
  45 * We can't add the split external and I/O sub classes since the first field
  46 * in the "intr" line in /proc/stat is supposed to be the sum of all other
  47 * fields.
  48 * Since the external and I/O interrupt fields are already sums we would end
  49 * up with having a sum which accounts each interrupt twice.
  50 */
  51static const struct irq_class irqclass_main_desc[NR_IRQS_BASE] = {
  52        {.irq = EXT_INTERRUPT,  .name = "EXT"},
  53        {.irq = IO_INTERRUPT,   .name = "I/O"},
  54        {.irq = THIN_INTERRUPT, .name = "AIO"},
  55};
  56
  57/*
  58 * The list of split external and I/O interrupts that appear only in
  59 * /proc/interrupts.
  60 * In addition this list contains non external / I/O events like NMIs.
  61 */
  62static const struct irq_class irqclass_sub_desc[] = {
  63        {.irq = IRQEXT_CLK, .name = "CLK", .desc = "[EXT] Clock Comparator"},
  64        {.irq = IRQEXT_EXC, .name = "EXC", .desc = "[EXT] External Call"},
  65        {.irq = IRQEXT_EMS, .name = "EMS", .desc = "[EXT] Emergency Signal"},
  66        {.irq = IRQEXT_TMR, .name = "TMR", .desc = "[EXT] CPU Timer"},
  67        {.irq = IRQEXT_TLA, .name = "TAL", .desc = "[EXT] Timing Alert"},
  68        {.irq = IRQEXT_PFL, .name = "PFL", .desc = "[EXT] Pseudo Page Fault"},
  69        {.irq = IRQEXT_DSD, .name = "DSD", .desc = "[EXT] DASD Diag"},
  70        {.irq = IRQEXT_VRT, .name = "VRT", .desc = "[EXT] Virtio"},
  71        {.irq = IRQEXT_SCP, .name = "SCP", .desc = "[EXT] Service Call"},
  72        {.irq = IRQEXT_IUC, .name = "IUC", .desc = "[EXT] IUCV"},
  73        {.irq = IRQEXT_CMS, .name = "CMS", .desc = "[EXT] CPU-Measurement: Sampling"},
  74        {.irq = IRQEXT_CMC, .name = "CMC", .desc = "[EXT] CPU-Measurement: Counter"},
  75        {.irq = IRQEXT_FTP, .name = "FTP", .desc = "[EXT] HMC FTP Service"},
  76        {.irq = IRQIO_CIO,  .name = "CIO", .desc = "[I/O] Common I/O Layer Interrupt"},
  77        {.irq = IRQIO_DAS,  .name = "DAS", .desc = "[I/O] DASD"},
  78        {.irq = IRQIO_C15,  .name = "C15", .desc = "[I/O] 3215"},
  79        {.irq = IRQIO_C70,  .name = "C70", .desc = "[I/O] 3270"},
  80        {.irq = IRQIO_TAP,  .name = "TAP", .desc = "[I/O] Tape"},
  81        {.irq = IRQIO_VMR,  .name = "VMR", .desc = "[I/O] Unit Record Devices"},
  82        {.irq = IRQIO_LCS,  .name = "LCS", .desc = "[I/O] LCS"},
  83        {.irq = IRQIO_CTC,  .name = "CTC", .desc = "[I/O] CTC"},
  84        {.irq = IRQIO_ADM,  .name = "ADM", .desc = "[I/O] EADM Subchannel"},
  85        {.irq = IRQIO_CSC,  .name = "CSC", .desc = "[I/O] CHSC Subchannel"},
  86        {.irq = IRQIO_VIR,  .name = "VIR", .desc = "[I/O] Virtual I/O Devices"},
  87        {.irq = IRQIO_QAI,  .name = "QAI", .desc = "[AIO] QDIO Adapter Interrupt"},
  88        {.irq = IRQIO_APB,  .name = "APB", .desc = "[AIO] AP Bus"},
  89        {.irq = IRQIO_PCF,  .name = "PCF", .desc = "[AIO] PCI Floating Interrupt"},
  90        {.irq = IRQIO_PCD,  .name = "PCD", .desc = "[AIO] PCI Directed Interrupt"},
  91        {.irq = IRQIO_MSI,  .name = "MSI", .desc = "[AIO] MSI Interrupt"},
  92        {.irq = IRQIO_VAI,  .name = "VAI", .desc = "[AIO] Virtual I/O Devices AI"},
  93        {.irq = IRQIO_GAL,  .name = "GAL", .desc = "[AIO] GIB Alert"},
  94        {.irq = NMI_NMI,    .name = "NMI", .desc = "[NMI] Machine Check"},
  95        {.irq = CPU_RST,    .name = "RST", .desc = "[CPU] CPU Restart"},
  96};
  97
  98void __init init_IRQ(void)
  99{
 100        BUILD_BUG_ON(ARRAY_SIZE(irqclass_sub_desc) != NR_ARCH_IRQS);
 101        init_cio_interrupts();
 102        init_airq_interrupts();
 103        init_ext_interrupts();
 104}
 105
 106void do_IRQ(struct pt_regs *regs, int irq)
 107{
 108        struct pt_regs *old_regs;
 109
 110        old_regs = set_irq_regs(regs);
 111        irq_enter();
 112        if (tod_after_eq(S390_lowcore.int_clock,
 113                         S390_lowcore.clock_comparator))
 114                /* Serve timer interrupts first. */
 115                clock_comparator_work();
 116        generic_handle_irq(irq);
 117        irq_exit();
 118        set_irq_regs(old_regs);
 119}
 120
 121static void show_msi_interrupt(struct seq_file *p, int irq)
 122{
 123        struct irq_desc *desc;
 124        unsigned long flags;
 125        int cpu;
 126
 127        irq_lock_sparse();
 128        desc = irq_to_desc(irq);
 129        if (!desc)
 130                goto out;
 131
 132        raw_spin_lock_irqsave(&desc->lock, flags);
 133        seq_printf(p, "%3d: ", irq);
 134        for_each_online_cpu(cpu)
 135                seq_printf(p, "%10u ", kstat_irqs_cpu(irq, cpu));
 136
 137        if (desc->irq_data.chip)
 138                seq_printf(p, " %8s", desc->irq_data.chip->name);
 139
 140        if (desc->action)
 141                seq_printf(p, "  %s", desc->action->name);
 142
 143        seq_putc(p, '\n');
 144        raw_spin_unlock_irqrestore(&desc->lock, flags);
 145out:
 146        irq_unlock_sparse();
 147}
 148
 149/*
 150 * show_interrupts is needed by /proc/interrupts.
 151 */
 152int show_interrupts(struct seq_file *p, void *v)
 153{
 154        int index = *(loff_t *) v;
 155        int cpu, irq;
 156
 157        get_online_cpus();
 158        if (index == 0) {
 159                seq_puts(p, "           ");
 160                for_each_online_cpu(cpu)
 161                        seq_printf(p, "CPU%-8d", cpu);
 162                seq_putc(p, '\n');
 163        }
 164        if (index < NR_IRQS_BASE) {
 165                seq_printf(p, "%s: ", irqclass_main_desc[index].name);
 166                irq = irqclass_main_desc[index].irq;
 167                for_each_online_cpu(cpu)
 168                        seq_printf(p, "%10u ", kstat_irqs_cpu(irq, cpu));
 169                seq_putc(p, '\n');
 170                goto out;
 171        }
 172        if (index < nr_irqs) {
 173                show_msi_interrupt(p, index);
 174                goto out;
 175        }
 176        for (index = 0; index < NR_ARCH_IRQS; index++) {
 177                seq_printf(p, "%s: ", irqclass_sub_desc[index].name);
 178                irq = irqclass_sub_desc[index].irq;
 179                for_each_online_cpu(cpu)
 180                        seq_printf(p, "%10u ",
 181                                   per_cpu(irq_stat, cpu).irqs[irq]);
 182                if (irqclass_sub_desc[index].desc)
 183                        seq_printf(p, "  %s", irqclass_sub_desc[index].desc);
 184                seq_putc(p, '\n');
 185        }
 186out:
 187        put_online_cpus();
 188        return 0;
 189}
 190
 191unsigned int arch_dynirq_lower_bound(unsigned int from)
 192{
 193        return from < NR_IRQS_BASE ? NR_IRQS_BASE : from;
 194}
 195
 196/*
 197 * Switch to the asynchronous interrupt stack for softirq execution.
 198 */
 199void do_softirq_own_stack(void)
 200{
 201        unsigned long old, new;
 202
 203        old = current_stack_pointer();
 204        /* Check against async. stack address range. */
 205        new = S390_lowcore.async_stack;
 206        if (((new - old) >> (PAGE_SHIFT + THREAD_SIZE_ORDER)) != 0) {
 207                CALL_ON_STACK(__do_softirq, new, 0);
 208        } else {
 209                /* We are already on the async stack. */
 210                __do_softirq();
 211        }
 212}
 213
 214/*
 215 * ext_int_hash[index] is the list head for all external interrupts that hash
 216 * to this index.
 217 */
 218static struct hlist_head ext_int_hash[32] ____cacheline_aligned;
 219
 220struct ext_int_info {
 221        ext_int_handler_t handler;
 222        struct hlist_node entry;
 223        struct rcu_head rcu;
 224        u16 code;
 225};
 226
 227/* ext_int_hash_lock protects the handler lists for external interrupts */
 228static DEFINE_SPINLOCK(ext_int_hash_lock);
 229
 230static inline int ext_hash(u16 code)
 231{
 232        BUILD_BUG_ON(!is_power_of_2(ARRAY_SIZE(ext_int_hash)));
 233
 234        return (code + (code >> 9)) & (ARRAY_SIZE(ext_int_hash) - 1);
 235}
 236
 237int register_external_irq(u16 code, ext_int_handler_t handler)
 238{
 239        struct ext_int_info *p;
 240        unsigned long flags;
 241        int index;
 242
 243        p = kmalloc(sizeof(*p), GFP_ATOMIC);
 244        if (!p)
 245                return -ENOMEM;
 246        p->code = code;
 247        p->handler = handler;
 248        index = ext_hash(code);
 249
 250        spin_lock_irqsave(&ext_int_hash_lock, flags);
 251        hlist_add_head_rcu(&p->entry, &ext_int_hash[index]);
 252        spin_unlock_irqrestore(&ext_int_hash_lock, flags);
 253        return 0;
 254}
 255EXPORT_SYMBOL(register_external_irq);
 256
 257int unregister_external_irq(u16 code, ext_int_handler_t handler)
 258{
 259        struct ext_int_info *p;
 260        unsigned long flags;
 261        int index = ext_hash(code);
 262
 263        spin_lock_irqsave(&ext_int_hash_lock, flags);
 264        hlist_for_each_entry_rcu(p, &ext_int_hash[index], entry) {
 265                if (p->code == code && p->handler == handler) {
 266                        hlist_del_rcu(&p->entry);
 267                        kfree_rcu(p, rcu);
 268                }
 269        }
 270        spin_unlock_irqrestore(&ext_int_hash_lock, flags);
 271        return 0;
 272}
 273EXPORT_SYMBOL(unregister_external_irq);
 274
 275static irqreturn_t do_ext_interrupt(int irq, void *dummy)
 276{
 277        struct pt_regs *regs = get_irq_regs();
 278        struct ext_code ext_code;
 279        struct ext_int_info *p;
 280        int index;
 281
 282        ext_code = *(struct ext_code *) &regs->int_code;
 283        if (ext_code.code != EXT_IRQ_CLK_COMP)
 284                set_cpu_flag(CIF_NOHZ_DELAY);
 285
 286        index = ext_hash(ext_code.code);
 287        rcu_read_lock();
 288        hlist_for_each_entry_rcu(p, &ext_int_hash[index], entry) {
 289                if (unlikely(p->code != ext_code.code))
 290                        continue;
 291                p->handler(ext_code, regs->int_parm, regs->int_parm_long);
 292        }
 293        rcu_read_unlock();
 294        return IRQ_HANDLED;
 295}
 296
 297static struct irqaction external_interrupt = {
 298        .name    = "EXT",
 299        .handler = do_ext_interrupt,
 300};
 301
 302void __init init_ext_interrupts(void)
 303{
 304        int idx;
 305
 306        for (idx = 0; idx < ARRAY_SIZE(ext_int_hash); idx++)
 307                INIT_HLIST_HEAD(&ext_int_hash[idx]);
 308
 309        irq_set_chip_and_handler(EXT_INTERRUPT,
 310                                 &dummy_irq_chip, handle_percpu_irq);
 311        setup_irq(EXT_INTERRUPT, &external_interrupt);
 312}
 313
 314static DEFINE_SPINLOCK(irq_subclass_lock);
 315static unsigned char irq_subclass_refcount[64];
 316
 317void irq_subclass_register(enum irq_subclass subclass)
 318{
 319        spin_lock(&irq_subclass_lock);
 320        if (!irq_subclass_refcount[subclass])
 321                ctl_set_bit(0, subclass);
 322        irq_subclass_refcount[subclass]++;
 323        spin_unlock(&irq_subclass_lock);
 324}
 325EXPORT_SYMBOL(irq_subclass_register);
 326
 327void irq_subclass_unregister(enum irq_subclass subclass)
 328{
 329        spin_lock(&irq_subclass_lock);
 330        irq_subclass_refcount[subclass]--;
 331        if (!irq_subclass_refcount[subclass])
 332                ctl_clear_bit(0, subclass);
 333        spin_unlock(&irq_subclass_lock);
 334}
 335EXPORT_SYMBOL(irq_subclass_unregister);
 336