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 do_IRQ(struct pt_regs *regs, int irq)
  99{
 100        struct pt_regs *old_regs;
 101
 102        old_regs = set_irq_regs(regs);
 103        irq_enter();
 104        if (tod_after_eq(S390_lowcore.int_clock,
 105                         S390_lowcore.clock_comparator))
 106                /* Serve timer interrupts first. */
 107                clock_comparator_work();
 108        generic_handle_irq(irq);
 109        irq_exit();
 110        set_irq_regs(old_regs);
 111}
 112
 113static void show_msi_interrupt(struct seq_file *p, int irq)
 114{
 115        struct irq_desc *desc;
 116        unsigned long flags;
 117        int cpu;
 118
 119        irq_lock_sparse();
 120        desc = irq_to_desc(irq);
 121        if (!desc)
 122                goto out;
 123
 124        raw_spin_lock_irqsave(&desc->lock, flags);
 125        seq_printf(p, "%3d: ", irq);
 126        for_each_online_cpu(cpu)
 127                seq_printf(p, "%10u ", kstat_irqs_cpu(irq, cpu));
 128
 129        if (desc->irq_data.chip)
 130                seq_printf(p, " %8s", desc->irq_data.chip->name);
 131
 132        if (desc->action)
 133                seq_printf(p, "  %s", desc->action->name);
 134
 135        seq_putc(p, '\n');
 136        raw_spin_unlock_irqrestore(&desc->lock, flags);
 137out:
 138        irq_unlock_sparse();
 139}
 140
 141/*
 142 * show_interrupts is needed by /proc/interrupts.
 143 */
 144int show_interrupts(struct seq_file *p, void *v)
 145{
 146        int index = *(loff_t *) v;
 147        int cpu, irq;
 148
 149        get_online_cpus();
 150        if (index == 0) {
 151                seq_puts(p, "           ");
 152                for_each_online_cpu(cpu)
 153                        seq_printf(p, "CPU%-8d", cpu);
 154                seq_putc(p, '\n');
 155        }
 156        if (index < NR_IRQS_BASE) {
 157                seq_printf(p, "%s: ", irqclass_main_desc[index].name);
 158                irq = irqclass_main_desc[index].irq;
 159                for_each_online_cpu(cpu)
 160                        seq_printf(p, "%10u ", kstat_irqs_cpu(irq, cpu));
 161                seq_putc(p, '\n');
 162                goto out;
 163        }
 164        if (index < nr_irqs) {
 165                show_msi_interrupt(p, index);
 166                goto out;
 167        }
 168        for (index = 0; index < NR_ARCH_IRQS; index++) {
 169                seq_printf(p, "%s: ", irqclass_sub_desc[index].name);
 170                irq = irqclass_sub_desc[index].irq;
 171                for_each_online_cpu(cpu)
 172                        seq_printf(p, "%10u ",
 173                                   per_cpu(irq_stat, cpu).irqs[irq]);
 174                if (irqclass_sub_desc[index].desc)
 175                        seq_printf(p, "  %s", irqclass_sub_desc[index].desc);
 176                seq_putc(p, '\n');
 177        }
 178out:
 179        put_online_cpus();
 180        return 0;
 181}
 182
 183unsigned int arch_dynirq_lower_bound(unsigned int from)
 184{
 185        return from < NR_IRQS_BASE ? NR_IRQS_BASE : from;
 186}
 187
 188/*
 189 * Switch to the asynchronous interrupt stack for softirq execution.
 190 */
 191void do_softirq_own_stack(void)
 192{
 193        unsigned long old, new;
 194
 195        old = current_stack_pointer();
 196        /* Check against async. stack address range. */
 197        new = S390_lowcore.async_stack;
 198        if (((new - old) >> (PAGE_SHIFT + THREAD_SIZE_ORDER)) != 0) {
 199                CALL_ON_STACK(__do_softirq, new, 0);
 200        } else {
 201                /* We are already on the async stack. */
 202                __do_softirq();
 203        }
 204}
 205
 206/*
 207 * ext_int_hash[index] is the list head for all external interrupts that hash
 208 * to this index.
 209 */
 210static struct hlist_head ext_int_hash[32] ____cacheline_aligned;
 211
 212struct ext_int_info {
 213        ext_int_handler_t handler;
 214        struct hlist_node entry;
 215        struct rcu_head rcu;
 216        u16 code;
 217};
 218
 219/* ext_int_hash_lock protects the handler lists for external interrupts */
 220static DEFINE_SPINLOCK(ext_int_hash_lock);
 221
 222static inline int ext_hash(u16 code)
 223{
 224        BUILD_BUG_ON(!is_power_of_2(ARRAY_SIZE(ext_int_hash)));
 225
 226        return (code + (code >> 9)) & (ARRAY_SIZE(ext_int_hash) - 1);
 227}
 228
 229int register_external_irq(u16 code, ext_int_handler_t handler)
 230{
 231        struct ext_int_info *p;
 232        unsigned long flags;
 233        int index;
 234
 235        p = kmalloc(sizeof(*p), GFP_ATOMIC);
 236        if (!p)
 237                return -ENOMEM;
 238        p->code = code;
 239        p->handler = handler;
 240        index = ext_hash(code);
 241
 242        spin_lock_irqsave(&ext_int_hash_lock, flags);
 243        hlist_add_head_rcu(&p->entry, &ext_int_hash[index]);
 244        spin_unlock_irqrestore(&ext_int_hash_lock, flags);
 245        return 0;
 246}
 247EXPORT_SYMBOL(register_external_irq);
 248
 249int unregister_external_irq(u16 code, ext_int_handler_t handler)
 250{
 251        struct ext_int_info *p;
 252        unsigned long flags;
 253        int index = ext_hash(code);
 254
 255        spin_lock_irqsave(&ext_int_hash_lock, flags);
 256        hlist_for_each_entry_rcu(p, &ext_int_hash[index], entry) {
 257                if (p->code == code && p->handler == handler) {
 258                        hlist_del_rcu(&p->entry);
 259                        kfree_rcu(p, rcu);
 260                }
 261        }
 262        spin_unlock_irqrestore(&ext_int_hash_lock, flags);
 263        return 0;
 264}
 265EXPORT_SYMBOL(unregister_external_irq);
 266
 267static irqreturn_t do_ext_interrupt(int irq, void *dummy)
 268{
 269        struct pt_regs *regs = get_irq_regs();
 270        struct ext_code ext_code;
 271        struct ext_int_info *p;
 272        int index;
 273
 274        ext_code = *(struct ext_code *) &regs->int_code;
 275        if (ext_code.code != EXT_IRQ_CLK_COMP)
 276                set_cpu_flag(CIF_NOHZ_DELAY);
 277
 278        index = ext_hash(ext_code.code);
 279        rcu_read_lock();
 280        hlist_for_each_entry_rcu(p, &ext_int_hash[index], entry) {
 281                if (unlikely(p->code != ext_code.code))
 282                        continue;
 283                p->handler(ext_code, regs->int_parm, regs->int_parm_long);
 284        }
 285        rcu_read_unlock();
 286        return IRQ_HANDLED;
 287}
 288
 289static void __init init_ext_interrupts(void)
 290{
 291        int idx;
 292
 293        for (idx = 0; idx < ARRAY_SIZE(ext_int_hash); idx++)
 294                INIT_HLIST_HEAD(&ext_int_hash[idx]);
 295
 296        irq_set_chip_and_handler(EXT_INTERRUPT,
 297                                 &dummy_irq_chip, handle_percpu_irq);
 298        if (request_irq(EXT_INTERRUPT, do_ext_interrupt, 0, "EXT", NULL))
 299                panic("Failed to register EXT interrupt\n");
 300}
 301
 302void __init init_IRQ(void)
 303{
 304        BUILD_BUG_ON(ARRAY_SIZE(irqclass_sub_desc) != NR_ARCH_IRQS);
 305        init_cio_interrupts();
 306        init_airq_interrupts();
 307        init_ext_interrupts();
 308}
 309
 310static DEFINE_SPINLOCK(irq_subclass_lock);
 311static unsigned char irq_subclass_refcount[64];
 312
 313void irq_subclass_register(enum irq_subclass subclass)
 314{
 315        spin_lock(&irq_subclass_lock);
 316        if (!irq_subclass_refcount[subclass])
 317                ctl_set_bit(0, subclass);
 318        irq_subclass_refcount[subclass]++;
 319        spin_unlock(&irq_subclass_lock);
 320}
 321EXPORT_SYMBOL(irq_subclass_register);
 322
 323void irq_subclass_unregister(enum irq_subclass subclass)
 324{
 325        spin_lock(&irq_subclass_lock);
 326        irq_subclass_refcount[subclass]--;
 327        if (!irq_subclass_refcount[subclass])
 328                ctl_clear_bit(0, subclass);
 329        spin_unlock(&irq_subclass_lock);
 330}
 331EXPORT_SYMBOL(irq_subclass_unregister);
 332