arch/s390/kernel/irq.c

   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 <asm/irq_regs.h>
  22 #include <asm/cputime.h>
  23 #include <asm/lowcore.h>
  24 #include <asm/irq.h>
  25 #include <asm/hw_irq.h>
  26 #include "entry.h"
  27
  28 DEFINE_PER_CPU_SHARED_ALIGNED(struct irq_stat, irq_stat);
  29 EXPORT_PER_CPU_SYMBOL_GPL(irq_stat);
  30
  31 struct irq_class {
  32         char *name;
  33         char *desc;
  34 };
  35
  36 /*
  37  * The list of "main" irq classes on s390. This is the list of interrupts
  38  * that appear both in /proc/stat ("intr" line) and /proc/interrupts.
  39  * Historically only external and I/O interrupts have been part of /proc/stat.
  40  * We can't add the split external and I/O sub classes since the first field
  41  * in the "intr" line in /proc/stat is supposed to be the sum of all other
  42  * fields.
  43  * Since the external and I/O interrupt fields are already sums we would end
  44  * up with having a sum which accounts each interrupt twice.
  45  */
  46 static const struct irq_class irqclass_main_desc[NR_IRQS_BASE] = {
  47         [EXT_INTERRUPT]  = {.name = "EXT"},
  48         [IO_INTERRUPT]   = {.name = "I/O"},
  49         [THIN_INTERRUPT] = {.name = "AIO"},
  50 };
  51
  52 /*
  53  * The list of split external and I/O interrupts that appear only in
  54  * /proc/interrupts.
  55  * In addition this list contains non external / I/O events like NMIs.
  56  */
  57 static const struct irq_class irqclass_sub_desc[NR_ARCH_IRQS] = {
  58         [IRQEXT_CLK] = {.name = "CLK", .desc = "[EXT] Clock Comparator"},
  59         [IRQEXT_EXC] = {.name = "EXC", .desc = "[EXT] External Call"},
  60         [IRQEXT_EMS] = {.name = "EMS", .desc = "[EXT] Emergency Signal"},
  61         [IRQEXT_TMR] = {.name = "TMR", .desc = "[EXT] CPU Timer"},
  62         [IRQEXT_TLA] = {.name = "TAL", .desc = "[EXT] Timing Alert"},
  63         [IRQEXT_PFL] = {.name = "PFL", .desc = "[EXT] Pseudo Page Fault"},
  64         [IRQEXT_DSD] = {.name = "DSD", .desc = "[EXT] DASD Diag"},
  65         [IRQEXT_VRT] = {.name = "VRT", .desc = "[EXT] Virtio"},
  66         [IRQEXT_SCP] = {.name = "SCP", .desc = "[EXT] Service Call"},
  67         [IRQEXT_IUC] = {.name = "IUC", .desc = "[EXT] IUCV"},
  68         [IRQEXT_CMS] = {.name = "CMS", .desc = "[EXT] CPU-Measurement: Sampling"},
  69         [IRQEXT_CMC] = {.name = "CMC", .desc = "[EXT] CPU-Measurement: Counter"},
  70         [IRQEXT_CMR] = {.name = "CMR", .desc = "[EXT] CPU-Measurement: RI"},
  71         [IRQIO_CIO]  = {.name = "CIO", .desc = "[I/O] Common I/O Layer Interrupt"},
  72         [IRQIO_QAI]  = {.name = "QAI", .desc = "[I/O] QDIO Adapter Interrupt"},
  73         [IRQIO_DAS]  = {.name = "DAS", .desc = "[I/O] DASD"},
  74         [IRQIO_C15]  = {.name = "C15", .desc = "[I/O] 3215"},
  75         [IRQIO_C70]  = {.name = "C70", .desc = "[I/O] 3270"},
  76         [IRQIO_TAP]  = {.name = "TAP", .desc = "[I/O] Tape"},
  77         [IRQIO_VMR]  = {.name = "VMR", .desc = "[I/O] Unit Record Devices"},
  78         [IRQIO_LCS]  = {.name = "LCS", .desc = "[I/O] LCS"},
  79         [IRQIO_CLW]  = {.name = "CLW", .desc = "[I/O] CLAW"},
  80         [IRQIO_CTC]  = {.name = "CTC", .desc = "[I/O] CTC"},
  81         [IRQIO_APB]  = {.name = "APB", .desc = "[I/O] AP Bus"},
  82         [IRQIO_ADM]  = {.name = "ADM", .desc = "[I/O] EADM Subchannel"},
  83         [IRQIO_CSC]  = {.name = "CSC", .desc = "[I/O] CHSC Subchannel"},
  84         [IRQIO_PCI]  = {.name = "PCI", .desc = "[I/O] PCI Interrupt" },
  85         [IRQIO_MSI]  = {.name = "MSI", .desc = "[I/O] MSI Interrupt" },
  86         [IRQIO_VIR]  = {.name = "VIR", .desc = "[I/O] Virtual I/O Devices"},
  87         [NMI_NMI]    = {.name = "NMI", .desc = "[NMI] Machine Check"},
  88         [CPU_RST]    = {.name = "RST", .desc = "[CPU] CPU Restart"},
  89 };
  90
  91 void __init init_IRQ(void)
  92 {
  93         irq_reserve_irqs(0, THIN_INTERRUPT);
  94         init_cio_interrupts();
  95         init_airq_interrupts();
  96         init_ext_interrupts();
  97 }
  98
  99 void do_IRQ(struct pt_regs *regs, int irq)
 100 {
 101         struct pt_regs *old_regs;
 102
 103         old_regs = set_irq_regs(regs);
 104         irq_enter();
 105         if (S390_lowcore.int_clock >= 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
 113 /*
 114  * show_interrupts is needed by /proc/interrupts.
 115  */
 116 int show_interrupts(struct seq_file *p, void *v)
 117 {
 118         int irq = *(loff_t *) v;
 119         int cpu;
 120
 121         get_online_cpus();
 122         if (irq == 0) {
 123                 seq_puts(p, "           ");
 124                 for_each_online_cpu(cpu)
 125                         seq_printf(p, "CPU%d       ", cpu);
 126                 seq_putc(p, '\n');
 127                 goto out;
 128         }
 129         if (irq < NR_IRQS) {
 130                 if (irq >= NR_IRQS_BASE)
 131                         goto out;
 132                 seq_printf(p, "%s: ", irqclass_main_desc[irq].name);
 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         for (irq = 0; irq < NR_ARCH_IRQS; irq++) {
 139                 seq_printf(p, "%s: ", irqclass_sub_desc[irq].name);
 140                 for_each_online_cpu(cpu)
 141                         seq_printf(p, "%10u ",
 142                                    per_cpu(irq_stat, cpu).irqs[irq]);
 143                 if (irqclass_sub_desc[irq].desc)
 144                         seq_printf(p, "  %s", irqclass_sub_desc[irq].desc);
 145                 seq_putc(p, '\n');
 146         }
 147 out:
 148         put_online_cpus();
 149         return 0;
 150 }
 151
 152 int arch_show_interrupts(struct seq_file *p, int prec)
 153 {
 154         return 0;
 155 }
 156
 157 /*
 158  * Switch to the asynchronous interrupt stack for softirq execution.
 159  */
 160 void do_softirq_own_stack(void)
 161 {
 162         unsigned long old, new;
 163
 164         /* Get current stack pointer. */
 165         asm volatile("la %0,0(15)" : "=a" (old));
 166         /* Check against async. stack address range. */
 167         new = S390_lowcore.async_stack;
 168         if (((new - old) >> (PAGE_SHIFT + THREAD_ORDER)) != 0) {
 169                 /* Need to switch to the async. stack. */
 170                 new -= STACK_FRAME_OVERHEAD;
 171                 ((struct stack_frame *) new)->back_chain = old;
 172                 asm volatile("   la    15,0(%0)\n"
 173                              "   basr  14,%2\n"
 174                              "   la    15,0(%1)\n"
 175                              : : "a" (new), "a" (old),
 176                                  "a" (__do_softirq)
 177                              : "0", "1", "2", "3", "4", "5", "14",
 178                                "cc", "memory" );
 179         } else {
 180                 /* We are already on the async stack. */
 181                 __do_softirq();
 182         }
 183 }
 184
 185 /*
 186  * ext_int_hash[index] is the list head for all external interrupts that hash
 187  * to this index.
 188  */
 189 static struct hlist_head ext_int_hash[32] ____cacheline_aligned;
 190
 191 struct ext_int_info {
 192         ext_int_handler_t handler;
 193         struct hlist_node entry;
 194         struct rcu_head rcu;
 195         u16 code;
 196 };
 197
 198 /* ext_int_hash_lock protects the handler lists for external interrupts */
 199 static DEFINE_SPINLOCK(ext_int_hash_lock);
 200
 201 static inline int ext_hash(u16 code)
 202 {
 203         BUILD_BUG_ON(!is_power_of_2(ARRAY_SIZE(ext_int_hash)));
 204
 205         return (code + (code >> 9)) & (ARRAY_SIZE(ext_int_hash) - 1);
 206 }
 207
 208 int register_external_interrupt(u16 code, ext_int_handler_t handler)
 209 {
 210         struct ext_int_info *p;
 211         unsigned long flags;
 212         int index;
 213
 214         p = kmalloc(sizeof(*p), GFP_ATOMIC);
 215         if (!p)
 216                 return -ENOMEM;
 217         p->code = code;
 218         p->handler = handler;
 219         index = ext_hash(code);
 220
 221         spin_lock_irqsave(&ext_int_hash_lock, flags);
 222         hlist_add_head_rcu(&p->entry, &ext_int_hash[index]);
 223         spin_unlock_irqrestore(&ext_int_hash_lock, flags);
 224         return 0;
 225 }
 226 EXPORT_SYMBOL(register_external_interrupt);
 227
 228 int unregister_external_interrupt(u16 code, ext_int_handler_t handler)
 229 {
 230         struct ext_int_info *p;
 231         unsigned long flags;
 232         int index = ext_hash(code);
 233
 234         spin_lock_irqsave(&ext_int_hash_lock, flags);
 235         hlist_for_each_entry_rcu(p, &ext_int_hash[index], entry) {
 236                 if (p->code == code && p->handler == handler) {
 237                         hlist_del_rcu(&p->entry);
 238                         kfree_rcu(p, rcu);
 239                 }
 240         }
 241         spin_unlock_irqrestore(&ext_int_hash_lock, flags);
 242         return 0;
 243 }
 244 EXPORT_SYMBOL(unregister_external_interrupt);
 245
 246 static irqreturn_t do_ext_interrupt(int irq, void *dummy)
 247 {
 248         struct pt_regs *regs = get_irq_regs();
 249         struct ext_code ext_code;
 250         struct ext_int_info *p;
 251         int index;
 252
 253         ext_code = *(struct ext_code *) &regs->int_code;
 254         if (ext_code.code != 0x1004)
 255                 __get_cpu_var(s390_idle).nohz_delay = 1;
 256
 257         index = ext_hash(ext_code.code);
 258         rcu_read_lock();
 259         hlist_for_each_entry_rcu(p, &ext_int_hash[index], entry) {
 260                 if (unlikely(p->code != ext_code.code))
 261                         continue;
 262                 p->handler(ext_code, regs->int_parm, regs->int_parm_long);
 263         }
 264         rcu_read_unlock();
 265         return IRQ_HANDLED;
 266 }
 267
 268 static struct irqaction external_interrupt = {
 269         .name    = "EXT",
 270         .handler = do_ext_interrupt,
 271 };
 272
 273 void __init init_ext_interrupts(void)
 274 {
 275         int idx;
 276
 277         for (idx = 0; idx < ARRAY_SIZE(ext_int_hash); idx++)
 278                 INIT_HLIST_HEAD(&ext_int_hash[idx]);
 279
 280         irq_set_chip_and_handler(EXT_INTERRUPT,
 281                                  &dummy_irq_chip, handle_percpu_irq);
 282         setup_irq(EXT_INTERRUPT, &external_interrupt);
 283 }
 284
 285 static DEFINE_SPINLOCK(irq_subclass_lock);
 286 static unsigned char irq_subclass_refcount[64];
 287
 288 void irq_subclass_register(enum irq_subclass subclass)
 289 {
 290         spin_lock(&irq_subclass_lock);
 291         if (!irq_subclass_refcount[subclass])
 292                 ctl_set_bit(0, subclass);
 293         irq_subclass_refcount[subclass]++;
 294         spin_unlock(&irq_subclass_lock);
 295 }
 296 EXPORT_SYMBOL(irq_subclass_register);
 297
 298 void irq_subclass_unregister(enum irq_subclass subclass)
 299 {
 300         spin_lock(&irq_subclass_lock);
 301         irq_subclass_refcount[subclass]--;
 302         if (!irq_subclass_refcount[subclass])
 303                 ctl_clear_bit(0, subclass);
 304         spin_unlock(&irq_subclass_lock);
 305 }
 306 EXPORT_SYMBOL(irq_subclass_unregister);