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 "entry.h"
  26
  27 struct irq_class {
  28         char *name;
  29         char *desc;
  30 };
  31
  32 static const struct irq_class intrclass_names[] = {
  33         {.name = "EXT" },
  34         {.name = "I/O" },
  35         {.name = "CLK", .desc = "[EXT] Clock Comparator" },
  36         {.name = "EXC", .desc = "[EXT] External Call" },
  37         {.name = "EMS", .desc = "[EXT] Emergency Signal" },
  38         {.name = "TMR", .desc = "[EXT] CPU Timer" },
  39         {.name = "TAL", .desc = "[EXT] Timing Alert" },
  40         {.name = "PFL", .desc = "[EXT] Pseudo Page Fault" },
  41         {.name = "DSD", .desc = "[EXT] DASD Diag" },
  42         {.name = "VRT", .desc = "[EXT] Virtio" },
  43         {.name = "SCP", .desc = "[EXT] Service Call" },
  44         {.name = "IUC", .desc = "[EXT] IUCV" },
  45         {.name = "CMS", .desc = "[EXT] CPU-Measurement: Sampling" },
  46         {.name = "CMC", .desc = "[EXT] CPU-Measurement: Counter" },
  47         {.name = "CIO", .desc = "[I/O] Common I/O Layer Interrupt" },
  48         {.name = "QAI", .desc = "[I/O] QDIO Adapter Interrupt" },
  49         {.name = "DAS", .desc = "[I/O] DASD" },
  50         {.name = "C15", .desc = "[I/O] 3215" },
  51         {.name = "C70", .desc = "[I/O] 3270" },
  52         {.name = "TAP", .desc = "[I/O] Tape" },
  53         {.name = "VMR", .desc = "[I/O] Unit Record Devices" },
  54         {.name = "LCS", .desc = "[I/O] LCS" },
  55         {.name = "CLW", .desc = "[I/O] CLAW" },
  56         {.name = "CTC", .desc = "[I/O] CTC" },
  57         {.name = "APB", .desc = "[I/O] AP Bus" },
  58         {.name = "CSC", .desc = "[I/O] CHSC Subchannel" },
  59         {.name = "NMI", .desc = "[NMI] Machine Check" },
  60 };
  61
  62 /*
  63  * show_interrupts is needed by /proc/interrupts.
  64  */
  65 int show_interrupts(struct seq_file *p, void *v)
  66 {
  67         int i = *(loff_t *) v, j;
  68
  69         get_online_cpus();
  70         if (i == 0) {
  71                 seq_puts(p, "           ");
  72                 for_each_online_cpu(j)
  73                         seq_printf(p, "CPU%d       ",j);
  74                 seq_putc(p, '\n');
  75         }
  76
  77         if (i < NR_IRQS) {
  78                 seq_printf(p, "%s: ", intrclass_names[i].name);
  79 #ifndef CONFIG_SMP
  80                 seq_printf(p, "%10u ", kstat_irqs(i));
  81 #else
  82                 for_each_online_cpu(j)
  83                         seq_printf(p, "%10u ", kstat_cpu(j).irqs[i]);
  84 #endif
  85                 if (intrclass_names[i].desc)
  86                         seq_printf(p, "  %s", intrclass_names[i].desc);
  87                 seq_putc(p, '\n');
  88         }
  89         put_online_cpus();
  90         return 0;
  91 }
  92
  93 /*
  94  * Switch to the asynchronous interrupt stack for softirq execution.
  95  */
  96 asmlinkage void do_softirq(void)
  97 {
  98         unsigned long flags, old, new;
  99
 100         if (in_interrupt())
 101                 return;
 102
 103         local_irq_save(flags);
 104
 105         if (local_softirq_pending()) {
 106                 /* Get current stack pointer. */
 107                 asm volatile("la %0,0(15)" : "=a" (old));
 108                 /* Check against async. stack address range. */
 109                 new = S390_lowcore.async_stack;
 110                 if (((new - old) >> (PAGE_SHIFT + THREAD_ORDER)) != 0) {
 111                         /* Need to switch to the async. stack. */
 112                         new -= STACK_FRAME_OVERHEAD;
 113                         ((struct stack_frame *) new)->back_chain = old;
 114
 115                         asm volatile("   la    15,0(%0)\n"
 116                                      "   basr  14,%2\n"
 117                                      "   la    15,0(%1)\n"
 118                                      : : "a" (new), "a" (old),
 119                                          "a" (__do_softirq)
 120                                      : "0", "1", "2", "3", "4", "5", "14",
 121                                        "cc", "memory" );
 122                 } else {
 123                         /* We are already on the async stack. */
 124                         __do_softirq();
 125                 }
 126         }
 127
 128         local_irq_restore(flags);
 129 }
 130
 131 #ifdef CONFIG_PROC_FS
 132 void init_irq_proc(void)
 133 {
 134         struct proc_dir_entry *root_irq_dir;
 135
 136         root_irq_dir = proc_mkdir("irq", NULL);
 137         create_prof_cpu_mask(root_irq_dir);
 138 }
 139 #endif
 140
 141 /*
 142  * ext_int_hash[index] is the list head for all external interrupts that hash
 143  * to this index.
 144  */
 145 static struct list_head ext_int_hash[256];
 146
 147 struct ext_int_info {
 148         ext_int_handler_t handler;
 149         u16 code;
 150         struct list_head entry;
 151         struct rcu_head rcu;
 152 };
 153
 154 /* ext_int_hash_lock protects the handler lists for external interrupts */
 155 DEFINE_SPINLOCK(ext_int_hash_lock);
 156
 157 static void __init init_external_interrupts(void)
 158 {
 159         int idx;
 160
 161         for (idx = 0; idx < ARRAY_SIZE(ext_int_hash); idx++)
 162                 INIT_LIST_HEAD(&ext_int_hash[idx]);
 163 }
 164
 165 static inline int ext_hash(u16 code)
 166 {
 167         return (code + (code >> 9)) & 0xff;
 168 }
 169
 170 int register_external_interrupt(u16 code, ext_int_handler_t handler)
 171 {
 172         struct ext_int_info *p;
 173         unsigned long flags;
 174         int index;
 175
 176         p = kmalloc(sizeof(*p), GFP_ATOMIC);
 177         if (!p)
 178                 return -ENOMEM;
 179         p->code = code;
 180         p->handler = handler;
 181         index = ext_hash(code);
 182
 183         spin_lock_irqsave(&ext_int_hash_lock, flags);
 184         list_add_rcu(&p->entry, &ext_int_hash[index]);
 185         spin_unlock_irqrestore(&ext_int_hash_lock, flags);
 186         return 0;
 187 }
 188 EXPORT_SYMBOL(register_external_interrupt);
 189
 190 int unregister_external_interrupt(u16 code, ext_int_handler_t handler)
 191 {
 192         struct ext_int_info *p;
 193         unsigned long flags;
 194         int index = ext_hash(code);
 195
 196         spin_lock_irqsave(&ext_int_hash_lock, flags);
 197         list_for_each_entry_rcu(p, &ext_int_hash[index], entry) {
 198                 if (p->code == code && p->handler == handler) {
 199                         list_del_rcu(&p->entry);
 200                         kfree_rcu(p, rcu);
 201                 }
 202         }
 203         spin_unlock_irqrestore(&ext_int_hash_lock, flags);
 204         return 0;
 205 }
 206 EXPORT_SYMBOL(unregister_external_interrupt);
 207
 208 void __irq_entry do_extint(struct pt_regs *regs, struct ext_code ext_code,
 209                            unsigned int param32, unsigned long param64)
 210 {
 211         struct pt_regs *old_regs;
 212         struct ext_int_info *p;
 213         int index;
 214
 215         old_regs = set_irq_regs(regs);
 216         irq_enter();
 217         if (S390_lowcore.int_clock >= S390_lowcore.clock_comparator) {
 218                 /* Serve timer interrupts first. */
 219                 clock_comparator_work();
 220         }
 221         kstat_cpu(smp_processor_id()).irqs[EXTERNAL_INTERRUPT]++;
 222         if (ext_code.code != 0x1004)
 223                 __get_cpu_var(s390_idle).nohz_delay = 1;
 224
 225         index = ext_hash(ext_code.code);
 226         rcu_read_lock();
 227         list_for_each_entry_rcu(p, &ext_int_hash[index], entry)
 228                 if (likely(p->code == ext_code.code))
 229                         p->handler(ext_code, param32, param64);
 230         rcu_read_unlock();
 231         irq_exit();
 232         set_irq_regs(old_regs);
 233 }
 234
 235 void __init init_IRQ(void)
 236 {
 237         init_external_interrupts();
 238 }
 239
 240 static DEFINE_SPINLOCK(sc_irq_lock);
 241 static int sc_irq_refcount;
 242
 243 void service_subclass_irq_register(void)
 244 {
 245         spin_lock(&sc_irq_lock);
 246         if (!sc_irq_refcount)
 247                 ctl_set_bit(0, 9);
 248         sc_irq_refcount++;
 249         spin_unlock(&sc_irq_lock);
 250 }
 251 EXPORT_SYMBOL(service_subclass_irq_register);
 252
 253 void service_subclass_irq_unregister(void)
 254 {
 255         spin_lock(&sc_irq_lock);
 256         sc_irq_refcount--;
 257         if (!sc_irq_refcount)
 258                 ctl_clear_bit(0, 9);
 259         spin_unlock(&sc_irq_lock);
 260 }
 261 EXPORT_SYMBOL(service_subclass_irq_unregister);
 262
 263 static DEFINE_SPINLOCK(ma_subclass_lock);
 264 static int ma_subclass_refcount;
 265
 266 void measurement_alert_subclass_register(void)
 267 {
 268         spin_lock(&ma_subclass_lock);
 269         if (!ma_subclass_refcount)
 270                 ctl_set_bit(0, 5);
 271         ma_subclass_refcount++;
 272         spin_unlock(&ma_subclass_lock);
 273 }
 274 EXPORT_SYMBOL(measurement_alert_subclass_register);
 275
 276 void measurement_alert_subclass_unregister(void)
 277 {
 278         spin_lock(&ma_subclass_lock);
 279         ma_subclass_refcount--;
 280         if (!ma_subclass_refcount)
 281                 ctl_clear_bit(0, 5);
 282         spin_unlock(&ma_subclass_lock);
 283 }
 284 EXPORT_SYMBOL(measurement_alert_subclass_unregister);