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 = "CPM", .desc = "[EXT] CPU Measurement" },
  46         {.name = "CIO", .desc = "[I/O] Common I/O Layer Interrupt" },
  47         {.name = "QAI", .desc = "[I/O] QDIO Adapter Interrupt" },
  48         {.name = "DAS", .desc = "[I/O] DASD" },
  49         {.name = "C15", .desc = "[I/O] 3215" },
  50         {.name = "C70", .desc = "[I/O] 3270" },
  51         {.name = "TAP", .desc = "[I/O] Tape" },
  52         {.name = "VMR", .desc = "[I/O] Unit Record Devices" },
  53         {.name = "LCS", .desc = "[I/O] LCS" },
  54         {.name = "CLW", .desc = "[I/O] CLAW" },
  55         {.name = "CTC", .desc = "[I/O] CTC" },
  56         {.name = "APB", .desc = "[I/O] AP Bus" },
  57         {.name = "CSC", .desc = "[I/O] CHSC Subchannel" },
  58         {.name = "NMI", .desc = "[NMI] Machine Check" },
  59 };
  60
  61 /*
  62  * show_interrupts is needed by /proc/interrupts.
  63  */
  64 int show_interrupts(struct seq_file *p, void *v)
  65 {
  66         int i = *(loff_t *) v, j;
  67
  68         get_online_cpus();
  69         if (i == 0) {
  70                 seq_puts(p, "           ");
  71                 for_each_online_cpu(j)
  72                         seq_printf(p, "CPU%d       ",j);
  73                 seq_putc(p, '\n');
  74         }
  75
  76         if (i < NR_IRQS) {
  77                 seq_printf(p, "%s: ", intrclass_names[i].name);
  78 #ifndef CONFIG_SMP
  79                 seq_printf(p, "%10u ", kstat_irqs(i));
  80 #else
  81                 for_each_online_cpu(j)
  82                         seq_printf(p, "%10u ", kstat_cpu(j).irqs[i]);
  83 #endif
  84                 if (intrclass_names[i].desc)
  85                         seq_printf(p, "  %s", intrclass_names[i].desc);
  86                 seq_putc(p, '\n');
  87         }
  88         put_online_cpus();
  89         return 0;
  90 }
  91
  92 /*
  93  * Switch to the asynchronous interrupt stack for softirq execution.
  94  */
  95 asmlinkage void do_softirq(void)
  96 {
  97         unsigned long flags, old, new;
  98
  99         if (in_interrupt())
 100                 return;
 101
 102         local_irq_save(flags);
 103
 104         if (local_softirq_pending()) {
 105                 /* Get current stack pointer. */
 106                 asm volatile("la %0,0(15)" : "=a" (old));
 107                 /* Check against async. stack address range. */
 108                 new = S390_lowcore.async_stack;
 109                 if (((new - old) >> (PAGE_SHIFT + THREAD_ORDER)) != 0) {
 110                         /* Need to switch to the async. stack. */
 111                         new -= STACK_FRAME_OVERHEAD;
 112                         ((struct stack_frame *) new)->back_chain = old;
 113
 114                         asm volatile("   la    15,0(%0)\n"
 115                                      "   basr  14,%2\n"
 116                                      "   la    15,0(%1)\n"
 117                                      : : "a" (new), "a" (old),
 118                                          "a" (__do_softirq)
 119                                      : "0", "1", "2", "3", "4", "5", "14",
 120                                        "cc", "memory" );
 121                 } else
 122                         /* We are already on the async stack. */
 123                         __do_softirq();
 124         }
 125
 126         local_irq_restore(flags);
 127 }
 128
 129 #ifdef CONFIG_PROC_FS
 130 void init_irq_proc(void)
 131 {
 132         struct proc_dir_entry *root_irq_dir;
 133
 134         root_irq_dir = proc_mkdir("irq", NULL);
 135         create_prof_cpu_mask(root_irq_dir);
 136 }
 137 #endif
 138
 139 /*
 140  * ext_int_hash[index] is the list head for all external interrupts that hash
 141  * to this index.
 142  */
 143 static struct list_head ext_int_hash[256];
 144
 145 struct ext_int_info {
 146         ext_int_handler_t handler;
 147         u16 code;
 148         struct list_head entry;
 149         struct rcu_head rcu;
 150 };
 151
 152 /* ext_int_hash_lock protects the handler lists for external interrupts */
 153 DEFINE_SPINLOCK(ext_int_hash_lock);
 154
 155 static void __init init_external_interrupts(void)
 156 {
 157         int idx;
 158
 159         for (idx = 0; idx < ARRAY_SIZE(ext_int_hash); idx++)
 160                 INIT_LIST_HEAD(&ext_int_hash[idx]);
 161 }
 162
 163 static inline int ext_hash(u16 code)
 164 {
 165         return (code + (code >> 9)) & 0xff;
 166 }
 167
 168 static void ext_int_hash_update(struct rcu_head *head)
 169 {
 170         struct ext_int_info *p = container_of(head, struct ext_int_info, rcu);
 171
 172         kfree(p);
 173 }
 174
 175 int register_external_interrupt(u16 code, ext_int_handler_t handler)
 176 {
 177         struct ext_int_info *p;
 178         unsigned long flags;
 179         int index;
 180
 181         p = kmalloc(sizeof(*p), GFP_ATOMIC);
 182         if (!p)
 183                 return -ENOMEM;
 184         p->code = code;
 185         p->handler = handler;
 186         index = ext_hash(code);
 187
 188         spin_lock_irqsave(&ext_int_hash_lock, flags);
 189         list_add_rcu(&p->entry, &ext_int_hash[index]);
 190         spin_unlock_irqrestore(&ext_int_hash_lock, flags);
 191         return 0;
 192 }
 193 EXPORT_SYMBOL(register_external_interrupt);
 194
 195 int unregister_external_interrupt(u16 code, ext_int_handler_t handler)
 196 {
 197         struct ext_int_info *p;
 198         unsigned long flags;
 199         int index = ext_hash(code);
 200
 201         spin_lock_irqsave(&ext_int_hash_lock, flags);
 202         list_for_each_entry_rcu(p, &ext_int_hash[index], entry)
 203                 if (p->code == code && p->handler == handler) {
 204                         list_del_rcu(&p->entry);
 205                         call_rcu(&p->rcu, ext_int_hash_update);
 206                 }
 207         spin_unlock_irqrestore(&ext_int_hash_lock, flags);
 208         return 0;
 209 }
 210 EXPORT_SYMBOL(unregister_external_interrupt);
 211
 212 void __irq_entry do_extint(struct pt_regs *regs, unsigned int ext_int_code,
 213                            unsigned int param32, unsigned long param64)
 214 {
 215         struct pt_regs *old_regs;
 216         unsigned short code;
 217         struct ext_int_info *p;
 218         int index;
 219
 220         code = (unsigned short) ext_int_code;
 221         old_regs = set_irq_regs(regs);
 222         s390_idle_check(regs, S390_lowcore.int_clock,
 223                         S390_lowcore.async_enter_timer);
 224         irq_enter();
 225         if (S390_lowcore.int_clock >= S390_lowcore.clock_comparator)
 226                 /* Serve timer interrupts first. */
 227                 clock_comparator_work();
 228         kstat_cpu(smp_processor_id()).irqs[EXTERNAL_INTERRUPT]++;
 229         if (code != 0x1004)
 230                 __get_cpu_var(s390_idle).nohz_delay = 1;
 231
 232         index = ext_hash(code);
 233         rcu_read_lock();
 234         list_for_each_entry_rcu(p, &ext_int_hash[index], entry)
 235                 if (likely(p->code == code))
 236                         p->handler(ext_int_code, param32, param64);
 237         rcu_read_unlock();
 238         irq_exit();
 239         set_irq_regs(old_regs);
 240 }
 241
 242 void __init init_IRQ(void)
 243 {
 244         init_external_interrupts();
 245 }
 246
 247 static DEFINE_SPINLOCK(sc_irq_lock);
 248 static int sc_irq_refcount;
 249
 250 void service_subclass_irq_register(void)
 251 {
 252         spin_lock(&sc_irq_lock);
 253         if (!sc_irq_refcount)
 254                 ctl_set_bit(0, 9);
 255         sc_irq_refcount++;
 256         spin_unlock(&sc_irq_lock);
 257 }
 258 EXPORT_SYMBOL(service_subclass_irq_register);
 259
 260 void service_subclass_irq_unregister(void)
 261 {
 262         spin_lock(&sc_irq_lock);
 263         sc_irq_refcount--;
 264         if (!sc_irq_refcount)
 265                 ctl_clear_bit(0, 9);
 266         spin_unlock(&sc_irq_lock);
 267 }
 268 EXPORT_SYMBOL(service_subclass_irq_unregister);