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