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