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  * For compatibilty only. S/390 specific setup of interrupts et al. is done
  92  * much later in init_channel_subsystem().
  93  */
  94 void __init init_IRQ(void)
  95 {
  96         /* nothing... */
  97 }
  98
  99 /*
 100  * Switch to the asynchronous interrupt stack for softirq execution.
 101  */
 102 asmlinkage void do_softirq(void)
 103 {
 104         unsigned long flags, old, new;
 105
 106         if (in_interrupt())
 107                 return;
 108
 109         local_irq_save(flags);
 110
 111         if (local_softirq_pending()) {
 112                 /* Get current stack pointer. */
 113                 asm volatile("la %0,0(15)" : "=a" (old));
 114                 /* Check against async. stack address range. */
 115                 new = S390_lowcore.async_stack;
 116                 if (((new - old) >> (PAGE_SHIFT + THREAD_ORDER)) != 0) {
 117                         /* Need to switch to the async. stack. */
 118                         new -= STACK_FRAME_OVERHEAD;
 119                         ((struct stack_frame *) new)->back_chain = old;
 120
 121                         asm volatile("   la    15,0(%0)\n"
 122                                      "   basr  14,%2\n"
 123                                      "   la    15,0(%1)\n"
 124                                      : : "a" (new), "a" (old),
 125                                          "a" (__do_softirq)
 126                                      : "0", "1", "2", "3", "4", "5", "14",
 127                                        "cc", "memory" );
 128                 } else
 129                         /* We are already on the async stack. */
 130                         __do_softirq();
 131         }
 132
 133         local_irq_restore(flags);
 134 }
 135
 136 #ifdef CONFIG_PROC_FS
 137 void init_irq_proc(void)
 138 {
 139         struct proc_dir_entry *root_irq_dir;
 140
 141         root_irq_dir = proc_mkdir("irq", NULL);
 142         create_prof_cpu_mask(root_irq_dir);
 143 }
 144 #endif
 145
 146 /*
 147  * ext_int_hash[index] is the start of the list for all external interrupts
 148  * that hash to this index. With the current set of external interrupts
 149  * (0x1202 external call, 0x1004 cpu timer, 0x2401 hwc console, 0x4000
 150  * iucv and 0x2603 pfault) this is always the first element.
 151  */
 152
 153 struct ext_int_info {
 154         struct ext_int_info *next;
 155         ext_int_handler_t handler;
 156         u16 code;
 157 };
 158
 159 static struct ext_int_info *ext_int_hash[256];
 160
 161 static inline int ext_hash(u16 code)
 162 {
 163         return (code + (code >> 9)) & 0xff;
 164 }
 165
 166 int register_external_interrupt(u16 code, ext_int_handler_t handler)
 167 {
 168         struct ext_int_info *p;
 169         int index;
 170
 171         p = kmalloc(sizeof(*p), GFP_ATOMIC);
 172         if (!p)
 173                 return -ENOMEM;
 174         p->code = code;
 175         p->handler = handler;
 176         index = ext_hash(code);
 177         p->next = ext_int_hash[index];
 178         ext_int_hash[index] = p;
 179         return 0;
 180 }
 181 EXPORT_SYMBOL(register_external_interrupt);
 182
 183 int unregister_external_interrupt(u16 code, ext_int_handler_t handler)
 184 {
 185         struct ext_int_info *p, *q;
 186         int index;
 187
 188         index = ext_hash(code);
 189         q = NULL;
 190         p = ext_int_hash[index];
 191         while (p) {
 192                 if (p->code == code && p->handler == handler)
 193                         break;
 194                 q = p;
 195                 p = p->next;
 196         }
 197         if (!p)
 198                 return -ENOENT;
 199         if (q)
 200                 q->next = p->next;
 201         else
 202                 ext_int_hash[index] = p->next;
 203         kfree(p);
 204         return 0;
 205 }
 206 EXPORT_SYMBOL(unregister_external_interrupt);
 207
 208 void __irq_entry do_extint(struct pt_regs *regs, unsigned int ext_int_code,
 209                            unsigned int param32, unsigned long param64)
 210 {
 211         struct pt_regs *old_regs;
 212         unsigned short code;
 213         struct ext_int_info *p;
 214         int index;
 215
 216         code = (unsigned short) ext_int_code;
 217         old_regs = set_irq_regs(regs);
 218         s390_idle_check(regs, S390_lowcore.int_clock,
 219                         S390_lowcore.async_enter_timer);
 220         irq_enter();
 221         if (S390_lowcore.int_clock >= S390_lowcore.clock_comparator)
 222                 /* Serve timer interrupts first. */
 223                 clock_comparator_work();
 224         kstat_cpu(smp_processor_id()).irqs[EXTERNAL_INTERRUPT]++;
 225         if (code != 0x1004)
 226                 __get_cpu_var(s390_idle).nohz_delay = 1;
 227         index = ext_hash(code);
 228         for (p = ext_int_hash[index]; p; p = p->next) {
 229                 if (likely(p->code == code))
 230                         p->handler(ext_int_code, param32, param64);
 231         }
 232         irq_exit();
 233         set_irq_regs(old_regs);
 234 }
 235
 236 static DEFINE_SPINLOCK(sc_irq_lock);
 237 static int sc_irq_refcount;
 238
 239 void service_subclass_irq_register(void)
 240 {
 241         spin_lock(&sc_irq_lock);
 242         if (!sc_irq_refcount)
 243                 ctl_set_bit(0, 9);
 244         sc_irq_refcount++;
 245         spin_unlock(&sc_irq_lock);
 246 }
 247 EXPORT_SYMBOL(service_subclass_irq_register);
 248
 249 void service_subclass_irq_unregister(void)
 250 {
 251         spin_lock(&sc_irq_lock);
 252         sc_irq_refcount--;
 253         if (!sc_irq_refcount)
 254                 ctl_clear_bit(0, 9);
 255         spin_unlock(&sc_irq_lock);
 256 }
 257 EXPORT_SYMBOL(service_subclass_irq_unregister);