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         [EXTERNAL_INTERRUPT] = {.name = "EXT"},
  34         [IO_INTERRUPT]       = {.name = "I/O"},
  35         [EXTINT_CLK] = {.name = "CLK", .desc = "[EXT] Clock Comparator"},
  36         [EXTINT_EXC] = {.name = "EXC", .desc = "[EXT] External Call"},
  37         [EXTINT_EMS] = {.name = "EMS", .desc = "[EXT] Emergency Signal"},
  38         [EXTINT_TMR] = {.name = "TMR", .desc = "[EXT] CPU Timer"},
  39         [EXTINT_TLA] = {.name = "TAL", .desc = "[EXT] Timing Alert"},
  40         [EXTINT_PFL] = {.name = "PFL", .desc = "[EXT] Pseudo Page Fault"},
  41         [EXTINT_DSD] = {.name = "DSD", .desc = "[EXT] DASD Diag"},
  42         [EXTINT_VRT] = {.name = "VRT", .desc = "[EXT] Virtio"},
  43         [EXTINT_SCP] = {.name = "SCP", .desc = "[EXT] Service Call"},
  44         [EXTINT_IUC] = {.name = "IUC", .desc = "[EXT] IUCV"},
  45         [EXTINT_CMS] = {.name = "CMS", .desc = "[EXT] CPU-Measurement: Sampling"},
  46         [EXTINT_CMC] = {.name = "CMC", .desc = "[EXT] CPU-Measurement: Counter"},
  47         [EXTINT_CMR] = {.name = "CMR", .desc = "[EXT] CPU-Measurement: RI"},
  48         [IOINT_CIO]  = {.name = "CIO", .desc = "[I/O] Common I/O Layer Interrupt"},
  49         [IOINT_QAI]  = {.name = "QAI", .desc = "[I/O] QDIO Adapter Interrupt"},
  50         [IOINT_DAS]  = {.name = "DAS", .desc = "[I/O] DASD"},
  51         [IOINT_C15]  = {.name = "C15", .desc = "[I/O] 3215"},
  52         [IOINT_C70]  = {.name = "C70", .desc = "[I/O] 3270"},
  53         [IOINT_TAP]  = {.name = "TAP", .desc = "[I/O] Tape"},
  54         [IOINT_VMR]  = {.name = "VMR", .desc = "[I/O] Unit Record Devices"},
  55         [IOINT_LCS]  = {.name = "LCS", .desc = "[I/O] LCS"},
  56         [IOINT_CLW]  = {.name = "CLW", .desc = "[I/O] CLAW"},
  57         [IOINT_CTC]  = {.name = "CTC", .desc = "[I/O] CTC"},
  58         [IOINT_APB]  = {.name = "APB", .desc = "[I/O] AP Bus"},
  59         [IOINT_ADM]  = {.name = "ADM", .desc = "[I/O] EADM Subchannel"},
  60         [IOINT_CSC]  = {.name = "CSC", .desc = "[I/O] CHSC Subchannel"},
  61         [NMI_NMI]    = {.name = "NMI", .desc = "[NMI] Machine Check"},
  62 };
  63
  64 /*
  65  * show_interrupts is needed by /proc/interrupts.
  66  */
  67 int show_interrupts(struct seq_file *p, void *v)
  68 {
  69         int i = *(loff_t *) v, j;
  70
  71         get_online_cpus();
  72         if (i == 0) {
  73                 seq_puts(p, "           ");
  74                 for_each_online_cpu(j)
  75                         seq_printf(p, "CPU%d       ",j);
  76                 seq_putc(p, '\n');
  77         }
  78
  79         if (i < NR_IRQS) {
  80                 seq_printf(p, "%s: ", intrclass_names[i].name);
  81 #ifndef CONFIG_SMP
  82                 seq_printf(p, "%10u ", kstat_irqs(i));
  83 #else
  84                 for_each_online_cpu(j)
  85                         seq_printf(p, "%10u ", kstat_cpu(j).irqs[i]);
  86 #endif
  87                 if (intrclass_names[i].desc)
  88                         seq_printf(p, "  %s", intrclass_names[i].desc);
  89                 seq_putc(p, '\n');
  90         }
  91         put_online_cpus();
  92         return 0;
  93 }
  94
  95 /*
  96  * Switch to the asynchronous interrupt stack for softirq execution.
  97  */
  98 asmlinkage void do_softirq(void)
  99 {
 100         unsigned long flags, old, new;
 101
 102         if (in_interrupt())
 103                 return;
 104
 105         local_irq_save(flags);
 106
 107         if (local_softirq_pending()) {
 108                 /* Get current stack pointer. */
 109                 asm volatile("la %0,0(15)" : "=a" (old));
 110                 /* Check against async. stack address range. */
 111                 new = S390_lowcore.async_stack;
 112                 if (((new - old) >> (PAGE_SHIFT + THREAD_ORDER)) != 0) {
 113                         /* Need to switch to the async. stack. */
 114                         new -= STACK_FRAME_OVERHEAD;
 115                         ((struct stack_frame *) new)->back_chain = old;
 116
 117                         asm volatile("   la    15,0(%0)\n"
 118                                      "   basr  14,%2\n"
 119                                      "   la    15,0(%1)\n"
 120                                      : : "a" (new), "a" (old),
 121                                          "a" (__do_softirq)
 122                                      : "0", "1", "2", "3", "4", "5", "14",
 123                                        "cc", "memory" );
 124                 } else {
 125                         /* We are already on the async stack. */
 126                         __do_softirq();
 127                 }
 128         }
 129
 130         local_irq_restore(flags);
 131 }
 132
 133 #ifdef CONFIG_PROC_FS
 134 void init_irq_proc(void)
 135 {
 136         struct proc_dir_entry *root_irq_dir;
 137
 138         root_irq_dir = proc_mkdir("irq", NULL);
 139         create_prof_cpu_mask(root_irq_dir);
 140 }
 141 #endif
 142
 143 /*
 144  * ext_int_hash[index] is the list head for all external interrupts that hash
 145  * to this index.
 146  */
 147 static struct list_head ext_int_hash[256];
 148
 149 struct ext_int_info {
 150         ext_int_handler_t handler;
 151         u16 code;
 152         struct list_head entry;
 153         struct rcu_head rcu;
 154 };
 155
 156 /* ext_int_hash_lock protects the handler lists for external interrupts */
 157 DEFINE_SPINLOCK(ext_int_hash_lock);
 158
 159 static void __init init_external_interrupts(void)
 160 {
 161         int idx;
 162
 163         for (idx = 0; idx < ARRAY_SIZE(ext_int_hash); idx++)
 164                 INIT_LIST_HEAD(&ext_int_hash[idx]);
 165 }
 166
 167 static inline int ext_hash(u16 code)
 168 {
 169         return (code + (code >> 9)) & 0xff;
 170 }
 171
 172 int register_external_interrupt(u16 code, ext_int_handler_t handler)
 173 {
 174         struct ext_int_info *p;
 175         unsigned long flags;
 176         int index;
 177
 178         p = kmalloc(sizeof(*p), GFP_ATOMIC);
 179         if (!p)
 180                 return -ENOMEM;
 181         p->code = code;
 182         p->handler = handler;
 183         index = ext_hash(code);
 184
 185         spin_lock_irqsave(&ext_int_hash_lock, flags);
 186         list_add_rcu(&p->entry, &ext_int_hash[index]);
 187         spin_unlock_irqrestore(&ext_int_hash_lock, flags);
 188         return 0;
 189 }
 190 EXPORT_SYMBOL(register_external_interrupt);
 191
 192 int unregister_external_interrupt(u16 code, ext_int_handler_t handler)
 193 {
 194         struct ext_int_info *p;
 195         unsigned long flags;
 196         int index = ext_hash(code);
 197
 198         spin_lock_irqsave(&ext_int_hash_lock, flags);
 199         list_for_each_entry_rcu(p, &ext_int_hash[index], entry) {
 200                 if (p->code == code && p->handler == handler) {
 201                         list_del_rcu(&p->entry);
 202                         kfree_rcu(p, rcu);
 203                 }
 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, struct ext_code ext_code,
 211                            unsigned int param32, unsigned long param64)
 212 {
 213         struct pt_regs *old_regs;
 214         struct ext_int_info *p;
 215         int index;
 216
 217         old_regs = set_irq_regs(regs);
 218         irq_enter();
 219         if (S390_lowcore.int_clock >= S390_lowcore.clock_comparator) {
 220                 /* Serve timer interrupts first. */
 221                 clock_comparator_work();
 222         }
 223         kstat_cpu(smp_processor_id()).irqs[EXTERNAL_INTERRUPT]++;
 224         if (ext_code.code != 0x1004)
 225                 __get_cpu_var(s390_idle).nohz_delay = 1;
 226
 227         index = ext_hash(ext_code.code);
 228         rcu_read_lock();
 229         list_for_each_entry_rcu(p, &ext_int_hash[index], entry)
 230                 if (likely(p->code == ext_code.code))
 231                         p->handler(ext_code, param32, param64);
 232         rcu_read_unlock();
 233         irq_exit();
 234         set_irq_regs(old_regs);
 235 }
 236
 237 void __init init_IRQ(void)
 238 {
 239         init_external_interrupts();
 240 }
 241
 242 static DEFINE_SPINLOCK(sc_irq_lock);
 243 static int sc_irq_refcount;
 244
 245 void service_subclass_irq_register(void)
 246 {
 247         spin_lock(&sc_irq_lock);
 248         if (!sc_irq_refcount)
 249                 ctl_set_bit(0, 9);
 250         sc_irq_refcount++;
 251         spin_unlock(&sc_irq_lock);
 252 }
 253 EXPORT_SYMBOL(service_subclass_irq_register);
 254
 255 void service_subclass_irq_unregister(void)
 256 {
 257         spin_lock(&sc_irq_lock);
 258         sc_irq_refcount--;
 259         if (!sc_irq_refcount)
 260                 ctl_clear_bit(0, 9);
 261         spin_unlock(&sc_irq_lock);
 262 }
 263 EXPORT_SYMBOL(service_subclass_irq_unregister);
 264
 265 static DEFINE_SPINLOCK(ma_subclass_lock);
 266 static int ma_subclass_refcount;
 267
 268 void measurement_alert_subclass_register(void)
 269 {
 270         spin_lock(&ma_subclass_lock);
 271         if (!ma_subclass_refcount)
 272                 ctl_set_bit(0, 5);
 273         ma_subclass_refcount++;
 274         spin_unlock(&ma_subclass_lock);
 275 }
 276 EXPORT_SYMBOL(measurement_alert_subclass_register);
 277
 278 void measurement_alert_subclass_unregister(void)
 279 {
 280         spin_lock(&ma_subclass_lock);
 281         ma_subclass_refcount--;
 282         if (!ma_subclass_refcount)
 283                 ctl_clear_bit(0, 5);
 284         spin_unlock(&ma_subclass_lock);
 285 }
 286 EXPORT_SYMBOL(measurement_alert_subclass_unregister);