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 <asm/hw_irq.h>
  26 #include "entry.h"
  27
  28 DEFINE_PER_CPU_SHARED_ALIGNED(struct irq_stat, irq_stat);
  29 EXPORT_PER_CPU_SYMBOL_GPL(irq_stat);
  30
  31 struct irq_class {
  32         char *name;
  33         char *desc;
  34 };
  35
  36 /*
  37  * The list of "main" irq classes on s390. This is the list of interrupts
  38  * that appear both in /proc/stat ("intr" line) and /proc/interrupts.
  39  * Historically only external and I/O interrupts have been part of /proc/stat.
  40  * We can't add the split external and I/O sub classes since the first field
  41  * in the "intr" line in /proc/stat is supposed to be the sum of all other
  42  * fields.
  43  * Since the external and I/O interrupt fields are already sums we would end
  44  * up with having a sum which accounts each interrupt twice.
  45  */
  46 static const struct irq_class irqclass_main_desc[NR_IRQS_BASE] = {
  47         [EXT_INTERRUPT]  = {.name = "EXT"},
  48         [IO_INTERRUPT]   = {.name = "I/O"},
  49         [THIN_INTERRUPT] = {.name = "AIO"},
  50 };
  51
  52 /*
  53  * The list of split external and I/O interrupts that appear only in
  54  * /proc/interrupts.
  55  * In addition this list contains non external / I/O events like NMIs.
  56  */
  57 static const struct irq_class irqclass_sub_desc[NR_ARCH_IRQS] = {
  58         [IRQEXT_CLK] = {.name = "CLK", .desc = "[EXT] Clock Comparator"},
  59         [IRQEXT_EXC] = {.name = "EXC", .desc = "[EXT] External Call"},
  60         [IRQEXT_EMS] = {.name = "EMS", .desc = "[EXT] Emergency Signal"},
  61         [IRQEXT_TMR] = {.name = "TMR", .desc = "[EXT] CPU Timer"},
  62         [IRQEXT_TLA] = {.name = "TAL", .desc = "[EXT] Timing Alert"},
  63         [IRQEXT_PFL] = {.name = "PFL", .desc = "[EXT] Pseudo Page Fault"},
  64         [IRQEXT_DSD] = {.name = "DSD", .desc = "[EXT] DASD Diag"},
  65         [IRQEXT_VRT] = {.name = "VRT", .desc = "[EXT] Virtio"},
  66         [IRQEXT_SCP] = {.name = "SCP", .desc = "[EXT] Service Call"},
  67         [IRQEXT_IUC] = {.name = "IUC", .desc = "[EXT] IUCV"},
  68         [IRQEXT_CMS] = {.name = "CMS", .desc = "[EXT] CPU-Measurement: Sampling"},
  69         [IRQEXT_CMC] = {.name = "CMC", .desc = "[EXT] CPU-Measurement: Counter"},
  70         [IRQEXT_CMR] = {.name = "CMR", .desc = "[EXT] CPU-Measurement: RI"},
  71         [IRQIO_CIO]  = {.name = "CIO", .desc = "[I/O] Common I/O Layer Interrupt"},
  72         [IRQIO_QAI]  = {.name = "QAI", .desc = "[I/O] QDIO Adapter Interrupt"},
  73         [IRQIO_DAS]  = {.name = "DAS", .desc = "[I/O] DASD"},
  74         [IRQIO_C15]  = {.name = "C15", .desc = "[I/O] 3215"},
  75         [IRQIO_C70]  = {.name = "C70", .desc = "[I/O] 3270"},
  76         [IRQIO_TAP]  = {.name = "TAP", .desc = "[I/O] Tape"},
  77         [IRQIO_VMR]  = {.name = "VMR", .desc = "[I/O] Unit Record Devices"},
  78         [IRQIO_LCS]  = {.name = "LCS", .desc = "[I/O] LCS"},
  79         [IRQIO_CLW]  = {.name = "CLW", .desc = "[I/O] CLAW"},
  80         [IRQIO_CTC]  = {.name = "CTC", .desc = "[I/O] CTC"},
  81         [IRQIO_APB]  = {.name = "APB", .desc = "[I/O] AP Bus"},
  82         [IRQIO_ADM]  = {.name = "ADM", .desc = "[I/O] EADM Subchannel"},
  83         [IRQIO_CSC]  = {.name = "CSC", .desc = "[I/O] CHSC Subchannel"},
  84         [IRQIO_PCI]  = {.name = "PCI", .desc = "[I/O] PCI Interrupt" },
  85         [IRQIO_MSI]  = {.name = "MSI", .desc = "[I/O] MSI Interrupt" },
  86         [IRQIO_VIR]  = {.name = "VIR", .desc = "[I/O] Virtual I/O Devices"},
  87         [NMI_NMI]    = {.name = "NMI", .desc = "[NMI] Machine Check"},
  88         [CPU_RST]    = {.name = "RST", .desc = "[CPU] CPU Restart"},
  89 };
  90
  91 void __init init_IRQ(void)
  92 {
  93         irq_reserve_irqs(0, THIN_INTERRUPT);
  94         init_cio_interrupts();
  95         init_airq_interrupts();
  96         init_ext_interrupts();
  97 }
  98
  99 void do_IRQ(struct pt_regs *regs, int irq)
 100 {
 101         struct pt_regs *old_regs;
 102
 103         old_regs = set_irq_regs(regs);
 104         irq_enter();
 105         if (S390_lowcore.int_clock >= S390_lowcore.clock_comparator)
 106                 /* Serve timer interrupts first. */
 107                 clock_comparator_work();
 108         generic_handle_irq(irq);
 109         irq_exit();
 110         set_irq_regs(old_regs);
 111 }
 112
 113 /*
 114  * show_interrupts is needed by /proc/interrupts.
 115  */
 116 int show_interrupts(struct seq_file *p, void *v)
 117 {
 118         int irq = *(loff_t *) v;
 119         int cpu;
 120
 121         get_online_cpus();
 122         if (irq == 0) {
 123                 seq_puts(p, "           ");
 124                 for_each_online_cpu(cpu)
 125                         seq_printf(p, "CPU%d       ", cpu);
 126                 seq_putc(p, '\n');
 127                 goto out;
 128         }
 129         if (irq < NR_IRQS) {
 130                 if (irq >= NR_IRQS_BASE)
 131                         goto out;
 132                 seq_printf(p, "%s: ", irqclass_main_desc[irq].name);
 133                 for_each_online_cpu(cpu)
 134                         seq_printf(p, "%10u ", kstat_irqs_cpu(irq, cpu));
 135                 seq_putc(p, '\n');
 136                 goto out;
 137         }
 138         for (irq = 0; irq < NR_ARCH_IRQS; irq++) {
 139                 seq_printf(p, "%s: ", irqclass_sub_desc[irq].name);
 140                 for_each_online_cpu(cpu)
 141                         seq_printf(p, "%10u ",
 142                                    per_cpu(irq_stat, cpu).irqs[irq]);
 143                 if (irqclass_sub_desc[irq].desc)
 144                         seq_printf(p, "  %s", irqclass_sub_desc[irq].desc);
 145                 seq_putc(p, '\n');
 146         }
 147 out:
 148         put_online_cpus();
 149         return 0;
 150 }
 151
 152 int arch_show_interrupts(struct seq_file *p, int prec)
 153 {
 154         return 0;
 155 }
 156
 157 /*
 158  * Switch to the asynchronous interrupt stack for softirq execution.
 159  */
 160 asmlinkage void do_softirq(void)
 161 {
 162         unsigned long flags, old, new;
 163
 164         if (in_interrupt())
 165                 return;
 166
 167         local_irq_save(flags);
 168
 169         if (local_softirq_pending()) {
 170                 /* Get current stack pointer. */
 171                 asm volatile("la %0,0(15)" : "=a" (old));
 172                 /* Check against async. stack address range. */
 173                 new = S390_lowcore.async_stack;
 174                 if (((new - old) >> (PAGE_SHIFT + THREAD_ORDER)) != 0) {
 175                         /* Need to switch to the async. stack. */
 176                         new -= STACK_FRAME_OVERHEAD;
 177                         ((struct stack_frame *) new)->back_chain = old;
 178
 179                         asm volatile("   la    15,0(%0)\n"
 180                                      "   basr  14,%2\n"
 181                                      "   la    15,0(%1)\n"
 182                                      : : "a" (new), "a" (old),
 183                                          "a" (__do_softirq)
 184                                      : "0", "1", "2", "3", "4", "5", "14",
 185                                        "cc", "memory" );
 186                 } else {
 187                         /* We are already on the async stack. */
 188                         __do_softirq();
 189                 }
 190         }
 191
 192         local_irq_restore(flags);
 193 }
 194
 195 /*
 196  * ext_int_hash[index] is the list head for all external interrupts that hash
 197  * to this index.
 198  */
 199 static struct hlist_head ext_int_hash[32] ____cacheline_aligned;
 200
 201 struct ext_int_info {
 202         ext_int_handler_t handler;
 203         struct hlist_node entry;
 204         struct rcu_head rcu;
 205         u16 code;
 206 };
 207
 208 /* ext_int_hash_lock protects the handler lists for external interrupts */
 209 static DEFINE_SPINLOCK(ext_int_hash_lock);
 210
 211 static inline int ext_hash(u16 code)
 212 {
 213         BUILD_BUG_ON(!is_power_of_2(ARRAY_SIZE(ext_int_hash)));
 214
 215         return (code + (code >> 9)) & (ARRAY_SIZE(ext_int_hash) - 1);
 216 }
 217
 218 int register_external_interrupt(u16 code, ext_int_handler_t handler)
 219 {
 220         struct ext_int_info *p;
 221         unsigned long flags;
 222         int index;
 223
 224         p = kmalloc(sizeof(*p), GFP_ATOMIC);
 225         if (!p)
 226                 return -ENOMEM;
 227         p->code = code;
 228         p->handler = handler;
 229         index = ext_hash(code);
 230
 231         spin_lock_irqsave(&ext_int_hash_lock, flags);
 232         hlist_add_head_rcu(&p->entry, &ext_int_hash[index]);
 233         spin_unlock_irqrestore(&ext_int_hash_lock, flags);
 234         return 0;
 235 }
 236 EXPORT_SYMBOL(register_external_interrupt);
 237
 238 int unregister_external_interrupt(u16 code, ext_int_handler_t handler)
 239 {
 240         struct ext_int_info *p;
 241         unsigned long flags;
 242         int index = ext_hash(code);
 243
 244         spin_lock_irqsave(&ext_int_hash_lock, flags);
 245         hlist_for_each_entry_rcu(p, &ext_int_hash[index], entry) {
 246                 if (p->code == code && p->handler == handler) {
 247                         hlist_del_rcu(&p->entry);
 248                         kfree_rcu(p, rcu);
 249                 }
 250         }
 251         spin_unlock_irqrestore(&ext_int_hash_lock, flags);
 252         return 0;
 253 }
 254 EXPORT_SYMBOL(unregister_external_interrupt);
 255
 256 static irqreturn_t do_ext_interrupt(int irq, void *dummy)
 257 {
 258         struct pt_regs *regs = get_irq_regs();
 259         struct ext_code ext_code;
 260         struct ext_int_info *p;
 261         int index;
 262
 263         ext_code = *(struct ext_code *) &regs->int_code;
 264         if (ext_code.code != 0x1004)
 265                 __get_cpu_var(s390_idle).nohz_delay = 1;
 266
 267         index = ext_hash(ext_code.code);
 268         rcu_read_lock();
 269         hlist_for_each_entry_rcu(p, &ext_int_hash[index], entry) {
 270                 if (unlikely(p->code != ext_code.code))
 271                         continue;
 272                 p->handler(ext_code, regs->int_parm, regs->int_parm_long);
 273         }
 274         rcu_read_unlock();
 275         return IRQ_HANDLED;
 276 }
 277
 278 static struct irqaction external_interrupt = {
 279         .name    = "EXT",
 280         .handler = do_ext_interrupt,
 281 };
 282
 283 void __init init_ext_interrupts(void)
 284 {
 285         int idx;
 286
 287         for (idx = 0; idx < ARRAY_SIZE(ext_int_hash); idx++)
 288                 INIT_HLIST_HEAD(&ext_int_hash[idx]);
 289
 290         irq_set_chip_and_handler(EXT_INTERRUPT,
 291                                  &dummy_irq_chip, handle_percpu_irq);
 292         setup_irq(EXT_INTERRUPT, &external_interrupt);
 293 }
 294
 295 static DEFINE_SPINLOCK(irq_subclass_lock);
 296 static unsigned char irq_subclass_refcount[64];
 297
 298 void irq_subclass_register(enum irq_subclass subclass)
 299 {
 300         spin_lock(&irq_subclass_lock);
 301         if (!irq_subclass_refcount[subclass])
 302                 ctl_set_bit(0, subclass);
 303         irq_subclass_refcount[subclass]++;
 304         spin_unlock(&irq_subclass_lock);
 305 }
 306 EXPORT_SYMBOL(irq_subclass_register);
 307
 308 void irq_subclass_unregister(enum irq_subclass subclass)
 309 {
 310         spin_lock(&irq_subclass_lock);
 311         irq_subclass_refcount[subclass]--;
 312         if (!irq_subclass_refcount[subclass])
 313                 ctl_clear_bit(0, subclass);
 314         spin_unlock(&irq_subclass_lock);
 315 }
 316 EXPORT_SYMBOL(irq_subclass_unregister);