arch/sh/kernel/irq.c

   1 /*
   2  * linux/arch/sh/kernel/irq.c
   3  *
   4  *      Copyright (C) 1992, 1998 Linus Torvalds, Ingo Molnar
   5  *
   6  *
   7  * SuperH version:  Copyright (C) 1999  Niibe Yutaka
   8  */
   9 #include <linux/irq.h>
  10 #include <linux/interrupt.h>
  11 #include <linux/module.h>
  12 #include <linux/kernel_stat.h>
  13 #include <linux/seq_file.h>
  14 #include <linux/ftrace.h>
  15 #include <linux/delay.h>
  16 #include <asm/processor.h>
  17 #include <asm/machvec.h>
  18 #include <asm/uaccess.h>
  19 #include <asm/thread_info.h>
  20 #include <cpu/mmu_context.h>
  21
  22 atomic_t irq_err_count;
  23
  24 /*
  25  * 'what should we do if we get a hw irq event on an illegal vector'.
  26  * each architecture has to answer this themselves, it doesn't deserve
  27  * a generic callback i think.
  28  */
  29 void ack_bad_irq(unsigned int irq)
  30 {
  31         atomic_inc(&irq_err_count);
  32         printk("unexpected IRQ trap at vector %02x\n", irq);
  33 }
  34
  35 #if defined(CONFIG_PROC_FS)
  36 /*
  37  * /proc/interrupts printing:
  38  */
  39 static int show_other_interrupts(struct seq_file *p, int prec)
  40 {
  41         int j;
  42
  43         seq_printf(p, "%*s: ", prec, "NMI");
  44         for_each_online_cpu(j)
  45                 seq_printf(p, "%10u ", irq_stat[j].__nmi_count);
  46         seq_printf(p, "  Non-maskable interrupts\n");
  47
  48         seq_printf(p, "%*s: %10u\n", prec, "ERR", atomic_read(&irq_err_count));
  49
  50         return 0;
  51 }
  52
  53 int show_interrupts(struct seq_file *p, void *v)
  54 {
  55         unsigned long flags, any_count = 0;
  56         int i = *(loff_t *)v, j, prec;
  57         struct irqaction *action;
  58         struct irq_desc *desc;
  59
  60         if (i > nr_irqs)
  61                 return 0;
  62
  63         for (prec = 3, j = 1000; prec < 10 && j <= nr_irqs; ++prec)
  64                 j *= 10;
  65
  66         if (i == nr_irqs)
  67                 return show_other_interrupts(p, prec);
  68
  69         if (i == 0) {
  70                 seq_printf(p, "%*s", prec + 8, "");
  71                 for_each_online_cpu(j)
  72                         seq_printf(p, "CPU%-8d", j);
  73                 seq_putc(p, '\n');
  74         }
  75
  76         desc = irq_to_desc(i);
  77         if (!desc)
  78                 return 0;
  79
  80         raw_spin_lock_irqsave(&desc->lock, flags);
  81         for_each_online_cpu(j)
  82                 any_count |= kstat_irqs_cpu(i, j);
  83         action = desc->action;
  84         if (!action && !any_count)
  85                 goto out;
  86
  87         seq_printf(p, "%*d: ", prec, i);
  88         for_each_online_cpu(j)
  89                 seq_printf(p, "%10u ", kstat_irqs_cpu(i, j));
  90         seq_printf(p, " %14s", desc->chip->name);
  91         seq_printf(p, "-%-8s", desc->name);
  92
  93         if (action) {
  94                 seq_printf(p, "  %s", action->name);
  95                 while ((action = action->next) != NULL)
  96                         seq_printf(p, ", %s", action->name);
  97         }
  98
  99         seq_putc(p, '\n');
 100 out:
 101         raw_spin_unlock_irqrestore(&desc->lock, flags);
 102         return 0;
 103 }
 104 #endif
 105
 106 #ifdef CONFIG_IRQSTACKS
 107 /*
 108  * per-CPU IRQ handling contexts (thread information and stack)
 109  */
 110 union irq_ctx {
 111         struct thread_info      tinfo;
 112         u32                     stack[THREAD_SIZE/sizeof(u32)];
 113 };
 114
 115 static union irq_ctx *hardirq_ctx[NR_CPUS] __read_mostly;
 116 static union irq_ctx *softirq_ctx[NR_CPUS] __read_mostly;
 117
 118 static char softirq_stack[NR_CPUS * THREAD_SIZE] __page_aligned_bss;
 119 static char hardirq_stack[NR_CPUS * THREAD_SIZE] __page_aligned_bss;
 120
 121 static inline void handle_one_irq(unsigned int irq)
 122 {
 123         union irq_ctx *curctx, *irqctx;
 124
 125         curctx = (union irq_ctx *)current_thread_info();
 126         irqctx = hardirq_ctx[smp_processor_id()];
 127
 128         /*
 129          * this is where we switch to the IRQ stack. However, if we are
 130          * already using the IRQ stack (because we interrupted a hardirq
 131          * handler) we can't do that and just have to keep using the
 132          * current stack (which is the irq stack already after all)
 133          */
 134         if (curctx != irqctx) {
 135                 u32 *isp;
 136
 137                 isp = (u32 *)((char *)irqctx + sizeof(*irqctx));
 138                 irqctx->tinfo.task = curctx->tinfo.task;
 139                 irqctx->tinfo.previous_sp = current_stack_pointer;
 140
 141                 /*
 142                  * Copy the softirq bits in preempt_count so that the
 143                  * softirq checks work in the hardirq context.
 144                  */
 145                 irqctx->tinfo.preempt_count =
 146                         (irqctx->tinfo.preempt_count & ~SOFTIRQ_MASK) |
 147                         (curctx->tinfo.preempt_count & SOFTIRQ_MASK);
 148
 149                 __asm__ __volatile__ (
 150                         "mov    %0, r4          \n"
 151                         "mov    r15, r8         \n"
 152                         "jsr    @%1             \n"
 153                         /* swith to the irq stack */
 154                         " mov   %2, r15         \n"
 155                         /* restore the stack (ring zero) */
 156                         "mov    r8, r15         \n"
 157                         : /* no outputs */
 158                         : "r" (irq), "r" (generic_handle_irq), "r" (isp)
 159                         : "memory", "r0", "r1", "r2", "r3", "r4",
 160                           "r5", "r6", "r7", "r8", "t", "pr"
 161                 );
 162         } else
 163                 generic_handle_irq(irq);
 164 }
 165
 166 /*
 167  * allocate per-cpu stacks for hardirq and for softirq processing
 168  */
 169 void irq_ctx_init(int cpu)
 170 {
 171         union irq_ctx *irqctx;
 172
 173         if (hardirq_ctx[cpu])
 174                 return;
 175
 176         irqctx = (union irq_ctx *)&hardirq_stack[cpu * THREAD_SIZE];
 177         irqctx->tinfo.task              = NULL;
 178         irqctx->tinfo.exec_domain       = NULL;
 179         irqctx->tinfo.cpu               = cpu;
 180         irqctx->tinfo.preempt_count     = HARDIRQ_OFFSET;
 181         irqctx->tinfo.addr_limit        = MAKE_MM_SEG(0);
 182
 183         hardirq_ctx[cpu] = irqctx;
 184
 185         irqctx = (union irq_ctx *)&softirq_stack[cpu * THREAD_SIZE];
 186         irqctx->tinfo.task              = NULL;
 187         irqctx->tinfo.exec_domain       = NULL;
 188         irqctx->tinfo.cpu               = cpu;
 189         irqctx->tinfo.preempt_count     = 0;
 190         irqctx->tinfo.addr_limit        = MAKE_MM_SEG(0);
 191
 192         softirq_ctx[cpu] = irqctx;
 193
 194         printk("CPU %u irqstacks, hard=%p soft=%p\n",
 195                 cpu, hardirq_ctx[cpu], softirq_ctx[cpu]);
 196 }
 197
 198 void irq_ctx_exit(int cpu)
 199 {
 200         hardirq_ctx[cpu] = NULL;
 201 }
 202
 203 asmlinkage void do_softirq(void)
 204 {
 205         unsigned long flags;
 206         struct thread_info *curctx;
 207         union irq_ctx *irqctx;
 208         u32 *isp;
 209
 210         if (in_interrupt())
 211                 return;
 212
 213         local_irq_save(flags);
 214
 215         if (local_softirq_pending()) {
 216                 curctx = current_thread_info();
 217                 irqctx = softirq_ctx[smp_processor_id()];
 218                 irqctx->tinfo.task = curctx->task;
 219                 irqctx->tinfo.previous_sp = current_stack_pointer;
 220
 221                 /* build the stack frame on the softirq stack */
 222                 isp = (u32 *)((char *)irqctx + sizeof(*irqctx));
 223
 224                 __asm__ __volatile__ (
 225                         "mov    r15, r9         \n"
 226                         "jsr    @%0             \n"
 227                         /* switch to the softirq stack */
 228                         " mov   %1, r15         \n"
 229                         /* restore the thread stack */
 230                         "mov    r9, r15         \n"
 231                         : /* no outputs */
 232                         : "r" (__do_softirq), "r" (isp)
 233                         : "memory", "r0", "r1", "r2", "r3", "r4",
 234                           "r5", "r6", "r7", "r8", "r9", "r15", "t", "pr"
 235                 );
 236
 237                 /*
 238                  * Shouldnt happen, we returned above if in_interrupt():
 239                  */
 240                 WARN_ON_ONCE(softirq_count());
 241         }
 242
 243         local_irq_restore(flags);
 244 }
 245 #else
 246 static inline void handle_one_irq(unsigned int irq)
 247 {
 248         generic_handle_irq(irq);
 249 }
 250 #endif
 251
 252 asmlinkage __irq_entry int do_IRQ(unsigned int irq, struct pt_regs *regs)
 253 {
 254         struct pt_regs *old_regs = set_irq_regs(regs);
 255
 256         irq_enter();
 257
 258         irq = irq_demux(irq_lookup(irq));
 259
 260         if (irq != NO_IRQ_IGNORE) {
 261                 handle_one_irq(irq);
 262                 irq_finish(irq);
 263         }
 264
 265         irq_exit();
 266
 267         set_irq_regs(old_regs);
 268
 269         return IRQ_HANDLED;
 270 }
 271
 272 void __init init_IRQ(void)
 273 {
 274         plat_irq_setup();
 275
 276         /*
 277          * Pin any of the legacy IRQ vectors that haven't already been
 278          * grabbed by the platform
 279          */
 280         reserve_irq_legacy();
 281
 282         /* Perform the machine specific initialisation */
 283         if (sh_mv.mv_init_irq)
 284                 sh_mv.mv_init_irq();
 285
 286         irq_ctx_init(smp_processor_id());
 287 }
 288
 289 #ifdef CONFIG_SPARSE_IRQ
 290 int __init arch_probe_nr_irqs(void)
 291 {
 292         nr_irqs = sh_mv.mv_nr_irqs;
 293         return 0;
 294 }
 295 #endif
 296
 297 #ifdef CONFIG_HOTPLUG_CPU
 298 static void route_irq(struct irq_desc *desc, unsigned int irq, unsigned int cpu)
 299 {
 300         printk(KERN_INFO "IRQ%u: moving from cpu%u to cpu%u\n",
 301                irq, desc->node, cpu);
 302
 303         raw_spin_lock_irq(&desc->lock);
 304         desc->chip->set_affinity(irq, cpumask_of(cpu));
 305         raw_spin_unlock_irq(&desc->lock);
 306 }
 307
 308 /*
 309  * The CPU has been marked offline.  Migrate IRQs off this CPU.  If
 310  * the affinity settings do not allow other CPUs, force them onto any
 311  * available CPU.
 312  */
 313 void migrate_irqs(void)
 314 {
 315         struct irq_desc *desc;
 316         unsigned int irq, cpu = smp_processor_id();
 317
 318         for_each_irq_desc(irq, desc) {
 319                 if (desc->node == cpu) {
 320                         unsigned int newcpu = cpumask_any_and(desc->affinity,
 321                                                               cpu_online_mask);
 322                         if (newcpu >= nr_cpu_ids) {
 323                                 if (printk_ratelimit())
 324                                         printk(KERN_INFO "IRQ%u no longer affine to CPU%u\n",
 325                                                irq, cpu);
 326
 327                                 cpumask_setall(desc->affinity);
 328                                 newcpu = cpumask_any_and(desc->affinity,
 329                                                          cpu_online_mask);
 330                         }
 331
 332                         route_irq(desc, irq, newcpu);
 333                 }
 334         }
 335 }
 336 #endif