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 <asm/processor.h>
  15 #include <asm/machvec.h>
  16 #include <asm/uaccess.h>
  17 #include <asm/thread_info.h>
  18 #include <cpu/mmu_context.h>
  19
  20 atomic_t irq_err_count;
  21
  22 /*
  23  * 'what should we do if we get a hw irq event on an illegal vector'.
  24  * each architecture has to answer this themselves, it doesn't deserve
  25  * a generic callback i think.
  26  */
  27 void ack_bad_irq(unsigned int irq)
  28 {
  29         atomic_inc(&irq_err_count);
  30         printk("unexpected IRQ trap at vector %02x\n", irq);
  31 }
  32
  33 #if defined(CONFIG_PROC_FS)
  34 /*
  35  * /proc/interrupts printing:
  36  */
  37 static int show_other_interrupts(struct seq_file *p, int prec)
  38 {
  39         seq_printf(p, "%*s: %10u\n", prec, "ERR", atomic_read(&irq_err_count));
  40         return 0;
  41 }
  42
  43 int show_interrupts(struct seq_file *p, void *v)
  44 {
  45         unsigned long flags, any_count = 0;
  46         int i = *(loff_t *)v, j, prec;
  47         struct irqaction *action;
  48         struct irq_desc *desc;
  49
  50         if (i > nr_irqs)
  51                 return 0;
  52
  53         for (prec = 3, j = 1000; prec < 10 && j <= nr_irqs; ++prec)
  54                 j *= 10;
  55
  56         if (i == nr_irqs)
  57                 return show_other_interrupts(p, prec);
  58
  59         if (i == 0) {
  60                 seq_printf(p, "%*s", prec + 8, "");
  61                 for_each_online_cpu(j)
  62                         seq_printf(p, "CPU%-8d", j);
  63                 seq_putc(p, '\n');
  64         }
  65
  66         desc = irq_to_desc(i);
  67         if (!desc)
  68                 return 0;
  69
  70         spin_lock_irqsave(&desc->lock, flags);
  71         for_each_online_cpu(j)
  72                 any_count |= kstat_irqs_cpu(i, j);
  73         action = desc->action;
  74         if (!action && !any_count)
  75                 goto out;
  76
  77         seq_printf(p, "%*d: ", prec, i);
  78         for_each_online_cpu(j)
  79                 seq_printf(p, "%10u ", kstat_irqs_cpu(i, j));
  80         seq_printf(p, " %14s", desc->chip->name);
  81         seq_printf(p, "-%-8s", desc->name);
  82
  83         if (action) {
  84                 seq_printf(p, "  %s", action->name);
  85                 while ((action = action->next) != NULL)
  86                         seq_printf(p, ", %s", action->name);
  87         }
  88
  89         seq_putc(p, '\n');
  90 out:
  91         spin_unlock_irqrestore(&desc->lock, flags);
  92         return 0;
  93 }
  94 #endif
  95
  96 #ifdef CONFIG_IRQSTACKS
  97 /*
  98  * per-CPU IRQ handling contexts (thread information and stack)
  99  */
 100 union irq_ctx {
 101         struct thread_info      tinfo;
 102         u32                     stack[THREAD_SIZE/sizeof(u32)];
 103 };
 104
 105 static union irq_ctx *hardirq_ctx[NR_CPUS] __read_mostly;
 106 static union irq_ctx *softirq_ctx[NR_CPUS] __read_mostly;
 107 #endif
 108
 109 asmlinkage int do_IRQ(unsigned int irq, struct pt_regs *regs)
 110 {
 111         struct pt_regs *old_regs = set_irq_regs(regs);
 112 #ifdef CONFIG_IRQSTACKS
 113         union irq_ctx *curctx, *irqctx;
 114 #endif
 115
 116         irq_enter();
 117
 118 #ifdef CONFIG_DEBUG_STACKOVERFLOW
 119         /* Debugging check for stack overflow: is there less than 1KB free? */
 120         {
 121                 long sp;
 122
 123                 __asm__ __volatile__ ("and r15, %0" :
 124                                         "=r" (sp) : "0" (THREAD_SIZE - 1));
 125
 126                 if (unlikely(sp < (sizeof(struct thread_info) + STACK_WARN))) {
 127                         printk("do_IRQ: stack overflow: %ld\n",
 128                                sp - sizeof(struct thread_info));
 129                         dump_stack();
 130                 }
 131         }
 132 #endif
 133
 134         irq = irq_demux(intc_evt2irq(irq));
 135
 136 #ifdef CONFIG_IRQSTACKS
 137         curctx = (union irq_ctx *)current_thread_info();
 138         irqctx = hardirq_ctx[smp_processor_id()];
 139
 140         /*
 141          * this is where we switch to the IRQ stack. However, if we are
 142          * already using the IRQ stack (because we interrupted a hardirq
 143          * handler) we can't do that and just have to keep using the
 144          * current stack (which is the irq stack already after all)
 145          */
 146         if (curctx != irqctx) {
 147                 u32 *isp;
 148
 149                 isp = (u32 *)((char *)irqctx + sizeof(*irqctx));
 150                 irqctx->tinfo.task = curctx->tinfo.task;
 151                 irqctx->tinfo.previous_sp = current_stack_pointer;
 152
 153                 /*
 154                  * Copy the softirq bits in preempt_count so that the
 155                  * softirq checks work in the hardirq context.
 156                  */
 157                 irqctx->tinfo.preempt_count =
 158                         (irqctx->tinfo.preempt_count & ~SOFTIRQ_MASK) |
 159                         (curctx->tinfo.preempt_count & SOFTIRQ_MASK);
 160
 161                 __asm__ __volatile__ (
 162                         "mov    %0, r4          \n"
 163                         "mov    r15, r8         \n"
 164                         "jsr    @%1             \n"
 165                         /* swith to the irq stack */
 166                         " mov   %2, r15         \n"
 167                         /* restore the stack (ring zero) */
 168                         "mov    r8, r15         \n"
 169                         : /* no outputs */
 170                         : "r" (irq), "r" (generic_handle_irq), "r" (isp)
 171                         : "memory", "r0", "r1", "r2", "r3", "r4",
 172                           "r5", "r6", "r7", "r8", "t", "pr"
 173                 );
 174         } else
 175 #endif
 176                 generic_handle_irq(irq);
 177
 178         irq_exit();
 179
 180         set_irq_regs(old_regs);
 181         return 1;
 182 }
 183
 184 #ifdef CONFIG_IRQSTACKS
 185 static char softirq_stack[NR_CPUS * THREAD_SIZE]
 186                 __attribute__((__section__(".bss.page_aligned")));
 187
 188 static char hardirq_stack[NR_CPUS * THREAD_SIZE]
 189                 __attribute__((__section__(".bss.page_aligned")));
 190
 191 /*
 192  * allocate per-cpu stacks for hardirq and for softirq processing
 193  */
 194 void irq_ctx_init(int cpu)
 195 {
 196         union irq_ctx *irqctx;
 197
 198         if (hardirq_ctx[cpu])
 199                 return;
 200
 201         irqctx = (union irq_ctx *)&hardirq_stack[cpu * THREAD_SIZE];
 202         irqctx->tinfo.task              = NULL;
 203         irqctx->tinfo.exec_domain       = NULL;
 204         irqctx->tinfo.cpu               = cpu;
 205         irqctx->tinfo.preempt_count     = HARDIRQ_OFFSET;
 206         irqctx->tinfo.addr_limit        = MAKE_MM_SEG(0);
 207
 208         hardirq_ctx[cpu] = irqctx;
 209
 210         irqctx = (union irq_ctx *)&softirq_stack[cpu * THREAD_SIZE];
 211         irqctx->tinfo.task              = NULL;
 212         irqctx->tinfo.exec_domain       = NULL;
 213         irqctx->tinfo.cpu               = cpu;
 214         irqctx->tinfo.preempt_count     = 0;
 215         irqctx->tinfo.addr_limit        = MAKE_MM_SEG(0);
 216
 217         softirq_ctx[cpu] = irqctx;
 218
 219         printk("CPU %u irqstacks, hard=%p soft=%p\n",
 220                 cpu, hardirq_ctx[cpu], softirq_ctx[cpu]);
 221 }
 222
 223 void irq_ctx_exit(int cpu)
 224 {
 225         hardirq_ctx[cpu] = NULL;
 226 }
 227
 228 asmlinkage void do_softirq(void)
 229 {
 230         unsigned long flags;
 231         struct thread_info *curctx;
 232         union irq_ctx *irqctx;
 233         u32 *isp;
 234
 235         if (in_interrupt())
 236                 return;
 237
 238         local_irq_save(flags);
 239
 240         if (local_softirq_pending()) {
 241                 curctx = current_thread_info();
 242                 irqctx = softirq_ctx[smp_processor_id()];
 243                 irqctx->tinfo.task = curctx->task;
 244                 irqctx->tinfo.previous_sp = current_stack_pointer;
 245
 246                 /* build the stack frame on the softirq stack */
 247                 isp = (u32 *)((char *)irqctx + sizeof(*irqctx));
 248
 249                 __asm__ __volatile__ (
 250                         "mov    r15, r9         \n"
 251                         "jsr    @%0             \n"
 252                         /* switch to the softirq stack */
 253                         " mov   %1, r15         \n"
 254                         /* restore the thread stack */
 255                         "mov    r9, r15         \n"
 256                         : /* no outputs */
 257                         : "r" (__do_softirq), "r" (isp)
 258                         : "memory", "r0", "r1", "r2", "r3", "r4",
 259                           "r5", "r6", "r7", "r8", "r9", "r15", "t", "pr"
 260                 );
 261
 262                 /*
 263                  * Shouldnt happen, we returned above if in_interrupt():
 264                  */
 265                 WARN_ON_ONCE(softirq_count());
 266         }
 267
 268         local_irq_restore(flags);
 269 }
 270 #endif
 271
 272 void __init init_IRQ(void)
 273 {
 274         plat_irq_setup();
 275
 276         /* Perform the machine specific initialisation */
 277         if (sh_mv.mv_init_irq)
 278                 sh_mv.mv_init_irq();
 279
 280         irq_ctx_init(smp_processor_id());
 281 }