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