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 <asm/processor.h>
  16 #include <asm/machvec.h>
  17 #include <asm/uaccess.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         int j;
  41
  42         seq_printf(p, "%*s: ", prec, "NMI");
  43         for_each_online_cpu(j)
  44                 seq_printf(p, "%10u ", irq_stat[j].__nmi_count);
  45         seq_printf(p, "  Non-maskable interrupts\n");
  46
  47         seq_printf(p, "%*s: %10u\n", prec, "ERR", atomic_read(&irq_err_count));
  48
  49         return 0;
  50 }
  51
  52 int show_interrupts(struct seq_file *p, void *v)
  53 {
  54         unsigned long flags, any_count = 0;
  55         int i = *(loff_t *)v, j, prec;
  56         struct irqaction *action;
  57         struct irq_desc *desc;
  58
  59         if (i > nr_irqs)
  60                 return 0;
  61
  62         for (prec = 3, j = 1000; prec < 10 && j <= nr_irqs; ++prec)
  63                 j *= 10;
  64
  65         if (i == nr_irqs)
  66                 return show_other_interrupts(p, prec);
  67
  68         if (i == 0) {
  69                 seq_printf(p, "%*s", prec + 8, "");
  70                 for_each_online_cpu(j)
  71                         seq_printf(p, "CPU%-8d", j);
  72                 seq_putc(p, '\n');
  73         }
  74
  75         desc = irq_to_desc(i);
  76         if (!desc)
  77                 return 0;
  78
  79         raw_spin_lock_irqsave(&desc->lock, flags);
  80         for_each_online_cpu(j)
  81                 any_count |= kstat_irqs_cpu(i, j);
  82         action = desc->action;
  83         if (!action && !any_count)
  84                 goto out;
  85
  86         seq_printf(p, "%*d: ", prec, i);
  87         for_each_online_cpu(j)
  88                 seq_printf(p, "%10u ", kstat_irqs_cpu(i, j));
  89         seq_printf(p, " %14s", desc->chip->name);
  90         seq_printf(p, "-%-8s", desc->name);
  91
  92         if (action) {
  93                 seq_printf(p, "  %s", action->name);
  94                 while ((action = action->next) != NULL)
  95                         seq_printf(p, ", %s", action->name);
  96         }
  97
  98         seq_putc(p, '\n');
  99 out:
 100         raw_spin_unlock_irqrestore(&desc->lock, flags);
 101         return 0;
 102 }
 103 #endif
 104
 105 #ifdef CONFIG_IRQSTACKS
 106 /*
 107  * per-CPU IRQ handling contexts (thread information and stack)
 108  */
 109 union irq_ctx {
 110         struct thread_info      tinfo;
 111         u32                     stack[THREAD_SIZE/sizeof(u32)];
 112 };
 113
 114 static union irq_ctx *hardirq_ctx[NR_CPUS] __read_mostly;
 115 static union irq_ctx *softirq_ctx[NR_CPUS] __read_mostly;
 116 #endif
 117
 118 asmlinkage __irq_entry int do_IRQ(unsigned int irq, struct pt_regs *regs)
 119 {
 120         struct pt_regs *old_regs = set_irq_regs(regs);
 121 #ifdef CONFIG_IRQSTACKS
 122         union irq_ctx *curctx, *irqctx;
 123 #endif
 124
 125         irq_enter();
 126         irq = irq_demux(irq);
 127
 128 #ifdef CONFIG_IRQSTACKS
 129         curctx = (union irq_ctx *)current_thread_info();
 130         irqctx = hardirq_ctx[smp_processor_id()];
 131
 132         /*
 133          * this is where we switch to the IRQ stack. However, if we are
 134          * already using the IRQ stack (because we interrupted a hardirq
 135          * handler) we can't do that and just have to keep using the
 136          * current stack (which is the irq stack already after all)
 137          */
 138         if (curctx != irqctx) {
 139                 u32 *isp;
 140
 141                 isp = (u32 *)((char *)irqctx + sizeof(*irqctx));
 142                 irqctx->tinfo.task = curctx->tinfo.task;
 143                 irqctx->tinfo.previous_sp = current_stack_pointer;
 144
 145                 /*
 146                  * Copy the softirq bits in preempt_count so that the
 147                  * softirq checks work in the hardirq context.
 148                  */
 149                 irqctx->tinfo.preempt_count =
 150                         (irqctx->tinfo.preempt_count & ~SOFTIRQ_MASK) |
 151                         (curctx->tinfo.preempt_count & SOFTIRQ_MASK);
 152
 153                 __asm__ __volatile__ (
 154                         "mov    %0, r4          \n"
 155                         "mov    r15, r8         \n"
 156                         "jsr    @%1             \n"
 157                         /* swith to the irq stack */
 158                         " mov   %2, r15         \n"
 159                         /* restore the stack (ring zero) */
 160                         "mov    r8, r15         \n"
 161                         : /* no outputs */
 162                         : "r" (irq), "r" (generic_handle_irq), "r" (isp)
 163                         : "memory", "r0", "r1", "r2", "r3", "r4",
 164                           "r5", "r6", "r7", "r8", "t", "pr"
 165                 );
 166         } else
 167 #endif
 168                 generic_handle_irq(irq);
 169
 170         irq_exit();
 171
 172         set_irq_regs(old_regs);
 173         return 1;
 174 }
 175
 176 #ifdef CONFIG_IRQSTACKS
 177 static char softirq_stack[NR_CPUS * THREAD_SIZE] __page_aligned_bss;
 178
 179 static char hardirq_stack[NR_CPUS * THREAD_SIZE] __page_aligned_bss;
 180
 181 /*
 182  * allocate per-cpu stacks for hardirq and for softirq processing
 183  */
 184 void irq_ctx_init(int cpu)
 185 {
 186         union irq_ctx *irqctx;
 187
 188         if (hardirq_ctx[cpu])
 189                 return;
 190
 191         irqctx = (union irq_ctx *)&hardirq_stack[cpu * THREAD_SIZE];
 192         irqctx->tinfo.task              = NULL;
 193         irqctx->tinfo.exec_domain       = NULL;
 194         irqctx->tinfo.cpu               = cpu;
 195         irqctx->tinfo.preempt_count     = HARDIRQ_OFFSET;
 196         irqctx->tinfo.addr_limit        = MAKE_MM_SEG(0);
 197
 198         hardirq_ctx[cpu] = irqctx;
 199
 200         irqctx = (union irq_ctx *)&softirq_stack[cpu * THREAD_SIZE];
 201         irqctx->tinfo.task              = NULL;
 202         irqctx->tinfo.exec_domain       = NULL;
 203         irqctx->tinfo.cpu               = cpu;
 204         irqctx->tinfo.preempt_count     = 0;
 205         irqctx->tinfo.addr_limit        = MAKE_MM_SEG(0);
 206
 207         softirq_ctx[cpu] = irqctx;
 208
 209         printk("CPU %u irqstacks, hard=%p soft=%p\n",
 210                 cpu, hardirq_ctx[cpu], softirq_ctx[cpu]);
 211 }
 212
 213 void irq_ctx_exit(int cpu)
 214 {
 215         hardirq_ctx[cpu] = NULL;
 216 }
 217
 218 asmlinkage void do_softirq(void)
 219 {
 220         unsigned long flags;
 221         struct thread_info *curctx;
 222         union irq_ctx *irqctx;
 223         u32 *isp;
 224
 225         if (in_interrupt())
 226                 return;
 227
 228         local_irq_save(flags);
 229
 230         if (local_softirq_pending()) {
 231                 curctx = current_thread_info();
 232                 irqctx = softirq_ctx[smp_processor_id()];
 233                 irqctx->tinfo.task = curctx->task;
 234                 irqctx->tinfo.previous_sp = current_stack_pointer;
 235
 236                 /* build the stack frame on the softirq stack */
 237                 isp = (u32 *)((char *)irqctx + sizeof(*irqctx));
 238
 239                 __asm__ __volatile__ (
 240                         "mov    r15, r9         \n"
 241                         "jsr    @%0             \n"
 242                         /* switch to the softirq stack */
 243                         " mov   %1, r15         \n"
 244                         /* restore the thread stack */
 245                         "mov    r9, r15         \n"
 246                         : /* no outputs */
 247                         : "r" (__do_softirq), "r" (isp)
 248                         : "memory", "r0", "r1", "r2", "r3", "r4",
 249                           "r5", "r6", "r7", "r8", "r9", "r15", "t", "pr"
 250                 );
 251
 252                 /*
 253                  * Shouldnt happen, we returned above if in_interrupt():
 254                  */
 255                 WARN_ON_ONCE(softirq_count());
 256         }
 257
 258         local_irq_restore(flags);
 259 }
 260 #endif
 261
 262 void __init init_IRQ(void)
 263 {
 264         plat_irq_setup();
 265
 266         /*
 267          * Pin any of the legacy IRQ vectors that haven't already been
 268          * grabbed by the platform
 269          */
 270         reserve_irq_legacy();
 271
 272         /* Perform the machine specific initialisation */
 273         if (sh_mv.mv_init_irq)
 274                 sh_mv.mv_init_irq();
 275
 276         irq_ctx_init(smp_processor_id());
 277 }
 278
 279 #ifdef CONFIG_SPARSE_IRQ
 280 int __init arch_probe_nr_irqs(void)
 281 {
 282         nr_irqs = sh_mv.mv_nr_irqs;
 283         return 0;
 284 }
 285 #endif