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/io.h>
  15 #include <linux/irq.h>
  16 #include <linux/vs_context.h>
  17 #include <asm/processor.h>
  18 #include <asm/uaccess.h>
  19 #include <asm/thread_info.h>
  20 #include <asm/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 int show_interrupts(struct seq_file *p, void *v)
  37 {
  38         int i = *(loff_t *) v, j;
  39         struct irqaction * action;
  40         unsigned long flags;
  41
  42         if (i == 0) {
  43                 seq_puts(p, "           ");
  44                 for_each_online_cpu(j)
  45                         seq_printf(p, "CPU%d       ",j);
  46                 seq_putc(p, '\n');
  47         }
  48
  49         if (i < NR_IRQS) {
  50                 spin_lock_irqsave(&irq_desc[i].lock, flags);
  51                 action = irq_desc[i].action;
  52                 if (!action)
  53                         goto unlock;
  54                 seq_printf(p, "%3d: ",i);
  55                 for_each_online_cpu(j)
  56                         seq_printf(p, "%10u ", kstat_cpu(j).irqs[i]);
  57                 seq_printf(p, " %14s", irq_desc[i].chip->name);
  58                 seq_printf(p, "-%-8s", irq_desc[i].name);
  59                 seq_printf(p, "  %s", action->name);
  60
  61                 for (action=action->next; action; action = action->next)
  62                         seq_printf(p, ", %s", action->name);
  63                 seq_putc(p, '\n');
  64 unlock:
  65                 spin_unlock_irqrestore(&irq_desc[i].lock, flags);
  66         } else if (i == NR_IRQS)
  67                 seq_printf(p, "Err: %10u\n", atomic_read(&irq_err_count));
  68
  69         return 0;
  70 }
  71 #endif
  72
  73 #ifdef CONFIG_4KSTACKS
  74 /*
  75  * per-CPU IRQ handling contexts (thread information and stack)
  76  */
  77 union irq_ctx {
  78         struct thread_info      tinfo;
  79         u32                     stack[THREAD_SIZE/sizeof(u32)];
  80 };
  81
  82 static union irq_ctx *hardirq_ctx[NR_CPUS] __read_mostly;
  83 static union irq_ctx *softirq_ctx[NR_CPUS] __read_mostly;
  84 #endif
  85
  86 asmlinkage int do_IRQ(unsigned long r4, unsigned long r5,
  87                       unsigned long r6, unsigned long r7,
  88                       struct pt_regs __regs)
  89 {
  90         struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
  91         struct pt_regs *old_regs = set_irq_regs(regs);
  92         int irq;
  93 #ifdef CONFIG_4KSTACKS
  94         union irq_ctx *curctx, *irqctx;
  95 #endif
  96
  97         irq_enter();
  98
  99 #ifdef CONFIG_DEBUG_STACKOVERFLOW
 100         /* Debugging check for stack overflow: is there less than 1KB free? */
 101         {
 102                 long sp;
 103
 104                 __asm__ __volatile__ ("and r15, %0" :
 105                                         "=r" (sp) : "0" (THREAD_SIZE - 1));
 106
 107                 if (unlikely(sp < (sizeof(struct thread_info) + STACK_WARN))) {
 108                         printk("do_IRQ: stack overflow: %ld\n",
 109                                sp - sizeof(struct thread_info));
 110                         dump_stack();
 111                 }
 112         }
 113 #endif
 114
 115 #ifdef CONFIG_CPU_HAS_INTEVT
 116         irq = evt2irq(ctrl_inl(INTEVT));
 117 #else
 118         irq = r4;
 119 #endif
 120
 121         irq = irq_demux(irq);
 122
 123 #ifdef CONFIG_4KSTACKS
 124         curctx = (union irq_ctx *)current_thread_info();
 125         irqctx = hardirq_ctx[smp_processor_id()];
 126
 127         /*
 128          * this is where we switch to the IRQ stack. However, if we are
 129          * already using the IRQ stack (because we interrupted a hardirq
 130          * handler) we can't do that and just have to keep using the
 131          * current stack (which is the irq stack already after all)
 132          */
 133         if (curctx != irqctx) {
 134                 u32 *isp;
 135
 136                 isp = (u32 *)((char *)irqctx + sizeof(*irqctx));
 137                 irqctx->tinfo.task = curctx->tinfo.task;
 138                 irqctx->tinfo.previous_sp = current_stack_pointer;
 139
 140                 /*
 141                  * Copy the softirq bits in preempt_count so that the
 142                  * softirq checks work in the hardirq context.
 143                  */
 144                 irqctx->tinfo.preempt_count =
 145                         (irqctx->tinfo.preempt_count & ~SOFTIRQ_MASK) |
 146                         (curctx->tinfo.preempt_count & SOFTIRQ_MASK);
 147
 148                 __asm__ __volatile__ (
 149                         "mov    %0, r4          \n"
 150                         "mov    r15, r8         \n"
 151                         "jsr    @%1             \n"
 152                         /* swith to the irq stack */
 153                         " mov   %2, r15         \n"
 154                         /* restore the stack (ring zero) */
 155                         "mov    r8, r15         \n"
 156                         : /* no outputs */
 157                         : "r" (irq), "r" (generic_handle_irq), "r" (isp)
 158                         : "memory", "r0", "r1", "r2", "r3", "r4",
 159                           "r5", "r6", "r7", "r8", "t", "pr"
 160                 );
 161         } else
 162 #endif
 163                 generic_handle_irq(irq);
 164
 165         irq_exit();
 166
 167         set_irq_regs(old_regs);
 168         return 1;
 169 }
 170
 171 #ifdef CONFIG_4KSTACKS
 172 /*
 173  * These should really be __section__(".bss.page_aligned") as well, but
 174  * gcc's 3.0 and earlier don't handle that correctly.
 175  */
 176 static char softirq_stack[NR_CPUS * THREAD_SIZE]
 177                 __attribute__((__aligned__(THREAD_SIZE)));
 178
 179 static char hardirq_stack[NR_CPUS * THREAD_SIZE]
 180                 __attribute__((__aligned__(THREAD_SIZE)));
 181
 182 /*
 183  * allocate per-cpu stacks for hardirq and for softirq processing
 184  */
 185 void irq_ctx_init(int cpu)
 186 {
 187         union irq_ctx *irqctx;
 188
 189         if (hardirq_ctx[cpu])
 190                 return;
 191
 192         irqctx = (union irq_ctx *)&hardirq_stack[cpu * THREAD_SIZE];
 193         irqctx->tinfo.task              = NULL;
 194         irqctx->tinfo.exec_domain       = NULL;
 195         irqctx->tinfo.cpu               = cpu;
 196         irqctx->tinfo.preempt_count     = HARDIRQ_OFFSET;
 197         irqctx->tinfo.addr_limit        = MAKE_MM_SEG(0);
 198
 199         hardirq_ctx[cpu] = irqctx;
 200
 201         irqctx = (union irq_ctx *)&softirq_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     = 0;
 206         irqctx->tinfo.addr_limit        = MAKE_MM_SEG(0);
 207
 208         softirq_ctx[cpu] = irqctx;
 209
 210         printk("CPU %u irqstacks, hard=%p soft=%p\n",
 211                 cpu, hardirq_ctx[cpu], softirq_ctx[cpu]);
 212 }
 213
 214 void irq_ctx_exit(int cpu)
 215 {
 216         hardirq_ctx[cpu] = NULL;
 217 }
 218
 219 extern asmlinkage void __do_softirq(void);
 220
 221 asmlinkage void do_softirq(void)
 222 {
 223         unsigned long flags;
 224         struct thread_info *curctx;
 225         union irq_ctx *irqctx;
 226         u32 *isp;
 227
 228         if (in_interrupt())
 229                 return;
 230
 231         local_irq_save(flags);
 232
 233         if (local_softirq_pending()) {
 234                 curctx = current_thread_info();
 235                 irqctx = softirq_ctx[smp_processor_id()];
 236                 irqctx->tinfo.task = curctx->task;
 237                 irqctx->tinfo.previous_sp = current_stack_pointer;
 238
 239                 /* build the stack frame on the softirq stack */
 240                 isp = (u32 *)((char *)irqctx + sizeof(*irqctx));
 241
 242                 __asm__ __volatile__ (
 243                         "mov    r15, r9         \n"
 244                         "jsr    @%0             \n"
 245                         /* switch to the softirq stack */
 246                         " mov   %1, r15         \n"
 247                         /* restore the thread stack */
 248                         "mov    r9, r15         \n"
 249                         : /* no outputs */
 250                         : "r" (__do_softirq), "r" (isp)
 251                         : "memory", "r0", "r1", "r2", "r3", "r4",
 252                           "r5", "r6", "r7", "r8", "r9", "r15", "t", "pr"
 253                 );
 254
 255                 /*
 256                  * Shouldnt happen, we returned above if in_interrupt():
 257                  */
 258                 WARN_ON_ONCE(softirq_count());
 259         }
 260
 261         local_irq_restore(flags);
 262 }
 263 EXPORT_SYMBOL(do_softirq);
 264 #endif
 265
 266 void __init init_IRQ(void)
 267 {
 268 #ifdef CONFIG_CPU_HAS_PINT_IRQ
 269         init_IRQ_pint();
 270 #endif
 271
 272 #ifdef CONFIG_CPU_HAS_INTC2_IRQ
 273         init_IRQ_intc2();
 274 #endif
 275
 276 #ifdef CONFIG_CPU_HAS_IPR_IRQ
 277         init_IRQ_ipr();
 278 #endif
 279
 280         /* Perform the machine specific initialisation */
 281         if (sh_mv.mv_init_irq)
 282                 sh_mv.mv_init_irq();
 283
 284         irq_ctx_init(smp_processor_id());
 285 }