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   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 <asm/irq.h>
  16 #include <asm/processor.h>
  17 #include <asm/uaccess.h>
  18 #include <asm/thread_info.h>
  19 #include <asm/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 int show_interrupts(struct seq_file *p, void *v)
  36 {
  37         int i = *(loff_t *) v, j;
  38         struct irqaction * action;
  39         unsigned long flags;
  40
  41         if (i == 0) {
  42                 seq_puts(p, "           ");
  43                 for_each_online_cpu(j)
  44                         seq_printf(p, "CPU%d       ",j);
  45                 seq_putc(p, '\n');
  46         }
  47
  48         if (i < NR_IRQS) {
  49                 spin_lock_irqsave(&irq_desc[i].lock, flags);
  50                 action = irq_desc[i].action;
  51                 if (!action)
  52                         goto unlock;
  53                 seq_printf(p, "%3d: ",i);
  54                 for_each_online_cpu(j)
  55                         seq_printf(p, "%10u ", kstat_cpu(j).irqs[i]);
  56                 seq_printf(p, " %14s", irq_desc[i].chip->name);
  57                 seq_printf(p, "-%-8s", irq_desc[i].name);
  58                 seq_printf(p, "  %s", action->name);
  59
  60                 for (action=action->next; action; action = action->next)
  61                         seq_printf(p, ", %s", action->name);
  62                 seq_putc(p, '\n');
  63 unlock:
  64                 spin_unlock_irqrestore(&irq_desc[i].lock, flags);
  65         } else if (i == NR_IRQS)
  66                 seq_printf(p, "Err: %10u\n", atomic_read(&irq_err_count));
  67
  68         return 0;
  69 }
  70 #endif
  71
  72 #ifdef CONFIG_4KSTACKS
  73 /*
  74  * per-CPU IRQ handling contexts (thread information and stack)
  75  */
  76 union irq_ctx {
  77         struct thread_info      tinfo;
  78         u32                     stack[THREAD_SIZE/sizeof(u32)];
  79 };
  80
  81 static union irq_ctx *hardirq_ctx[NR_CPUS];
  82 static union irq_ctx *softirq_ctx[NR_CPUS];
  83 #endif
  84
  85 asmlinkage int do_IRQ(unsigned long r4, unsigned long r5,
  86                       unsigned long r6, unsigned long r7,
  87                       struct pt_regs __regs)
  88 {
  89         struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
  90         struct pt_regs *old_regs = set_irq_regs(regs);
  91         int irq;
  92 #ifdef CONFIG_4KSTACKS
  93         union irq_ctx *curctx, *irqctx;
  94 #endif
  95
  96         irq_enter();
  97
  98 #ifdef CONFIG_DEBUG_STACKOVERFLOW
  99         /* Debugging check for stack overflow: is there less than 1KB free? */
 100         {
 101                 long sp;
 102
 103                 __asm__ __volatile__ ("and r15, %0" :
 104                                         "=r" (sp) : "0" (THREAD_SIZE - 1));
 105
 106                 if (unlikely(sp < (sizeof(struct thread_info) + STACK_WARN))) {
 107                         printk("do_IRQ: stack overflow: %ld\n",
 108                                sp - sizeof(struct thread_info));
 109                         dump_stack();
 110                 }
 111         }
 112 #endif
 113
 114 #ifdef CONFIG_CPU_HAS_INTEVT
 115         irq = (ctrl_inl(INTEVT) >> 5) - 16;
 116 #else
 117         irq = r4;
 118 #endif
 119
 120         irq = irq_demux(irq);
 121
 122 #ifdef CONFIG_4KSTACKS
 123         curctx = (union irq_ctx *)current_thread_info();
 124         irqctx = hardirq_ctx[smp_processor_id()];
 125
 126         /*
 127          * this is where we switch to the IRQ stack. However, if we are
 128          * already using the IRQ stack (because we interrupted a hardirq
 129          * handler) we can't do that and just have to keep using the
 130          * current stack (which is the irq stack already after all)
 131          */
 132         if (curctx != irqctx) {
 133                 u32 *isp;
 134
 135                 isp = (u32 *)((char *)irqctx + sizeof(*irqctx));
 136                 irqctx->tinfo.task = curctx->tinfo.task;
 137                 irqctx->tinfo.previous_sp = current_stack_pointer;
 138
 139                 __asm__ __volatile__ (
 140                         "mov    %0, r4          \n"
 141                         "mov    r15, r9         \n"
 142                         "jsr    @%1             \n"
 143                         /* swith to the irq stack */
 144                         " mov   %2, r15         \n"
 145                         /* restore the stack (ring zero) */
 146                         "mov    r9, r15         \n"
 147                         : /* no outputs */
 148                         : "r" (irq), "r" (generic_handle_irq), "r" (isp)
 149                         /* XXX: A somewhat excessive clobber list? -PFM */
 150                         : "memory", "r0", "r1", "r2", "r3", "r4",
 151                           "r5", "r6", "r7", "r8", "t", "pr"
 152                 );
 153         } else
 154 #endif
 155                 generic_handle_irq(irq);
 156
 157         irq_exit();
 158
 159         set_irq_regs(old_regs);
 160         return 1;
 161 }
 162
 163 #ifdef CONFIG_4KSTACKS
 164 /*
 165  * These should really be __section__(".bss.page_aligned") as well, but
 166  * gcc's 3.0 and earlier don't handle that correctly.
 167  */
 168 static char softirq_stack[NR_CPUS * THREAD_SIZE]
 169                 __attribute__((__aligned__(THREAD_SIZE)));
 170
 171 static char hardirq_stack[NR_CPUS * THREAD_SIZE]
 172                 __attribute__((__aligned__(THREAD_SIZE)));
 173
 174 /*
 175  * allocate per-cpu stacks for hardirq and for softirq processing
 176  */
 177 void irq_ctx_init(int cpu)
 178 {
 179         union irq_ctx *irqctx;
 180
 181         if (hardirq_ctx[cpu])
 182                 return;
 183
 184         irqctx = (union irq_ctx *)&hardirq_stack[cpu * THREAD_SIZE];
 185         irqctx->tinfo.task              = NULL;
 186         irqctx->tinfo.exec_domain       = NULL;
 187         irqctx->tinfo.cpu               = cpu;
 188         irqctx->tinfo.preempt_count     = HARDIRQ_OFFSET;
 189         irqctx->tinfo.addr_limit        = MAKE_MM_SEG(0);
 190
 191         hardirq_ctx[cpu] = irqctx;
 192
 193         irqctx = (union irq_ctx *)&softirq_stack[cpu * THREAD_SIZE];
 194         irqctx->tinfo.task              = NULL;
 195         irqctx->tinfo.exec_domain       = NULL;
 196         irqctx->tinfo.cpu               = cpu;
 197         irqctx->tinfo.preempt_count     = SOFTIRQ_OFFSET;
 198         irqctx->tinfo.addr_limit        = MAKE_MM_SEG(0);
 199
 200         softirq_ctx[cpu] = irqctx;
 201
 202         printk("CPU %u irqstacks, hard=%p soft=%p\n",
 203                 cpu, hardirq_ctx[cpu], softirq_ctx[cpu]);
 204 }
 205
 206 void irq_ctx_exit(int cpu)
 207 {
 208         hardirq_ctx[cpu] = NULL;
 209 }
 210
 211 extern asmlinkage void __do_softirq(void);
 212
 213 asmlinkage void do_softirq(void)
 214 {
 215         unsigned long flags;
 216         struct thread_info *curctx;
 217         union irq_ctx *irqctx;
 218         u32 *isp;
 219
 220         if (in_interrupt())
 221                 return;
 222
 223         local_irq_save(flags);
 224
 225         if (local_softirq_pending()) {
 226                 curctx = current_thread_info();
 227                 irqctx = softirq_ctx[smp_processor_id()];
 228                 irqctx->tinfo.task = curctx->task;
 229                 irqctx->tinfo.previous_sp = current_stack_pointer;
 230
 231                 /* build the stack frame on the softirq stack */
 232                 isp = (u32 *)((char *)irqctx + sizeof(*irqctx));
 233
 234                 __asm__ __volatile__ (
 235                         "mov    r15, r9         \n"
 236                         "jsr    @%0             \n"
 237                         /* switch to the softirq stack */
 238                         " mov   %1, r15         \n"
 239                         /* restore the thread stack */
 240                         "mov    r9, r15         \n"
 241                         : /* no outputs */
 242                         : "r" (__do_softirq), "r" (isp)
 243                         /* XXX: A somewhat excessive clobber list? -PFM */
 244                         : "memory", "r0", "r1", "r2", "r3", "r4",
 245                           "r5", "r6", "r7", "r8", "r9", "r15", "t", "pr"
 246                 );
 247         }
 248
 249         local_irq_restore(flags);
 250 }
 251 EXPORT_SYMBOL(do_softirq);
 252 #endif