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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 <asm/processor.h>
  15 #include <asm/machvec.h>
  16 #include <asm/uaccess.h>
  17 #include <asm/thread_info.h>
  18 #include <asm/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 int show_interrupts(struct seq_file *p, void *v)
  35 {
  36         int i = *(loff_t *) v, j;
  37         struct irqaction * action;
  38         unsigned long flags;
  39
  40         if (i == 0) {
  41                 seq_puts(p, "           ");
  42                 for_each_online_cpu(j)
  43                         seq_printf(p, "CPU%d       ",j);
  44                 seq_putc(p, '\n');
  45         }
  46
  47         if (i < sh_mv.mv_nr_irqs) {
  48                 spin_lock_irqsave(&irq_desc[i].lock, flags);
  49                 action = irq_desc[i].action;
  50                 if (!action)
  51                         goto unlock;
  52                 seq_printf(p, "%3d: ",i);
  53                 for_each_online_cpu(j)
  54                         seq_printf(p, "%10u ", kstat_cpu(j).irqs[i]);
  55                 seq_printf(p, " %14s", irq_desc[i].chip->name);
  56                 seq_printf(p, "-%-8s", irq_desc[i].name);
  57                 seq_printf(p, "  %s", action->name);
  58
  59                 for (action=action->next; action; action = action->next)
  60                         seq_printf(p, ", %s", action->name);
  61                 seq_putc(p, '\n');
  62 unlock:
  63                 spin_unlock_irqrestore(&irq_desc[i].lock, flags);
  64         } else if (i == sh_mv.mv_nr_irqs)
  65                 seq_printf(p, "Err: %10u\n", atomic_read(&irq_err_count));
  66
  67         return 0;
  68 }
  69 #endif
  70
  71 #ifdef CONFIG_IRQSTACKS
  72 /*
  73  * per-CPU IRQ handling contexts (thread information and stack)
  74  */
  75 union irq_ctx {
  76         struct thread_info      tinfo;
  77         u32                     stack[THREAD_SIZE/sizeof(u32)];
  78 };
  79
  80 static union irq_ctx *hardirq_ctx[NR_CPUS] __read_mostly;
  81 static union irq_ctx *softirq_ctx[NR_CPUS] __read_mostly;
  82 #endif
  83
  84 asmlinkage int do_IRQ(unsigned int irq, struct pt_regs *regs)
  85 {
  86         struct pt_regs *old_regs = set_irq_regs(regs);
  87 #ifdef CONFIG_IRQSTACKS
  88         union irq_ctx *curctx, *irqctx;
  89 #endif
  90
  91         irq_enter();
  92
  93 #ifdef CONFIG_DEBUG_STACKOVERFLOW
  94         /* Debugging check for stack overflow: is there less than 1KB free? */
  95         {
  96                 long sp;
  97
  98                 __asm__ __volatile__ ("and r15, %0" :
  99                                         "=r" (sp) : "0" (THREAD_SIZE - 1));
 100
 101                 if (unlikely(sp < (sizeof(struct thread_info) + STACK_WARN))) {
 102                         printk("do_IRQ: stack overflow: %ld\n",
 103                                sp - sizeof(struct thread_info));
 104                         dump_stack();
 105                 }
 106         }
 107 #endif
 108
 109         irq = irq_demux(evt2irq(irq));
 110
 111 #ifdef CONFIG_IRQSTACKS
 112         curctx = (union irq_ctx *)current_thread_info();
 113         irqctx = hardirq_ctx[smp_processor_id()];
 114
 115         /*
 116          * this is where we switch to the IRQ stack. However, if we are
 117          * already using the IRQ stack (because we interrupted a hardirq
 118          * handler) we can't do that and just have to keep using the
 119          * current stack (which is the irq stack already after all)
 120          */
 121         if (curctx != irqctx) {
 122                 u32 *isp;
 123
 124                 isp = (u32 *)((char *)irqctx + sizeof(*irqctx));
 125                 irqctx->tinfo.task = curctx->tinfo.task;
 126                 irqctx->tinfo.previous_sp = current_stack_pointer;
 127
 128                 /*
 129                  * Copy the softirq bits in preempt_count so that the
 130                  * softirq checks work in the hardirq context.
 131                  */
 132                 irqctx->tinfo.preempt_count =
 133                         (irqctx->tinfo.preempt_count & ~SOFTIRQ_MASK) |
 134                         (curctx->tinfo.preempt_count & SOFTIRQ_MASK);
 135
 136                 __asm__ __volatile__ (
 137                         "mov    %0, r4          \n"
 138                         "mov    r15, r8         \n"
 139                         "jsr    @%1             \n"
 140                         /* swith to the irq stack */
 141                         " mov   %2, r15         \n"
 142                         /* restore the stack (ring zero) */
 143                         "mov    r8, r15         \n"
 144                         : /* no outputs */
 145                         : "r" (irq), "r" (generic_handle_irq), "r" (isp)
 146                         : "memory", "r0", "r1", "r2", "r3", "r4",
 147                           "r5", "r6", "r7", "r8", "t", "pr"
 148                 );
 149         } else
 150 #endif
 151                 generic_handle_irq(irq);
 152
 153         irq_exit();
 154
 155         set_irq_regs(old_regs);
 156         return 1;
 157 }
 158
 159 #ifdef CONFIG_IRQSTACKS
 160 static char softirq_stack[NR_CPUS * THREAD_SIZE]
 161                 __attribute__((__section__(".bss.page_aligned")));
 162
 163 static char hardirq_stack[NR_CPUS * THREAD_SIZE]
 164                 __attribute__((__section__(".bss.page_aligned")));
 165
 166 /*
 167  * allocate per-cpu stacks for hardirq and for softirq processing
 168  */
 169 void irq_ctx_init(int cpu)
 170 {
 171         union irq_ctx *irqctx;
 172
 173         if (hardirq_ctx[cpu])
 174                 return;
 175
 176         irqctx = (union irq_ctx *)&hardirq_stack[cpu * THREAD_SIZE];
 177         irqctx->tinfo.task              = NULL;
 178         irqctx->tinfo.exec_domain       = NULL;
 179         irqctx->tinfo.cpu               = cpu;
 180         irqctx->tinfo.preempt_count     = HARDIRQ_OFFSET;
 181         irqctx->tinfo.addr_limit        = MAKE_MM_SEG(0);
 182
 183         hardirq_ctx[cpu] = irqctx;
 184
 185         irqctx = (union irq_ctx *)&softirq_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     = 0;
 190         irqctx->tinfo.addr_limit        = MAKE_MM_SEG(0);
 191
 192         softirq_ctx[cpu] = irqctx;
 193
 194         printk("CPU %u irqstacks, hard=%p soft=%p\n",
 195                 cpu, hardirq_ctx[cpu], softirq_ctx[cpu]);
 196 }
 197
 198 void irq_ctx_exit(int cpu)
 199 {
 200         hardirq_ctx[cpu] = NULL;
 201 }
 202
 203 extern asmlinkage void __do_softirq(void);
 204
 205 asmlinkage void do_softirq(void)
 206 {
 207         unsigned long flags;
 208         struct thread_info *curctx;
 209         union irq_ctx *irqctx;
 210         u32 *isp;
 211
 212         if (in_interrupt())
 213                 return;
 214
 215         local_irq_save(flags);
 216
 217         if (local_softirq_pending()) {
 218                 curctx = current_thread_info();
 219                 irqctx = softirq_ctx[smp_processor_id()];
 220                 irqctx->tinfo.task = curctx->task;
 221                 irqctx->tinfo.previous_sp = current_stack_pointer;
 222
 223                 /* build the stack frame on the softirq stack */
 224                 isp = (u32 *)((char *)irqctx + sizeof(*irqctx));
 225
 226                 __asm__ __volatile__ (
 227                         "mov    r15, r9         \n"
 228                         "jsr    @%0             \n"
 229                         /* switch to the softirq stack */
 230                         " mov   %1, r15         \n"
 231                         /* restore the thread stack */
 232                         "mov    r9, r15         \n"
 233                         : /* no outputs */
 234                         : "r" (__do_softirq), "r" (isp)
 235                         : "memory", "r0", "r1", "r2", "r3", "r4",
 236                           "r5", "r6", "r7", "r8", "r9", "r15", "t", "pr"
 237                 );
 238
 239                 /*
 240                  * Shouldnt happen, we returned above if in_interrupt():
 241                  */
 242                 WARN_ON_ONCE(softirq_count());
 243         }
 244
 245         local_irq_restore(flags);
 246 }
 247 #endif
 248
 249 void __init init_IRQ(void)
 250 {
 251         plat_irq_setup();
 252
 253         /* Perform the machine specific initialisation */
 254         if (sh_mv.mv_init_irq)
 255                 sh_mv.mv_init_irq();
 256
 257         irq_ctx_init(smp_processor_id());
 258 }