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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/irq.h>
  15 #include <asm/processor.h>
  16 #include <asm/machvec.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 < sh_mv.mv_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 == sh_mv.mv_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] __read_mostly;
  82 static union irq_ctx *softirq_ctx[NR_CPUS] __read_mostly;
  83 #endif
  84
  85 asmlinkage int do_IRQ(unsigned int irq, struct pt_regs *regs)
  86 {
  87         struct pt_regs *old_regs = set_irq_regs(regs);
  88 #ifdef CONFIG_4KSTACKS
  89         union irq_ctx *curctx, *irqctx;
  90 #endif
  91
  92         irq_enter();
  93
  94 #ifdef CONFIG_DEBUG_STACKOVERFLOW
  95         /* Debugging check for stack overflow: is there less than 1KB free? */
  96         {
  97                 long sp;
  98
  99                 __asm__ __volatile__ ("and r15, %0" :
 100                                         "=r" (sp) : "0" (THREAD_SIZE - 1));
 101
 102                 if (unlikely(sp < (sizeof(struct thread_info) + STACK_WARN))) {
 103                         printk("do_IRQ: stack overflow: %ld\n",
 104                                sp - sizeof(struct thread_info));
 105                         dump_stack();
 106                 }
 107         }
 108 #endif
 109
 110         irq = irq_demux(evt2irq(irq));
 111
 112 #ifdef CONFIG_4KSTACKS
 113         curctx = (union irq_ctx *)current_thread_info();
 114         irqctx = hardirq_ctx[smp_processor_id()];
 115
 116         /*
 117          * this is where we switch to the IRQ stack. However, if we are
 118          * already using the IRQ stack (because we interrupted a hardirq
 119          * handler) we can't do that and just have to keep using the
 120          * current stack (which is the irq stack already after all)
 121          */
 122         if (curctx != irqctx) {
 123                 u32 *isp;
 124
 125                 isp = (u32 *)((char *)irqctx + sizeof(*irqctx));
 126                 irqctx->tinfo.task = curctx->tinfo.task;
 127                 irqctx->tinfo.previous_sp = current_stack_pointer;
 128
 129                 /*
 130                  * Copy the softirq bits in preempt_count so that the
 131                  * softirq checks work in the hardirq context.
 132                  */
 133                 irqctx->tinfo.preempt_count =
 134                         (irqctx->tinfo.preempt_count & ~SOFTIRQ_MASK) |
 135                         (curctx->tinfo.preempt_count & SOFTIRQ_MASK);
 136
 137                 __asm__ __volatile__ (
 138                         "mov    %0, r4          \n"
 139                         "mov    r15, r8         \n"
 140                         "jsr    @%1             \n"
 141                         /* swith to the irq stack */
 142                         " mov   %2, r15         \n"
 143                         /* restore the stack (ring zero) */
 144                         "mov    r8, r15         \n"
 145                         : /* no outputs */
 146                         : "r" (irq), "r" (generic_handle_irq), "r" (isp)
 147                         : "memory", "r0", "r1", "r2", "r3", "r4",
 148                           "r5", "r6", "r7", "r8", "t", "pr"
 149                 );
 150         } else
 151 #endif
 152                 generic_handle_irq(irq);
 153
 154         irq_exit();
 155
 156         set_irq_regs(old_regs);
 157         return 1;
 158 }
 159
 160 #ifdef CONFIG_4KSTACKS
 161 static char softirq_stack[NR_CPUS * THREAD_SIZE]
 162                 __attribute__((__section__(".bss.page_aligned")));
 163
 164 static char hardirq_stack[NR_CPUS * THREAD_SIZE]
 165                 __attribute__((__section__(".bss.page_aligned")));
 166
 167 /*
 168  * allocate per-cpu stacks for hardirq and for softirq processing
 169  */
 170 void irq_ctx_init(int cpu)
 171 {
 172         union irq_ctx *irqctx;
 173
 174         if (hardirq_ctx[cpu])
 175                 return;
 176
 177         irqctx = (union irq_ctx *)&hardirq_stack[cpu * THREAD_SIZE];
 178         irqctx->tinfo.task              = NULL;
 179         irqctx->tinfo.exec_domain       = NULL;
 180         irqctx->tinfo.cpu               = cpu;
 181         irqctx->tinfo.preempt_count     = HARDIRQ_OFFSET;
 182         irqctx->tinfo.addr_limit        = MAKE_MM_SEG(0);
 183
 184         hardirq_ctx[cpu] = irqctx;
 185
 186         irqctx = (union irq_ctx *)&softirq_stack[cpu * THREAD_SIZE];
 187         irqctx->tinfo.task              = NULL;
 188         irqctx->tinfo.exec_domain       = NULL;
 189         irqctx->tinfo.cpu               = cpu;
 190         irqctx->tinfo.preempt_count     = 0;
 191         irqctx->tinfo.addr_limit        = MAKE_MM_SEG(0);
 192
 193         softirq_ctx[cpu] = irqctx;
 194
 195         printk("CPU %u irqstacks, hard=%p soft=%p\n",
 196                 cpu, hardirq_ctx[cpu], softirq_ctx[cpu]);
 197 }
 198
 199 void irq_ctx_exit(int cpu)
 200 {
 201         hardirq_ctx[cpu] = NULL;
 202 }
 203
 204 extern asmlinkage void __do_softirq(void);
 205
 206 asmlinkage void do_softirq(void)
 207 {
 208         unsigned long flags;
 209         struct thread_info *curctx;
 210         union irq_ctx *irqctx;
 211         u32 *isp;
 212
 213         if (in_interrupt())
 214                 return;
 215
 216         local_irq_save(flags);
 217
 218         if (local_softirq_pending()) {
 219                 curctx = current_thread_info();
 220                 irqctx = softirq_ctx[smp_processor_id()];
 221                 irqctx->tinfo.task = curctx->task;
 222                 irqctx->tinfo.previous_sp = current_stack_pointer;
 223
 224                 /* build the stack frame on the softirq stack */
 225                 isp = (u32 *)((char *)irqctx + sizeof(*irqctx));
 226
 227                 __asm__ __volatile__ (
 228                         "mov    r15, r9         \n"
 229                         "jsr    @%0             \n"
 230                         /* switch to the softirq stack */
 231                         " mov   %1, r15         \n"
 232                         /* restore the thread stack */
 233                         "mov    r9, r15         \n"
 234                         : /* no outputs */
 235                         : "r" (__do_softirq), "r" (isp)
 236                         : "memory", "r0", "r1", "r2", "r3", "r4",
 237                           "r5", "r6", "r7", "r8", "r9", "r15", "t", "pr"
 238                 );
 239
 240                 /*
 241                  * Shouldnt happen, we returned above if in_interrupt():
 242                  */
 243                 WARN_ON_ONCE(softirq_count());
 244         }
 245
 246         local_irq_restore(flags);
 247 }
 248 #endif
 249
 250 void __init init_IRQ(void)
 251 {
 252 #ifdef CONFIG_CPU_HAS_PINT_IRQ
 253         init_IRQ_pint();
 254 #endif
 255         plat_irq_setup();
 256
 257         /* Perform the machine specific initialisation */
 258         if (sh_mv.mv_init_irq)
 259                 sh_mv.mv_init_irq();
 260
 261         irq_ctx_init(smp_processor_id());
 262 }