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 <linux/delay.h>
  16 #include <asm/processor.h>
  17 #include <asm/machvec.h>
  18 #include <asm/uaccess.h>
  19 #include <asm/thread_info.h>
  20 #include <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 /*
  37  * /proc/interrupts printing for arch specific interrupts
  38  */
  39 int arch_show_interrupts(struct seq_file *p, int prec)
  40 {
  41         int j;
  42
  43         seq_printf(p, "%*s: ", prec, "NMI");
  44         for_each_online_cpu(j)
  45                 seq_printf(p, "%10u ", irq_stat[j].__nmi_count);
  46         seq_printf(p, "  Non-maskable interrupts\n");
  47
  48         seq_printf(p, "%*s: %10u\n", prec, "ERR", atomic_read(&irq_err_count));
  49
  50         return 0;
  51 }
  52 #endif
  53
  54 #ifdef CONFIG_IRQSTACKS
  55 /*
  56  * per-CPU IRQ handling contexts (thread information and stack)
  57  */
  58 union irq_ctx {
  59         struct thread_info      tinfo;
  60         u32                     stack[THREAD_SIZE/sizeof(u32)];
  61 };
  62
  63 static union irq_ctx *hardirq_ctx[NR_CPUS] __read_mostly;
  64 static union irq_ctx *softirq_ctx[NR_CPUS] __read_mostly;
  65
  66 static char softirq_stack[NR_CPUS * THREAD_SIZE] __page_aligned_bss;
  67 static char hardirq_stack[NR_CPUS * THREAD_SIZE] __page_aligned_bss;
  68
  69 static inline void handle_one_irq(unsigned int irq)
  70 {
  71         union irq_ctx *curctx, *irqctx;
  72
  73         curctx = (union irq_ctx *)current_thread_info();
  74         irqctx = hardirq_ctx[smp_processor_id()];
  75
  76         /*
  77          * this is where we switch to the IRQ stack. However, if we are
  78          * already using the IRQ stack (because we interrupted a hardirq
  79          * handler) we can't do that and just have to keep using the
  80          * current stack (which is the irq stack already after all)
  81          */
  82         if (curctx != irqctx) {
  83                 u32 *isp;
  84
  85                 isp = (u32 *)((char *)irqctx + sizeof(*irqctx));
  86                 irqctx->tinfo.task = curctx->tinfo.task;
  87                 irqctx->tinfo.previous_sp = current_stack_pointer;
  88
  89                 /*
  90                  * Copy the softirq bits in preempt_count so that the
  91                  * softirq checks work in the hardirq context.
  92                  */
  93                 irqctx->tinfo.preempt_count =
  94                         (irqctx->tinfo.preempt_count & ~SOFTIRQ_MASK) |
  95                         (curctx->tinfo.preempt_count & SOFTIRQ_MASK);
  96
  97                 __asm__ __volatile__ (
  98                         "mov    %0, r4          \n"
  99                         "mov    r15, r8         \n"
 100                         "jsr    @%1             \n"
 101                         /* swith to the irq stack */
 102                         " mov   %2, r15         \n"
 103                         /* restore the stack (ring zero) */
 104                         "mov    r8, r15         \n"
 105                         : /* no outputs */
 106                         : "r" (irq), "r" (generic_handle_irq), "r" (isp)
 107                         : "memory", "r0", "r1", "r2", "r3", "r4",
 108                           "r5", "r6", "r7", "r8", "t", "pr"
 109                 );
 110         } else
 111                 generic_handle_irq(irq);
 112 }
 113
 114 /*
 115  * allocate per-cpu stacks for hardirq and for softirq processing
 116  */
 117 void irq_ctx_init(int cpu)
 118 {
 119         union irq_ctx *irqctx;
 120
 121         if (hardirq_ctx[cpu])
 122                 return;
 123
 124         irqctx = (union irq_ctx *)&hardirq_stack[cpu * THREAD_SIZE];
 125         irqctx->tinfo.task              = NULL;
 126         irqctx->tinfo.exec_domain       = NULL;
 127         irqctx->tinfo.cpu               = cpu;
 128         irqctx->tinfo.preempt_count     = HARDIRQ_OFFSET;
 129         irqctx->tinfo.addr_limit        = MAKE_MM_SEG(0);
 130
 131         hardirq_ctx[cpu] = irqctx;
 132
 133         irqctx = (union irq_ctx *)&softirq_stack[cpu * THREAD_SIZE];
 134         irqctx->tinfo.task              = NULL;
 135         irqctx->tinfo.exec_domain       = NULL;
 136         irqctx->tinfo.cpu               = cpu;
 137         irqctx->tinfo.preempt_count     = 0;
 138         irqctx->tinfo.addr_limit        = MAKE_MM_SEG(0);
 139
 140         softirq_ctx[cpu] = irqctx;
 141
 142         printk("CPU %u irqstacks, hard=%p soft=%p\n",
 143                 cpu, hardirq_ctx[cpu], softirq_ctx[cpu]);
 144 }
 145
 146 void irq_ctx_exit(int cpu)
 147 {
 148         hardirq_ctx[cpu] = NULL;
 149 }
 150
 151 asmlinkage void do_softirq(void)
 152 {
 153         unsigned long flags;
 154         struct thread_info *curctx;
 155         union irq_ctx *irqctx;
 156         u32 *isp;
 157
 158         if (in_interrupt())
 159                 return;
 160
 161         local_irq_save(flags);
 162
 163         if (local_softirq_pending()) {
 164                 curctx = current_thread_info();
 165                 irqctx = softirq_ctx[smp_processor_id()];
 166                 irqctx->tinfo.task = curctx->task;
 167                 irqctx->tinfo.previous_sp = current_stack_pointer;
 168
 169                 /* build the stack frame on the softirq stack */
 170                 isp = (u32 *)((char *)irqctx + sizeof(*irqctx));
 171
 172                 __asm__ __volatile__ (
 173                         "mov    r15, r9         \n"
 174                         "jsr    @%0             \n"
 175                         /* switch to the softirq stack */
 176                         " mov   %1, r15         \n"
 177                         /* restore the thread stack */
 178                         "mov    r9, r15         \n"
 179                         : /* no outputs */
 180                         : "r" (__do_softirq), "r" (isp)
 181                         : "memory", "r0", "r1", "r2", "r3", "r4",
 182                           "r5", "r6", "r7", "r8", "r9", "r15", "t", "pr"
 183                 );
 184
 185                 /*
 186                  * Shouldn't happen, we returned above if in_interrupt():
 187                  */
 188                 WARN_ON_ONCE(softirq_count());
 189         }
 190
 191         local_irq_restore(flags);
 192 }
 193 #else
 194 static inline void handle_one_irq(unsigned int irq)
 195 {
 196         generic_handle_irq(irq);
 197 }
 198 #endif
 199
 200 asmlinkage __irq_entry int do_IRQ(unsigned int irq, struct pt_regs *regs)
 201 {
 202         struct pt_regs *old_regs = set_irq_regs(regs);
 203
 204         irq_enter();
 205
 206         irq = irq_demux(irq_lookup(irq));
 207
 208         if (irq != NO_IRQ_IGNORE) {
 209                 handle_one_irq(irq);
 210                 irq_finish(irq);
 211         }
 212
 213         irq_exit();
 214
 215         set_irq_regs(old_regs);
 216
 217         return IRQ_HANDLED;
 218 }
 219
 220 void __init init_IRQ(void)
 221 {
 222         plat_irq_setup();
 223
 224         /* Perform the machine specific initialisation */
 225         if (sh_mv.mv_init_irq)
 226                 sh_mv.mv_init_irq();
 227
 228         intc_finalize();
 229
 230         irq_ctx_init(smp_processor_id());
 231 }
 232
 233 #ifdef CONFIG_SPARSE_IRQ
 234 int __init arch_probe_nr_irqs(void)
 235 {
 236         nr_irqs = sh_mv.mv_nr_irqs;
 237         return NR_IRQS_LEGACY;
 238 }
 239 #endif
 240
 241 #ifdef CONFIG_HOTPLUG_CPU
 242 static void route_irq(struct irq_data *data, unsigned int irq, unsigned int cpu)
 243 {
 244         struct irq_desc *desc = irq_to_desc(irq);
 245         struct irq_chip *chip = irq_data_get_irq_chip(data);
 246
 247         printk(KERN_INFO "IRQ%u: moving from cpu%u to cpu%u\n",
 248                irq, data->node, cpu);
 249
 250         raw_spin_lock_irq(&desc->lock);
 251         chip->irq_set_affinity(data, cpumask_of(cpu), false);
 252         raw_spin_unlock_irq(&desc->lock);
 253 }
 254
 255 /*
 256  * The CPU has been marked offline.  Migrate IRQs off this CPU.  If
 257  * the affinity settings do not allow other CPUs, force them onto any
 258  * available CPU.
 259  */
 260 void migrate_irqs(void)
 261 {
 262         unsigned int irq, cpu = smp_processor_id();
 263
 264         for_each_active_irq(irq) {
 265                 struct irq_data *data = irq_get_irq_data(irq);
 266
 267                 if (data->node == cpu) {
 268                         unsigned int newcpu = cpumask_any_and(data->affinity,
 269                                                               cpu_online_mask);
 270                         if (newcpu >= nr_cpu_ids) {
 271                                 if (printk_ratelimit())
 272                                         printk(KERN_INFO "IRQ%u no longer affine to CPU%u\n",
 273                                                irq, cpu);
 274
 275                                 cpumask_setall(data->affinity);
 276                                 newcpu = cpumask_any_and(data->affinity,
 277                                                          cpu_online_mask);
 278                         }
 279
 280                         route_irq(data, irq, newcpu);
 281                 }
 282         }
 283 }
 284 #endif