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 <linux/ratelimit.h>
  17 #include <asm/processor.h>
  18 #include <asm/machvec.h>
  19 #include <asm/uaccess.h>
  20 #include <asm/thread_info.h>
  21 #include <cpu/mmu_context.h>
  22
  23 atomic_t irq_err_count;
  24
  25 /*
  26  * 'what should we do if we get a hw irq event on an illegal vector'.
  27  * each architecture has to answer this themselves, it doesn't deserve
  28  * a generic callback i think.
  29  */
  30 void ack_bad_irq(unsigned int irq)
  31 {
  32         atomic_inc(&irq_err_count);
  33         printk("unexpected IRQ trap at vector %02x\n", irq);
  34 }
  35
  36 #if defined(CONFIG_PROC_FS)
  37 /*
  38  * /proc/interrupts printing for arch specific interrupts
  39  */
  40 int arch_show_interrupts(struct seq_file *p, int prec)
  41 {
  42         int j;
  43
  44         seq_printf(p, "%*s: ", prec, "NMI");
  45         for_each_online_cpu(j)
  46                 seq_printf(p, "%10u ", irq_stat[j].__nmi_count);
  47         seq_printf(p, "  Non-maskable interrupts\n");
  48
  49         seq_printf(p, "%*s: %10u\n", prec, "ERR", atomic_read(&irq_err_count));
  50
  51         return 0;
  52 }
  53 #endif
  54
  55 #ifdef CONFIG_IRQSTACKS
  56 /*
  57  * per-CPU IRQ handling contexts (thread information and stack)
  58  */
  59 union irq_ctx {
  60         struct thread_info      tinfo;
  61         u32                     stack[THREAD_SIZE/sizeof(u32)];
  62 };
  63
  64 static union irq_ctx *hardirq_ctx[NR_CPUS] __read_mostly;
  65 static union irq_ctx *softirq_ctx[NR_CPUS] __read_mostly;
  66
  67 static char softirq_stack[NR_CPUS * THREAD_SIZE] __page_aligned_bss;
  68 static char hardirq_stack[NR_CPUS * THREAD_SIZE] __page_aligned_bss;
  69
  70 static inline void handle_one_irq(unsigned int irq)
  71 {
  72         union irq_ctx *curctx, *irqctx;
  73
  74         curctx = (union irq_ctx *)current_thread_info();
  75         irqctx = hardirq_ctx[smp_processor_id()];
  76
  77         /*
  78          * this is where we switch to the IRQ stack. However, if we are
  79          * already using the IRQ stack (because we interrupted a hardirq
  80          * handler) we can't do that and just have to keep using the
  81          * current stack (which is the irq stack already after all)
  82          */
  83         if (curctx != irqctx) {
  84                 u32 *isp;
  85
  86                 isp = (u32 *)((char *)irqctx + sizeof(*irqctx));
  87                 irqctx->tinfo.task = curctx->tinfo.task;
  88                 irqctx->tinfo.previous_sp = current_stack_pointer;
  89
  90                 /*
  91                  * Copy the softirq bits in preempt_count so that the
  92                  * softirq checks work in the hardirq context.
  93                  */
  94                 irqctx->tinfo.preempt_count =
  95                         (irqctx->tinfo.preempt_count & ~SOFTIRQ_MASK) |
  96                         (curctx->tinfo.preempt_count & SOFTIRQ_MASK);
  97
  98                 __asm__ __volatile__ (
  99                         "mov    %0, r4          \n"
 100                         "mov    r15, r8         \n"
 101                         "jsr    @%1             \n"
 102                         /* swith to the irq stack */
 103                         " mov   %2, r15         \n"
 104                         /* restore the stack (ring zero) */
 105                         "mov    r8, r15         \n"
 106                         : /* no outputs */
 107                         : "r" (irq), "r" (generic_handle_irq), "r" (isp)
 108                         : "memory", "r0", "r1", "r2", "r3", "r4",
 109                           "r5", "r6", "r7", "r8", "t", "pr"
 110                 );
 111         } else
 112                 generic_handle_irq(irq);
 113 }
 114
 115 /*
 116  * allocate per-cpu stacks for hardirq and for softirq processing
 117  */
 118 void irq_ctx_init(int cpu)
 119 {
 120         union irq_ctx *irqctx;
 121
 122         if (hardirq_ctx[cpu])
 123                 return;
 124
 125         irqctx = (union irq_ctx *)&hardirq_stack[cpu * THREAD_SIZE];
 126         irqctx->tinfo.task              = NULL;
 127         irqctx->tinfo.exec_domain       = NULL;
 128         irqctx->tinfo.cpu               = cpu;
 129         irqctx->tinfo.preempt_count     = HARDIRQ_OFFSET;
 130         irqctx->tinfo.addr_limit        = MAKE_MM_SEG(0);
 131
 132         hardirq_ctx[cpu] = irqctx;
 133
 134         irqctx = (union irq_ctx *)&softirq_stack[cpu * THREAD_SIZE];
 135         irqctx->tinfo.task              = NULL;
 136         irqctx->tinfo.exec_domain       = NULL;
 137         irqctx->tinfo.cpu               = cpu;
 138         irqctx->tinfo.preempt_count     = 0;
 139         irqctx->tinfo.addr_limit        = MAKE_MM_SEG(0);
 140
 141         softirq_ctx[cpu] = irqctx;
 142
 143         printk("CPU %u irqstacks, hard=%p soft=%p\n",
 144                 cpu, hardirq_ctx[cpu], softirq_ctx[cpu]);
 145 }
 146
 147 void irq_ctx_exit(int cpu)
 148 {
 149         hardirq_ctx[cpu] = NULL;
 150 }
 151
 152 asmlinkage void do_softirq(void)
 153 {
 154         unsigned long flags;
 155         struct thread_info *curctx;
 156         union irq_ctx *irqctx;
 157         u32 *isp;
 158
 159         if (in_interrupt())
 160                 return;
 161
 162         local_irq_save(flags);
 163
 164         if (local_softirq_pending()) {
 165                 curctx = current_thread_info();
 166                 irqctx = softirq_ctx[smp_processor_id()];
 167                 irqctx->tinfo.task = curctx->task;
 168                 irqctx->tinfo.previous_sp = current_stack_pointer;
 169
 170                 /* build the stack frame on the softirq stack */
 171                 isp = (u32 *)((char *)irqctx + sizeof(*irqctx));
 172
 173                 __asm__ __volatile__ (
 174                         "mov    r15, r9         \n"
 175                         "jsr    @%0             \n"
 176                         /* switch to the softirq stack */
 177                         " mov   %1, r15         \n"
 178                         /* restore the thread stack */
 179                         "mov    r9, r15         \n"
 180                         : /* no outputs */
 181                         : "r" (__do_softirq), "r" (isp)
 182                         : "memory", "r0", "r1", "r2", "r3", "r4",
 183                           "r5", "r6", "r7", "r8", "r9", "r15", "t", "pr"
 184                 );
 185
 186                 /*
 187                  * Shouldn't happen, we returned above if in_interrupt():
 188                  */
 189                 WARN_ON_ONCE(softirq_count());
 190         }
 191
 192         local_irq_restore(flags);
 193 }
 194 #else
 195 static inline void handle_one_irq(unsigned int irq)
 196 {
 197         generic_handle_irq(irq);
 198 }
 199 #endif
 200
 201 asmlinkage __irq_entry int do_IRQ(unsigned int irq, struct pt_regs *regs)
 202 {
 203         struct pt_regs *old_regs = set_irq_regs(regs);
 204
 205         irq_enter();
 206
 207         irq = irq_demux(irq_lookup(irq));
 208
 209         if (irq != NO_IRQ_IGNORE) {
 210                 handle_one_irq(irq);
 211                 irq_finish(irq);
 212         }
 213
 214         irq_exit();
 215
 216         set_irq_regs(old_regs);
 217
 218         return IRQ_HANDLED;
 219 }
 220
 221 void __init init_IRQ(void)
 222 {
 223         plat_irq_setup();
 224
 225         /* Perform the machine specific initialisation */
 226         if (sh_mv.mv_init_irq)
 227                 sh_mv.mv_init_irq();
 228
 229         intc_finalize();
 230
 231         irq_ctx_init(smp_processor_id());
 232 }
 233
 234 #ifdef CONFIG_HOTPLUG_CPU
 235 static void route_irq(struct irq_data *data, unsigned int irq, unsigned int cpu)
 236 {
 237         struct irq_desc *desc = irq_to_desc(irq);
 238         struct irq_chip *chip = irq_data_get_irq_chip(data);
 239
 240         printk(KERN_INFO "IRQ%u: moving from cpu%u to cpu%u\n",
 241                irq, data->node, cpu);
 242
 243         raw_spin_lock_irq(&desc->lock);
 244         chip->irq_set_affinity(data, cpumask_of(cpu), false);
 245         raw_spin_unlock_irq(&desc->lock);
 246 }
 247
 248 /*
 249  * The CPU has been marked offline.  Migrate IRQs off this CPU.  If
 250  * the affinity settings do not allow other CPUs, force them onto any
 251  * available CPU.
 252  */
 253 void migrate_irqs(void)
 254 {
 255         unsigned int irq, cpu = smp_processor_id();
 256
 257         for_each_active_irq(irq) {
 258                 struct irq_data *data = irq_get_irq_data(irq);
 259
 260                 if (data->node == cpu) {
 261                         unsigned int newcpu = cpumask_any_and(data->affinity,
 262                                                               cpu_online_mask);
 263                         if (newcpu >= nr_cpu_ids) {
 264                                 pr_info_ratelimited("IRQ%u no longer affine to CPU%u\n",
 265                                                     irq, cpu);
 266
 267                                 cpumask_setall(data->affinity);
 268                                 newcpu = cpumask_any_and(data->affinity,
 269                                                          cpu_online_mask);
 270                         }
 271
 272                         route_irq(data, irq, newcpu);
 273                 }
 274         }
 275 }
 276 #endif