arch/sh/kernel/irq.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * linux/arch/sh/kernel/irq.c
   4  *
   5  *      Copyright (C) 1992, 1998 Linus Torvalds, Ingo Molnar
   6  *
   7  *
   8  * SuperH version:  Copyright (C) 1999  Niibe Yutaka
   9  */
  10 #include <linux/irq.h>
  11 #include <linux/interrupt.h>
  12 #include <linux/module.h>
  13 #include <linux/kernel_stat.h>
  14 #include <linux/seq_file.h>
  15 #include <linux/ftrace.h>
  16 #include <linux/delay.h>
  17 #include <linux/ratelimit.h>
  18 #include <asm/processor.h>
  19 #include <asm/machvec.h>
  20 #include <linux/uaccess.h>
  21 #include <asm/thread_info.h>
  22 #include <cpu/mmu_context.h>
  23
  24 atomic_t irq_err_count;
  25
  26 /*
  27  * 'what should we do if we get a hw irq event on an illegal vector'.
  28  * each architecture has to answer this themselves, it doesn't deserve
  29  * a generic callback i think.
  30  */
  31 void ack_bad_irq(unsigned int irq)
  32 {
  33         atomic_inc(&irq_err_count);
  34         printk("unexpected IRQ trap at vector %02x\n", irq);
  35 }
  36
  37 #if defined(CONFIG_PROC_FS)
  38 /*
  39  * /proc/interrupts printing for arch specific interrupts
  40  */
  41 int arch_show_interrupts(struct seq_file *p, int prec)
  42 {
  43         int j;
  44
  45         seq_printf(p, "%*s: ", prec, "NMI");
  46         for_each_online_cpu(j)
  47                 seq_printf(p, "%10u ", nmi_count(j));
  48         seq_printf(p, "  Non-maskable interrupts\n");
  49
  50         seq_printf(p, "%*s: %10u\n", prec, "ERR", atomic_read(&irq_err_count));
  51
  52         return 0;
  53 }
  54 #endif
  55
  56 #ifdef CONFIG_IRQSTACKS
  57 /*
  58  * per-CPU IRQ handling contexts (thread information and stack)
  59  */
  60 union irq_ctx {
  61         struct thread_info      tinfo;
  62         u32                     stack[THREAD_SIZE/sizeof(u32)];
  63 };
  64
  65 static union irq_ctx *hardirq_ctx[NR_CPUS] __read_mostly;
  66 static union irq_ctx *softirq_ctx[NR_CPUS] __read_mostly;
  67
  68 static char softirq_stack[NR_CPUS * THREAD_SIZE] __page_aligned_bss;
  69 static char hardirq_stack[NR_CPUS * THREAD_SIZE] __page_aligned_bss;
  70
  71 static inline void handle_one_irq(unsigned int irq)
  72 {
  73         union irq_ctx *curctx, *irqctx;
  74
  75         curctx = (union irq_ctx *)current_thread_info();
  76         irqctx = hardirq_ctx[smp_processor_id()];
  77
  78         /*
  79          * this is where we switch to the IRQ stack. However, if we are
  80          * already using the IRQ stack (because we interrupted a hardirq
  81          * handler) we can't do that and just have to keep using the
  82          * current stack (which is the irq stack already after all)
  83          */
  84         if (curctx != irqctx) {
  85                 u32 *isp;
  86
  87                 isp = (u32 *)((char *)irqctx + sizeof(*irqctx));
  88                 irqctx->tinfo.task = curctx->tinfo.task;
  89                 irqctx->tinfo.previous_sp = current_stack_pointer;
  90
  91                 /*
  92                  * Copy the softirq bits in preempt_count so that the
  93                  * softirq checks work in the hardirq context.
  94                  */
  95                 irqctx->tinfo.preempt_count =
  96                         (irqctx->tinfo.preempt_count & ~SOFTIRQ_MASK) |
  97                         (curctx->tinfo.preempt_count & SOFTIRQ_MASK);
  98
  99                 __asm__ __volatile__ (
 100                         "mov    %0, r4          \n"
 101                         "mov    r15, r8         \n"
 102                         "jsr    @%1             \n"
 103                         /* switch to the irq stack */
 104                         " mov   %2, r15         \n"
 105                         /* restore the stack (ring zero) */
 106                         "mov    r8, r15         \n"
 107                         : /* no outputs */
 108                         : "r" (irq), "r" (generic_handle_irq), "r" (isp)
 109                         : "memory", "r0", "r1", "r2", "r3", "r4",
 110                           "r5", "r6", "r7", "r8", "t", "pr"
 111                 );
 112         } else
 113                 generic_handle_irq(irq);
 114 }
 115
 116 /*
 117  * allocate per-cpu stacks for hardirq and for softirq processing
 118  */
 119 void irq_ctx_init(int cpu)
 120 {
 121         union irq_ctx *irqctx;
 122
 123         if (hardirq_ctx[cpu])
 124                 return;
 125
 126         irqctx = (union irq_ctx *)&hardirq_stack[cpu * THREAD_SIZE];
 127         irqctx->tinfo.task              = 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.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 void do_softirq_own_stack(void)
 152 {
 153         struct thread_info *curctx;
 154         union irq_ctx *irqctx;
 155         u32 *isp;
 156
 157         curctx = current_thread_info();
 158         irqctx = softirq_ctx[smp_processor_id()];
 159         irqctx->tinfo.task = curctx->task;
 160         irqctx->tinfo.previous_sp = current_stack_pointer;
 161
 162         /* build the stack frame on the softirq stack */
 163         isp = (u32 *)((char *)irqctx + sizeof(*irqctx));
 164
 165         __asm__ __volatile__ (
 166                 "mov    r15, r9         \n"
 167                 "jsr    @%0             \n"
 168                 /* switch to the softirq stack */
 169                 " mov   %1, r15         \n"
 170                 /* restore the thread stack */
 171                 "mov    r9, r15         \n"
 172                 : /* no outputs */
 173                 : "r" (__do_softirq), "r" (isp)
 174                 : "memory", "r0", "r1", "r2", "r3", "r4",
 175                   "r5", "r6", "r7", "r8", "r9", "r15", "t", "pr"
 176         );
 177 }
 178 #else
 179 static inline void handle_one_irq(unsigned int irq)
 180 {
 181         generic_handle_irq(irq);
 182 }
 183 #endif
 184
 185 asmlinkage __irq_entry int do_IRQ(unsigned int irq, struct pt_regs *regs)
 186 {
 187         struct pt_regs *old_regs = set_irq_regs(regs);
 188
 189         irq_enter();
 190
 191         irq = irq_demux(irq_lookup(irq));
 192
 193         if (irq != NO_IRQ_IGNORE) {
 194                 handle_one_irq(irq);
 195                 irq_finish(irq);
 196         }
 197
 198         irq_exit();
 199
 200         set_irq_regs(old_regs);
 201
 202         return IRQ_HANDLED;
 203 }
 204
 205 void __init init_IRQ(void)
 206 {
 207         plat_irq_setup();
 208
 209         /* Perform the machine specific initialisation */
 210         if (sh_mv.mv_init_irq)
 211                 sh_mv.mv_init_irq();
 212
 213         intc_finalize();
 214
 215         irq_ctx_init(smp_processor_id());
 216 }
 217
 218 #ifdef CONFIG_HOTPLUG_CPU
 219 /*
 220  * The CPU has been marked offline.  Migrate IRQs off this CPU.  If
 221  * the affinity settings do not allow other CPUs, force them onto any
 222  * available CPU.
 223  */
 224 void migrate_irqs(void)
 225 {
 226         unsigned int irq, cpu = smp_processor_id();
 227
 228         for_each_active_irq(irq) {
 229                 struct irq_data *data = irq_get_irq_data(irq);
 230
 231                 if (irq_data_get_node(data) == cpu) {
 232                         struct cpumask *mask = irq_data_get_affinity_mask(data);
 233                         unsigned int newcpu = cpumask_any_and(mask,
 234                                                               cpu_online_mask);
 235                         if (newcpu >= nr_cpu_ids) {
 236                                 pr_info_ratelimited("IRQ%u no longer affine to CPU%u\n",
 237                                                     irq, cpu);
 238
 239                                 cpumask_setall(mask);
 240                         }
 241                         irq_set_affinity(irq, mask);
 242                 }
 243         }
 244 }
 245 #endif