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