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 } 263