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Linux/arch/sh/kernel/irq.c

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  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 <linux/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                         /* switch 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.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.cpu               = cpu;
136         irqctx->tinfo.preempt_count     = 0;
137         irqctx->tinfo.addr_limit        = MAKE_MM_SEG(0);
138 
139         softirq_ctx[cpu] = irqctx;
140 
141         printk("CPU %u irqstacks, hard=%p soft=%p\n",
142                 cpu, hardirq_ctx[cpu], softirq_ctx[cpu]);
143 }
144 
145 void irq_ctx_exit(int cpu)
146 {
147         hardirq_ctx[cpu] = NULL;
148 }
149 
150 void do_softirq_own_stack(void)
151 {
152         struct thread_info *curctx;
153         union irq_ctx *irqctx;
154         u32 *isp;
155 
156         curctx = current_thread_info();
157         irqctx = softirq_ctx[smp_processor_id()];
158         irqctx->tinfo.task = curctx->task;
159         irqctx->tinfo.previous_sp = current_stack_pointer;
160 
161         /* build the stack frame on the softirq stack */
162         isp = (u32 *)((char *)irqctx + sizeof(*irqctx));
163 
164         __asm__ __volatile__ (
165                 "mov    r15, r9         \n"
166                 "jsr    @%0             \n"
167                 /* switch to the softirq stack */
168                 " mov   %1, r15         \n"
169                 /* restore the thread stack */
170                 "mov    r9, r15         \n"
171                 : /* no outputs */
172                 : "r" (__do_softirq), "r" (isp)
173                 : "memory", "r0", "r1", "r2", "r3", "r4",
174                   "r5", "r6", "r7", "r8", "r9", "r15", "t", "pr"
175         );
176 }
177 #else
178 static inline void handle_one_irq(unsigned int irq)
179 {
180         generic_handle_irq(irq);
181 }
182 #endif
183 
184 asmlinkage __irq_entry int do_IRQ(unsigned int irq, struct pt_regs *regs)
185 {
186         struct pt_regs *old_regs = set_irq_regs(regs);
187 
188         irq_enter();
189 
190         irq = irq_demux(irq_lookup(irq));
191 
192         if (irq != NO_IRQ_IGNORE) {
193                 handle_one_irq(irq);
194                 irq_finish(irq);
195         }
196 
197         irq_exit();
198 
199         set_irq_regs(old_regs);
200 
201         return IRQ_HANDLED;
202 }
203 
204 void __init init_IRQ(void)
205 {
206         plat_irq_setup();
207 
208         /* Perform the machine specific initialisation */
209         if (sh_mv.mv_init_irq)
210                 sh_mv.mv_init_irq();
211 
212         intc_finalize();
213 
214         irq_ctx_init(smp_processor_id());
215 }
216 
217 #ifdef CONFIG_HOTPLUG_CPU
218 /*
219  * The CPU has been marked offline.  Migrate IRQs off this CPU.  If
220  * the affinity settings do not allow other CPUs, force them onto any
221  * available CPU.
222  */
223 void migrate_irqs(void)
224 {
225         unsigned int irq, cpu = smp_processor_id();
226 
227         for_each_active_irq(irq) {
228                 struct irq_data *data = irq_get_irq_data(irq);
229 
230                 if (irq_data_get_node(data) == cpu) {
231                         struct cpumask *mask = irq_data_get_affinity_mask(data);
232                         unsigned int newcpu = cpumask_any_and(mask,
233                                                               cpu_online_mask);
234                         if (newcpu >= nr_cpu_ids) {
235                                 pr_info_ratelimited("IRQ%u no longer affine to CPU%u\n",
236                                                     irq, cpu);
237 
238                                 cpumask_setall(mask);
239                         }
240                         irq_set_affinity(irq, mask);
241                 }
242         }
243 }
244 #endif
245 

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