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Linux/arch/sh/kernel/irq.c

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  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 void do_softirq_own_stack(void)
153 {
154         struct thread_info *curctx;
155         union irq_ctx *irqctx;
156         u32 *isp;
157 
158         curctx = current_thread_info();
159         irqctx = softirq_ctx[smp_processor_id()];
160         irqctx->tinfo.task = curctx->task;
161         irqctx->tinfo.previous_sp = current_stack_pointer;
162 
163         /* build the stack frame on the softirq stack */
164         isp = (u32 *)((char *)irqctx + sizeof(*irqctx));
165 
166         __asm__ __volatile__ (
167                 "mov    r15, r9         \n"
168                 "jsr    @%0             \n"
169                 /* switch to the softirq stack */
170                 " mov   %1, r15         \n"
171                 /* restore the thread stack */
172                 "mov    r9, r15         \n"
173                 : /* no outputs */
174                 : "r" (__do_softirq), "r" (isp)
175                 : "memory", "r0", "r1", "r2", "r3", "r4",
176                   "r5", "r6", "r7", "r8", "r9", "r15", "t", "pr"
177         );
178 }
179 #else
180 static inline void handle_one_irq(unsigned int irq)
181 {
182         generic_handle_irq(irq);
183 }
184 #endif
185 
186 asmlinkage __irq_entry int do_IRQ(unsigned int irq, struct pt_regs *regs)
187 {
188         struct pt_regs *old_regs = set_irq_regs(regs);
189 
190         irq_enter();
191 
192         irq = irq_demux(irq_lookup(irq));
193 
194         if (irq != NO_IRQ_IGNORE) {
195                 handle_one_irq(irq);
196                 irq_finish(irq);
197         }
198 
199         irq_exit();
200 
201         set_irq_regs(old_regs);
202 
203         return IRQ_HANDLED;
204 }
205 
206 void __init init_IRQ(void)
207 {
208         plat_irq_setup();
209 
210         /* Perform the machine specific initialisation */
211         if (sh_mv.mv_init_irq)
212                 sh_mv.mv_init_irq();
213 
214         intc_finalize();
215 
216         irq_ctx_init(smp_processor_id());
217 }
218 
219 #ifdef CONFIG_HOTPLUG_CPU
220 /*
221  * The CPU has been marked offline.  Migrate IRQs off this CPU.  If
222  * the affinity settings do not allow other CPUs, force them onto any
223  * available CPU.
224  */
225 void migrate_irqs(void)
226 {
227         unsigned int irq, cpu = smp_processor_id();
228 
229         for_each_active_irq(irq) {
230                 struct irq_data *data = irq_get_irq_data(irq);
231 
232                 if (irq_data_get_node(data) == cpu) {
233                         struct cpumask *mask = irq_data_get_affinity_mask(data);
234                         unsigned int newcpu = cpumask_any_and(mask,
235                                                               cpu_online_mask);
236                         if (newcpu >= nr_cpu_ids) {
237                                 pr_info_ratelimited("IRQ%u no longer affine to CPU%u\n",
238                                                     irq, cpu);
239 
240                                 cpumask_setall(mask);
241                         }
242                         irq_set_affinity(irq, mask);
243                 }
244         }
245 }
246 #endif
247 

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