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
250
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