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
25atomic_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 */
32void 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 */
42int 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 */
61union irq_ctx {
62	struct thread_info	tinfo;
63	u32			stack[THREAD_SIZE/sizeof(u32)];
64};
65
66static union irq_ctx *hardirq_ctx[NR_CPUS] __read_mostly;
67static union irq_ctx *softirq_ctx[NR_CPUS] __read_mostly;
68
69static char softirq_stack[NR_CPUS * THREAD_SIZE] __page_aligned_bss;
70static char hardirq_stack[NR_CPUS * THREAD_SIZE] __page_aligned_bss;
71
72static 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 */
120void 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
147void irq_ctx_exit(int cpu)
148{
149	hardirq_ctx[cpu] = NULL;
150}
151
152#ifdef CONFIG_SOFTIRQ_ON_OWN_STACK
153void 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
182static inline void handle_one_irq(unsigned int irq)
183{
184	generic_handle_irq(irq);
185}
186#endif
187
188asmlinkage __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
208void __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 */
227void 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