xref: /openbmc/linux/arch/sh/kernel/irq.c (revision e868d61272caa648214046a096e5a6bfc068dc8c)
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 /*
162  * These should really be __section__(".bss.page_aligned") as well, but
163  * gcc's 3.0 and earlier don't handle that correctly.
164  */
165 static char softirq_stack[NR_CPUS * THREAD_SIZE]
166 		__attribute__((__aligned__(THREAD_SIZE)));
167 
168 static char hardirq_stack[NR_CPUS * THREAD_SIZE]
169 		__attribute__((__aligned__(THREAD_SIZE)));
170 
171 /*
172  * allocate per-cpu stacks for hardirq and for softirq processing
173  */
174 void irq_ctx_init(int cpu)
175 {
176 	union irq_ctx *irqctx;
177 
178 	if (hardirq_ctx[cpu])
179 		return;
180 
181 	irqctx = (union irq_ctx *)&hardirq_stack[cpu * THREAD_SIZE];
182 	irqctx->tinfo.task		= NULL;
183 	irqctx->tinfo.exec_domain	= NULL;
184 	irqctx->tinfo.cpu		= cpu;
185 	irqctx->tinfo.preempt_count	= HARDIRQ_OFFSET;
186 	irqctx->tinfo.addr_limit	= MAKE_MM_SEG(0);
187 
188 	hardirq_ctx[cpu] = irqctx;
189 
190 	irqctx = (union irq_ctx *)&softirq_stack[cpu * THREAD_SIZE];
191 	irqctx->tinfo.task		= NULL;
192 	irqctx->tinfo.exec_domain	= NULL;
193 	irqctx->tinfo.cpu		= cpu;
194 	irqctx->tinfo.preempt_count	= 0;
195 	irqctx->tinfo.addr_limit	= MAKE_MM_SEG(0);
196 
197 	softirq_ctx[cpu] = irqctx;
198 
199 	printk("CPU %u irqstacks, hard=%p soft=%p\n",
200 		cpu, hardirq_ctx[cpu], softirq_ctx[cpu]);
201 }
202 
203 void irq_ctx_exit(int cpu)
204 {
205 	hardirq_ctx[cpu] = NULL;
206 }
207 
208 extern asmlinkage void __do_softirq(void);
209 
210 asmlinkage void do_softirq(void)
211 {
212 	unsigned long flags;
213 	struct thread_info *curctx;
214 	union irq_ctx *irqctx;
215 	u32 *isp;
216 
217 	if (in_interrupt())
218 		return;
219 
220 	local_irq_save(flags);
221 
222 	if (local_softirq_pending()) {
223 		curctx = current_thread_info();
224 		irqctx = softirq_ctx[smp_processor_id()];
225 		irqctx->tinfo.task = curctx->task;
226 		irqctx->tinfo.previous_sp = current_stack_pointer;
227 
228 		/* build the stack frame on the softirq stack */
229 		isp = (u32 *)((char *)irqctx + sizeof(*irqctx));
230 
231 		__asm__ __volatile__ (
232 			"mov	r15, r9		\n"
233 			"jsr	@%0		\n"
234 			/* switch to the softirq stack */
235 			" mov	%1, r15		\n"
236 			/* restore the thread stack */
237 			"mov	r9, r15		\n"
238 			: /* no outputs */
239 			: "r" (__do_softirq), "r" (isp)
240 			: "memory", "r0", "r1", "r2", "r3", "r4",
241 			  "r5", "r6", "r7", "r8", "r9", "r15", "t", "pr"
242 		);
243 
244 		/*
245 		 * Shouldnt happen, we returned above if in_interrupt():
246 		 */
247 		WARN_ON_ONCE(softirq_count());
248 	}
249 
250 	local_irq_restore(flags);
251 }
252 EXPORT_SYMBOL(do_softirq);
253 #endif
254 
255 void __init init_IRQ(void)
256 {
257 #ifdef CONFIG_CPU_HAS_PINT_IRQ
258 	init_IRQ_pint();
259 #endif
260 
261 #ifdef CONFIG_CPU_HAS_INTC2_IRQ
262 	init_IRQ_intc2();
263 #endif
264 
265 #ifdef CONFIG_CPU_HAS_IPR_IRQ
266 	init_IRQ_ipr();
267 #endif
268 
269 	/* Perform the machine specific initialisation */
270 	if (sh_mv.mv_init_irq)
271 		sh_mv.mv_init_irq();
272 
273 	irq_ctx_init(smp_processor_id());
274 }
275