Merge git://git.kernel.org/pub/scm/linux/kernel/git/steve/gfs2-2.6-nmw
[linux-2.6] / arch / sh / kernel / irq.c
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 static char softirq_stack[NR_CPUS * THREAD_SIZE]
162                 __attribute__((__section__(".bss.page_aligned")));
163
164 static char hardirq_stack[NR_CPUS * THREAD_SIZE]
165                 __attribute__((__section__(".bss.page_aligned")));
166
167 /*
168  * allocate per-cpu stacks for hardirq and for softirq processing
169  */
170 void irq_ctx_init(int cpu)
171 {
172         union irq_ctx *irqctx;
173
174         if (hardirq_ctx[cpu])
175                 return;
176
177         irqctx = (union irq_ctx *)&hardirq_stack[cpu * THREAD_SIZE];
178         irqctx->tinfo.task              = NULL;
179         irqctx->tinfo.exec_domain       = NULL;
180         irqctx->tinfo.cpu               = cpu;
181         irqctx->tinfo.preempt_count     = HARDIRQ_OFFSET;
182         irqctx->tinfo.addr_limit        = MAKE_MM_SEG(0);
183
184         hardirq_ctx[cpu] = irqctx;
185
186         irqctx = (union irq_ctx *)&softirq_stack[cpu * THREAD_SIZE];
187         irqctx->tinfo.task              = NULL;
188         irqctx->tinfo.exec_domain       = NULL;
189         irqctx->tinfo.cpu               = cpu;
190         irqctx->tinfo.preempt_count     = 0;
191         irqctx->tinfo.addr_limit        = MAKE_MM_SEG(0);
192
193         softirq_ctx[cpu] = irqctx;
194
195         printk("CPU %u irqstacks, hard=%p soft=%p\n",
196                 cpu, hardirq_ctx[cpu], softirq_ctx[cpu]);
197 }
198
199 void irq_ctx_exit(int cpu)
200 {
201         hardirq_ctx[cpu] = NULL;
202 }
203
204 extern asmlinkage void __do_softirq(void);
205
206 asmlinkage void do_softirq(void)
207 {
208         unsigned long flags;
209         struct thread_info *curctx;
210         union irq_ctx *irqctx;
211         u32 *isp;
212
213         if (in_interrupt())
214                 return;
215
216         local_irq_save(flags);
217
218         if (local_softirq_pending()) {
219                 curctx = current_thread_info();
220                 irqctx = softirq_ctx[smp_processor_id()];
221                 irqctx->tinfo.task = curctx->task;
222                 irqctx->tinfo.previous_sp = current_stack_pointer;
223
224                 /* build the stack frame on the softirq stack */
225                 isp = (u32 *)((char *)irqctx + sizeof(*irqctx));
226
227                 __asm__ __volatile__ (
228                         "mov    r15, r9         \n"
229                         "jsr    @%0             \n"
230                         /* switch to the softirq stack */
231                         " mov   %1, r15         \n"
232                         /* restore the thread stack */
233                         "mov    r9, r15         \n"
234                         : /* no outputs */
235                         : "r" (__do_softirq), "r" (isp)
236                         : "memory", "r0", "r1", "r2", "r3", "r4",
237                           "r5", "r6", "r7", "r8", "r9", "r15", "t", "pr"
238                 );
239
240                 /*
241                  * Shouldnt happen, we returned above if in_interrupt():
242                  */
243                 WARN_ON_ONCE(softirq_count());
244         }
245
246         local_irq_restore(flags);
247 }
248 #endif
249
250 void __init init_IRQ(void)
251 {
252 #ifdef CONFIG_CPU_HAS_PINT_IRQ
253         init_IRQ_pint();
254 #endif
255         plat_irq_setup();
256
257         /* Perform the machine specific initialisation */
258         if (sh_mv.mv_init_irq)
259                 sh_mv.mv_init_irq();
260
261         irq_ctx_init(smp_processor_id());
262 }