[PATCH] genirq: cleanup: merge irq_affinity[] into irq_desc[]
[linux-2.6.git] / arch / i386 / kernel / irq.c
1 /*
2  *      linux/arch/i386/kernel/irq.c
3  *
4  *      Copyright (C) 1992, 1998 Linus Torvalds, Ingo Molnar
5  *
6  * This file contains the lowest level x86-specific interrupt
7  * entry, irq-stacks and irq statistics code. All the remaining
8  * irq logic is done by the generic kernel/irq/ code and
9  * by the x86-specific irq controller code. (e.g. i8259.c and
10  * io_apic.c.)
11  */
12
13 #include <asm/uaccess.h>
14 #include <linux/module.h>
15 #include <linux/seq_file.h>
16 #include <linux/interrupt.h>
17 #include <linux/kernel_stat.h>
18 #include <linux/notifier.h>
19 #include <linux/cpu.h>
20 #include <linux/delay.h>
21
22 DEFINE_PER_CPU(irq_cpustat_t, irq_stat) ____cacheline_internodealigned_in_smp;
23 EXPORT_PER_CPU_SYMBOL(irq_stat);
24
25 #ifndef CONFIG_X86_LOCAL_APIC
26 /*
27  * 'what should we do if we get a hw irq event on an illegal vector'.
28  * each architecture has to answer this themselves.
29  */
30 void ack_bad_irq(unsigned int irq)
31 {
32         printk("unexpected IRQ trap at vector %02x\n", irq);
33 }
34 #endif
35
36 #ifdef CONFIG_4KSTACKS
37 /*
38  * per-CPU IRQ handling contexts (thread information and stack)
39  */
40 union irq_ctx {
41         struct thread_info      tinfo;
42         u32                     stack[THREAD_SIZE/sizeof(u32)];
43 };
44
45 static union irq_ctx *hardirq_ctx[NR_CPUS] __read_mostly;
46 static union irq_ctx *softirq_ctx[NR_CPUS] __read_mostly;
47 #endif
48
49 /*
50  * do_IRQ handles all normal device IRQ's (the special
51  * SMP cross-CPU interrupts have their own specific
52  * handlers).
53  */
54 fastcall unsigned int do_IRQ(struct pt_regs *regs)
55 {       
56         /* high bit used in ret_from_ code */
57         int irq = ~regs->orig_eax;
58 #ifdef CONFIG_4KSTACKS
59         union irq_ctx *curctx, *irqctx;
60         u32 *isp;
61 #endif
62
63         if (unlikely((unsigned)irq >= NR_IRQS)) {
64                 printk(KERN_EMERG "%s: cannot handle IRQ %d\n",
65                                         __FUNCTION__, irq);
66                 BUG();
67         }
68
69         irq_enter();
70 #ifdef CONFIG_DEBUG_STACKOVERFLOW
71         /* Debugging check for stack overflow: is there less than 1KB free? */
72         {
73                 long esp;
74
75                 __asm__ __volatile__("andl %%esp,%0" :
76                                         "=r" (esp) : "0" (THREAD_SIZE - 1));
77                 if (unlikely(esp < (sizeof(struct thread_info) + STACK_WARN))) {
78                         printk("do_IRQ: stack overflow: %ld\n",
79                                 esp - sizeof(struct thread_info));
80                         dump_stack();
81                 }
82         }
83 #endif
84
85 #ifdef CONFIG_4KSTACKS
86
87         curctx = (union irq_ctx *) current_thread_info();
88         irqctx = hardirq_ctx[smp_processor_id()];
89
90         /*
91          * this is where we switch to the IRQ stack. However, if we are
92          * already using the IRQ stack (because we interrupted a hardirq
93          * handler) we can't do that and just have to keep using the
94          * current stack (which is the irq stack already after all)
95          */
96         if (curctx != irqctx) {
97                 int arg1, arg2, ebx;
98
99                 /* build the stack frame on the IRQ stack */
100                 isp = (u32*) ((char*)irqctx + sizeof(*irqctx));
101                 irqctx->tinfo.task = curctx->tinfo.task;
102                 irqctx->tinfo.previous_esp = current_stack_pointer;
103
104                 /*
105                  * Copy the softirq bits in preempt_count so that the
106                  * softirq checks work in the hardirq context.
107                  */
108                 irqctx->tinfo.preempt_count =
109                         (irqctx->tinfo.preempt_count & ~SOFTIRQ_MASK) |
110                         (curctx->tinfo.preempt_count & SOFTIRQ_MASK);
111
112                 asm volatile(
113                         "       xchgl   %%ebx,%%esp      \n"
114                         "       call    __do_IRQ         \n"
115                         "       movl   %%ebx,%%esp      \n"
116                         : "=a" (arg1), "=d" (arg2), "=b" (ebx)
117                         :  "0" (irq),   "1" (regs),  "2" (isp)
118                         : "memory", "cc", "ecx"
119                 );
120         } else
121 #endif
122                 __do_IRQ(irq, regs);
123
124         irq_exit();
125
126         return 1;
127 }
128
129 #ifdef CONFIG_4KSTACKS
130
131 /*
132  * These should really be __section__(".bss.page_aligned") as well, but
133  * gcc's 3.0 and earlier don't handle that correctly.
134  */
135 static char softirq_stack[NR_CPUS * THREAD_SIZE]
136                 __attribute__((__aligned__(THREAD_SIZE)));
137
138 static char hardirq_stack[NR_CPUS * THREAD_SIZE]
139                 __attribute__((__aligned__(THREAD_SIZE)));
140
141 /*
142  * allocate per-cpu stacks for hardirq and for softirq processing
143  */
144 void irq_ctx_init(int cpu)
145 {
146         union irq_ctx *irqctx;
147
148         if (hardirq_ctx[cpu])
149                 return;
150
151         irqctx = (union irq_ctx*) &hardirq_stack[cpu*THREAD_SIZE];
152         irqctx->tinfo.task              = NULL;
153         irqctx->tinfo.exec_domain       = NULL;
154         irqctx->tinfo.cpu               = cpu;
155         irqctx->tinfo.preempt_count     = HARDIRQ_OFFSET;
156         irqctx->tinfo.addr_limit        = MAKE_MM_SEG(0);
157
158         hardirq_ctx[cpu] = irqctx;
159
160         irqctx = (union irq_ctx*) &softirq_stack[cpu*THREAD_SIZE];
161         irqctx->tinfo.task              = NULL;
162         irqctx->tinfo.exec_domain       = NULL;
163         irqctx->tinfo.cpu               = cpu;
164         irqctx->tinfo.preempt_count     = SOFTIRQ_OFFSET;
165         irqctx->tinfo.addr_limit        = MAKE_MM_SEG(0);
166
167         softirq_ctx[cpu] = irqctx;
168
169         printk("CPU %u irqstacks, hard=%p soft=%p\n",
170                 cpu,hardirq_ctx[cpu],softirq_ctx[cpu]);
171 }
172
173 void irq_ctx_exit(int cpu)
174 {
175         hardirq_ctx[cpu] = NULL;
176 }
177
178 extern asmlinkage void __do_softirq(void);
179
180 asmlinkage void do_softirq(void)
181 {
182         unsigned long flags;
183         struct thread_info *curctx;
184         union irq_ctx *irqctx;
185         u32 *isp;
186
187         if (in_interrupt())
188                 return;
189
190         local_irq_save(flags);
191
192         if (local_softirq_pending()) {
193                 curctx = current_thread_info();
194                 irqctx = softirq_ctx[smp_processor_id()];
195                 irqctx->tinfo.task = curctx->task;
196                 irqctx->tinfo.previous_esp = current_stack_pointer;
197
198                 /* build the stack frame on the softirq stack */
199                 isp = (u32*) ((char*)irqctx + sizeof(*irqctx));
200
201                 asm volatile(
202                         "       xchgl   %%ebx,%%esp     \n"
203                         "       call    __do_softirq    \n"
204                         "       movl    %%ebx,%%esp     \n"
205                         : "=b"(isp)
206                         : "0"(isp)
207                         : "memory", "cc", "edx", "ecx", "eax"
208                 );
209         }
210
211         local_irq_restore(flags);
212 }
213
214 EXPORT_SYMBOL(do_softirq);
215 #endif
216
217 /*
218  * Interrupt statistics:
219  */
220
221 atomic_t irq_err_count;
222
223 /*
224  * /proc/interrupts printing:
225  */
226
227 int show_interrupts(struct seq_file *p, void *v)
228 {
229         int i = *(loff_t *) v, j;
230         struct irqaction * action;
231         unsigned long flags;
232
233         if (i == 0) {
234                 seq_printf(p, "           ");
235                 for_each_online_cpu(j)
236                         seq_printf(p, "CPU%-8d",j);
237                 seq_putc(p, '\n');
238         }
239
240         if (i < NR_IRQS) {
241                 spin_lock_irqsave(&irq_desc[i].lock, flags);
242                 action = irq_desc[i].action;
243                 if (!action)
244                         goto skip;
245                 seq_printf(p, "%3d: ",i);
246 #ifndef CONFIG_SMP
247                 seq_printf(p, "%10u ", kstat_irqs(i));
248 #else
249                 for_each_online_cpu(j)
250                         seq_printf(p, "%10u ", kstat_cpu(j).irqs[i]);
251 #endif
252                 seq_printf(p, " %14s", irq_desc[i].chip->typename);
253                 seq_printf(p, "  %s", action->name);
254
255                 for (action=action->next; action; action = action->next)
256                         seq_printf(p, ", %s", action->name);
257
258                 seq_putc(p, '\n');
259 skip:
260                 spin_unlock_irqrestore(&irq_desc[i].lock, flags);
261         } else if (i == NR_IRQS) {
262                 seq_printf(p, "NMI: ");
263                 for_each_online_cpu(j)
264                         seq_printf(p, "%10u ", nmi_count(j));
265                 seq_putc(p, '\n');
266 #ifdef CONFIG_X86_LOCAL_APIC
267                 seq_printf(p, "LOC: ");
268                 for_each_online_cpu(j)
269                         seq_printf(p, "%10u ",
270                                 per_cpu(irq_stat,j).apic_timer_irqs);
271                 seq_putc(p, '\n');
272 #endif
273                 seq_printf(p, "ERR: %10u\n", atomic_read(&irq_err_count));
274 #if defined(CONFIG_X86_IO_APIC)
275                 seq_printf(p, "MIS: %10u\n", atomic_read(&irq_mis_count));
276 #endif
277         }
278         return 0;
279 }
280
281 #ifdef CONFIG_HOTPLUG_CPU
282 #include <mach_apic.h>
283
284 void fixup_irqs(cpumask_t map)
285 {
286         unsigned int irq;
287         static int warned;
288
289         for (irq = 0; irq < NR_IRQS; irq++) {
290                 cpumask_t mask;
291                 if (irq == 2)
292                         continue;
293
294                 cpus_and(mask, irq_desc[irq].affinity, map);
295                 if (any_online_cpu(mask) == NR_CPUS) {
296                         printk("Breaking affinity for irq %i\n", irq);
297                         mask = map;
298                 }
299                 if (irq_desc[irq].chip->set_affinity)
300                         irq_desc[irq].chip->set_affinity(irq, mask);
301                 else if (irq_desc[irq].action && !(warned++))
302                         printk("Cannot set affinity for irq %i\n", irq);
303         }
304
305 #if 0
306         barrier();
307         /* Ingo Molnar says: "after the IO-APIC masks have been redirected
308            [note the nop - the interrupt-enable boundary on x86 is two
309            instructions from sti] - to flush out pending hardirqs and
310            IPIs. After this point nothing is supposed to reach this CPU." */
311         __asm__ __volatile__("sti; nop; cli");
312         barrier();
313 #else
314         /* That doesn't seem sufficient.  Give it 1ms. */
315         local_irq_enable();
316         mdelay(1);
317         local_irq_disable();
318 #endif
319 }
320 #endif
321