Merge branch 'for-linus' of git://git.o-hand.com/linux-rpurdie-backlight
[linux-2.6] / arch / x86 / kernel / irq_32.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 <linux/module.h>
14 #include <linux/seq_file.h>
15 #include <linux/interrupt.h>
16 #include <linux/kernel_stat.h>
17 #include <linux/notifier.h>
18 #include <linux/cpu.h>
19 #include <linux/delay.h>
20
21 #include <asm/apic.h>
22 #include <asm/uaccess.h>
23
24 DEFINE_PER_CPU_SHARED_ALIGNED(irq_cpustat_t, irq_stat);
25 EXPORT_PER_CPU_SYMBOL(irq_stat);
26
27 DEFINE_PER_CPU(struct pt_regs *, irq_regs);
28 EXPORT_PER_CPU_SYMBOL(irq_regs);
29
30 /*
31  * 'what should we do if we get a hw irq event on an illegal vector'.
32  * each architecture has to answer this themselves.
33  */
34 void ack_bad_irq(unsigned int irq)
35 {
36         printk(KERN_ERR "unexpected IRQ trap at vector %02x\n", irq);
37
38 #ifdef CONFIG_X86_LOCAL_APIC
39         /*
40          * Currently unexpected vectors happen only on SMP and APIC.
41          * We _must_ ack these because every local APIC has only N
42          * irq slots per priority level, and a 'hanging, unacked' IRQ
43          * holds up an irq slot - in excessive cases (when multiple
44          * unexpected vectors occur) that might lock up the APIC
45          * completely.
46          * But only ack when the APIC is enabled -AK
47          */
48         if (cpu_has_apic)
49                 ack_APIC_irq();
50 #endif
51 }
52
53 #ifdef CONFIG_4KSTACKS
54 /*
55  * per-CPU IRQ handling contexts (thread information and stack)
56  */
57 union irq_ctx {
58         struct thread_info      tinfo;
59         u32                     stack[THREAD_SIZE/sizeof(u32)];
60 };
61
62 static union irq_ctx *hardirq_ctx[NR_CPUS] __read_mostly;
63 static union irq_ctx *softirq_ctx[NR_CPUS] __read_mostly;
64 #endif
65
66 /*
67  * do_IRQ handles all normal device IRQ's (the special
68  * SMP cross-CPU interrupts have their own specific
69  * handlers).
70  */
71 fastcall unsigned int do_IRQ(struct pt_regs *regs)
72 {       
73         struct pt_regs *old_regs;
74         /* high bit used in ret_from_ code */
75         int irq = ~regs->orig_eax;
76         struct irq_desc *desc = irq_desc + irq;
77 #ifdef CONFIG_4KSTACKS
78         union irq_ctx *curctx, *irqctx;
79         u32 *isp;
80 #endif
81
82         if (unlikely((unsigned)irq >= NR_IRQS)) {
83                 printk(KERN_EMERG "%s: cannot handle IRQ %d\n",
84                                         __FUNCTION__, irq);
85                 BUG();
86         }
87
88         old_regs = set_irq_regs(regs);
89         irq_enter();
90 #ifdef CONFIG_DEBUG_STACKOVERFLOW
91         /* Debugging check for stack overflow: is there less than 1KB free? */
92         {
93                 long esp;
94
95                 __asm__ __volatile__("andl %%esp,%0" :
96                                         "=r" (esp) : "0" (THREAD_SIZE - 1));
97                 if (unlikely(esp < (sizeof(struct thread_info) + STACK_WARN))) {
98                         printk("do_IRQ: stack overflow: %ld\n",
99                                 esp - sizeof(struct thread_info));
100                         dump_stack();
101                 }
102         }
103 #endif
104
105 #ifdef CONFIG_4KSTACKS
106
107         curctx = (union irq_ctx *) current_thread_info();
108         irqctx = hardirq_ctx[smp_processor_id()];
109
110         /*
111          * this is where we switch to the IRQ stack. However, if we are
112          * already using the IRQ stack (because we interrupted a hardirq
113          * handler) we can't do that and just have to keep using the
114          * current stack (which is the irq stack already after all)
115          */
116         if (curctx != irqctx) {
117                 int arg1, arg2, ebx;
118
119                 /* build the stack frame on the IRQ stack */
120                 isp = (u32*) ((char*)irqctx + sizeof(*irqctx));
121                 irqctx->tinfo.task = curctx->tinfo.task;
122                 irqctx->tinfo.previous_esp = current_stack_pointer;
123
124                 /*
125                  * Copy the softirq bits in preempt_count so that the
126                  * softirq checks work in the hardirq context.
127                  */
128                 irqctx->tinfo.preempt_count =
129                         (irqctx->tinfo.preempt_count & ~SOFTIRQ_MASK) |
130                         (curctx->tinfo.preempt_count & SOFTIRQ_MASK);
131
132                 asm volatile(
133                         "       xchgl  %%ebx,%%esp      \n"
134                         "       call   *%%edi           \n"
135                         "       movl   %%ebx,%%esp      \n"
136                         : "=a" (arg1), "=d" (arg2), "=b" (ebx)
137                         :  "0" (irq),   "1" (desc),  "2" (isp),
138                            "D" (desc->handle_irq)
139                         : "memory", "cc"
140                 );
141         } else
142 #endif
143                 desc->handle_irq(irq, desc);
144
145         irq_exit();
146         set_irq_regs(old_regs);
147         return 1;
148 }
149
150 #ifdef CONFIG_4KSTACKS
151
152 static char softirq_stack[NR_CPUS * THREAD_SIZE]
153                 __attribute__((__section__(".bss.page_aligned")));
154
155 static char hardirq_stack[NR_CPUS * THREAD_SIZE]
156                 __attribute__((__section__(".bss.page_aligned")));
157
158 /*
159  * allocate per-cpu stacks for hardirq and for softirq processing
160  */
161 void irq_ctx_init(int cpu)
162 {
163         union irq_ctx *irqctx;
164
165         if (hardirq_ctx[cpu])
166                 return;
167
168         irqctx = (union irq_ctx*) &hardirq_stack[cpu*THREAD_SIZE];
169         irqctx->tinfo.task              = NULL;
170         irqctx->tinfo.exec_domain       = NULL;
171         irqctx->tinfo.cpu               = cpu;
172         irqctx->tinfo.preempt_count     = HARDIRQ_OFFSET;
173         irqctx->tinfo.addr_limit        = MAKE_MM_SEG(0);
174
175         hardirq_ctx[cpu] = irqctx;
176
177         irqctx = (union irq_ctx*) &softirq_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     = 0;
182         irqctx->tinfo.addr_limit        = MAKE_MM_SEG(0);
183
184         softirq_ctx[cpu] = irqctx;
185
186         printk("CPU %u irqstacks, hard=%p soft=%p\n",
187                 cpu,hardirq_ctx[cpu],softirq_ctx[cpu]);
188 }
189
190 void irq_ctx_exit(int cpu)
191 {
192         hardirq_ctx[cpu] = NULL;
193 }
194
195 extern asmlinkage void __do_softirq(void);
196
197 asmlinkage void do_softirq(void)
198 {
199         unsigned long flags;
200         struct thread_info *curctx;
201         union irq_ctx *irqctx;
202         u32 *isp;
203
204         if (in_interrupt())
205                 return;
206
207         local_irq_save(flags);
208
209         if (local_softirq_pending()) {
210                 curctx = current_thread_info();
211                 irqctx = softirq_ctx[smp_processor_id()];
212                 irqctx->tinfo.task = curctx->task;
213                 irqctx->tinfo.previous_esp = current_stack_pointer;
214
215                 /* build the stack frame on the softirq stack */
216                 isp = (u32*) ((char*)irqctx + sizeof(*irqctx));
217
218                 asm volatile(
219                         "       xchgl   %%ebx,%%esp     \n"
220                         "       call    __do_softirq    \n"
221                         "       movl    %%ebx,%%esp     \n"
222                         : "=b"(isp)
223                         : "0"(isp)
224                         : "memory", "cc", "edx", "ecx", "eax"
225                 );
226                 /*
227                  * Shouldnt happen, we returned above if in_interrupt():
228                  */
229                 WARN_ON_ONCE(softirq_count());
230         }
231
232         local_irq_restore(flags);
233 }
234
235 EXPORT_SYMBOL(do_softirq);
236 #endif
237
238 /*
239  * Interrupt statistics:
240  */
241
242 atomic_t irq_err_count;
243
244 /*
245  * /proc/interrupts printing:
246  */
247
248 int show_interrupts(struct seq_file *p, void *v)
249 {
250         int i = *(loff_t *) v, j;
251         struct irqaction * action;
252         unsigned long flags;
253
254         if (i == 0) {
255                 seq_printf(p, "           ");
256                 for_each_online_cpu(j)
257                         seq_printf(p, "CPU%-8d",j);
258                 seq_putc(p, '\n');
259         }
260
261         if (i < NR_IRQS) {
262                 spin_lock_irqsave(&irq_desc[i].lock, flags);
263                 action = irq_desc[i].action;
264                 if (!action)
265                         goto skip;
266                 seq_printf(p, "%3d: ",i);
267 #ifndef CONFIG_SMP
268                 seq_printf(p, "%10u ", kstat_irqs(i));
269 #else
270                 for_each_online_cpu(j)
271                         seq_printf(p, "%10u ", kstat_cpu(j).irqs[i]);
272 #endif
273                 seq_printf(p, " %8s", irq_desc[i].chip->name);
274                 seq_printf(p, "-%-8s", irq_desc[i].name);
275                 seq_printf(p, "  %s", action->name);
276
277                 for (action=action->next; action; action = action->next)
278                         seq_printf(p, ", %s", action->name);
279
280                 seq_putc(p, '\n');
281 skip:
282                 spin_unlock_irqrestore(&irq_desc[i].lock, flags);
283         } else if (i == NR_IRQS) {
284                 seq_printf(p, "NMI: ");
285                 for_each_online_cpu(j)
286                         seq_printf(p, "%10u ", nmi_count(j));
287                 seq_putc(p, '\n');
288 #ifdef CONFIG_X86_LOCAL_APIC
289                 seq_printf(p, "LOC: ");
290                 for_each_online_cpu(j)
291                         seq_printf(p, "%10u ",
292                                 per_cpu(irq_stat,j).apic_timer_irqs);
293                 seq_putc(p, '\n');
294 #endif
295                 seq_printf(p, "ERR: %10u\n", atomic_read(&irq_err_count));
296 #if defined(CONFIG_X86_IO_APIC)
297                 seq_printf(p, "MIS: %10u\n", atomic_read(&irq_mis_count));
298 #endif
299         }
300         return 0;
301 }
302
303 #ifdef CONFIG_HOTPLUG_CPU
304 #include <mach_apic.h>
305
306 void fixup_irqs(cpumask_t map)
307 {
308         unsigned int irq;
309         static int warned;
310
311         for (irq = 0; irq < NR_IRQS; irq++) {
312                 cpumask_t mask;
313                 if (irq == 2)
314                         continue;
315
316                 cpus_and(mask, irq_desc[irq].affinity, map);
317                 if (any_online_cpu(mask) == NR_CPUS) {
318                         printk("Breaking affinity for irq %i\n", irq);
319                         mask = map;
320                 }
321                 if (irq_desc[irq].chip->set_affinity)
322                         irq_desc[irq].chip->set_affinity(irq, mask);
323                 else if (irq_desc[irq].action && !(warned++))
324                         printk("Cannot set affinity for irq %i\n", irq);
325         }
326
327 #if 0
328         barrier();
329         /* Ingo Molnar says: "after the IO-APIC masks have been redirected
330            [note the nop - the interrupt-enable boundary on x86 is two
331            instructions from sti] - to flush out pending hardirqs and
332            IPIs. After this point nothing is supposed to reach this CPU." */
333         __asm__ __volatile__("sti; nop; cli");
334         barrier();
335 #else
336         /* That doesn't seem sufficient.  Give it 1ms. */
337         local_irq_enable();
338         mdelay(1);
339         local_irq_disable();
340 #endif
341 }
342 #endif
343