Merge branch 'audit.b32' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/audit...
[linux-2.6] / 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         struct irq_desc *desc = irq_desc + irq;
59 #ifdef CONFIG_4KSTACKS
60         union irq_ctx *curctx, *irqctx;
61         u32 *isp;
62 #endif
63
64         if (unlikely((unsigned)irq >= NR_IRQS)) {
65                 printk(KERN_EMERG "%s: cannot handle IRQ %d\n",
66                                         __FUNCTION__, irq);
67                 BUG();
68         }
69
70         irq_enter();
71 #ifdef CONFIG_DEBUG_STACKOVERFLOW
72         /* Debugging check for stack overflow: is there less than 1KB free? */
73         {
74                 long esp;
75
76                 __asm__ __volatile__("andl %%esp,%0" :
77                                         "=r" (esp) : "0" (THREAD_SIZE - 1));
78                 if (unlikely(esp < (sizeof(struct thread_info) + STACK_WARN))) {
79                         printk("do_IRQ: stack overflow: %ld\n",
80                                 esp - sizeof(struct thread_info));
81                         dump_stack();
82                 }
83         }
84 #endif
85
86 #ifdef CONFIG_4KSTACKS
87
88         curctx = (union irq_ctx *) current_thread_info();
89         irqctx = hardirq_ctx[smp_processor_id()];
90
91         /*
92          * this is where we switch to the IRQ stack. However, if we are
93          * already using the IRQ stack (because we interrupted a hardirq
94          * handler) we can't do that and just have to keep using the
95          * current stack (which is the irq stack already after all)
96          */
97         if (curctx != irqctx) {
98                 int arg1, arg2, arg3, ebx;
99
100                 /* build the stack frame on the IRQ stack */
101                 isp = (u32*) ((char*)irqctx + sizeof(*irqctx));
102                 irqctx->tinfo.task = curctx->tinfo.task;
103                 irqctx->tinfo.previous_esp = current_stack_pointer;
104
105                 /*
106                  * Copy the softirq bits in preempt_count so that the
107                  * softirq checks work in the hardirq context.
108                  */
109                 irqctx->tinfo.preempt_count =
110                         (irqctx->tinfo.preempt_count & ~SOFTIRQ_MASK) |
111                         (curctx->tinfo.preempt_count & SOFTIRQ_MASK);
112
113                 asm volatile(
114                         "       xchgl  %%ebx,%%esp      \n"
115                         "       call   *%%edi           \n"
116                         "       movl   %%ebx,%%esp      \n"
117                         : "=a" (arg1), "=d" (arg2), "=c" (arg3), "=b" (ebx)
118                         :  "0" (irq),   "1" (desc),  "2" (regs),  "3" (isp),
119                            "D" (desc->handle_irq)
120                         : "memory", "cc"
121                 );
122         } else
123 #endif
124                 desc->handle_irq(irq, desc, regs);
125
126         irq_exit();
127
128         return 1;
129 }
130
131 #ifdef CONFIG_4KSTACKS
132
133 /*
134  * These should really be __section__(".bss.page_aligned") as well, but
135  * gcc's 3.0 and earlier don't handle that correctly.
136  */
137 static char softirq_stack[NR_CPUS * THREAD_SIZE]
138                 __attribute__((__aligned__(THREAD_SIZE)));
139
140 static char hardirq_stack[NR_CPUS * THREAD_SIZE]
141                 __attribute__((__aligned__(THREAD_SIZE)));
142
143 /*
144  * allocate per-cpu stacks for hardirq and for softirq processing
145  */
146 void irq_ctx_init(int cpu)
147 {
148         union irq_ctx *irqctx;
149
150         if (hardirq_ctx[cpu])
151                 return;
152
153         irqctx = (union irq_ctx*) &hardirq_stack[cpu*THREAD_SIZE];
154         irqctx->tinfo.task              = NULL;
155         irqctx->tinfo.exec_domain       = NULL;
156         irqctx->tinfo.cpu               = cpu;
157         irqctx->tinfo.preempt_count     = HARDIRQ_OFFSET;
158         irqctx->tinfo.addr_limit        = MAKE_MM_SEG(0);
159
160         hardirq_ctx[cpu] = irqctx;
161
162         irqctx = (union irq_ctx*) &softirq_stack[cpu*THREAD_SIZE];
163         irqctx->tinfo.task              = NULL;
164         irqctx->tinfo.exec_domain       = NULL;
165         irqctx->tinfo.cpu               = cpu;
166         irqctx->tinfo.preempt_count     = 0;
167         irqctx->tinfo.addr_limit        = MAKE_MM_SEG(0);
168
169         softirq_ctx[cpu] = irqctx;
170
171         printk("CPU %u irqstacks, hard=%p soft=%p\n",
172                 cpu,hardirq_ctx[cpu],softirq_ctx[cpu]);
173 }
174
175 void irq_ctx_exit(int cpu)
176 {
177         hardirq_ctx[cpu] = NULL;
178 }
179
180 extern asmlinkage void __do_softirq(void);
181
182 asmlinkage void do_softirq(void)
183 {
184         unsigned long flags;
185         struct thread_info *curctx;
186         union irq_ctx *irqctx;
187         u32 *isp;
188
189         if (in_interrupt())
190                 return;
191
192         local_irq_save(flags);
193
194         if (local_softirq_pending()) {
195                 curctx = current_thread_info();
196                 irqctx = softirq_ctx[smp_processor_id()];
197                 irqctx->tinfo.task = curctx->task;
198                 irqctx->tinfo.previous_esp = current_stack_pointer;
199
200                 /* build the stack frame on the softirq stack */
201                 isp = (u32*) ((char*)irqctx + sizeof(*irqctx));
202
203                 asm volatile(
204                         "       xchgl   %%ebx,%%esp     \n"
205                         "       call    __do_softirq    \n"
206                         "       movl    %%ebx,%%esp     \n"
207                         : "=b"(isp)
208                         : "0"(isp)
209                         : "memory", "cc", "edx", "ecx", "eax"
210                 );
211                 /*
212                  * Shouldnt happen, we returned above if in_interrupt():
213                  */
214                 WARN_ON_ONCE(softirq_count());
215         }
216
217         local_irq_restore(flags);
218 }
219
220 EXPORT_SYMBOL(do_softirq);
221 #endif
222
223 /*
224  * Interrupt statistics:
225  */
226
227 atomic_t irq_err_count;
228
229 /*
230  * /proc/interrupts printing:
231  */
232
233 int show_interrupts(struct seq_file *p, void *v)
234 {
235         int i = *(loff_t *) v, j;
236         struct irqaction * action;
237         unsigned long flags;
238
239         if (i == 0) {
240                 seq_printf(p, "           ");
241                 for_each_online_cpu(j)
242                         seq_printf(p, "CPU%-8d",j);
243                 seq_putc(p, '\n');
244         }
245
246         if (i < NR_IRQS) {
247                 spin_lock_irqsave(&irq_desc[i].lock, flags);
248                 action = irq_desc[i].action;
249                 if (!action)
250                         goto skip;
251                 seq_printf(p, "%3d: ",i);
252 #ifndef CONFIG_SMP
253                 seq_printf(p, "%10u ", kstat_irqs(i));
254 #else
255                 for_each_online_cpu(j)
256                         seq_printf(p, "%10u ", kstat_cpu(j).irqs[i]);
257 #endif
258                 seq_printf(p, " %8s", irq_desc[i].chip->name);
259                 seq_printf(p, "-%s", handle_irq_name(irq_desc[i].handle_irq));
260                 seq_printf(p, "  %s", action->name);
261
262                 for (action=action->next; action; action = action->next)
263                         seq_printf(p, ", %s", action->name);
264
265                 seq_putc(p, '\n');
266 skip:
267                 spin_unlock_irqrestore(&irq_desc[i].lock, flags);
268         } else if (i == NR_IRQS) {
269                 seq_printf(p, "NMI: ");
270                 for_each_online_cpu(j)
271                         seq_printf(p, "%10u ", nmi_count(j));
272                 seq_putc(p, '\n');
273 #ifdef CONFIG_X86_LOCAL_APIC
274                 seq_printf(p, "LOC: ");
275                 for_each_online_cpu(j)
276                         seq_printf(p, "%10u ",
277                                 per_cpu(irq_stat,j).apic_timer_irqs);
278                 seq_putc(p, '\n');
279 #endif
280                 seq_printf(p, "ERR: %10u\n", atomic_read(&irq_err_count));
281 #if defined(CONFIG_X86_IO_APIC)
282                 seq_printf(p, "MIS: %10u\n", atomic_read(&irq_mis_count));
283 #endif
284         }
285         return 0;
286 }
287
288 #ifdef CONFIG_HOTPLUG_CPU
289 #include <mach_apic.h>
290
291 void fixup_irqs(cpumask_t map)
292 {
293         unsigned int irq;
294         static int warned;
295
296         for (irq = 0; irq < NR_IRQS; irq++) {
297                 cpumask_t mask;
298                 if (irq == 2)
299                         continue;
300
301                 cpus_and(mask, irq_desc[irq].affinity, map);
302                 if (any_online_cpu(mask) == NR_CPUS) {
303                         printk("Breaking affinity for irq %i\n", irq);
304                         mask = map;
305                 }
306                 if (irq_desc[irq].chip->set_affinity)
307                         irq_desc[irq].chip->set_affinity(irq, mask);
308                 else if (irq_desc[irq].action && !(warned++))
309                         printk("Cannot set affinity for irq %i\n", irq);
310         }
311
312 #if 0
313         barrier();
314         /* Ingo Molnar says: "after the IO-APIC masks have been redirected
315            [note the nop - the interrupt-enable boundary on x86 is two
316            instructions from sti] - to flush out pending hardirqs and
317            IPIs. After this point nothing is supposed to reach this CPU." */
318         __asm__ __volatile__("sti; nop; cli");
319         barrier();
320 #else
321         /* That doesn't seem sufficient.  Give it 1ms. */
322         local_irq_enable();
323         mdelay(1);
324         local_irq_disable();
325 #endif
326 }
327 #endif
328