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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/i386/kernel/irq.c
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'arch/i386/kernel/irq.c')
-rw-r--r--arch/i386/kernel/irq.c261
1 files changed, 261 insertions, 0 deletions
diff --git a/arch/i386/kernel/irq.c b/arch/i386/kernel/irq.c
new file mode 100644
index 000000000000..73945a3c53c4
--- /dev/null
+++ b/arch/i386/kernel/irq.c
@@ -0,0 +1,261 @@
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
19DEFINE_PER_CPU(irq_cpustat_t, irq_stat) ____cacheline_maxaligned_in_smp;
20EXPORT_PER_CPU_SYMBOL(irq_stat);
21
22#ifndef CONFIG_X86_LOCAL_APIC
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.
26 */
27void ack_bad_irq(unsigned int irq)
28{
29 printk("unexpected IRQ trap at vector %02x\n", irq);
30}
31#endif
32
33#ifdef CONFIG_4KSTACKS
34/*
35 * per-CPU IRQ handling contexts (thread information and stack)
36 */
37union irq_ctx {
38 struct thread_info tinfo;
39 u32 stack[THREAD_SIZE/sizeof(u32)];
40};
41
42static union irq_ctx *hardirq_ctx[NR_CPUS];
43static union irq_ctx *softirq_ctx[NR_CPUS];
44#endif
45
46/*
47 * do_IRQ handles all normal device IRQ's (the special
48 * SMP cross-CPU interrupts have their own specific
49 * handlers).
50 */
51fastcall unsigned int do_IRQ(struct pt_regs *regs)
52{
53 /* high bits used in ret_from_ code */
54 int irq = regs->orig_eax & 0xff;
55#ifdef CONFIG_4KSTACKS
56 union irq_ctx *curctx, *irqctx;
57 u32 *isp;
58#endif
59
60 irq_enter();
61#ifdef CONFIG_DEBUG_STACKOVERFLOW
62 /* Debugging check for stack overflow: is there less than 1KB free? */
63 {
64 long esp;
65
66 __asm__ __volatile__("andl %%esp,%0" :
67 "=r" (esp) : "0" (THREAD_SIZE - 1));
68 if (unlikely(esp < (sizeof(struct thread_info) + STACK_WARN))) {
69 printk("do_IRQ: stack overflow: %ld\n",
70 esp - sizeof(struct thread_info));
71 dump_stack();
72 }
73 }
74#endif
75
76#ifdef CONFIG_4KSTACKS
77
78 curctx = (union irq_ctx *) current_thread_info();
79 irqctx = hardirq_ctx[smp_processor_id()];
80
81 /*
82 * this is where we switch to the IRQ stack. However, if we are
83 * already using the IRQ stack (because we interrupted a hardirq
84 * handler) we can't do that and just have to keep using the
85 * current stack (which is the irq stack already after all)
86 */
87 if (curctx != irqctx) {
88 int arg1, arg2, ebx;
89
90 /* build the stack frame on the IRQ stack */
91 isp = (u32*) ((char*)irqctx + sizeof(*irqctx));
92 irqctx->tinfo.task = curctx->tinfo.task;
93 irqctx->tinfo.previous_esp = current_stack_pointer;
94
95 asm volatile(
96 " xchgl %%ebx,%%esp \n"
97 " call __do_IRQ \n"
98 " movl %%ebx,%%esp \n"
99 : "=a" (arg1), "=d" (arg2), "=b" (ebx)
100 : "0" (irq), "1" (regs), "2" (isp)
101 : "memory", "cc", "ecx"
102 );
103 } else
104#endif
105 __do_IRQ(irq, regs);
106
107 irq_exit();
108
109 return 1;
110}
111
112#ifdef CONFIG_4KSTACKS
113
114/*
115 * These should really be __section__(".bss.page_aligned") as well, but
116 * gcc's 3.0 and earlier don't handle that correctly.
117 */
118static char softirq_stack[NR_CPUS * THREAD_SIZE]
119 __attribute__((__aligned__(THREAD_SIZE)));
120
121static char hardirq_stack[NR_CPUS * THREAD_SIZE]
122 __attribute__((__aligned__(THREAD_SIZE)));
123
124/*
125 * allocate per-cpu stacks for hardirq and for softirq processing
126 */
127void irq_ctx_init(int cpu)
128{
129 union irq_ctx *irqctx;
130
131 if (hardirq_ctx[cpu])
132 return;
133
134 irqctx = (union irq_ctx*) &hardirq_stack[cpu*THREAD_SIZE];
135 irqctx->tinfo.task = NULL;
136 irqctx->tinfo.exec_domain = NULL;
137 irqctx->tinfo.cpu = cpu;
138 irqctx->tinfo.preempt_count = HARDIRQ_OFFSET;
139 irqctx->tinfo.addr_limit = MAKE_MM_SEG(0);
140
141 hardirq_ctx[cpu] = irqctx;
142
143 irqctx = (union irq_ctx*) &softirq_stack[cpu*THREAD_SIZE];
144 irqctx->tinfo.task = NULL;
145 irqctx->tinfo.exec_domain = NULL;
146 irqctx->tinfo.cpu = cpu;
147 irqctx->tinfo.preempt_count = SOFTIRQ_OFFSET;
148 irqctx->tinfo.addr_limit = MAKE_MM_SEG(0);
149
150 softirq_ctx[cpu] = irqctx;
151
152 printk("CPU %u irqstacks, hard=%p soft=%p\n",
153 cpu,hardirq_ctx[cpu],softirq_ctx[cpu]);
154}
155
156extern asmlinkage void __do_softirq(void);
157
158asmlinkage void do_softirq(void)
159{
160 unsigned long flags;
161 struct thread_info *curctx;
162 union irq_ctx *irqctx;
163 u32 *isp;
164
165 if (in_interrupt())
166 return;
167
168 local_irq_save(flags);
169
170 if (local_softirq_pending()) {
171 curctx = current_thread_info();
172 irqctx = softirq_ctx[smp_processor_id()];
173 irqctx->tinfo.task = curctx->task;
174 irqctx->tinfo.previous_esp = current_stack_pointer;
175
176 /* build the stack frame on the softirq stack */
177 isp = (u32*) ((char*)irqctx + sizeof(*irqctx));
178
179 asm volatile(
180 " xchgl %%ebx,%%esp \n"
181 " call __do_softirq \n"
182 " movl %%ebx,%%esp \n"
183 : "=b"(isp)
184 : "0"(isp)
185 : "memory", "cc", "edx", "ecx", "eax"
186 );
187 }
188
189 local_irq_restore(flags);
190}
191
192EXPORT_SYMBOL(do_softirq);
193#endif
194
195/*
196 * Interrupt statistics:
197 */
198
199atomic_t irq_err_count;
200
201/*
202 * /proc/interrupts printing:
203 */
204
205int show_interrupts(struct seq_file *p, void *v)
206{
207 int i = *(loff_t *) v, j;
208 struct irqaction * action;
209 unsigned long flags;
210
211 if (i == 0) {
212 seq_printf(p, " ");
213 for (j=0; j<NR_CPUS; j++)
214 if (cpu_online(j))
215 seq_printf(p, "CPU%d ",j);
216 seq_putc(p, '\n');
217 }
218
219 if (i < NR_IRQS) {
220 spin_lock_irqsave(&irq_desc[i].lock, flags);
221 action = irq_desc[i].action;
222 if (!action)
223 goto skip;
224 seq_printf(p, "%3d: ",i);
225#ifndef CONFIG_SMP
226 seq_printf(p, "%10u ", kstat_irqs(i));
227#else
228 for (j = 0; j < NR_CPUS; j++)
229 if (cpu_online(j))
230 seq_printf(p, "%10u ", kstat_cpu(j).irqs[i]);
231#endif
232 seq_printf(p, " %14s", irq_desc[i].handler->typename);
233 seq_printf(p, " %s", action->name);
234
235 for (action=action->next; action; action = action->next)
236 seq_printf(p, ", %s", action->name);
237
238 seq_putc(p, '\n');
239skip:
240 spin_unlock_irqrestore(&irq_desc[i].lock, flags);
241 } else if (i == NR_IRQS) {
242 seq_printf(p, "NMI: ");
243 for (j = 0; j < NR_CPUS; j++)
244 if (cpu_online(j))
245 seq_printf(p, "%10u ", nmi_count(j));
246 seq_putc(p, '\n');
247#ifdef CONFIG_X86_LOCAL_APIC
248 seq_printf(p, "LOC: ");
249 for (j = 0; j < NR_CPUS; j++)
250 if (cpu_online(j))
251 seq_printf(p, "%10u ",
252 per_cpu(irq_stat,j).apic_timer_irqs);
253 seq_putc(p, '\n');
254#endif
255 seq_printf(p, "ERR: %10u\n", atomic_read(&irq_err_count));
256#if defined(CONFIG_X86_IO_APIC)
257 seq_printf(p, "MIS: %10u\n", atomic_read(&irq_mis_count));
258#endif
259 }
260 return 0;
261}