Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux
[~shefty/rdma-dev.git] / arch / s390 / kernel / irq.c
1 /*
2  *    Copyright IBM Corp. 2004,2011
3  *    Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>,
4  *               Holger Smolinski <Holger.Smolinski@de.ibm.com>,
5  *               Thomas Spatzier <tspat@de.ibm.com>,
6  *
7  * This file contains interrupt related functions.
8  */
9
10 #include <linux/kernel_stat.h>
11 #include <linux/interrupt.h>
12 #include <linux/seq_file.h>
13 #include <linux/proc_fs.h>
14 #include <linux/profile.h>
15 #include <linux/module.h>
16 #include <linux/kernel.h>
17 #include <linux/ftrace.h>
18 #include <linux/errno.h>
19 #include <linux/slab.h>
20 #include <linux/cpu.h>
21 #include <asm/irq_regs.h>
22 #include <asm/cputime.h>
23 #include <asm/lowcore.h>
24 #include <asm/irq.h>
25 #include "entry.h"
26
27 struct irq_class {
28         char *name;
29         char *desc;
30 };
31
32 static const struct irq_class intrclass_names[] = {
33         {.name = "EXT" },
34         {.name = "I/O" },
35         {.name = "CLK", .desc = "[EXT] Clock Comparator" },
36         {.name = "EXC", .desc = "[EXT] External Call" },
37         {.name = "EMS", .desc = "[EXT] Emergency Signal" },
38         {.name = "TMR", .desc = "[EXT] CPU Timer" },
39         {.name = "TAL", .desc = "[EXT] Timing Alert" },
40         {.name = "PFL", .desc = "[EXT] Pseudo Page Fault" },
41         {.name = "DSD", .desc = "[EXT] DASD Diag" },
42         {.name = "VRT", .desc = "[EXT] Virtio" },
43         {.name = "SCP", .desc = "[EXT] Service Call" },
44         {.name = "IUC", .desc = "[EXT] IUCV" },
45         {.name = "CPM", .desc = "[EXT] CPU Measurement" },
46         {.name = "CIO", .desc = "[I/O] Common I/O Layer Interrupt" },
47         {.name = "QAI", .desc = "[I/O] QDIO Adapter Interrupt" },
48         {.name = "DAS", .desc = "[I/O] DASD" },
49         {.name = "C15", .desc = "[I/O] 3215" },
50         {.name = "C70", .desc = "[I/O] 3270" },
51         {.name = "TAP", .desc = "[I/O] Tape" },
52         {.name = "VMR", .desc = "[I/O] Unit Record Devices" },
53         {.name = "LCS", .desc = "[I/O] LCS" },
54         {.name = "CLW", .desc = "[I/O] CLAW" },
55         {.name = "CTC", .desc = "[I/O] CTC" },
56         {.name = "APB", .desc = "[I/O] AP Bus" },
57         {.name = "CSC", .desc = "[I/O] CHSC Subchannel" },
58         {.name = "NMI", .desc = "[NMI] Machine Check" },
59 };
60
61 /*
62  * show_interrupts is needed by /proc/interrupts.
63  */
64 int show_interrupts(struct seq_file *p, void *v)
65 {
66         int i = *(loff_t *) v, j;
67
68         get_online_cpus();
69         if (i == 0) {
70                 seq_puts(p, "           ");
71                 for_each_online_cpu(j)
72                         seq_printf(p, "CPU%d       ",j);
73                 seq_putc(p, '\n');
74         }
75
76         if (i < NR_IRQS) {
77                 seq_printf(p, "%s: ", intrclass_names[i].name);
78 #ifndef CONFIG_SMP
79                 seq_printf(p, "%10u ", kstat_irqs(i));
80 #else
81                 for_each_online_cpu(j)
82                         seq_printf(p, "%10u ", kstat_cpu(j).irqs[i]);
83 #endif
84                 if (intrclass_names[i].desc)
85                         seq_printf(p, "  %s", intrclass_names[i].desc);
86                 seq_putc(p, '\n');
87         }
88         put_online_cpus();
89         return 0;
90 }
91
92 /*
93  * Switch to the asynchronous interrupt stack for softirq execution.
94  */
95 asmlinkage void do_softirq(void)
96 {
97         unsigned long flags, old, new;
98
99         if (in_interrupt())
100                 return;
101
102         local_irq_save(flags);
103
104         if (local_softirq_pending()) {
105                 /* Get current stack pointer. */
106                 asm volatile("la %0,0(15)" : "=a" (old));
107                 /* Check against async. stack address range. */
108                 new = S390_lowcore.async_stack;
109                 if (((new - old) >> (PAGE_SHIFT + THREAD_ORDER)) != 0) {
110                         /* Need to switch to the async. stack. */
111                         new -= STACK_FRAME_OVERHEAD;
112                         ((struct stack_frame *) new)->back_chain = old;
113
114                         asm volatile("   la    15,0(%0)\n"
115                                      "   basr  14,%2\n"
116                                      "   la    15,0(%1)\n"
117                                      : : "a" (new), "a" (old),
118                                          "a" (__do_softirq)
119                                      : "0", "1", "2", "3", "4", "5", "14",
120                                        "cc", "memory" );
121                 } else
122                         /* We are already on the async stack. */
123                         __do_softirq();
124         }
125
126         local_irq_restore(flags);
127 }
128
129 #ifdef CONFIG_PROC_FS
130 void init_irq_proc(void)
131 {
132         struct proc_dir_entry *root_irq_dir;
133
134         root_irq_dir = proc_mkdir("irq", NULL);
135         create_prof_cpu_mask(root_irq_dir);
136 }
137 #endif
138
139 /*
140  * ext_int_hash[index] is the list head for all external interrupts that hash
141  * to this index.
142  */
143 static struct list_head ext_int_hash[256];
144
145 struct ext_int_info {
146         ext_int_handler_t handler;
147         u16 code;
148         struct list_head entry;
149         struct rcu_head rcu;
150 };
151
152 /* ext_int_hash_lock protects the handler lists for external interrupts */
153 DEFINE_SPINLOCK(ext_int_hash_lock);
154
155 static void __init init_external_interrupts(void)
156 {
157         int idx;
158
159         for (idx = 0; idx < ARRAY_SIZE(ext_int_hash); idx++)
160                 INIT_LIST_HEAD(&ext_int_hash[idx]);
161 }
162
163 static inline int ext_hash(u16 code)
164 {
165         return (code + (code >> 9)) & 0xff;
166 }
167
168 int register_external_interrupt(u16 code, ext_int_handler_t handler)
169 {
170         struct ext_int_info *p;
171         unsigned long flags;
172         int index;
173
174         p = kmalloc(sizeof(*p), GFP_ATOMIC);
175         if (!p)
176                 return -ENOMEM;
177         p->code = code;
178         p->handler = handler;
179         index = ext_hash(code);
180
181         spin_lock_irqsave(&ext_int_hash_lock, flags);
182         list_add_rcu(&p->entry, &ext_int_hash[index]);
183         spin_unlock_irqrestore(&ext_int_hash_lock, flags);
184         return 0;
185 }
186 EXPORT_SYMBOL(register_external_interrupt);
187
188 int unregister_external_interrupt(u16 code, ext_int_handler_t handler)
189 {
190         struct ext_int_info *p;
191         unsigned long flags;
192         int index = ext_hash(code);
193
194         spin_lock_irqsave(&ext_int_hash_lock, flags);
195         list_for_each_entry_rcu(p, &ext_int_hash[index], entry)
196                 if (p->code == code && p->handler == handler) {
197                         list_del_rcu(&p->entry);
198                         kfree_rcu(p, rcu);
199                 }
200         spin_unlock_irqrestore(&ext_int_hash_lock, flags);
201         return 0;
202 }
203 EXPORT_SYMBOL(unregister_external_interrupt);
204
205 void __irq_entry do_extint(struct pt_regs *regs, struct ext_code ext_code,
206                            unsigned int param32, unsigned long param64)
207 {
208         struct pt_regs *old_regs;
209         struct ext_int_info *p;
210         int index;
211
212         old_regs = set_irq_regs(regs);
213         irq_enter();
214         if (S390_lowcore.int_clock >= S390_lowcore.clock_comparator)
215                 /* Serve timer interrupts first. */
216                 clock_comparator_work();
217         kstat_cpu(smp_processor_id()).irqs[EXTERNAL_INTERRUPT]++;
218         if (ext_code.code != 0x1004)
219                 __get_cpu_var(s390_idle).nohz_delay = 1;
220
221         index = ext_hash(ext_code.code);
222         rcu_read_lock();
223         list_for_each_entry_rcu(p, &ext_int_hash[index], entry)
224                 if (likely(p->code == ext_code.code))
225                         p->handler(ext_code, param32, param64);
226         rcu_read_unlock();
227         irq_exit();
228         set_irq_regs(old_regs);
229 }
230
231 void __init init_IRQ(void)
232 {
233         init_external_interrupts();
234 }
235
236 static DEFINE_SPINLOCK(sc_irq_lock);
237 static int sc_irq_refcount;
238
239 void service_subclass_irq_register(void)
240 {
241         spin_lock(&sc_irq_lock);
242         if (!sc_irq_refcount)
243                 ctl_set_bit(0, 9);
244         sc_irq_refcount++;
245         spin_unlock(&sc_irq_lock);
246 }
247 EXPORT_SYMBOL(service_subclass_irq_register);
248
249 void service_subclass_irq_unregister(void)
250 {
251         spin_lock(&sc_irq_lock);
252         sc_irq_refcount--;
253         if (!sc_irq_refcount)
254                 ctl_clear_bit(0, 9);
255         spin_unlock(&sc_irq_lock);
256 }
257 EXPORT_SYMBOL(service_subclass_irq_unregister);