Merge branch 'master' into next
[linux-2.6] / arch / ia64 / kernel / smp.c
1 /*
2  * SMP Support
3  *
4  * Copyright (C) 1999 Walt Drummond <drummond@valinux.com>
5  * Copyright (C) 1999, 2001, 2003 David Mosberger-Tang <davidm@hpl.hp.com>
6  *
7  * Lots of stuff stolen from arch/alpha/kernel/smp.c
8  *
9  * 01/05/16 Rohit Seth <rohit.seth@intel.com>  IA64-SMP functions. Reorganized
10  * the existing code (on the lines of x86 port).
11  * 00/09/11 David Mosberger <davidm@hpl.hp.com> Do loops_per_jiffy
12  * calibration on each CPU.
13  * 00/08/23 Asit Mallick <asit.k.mallick@intel.com> fixed logical processor id
14  * 00/03/31 Rohit Seth <rohit.seth@intel.com>   Fixes for Bootstrap Processor
15  * & cpu_online_map now gets done here (instead of setup.c)
16  * 99/10/05 davidm      Update to bring it in sync with new command-line processing
17  *  scheme.
18  * 10/13/00 Goutham Rao <goutham.rao@intel.com> Updated smp_call_function and
19  *              smp_call_function_single to resend IPI on timeouts
20  */
21 #include <linux/module.h>
22 #include <linux/kernel.h>
23 #include <linux/sched.h>
24 #include <linux/init.h>
25 #include <linux/interrupt.h>
26 #include <linux/smp.h>
27 #include <linux/kernel_stat.h>
28 #include <linux/mm.h>
29 #include <linux/cache.h>
30 #include <linux/delay.h>
31 #include <linux/efi.h>
32 #include <linux/bitops.h>
33 #include <linux/kexec.h>
34
35 #include <asm/atomic.h>
36 #include <asm/current.h>
37 #include <asm/delay.h>
38 #include <asm/machvec.h>
39 #include <asm/io.h>
40 #include <asm/irq.h>
41 #include <asm/page.h>
42 #include <asm/pgalloc.h>
43 #include <asm/pgtable.h>
44 #include <asm/processor.h>
45 #include <asm/ptrace.h>
46 #include <asm/sal.h>
47 #include <asm/system.h>
48 #include <asm/tlbflush.h>
49 #include <asm/unistd.h>
50 #include <asm/mca.h>
51
52 /*
53  * Note: alignment of 4 entries/cacheline was empirically determined
54  * to be a good tradeoff between hot cachelines & spreading the array
55  * across too many cacheline.
56  */
57 static struct local_tlb_flush_counts {
58         unsigned int count;
59 } __attribute__((__aligned__(32))) local_tlb_flush_counts[NR_CPUS];
60
61 static DEFINE_PER_CPU(unsigned short, shadow_flush_counts[NR_CPUS]) ____cacheline_aligned;
62
63 #define IPI_CALL_FUNC           0
64 #define IPI_CPU_STOP            1
65 #define IPI_CALL_FUNC_SINGLE    2
66 #define IPI_KDUMP_CPU_STOP      3
67
68 /* This needs to be cacheline aligned because it is written to by *other* CPUs.  */
69 static DEFINE_PER_CPU_SHARED_ALIGNED(u64, ipi_operation);
70
71 extern void cpu_halt (void);
72
73 static void
74 stop_this_cpu(void)
75 {
76         /*
77          * Remove this CPU:
78          */
79         cpu_clear(smp_processor_id(), cpu_online_map);
80         max_xtp();
81         local_irq_disable();
82         cpu_halt();
83 }
84
85 void
86 cpu_die(void)
87 {
88         max_xtp();
89         local_irq_disable();
90         cpu_halt();
91         /* Should never be here */
92         BUG();
93         for (;;);
94 }
95
96 irqreturn_t
97 handle_IPI (int irq, void *dev_id)
98 {
99         int this_cpu = get_cpu();
100         unsigned long *pending_ipis = &__ia64_per_cpu_var(ipi_operation);
101         unsigned long ops;
102
103         mb();   /* Order interrupt and bit testing. */
104         while ((ops = xchg(pending_ipis, 0)) != 0) {
105                 mb();   /* Order bit clearing and data access. */
106                 do {
107                         unsigned long which;
108
109                         which = ffz(~ops);
110                         ops &= ~(1 << which);
111
112                         switch (which) {
113                         case IPI_CPU_STOP:
114                                 stop_this_cpu();
115                                 break;
116                         case IPI_CALL_FUNC:
117                                 generic_smp_call_function_interrupt();
118                                 break;
119                         case IPI_CALL_FUNC_SINGLE:
120                                 generic_smp_call_function_single_interrupt();
121                                 break;
122 #ifdef CONFIG_KEXEC
123                         case IPI_KDUMP_CPU_STOP:
124                                 unw_init_running(kdump_cpu_freeze, NULL);
125                                 break;
126 #endif
127                         default:
128                                 printk(KERN_CRIT "Unknown IPI on CPU %d: %lu\n",
129                                                 this_cpu, which);
130                                 break;
131                         }
132                 } while (ops);
133                 mb();   /* Order data access and bit testing. */
134         }
135         put_cpu();
136         return IRQ_HANDLED;
137 }
138
139
140
141 /*
142  * Called with preemption disabled.
143  */
144 static inline void
145 send_IPI_single (int dest_cpu, int op)
146 {
147         set_bit(op, &per_cpu(ipi_operation, dest_cpu));
148         platform_send_ipi(dest_cpu, IA64_IPI_VECTOR, IA64_IPI_DM_INT, 0);
149 }
150
151 /*
152  * Called with preemption disabled.
153  */
154 static inline void
155 send_IPI_allbutself (int op)
156 {
157         unsigned int i;
158
159         for_each_online_cpu(i) {
160                 if (i != smp_processor_id())
161                         send_IPI_single(i, op);
162         }
163 }
164
165 /*
166  * Called with preemption disabled.
167  */
168 static inline void
169 send_IPI_mask(cpumask_t mask, int op)
170 {
171         unsigned int cpu;
172
173         for_each_cpu_mask(cpu, mask) {
174                         send_IPI_single(cpu, op);
175         }
176 }
177
178 /*
179  * Called with preemption disabled.
180  */
181 static inline void
182 send_IPI_all (int op)
183 {
184         int i;
185
186         for_each_online_cpu(i) {
187                 send_IPI_single(i, op);
188         }
189 }
190
191 /*
192  * Called with preemption disabled.
193  */
194 static inline void
195 send_IPI_self (int op)
196 {
197         send_IPI_single(smp_processor_id(), op);
198 }
199
200 #ifdef CONFIG_KEXEC
201 void
202 kdump_smp_send_stop(void)
203 {
204         send_IPI_allbutself(IPI_KDUMP_CPU_STOP);
205 }
206
207 void
208 kdump_smp_send_init(void)
209 {
210         unsigned int cpu, self_cpu;
211         self_cpu = smp_processor_id();
212         for_each_online_cpu(cpu) {
213                 if (cpu != self_cpu) {
214                         if(kdump_status[cpu] == 0)
215                                 platform_send_ipi(cpu, 0, IA64_IPI_DM_INIT, 0);
216                 }
217         }
218 }
219 #endif
220 /*
221  * Called with preemption disabled.
222  */
223 void
224 smp_send_reschedule (int cpu)
225 {
226         platform_send_ipi(cpu, IA64_IPI_RESCHEDULE, IA64_IPI_DM_INT, 0);
227 }
228
229 /*
230  * Called with preemption disabled.
231  */
232 static void
233 smp_send_local_flush_tlb (int cpu)
234 {
235         platform_send_ipi(cpu, IA64_IPI_LOCAL_TLB_FLUSH, IA64_IPI_DM_INT, 0);
236 }
237
238 void
239 smp_local_flush_tlb(void)
240 {
241         /*
242          * Use atomic ops. Otherwise, the load/increment/store sequence from
243          * a "++" operation can have the line stolen between the load & store.
244          * The overhead of the atomic op in negligible in this case & offers
245          * significant benefit for the brief periods where lots of cpus
246          * are simultaneously flushing TLBs.
247          */
248         ia64_fetchadd(1, &local_tlb_flush_counts[smp_processor_id()].count, acq);
249         local_flush_tlb_all();
250 }
251
252 #define FLUSH_DELAY     5 /* Usec backoff to eliminate excessive cacheline bouncing */
253
254 void
255 smp_flush_tlb_cpumask(cpumask_t xcpumask)
256 {
257         unsigned short *counts = __ia64_per_cpu_var(shadow_flush_counts);
258         cpumask_t cpumask = xcpumask;
259         int mycpu, cpu, flush_mycpu = 0;
260
261         preempt_disable();
262         mycpu = smp_processor_id();
263
264         for_each_cpu_mask(cpu, cpumask)
265                 counts[cpu] = local_tlb_flush_counts[cpu].count & 0xffff;
266
267         mb();
268         for_each_cpu_mask(cpu, cpumask) {
269                 if (cpu == mycpu)
270                         flush_mycpu = 1;
271                 else
272                         smp_send_local_flush_tlb(cpu);
273         }
274
275         if (flush_mycpu)
276                 smp_local_flush_tlb();
277
278         for_each_cpu_mask(cpu, cpumask)
279                 while(counts[cpu] == (local_tlb_flush_counts[cpu].count & 0xffff))
280                         udelay(FLUSH_DELAY);
281
282         preempt_enable();
283 }
284
285 void
286 smp_flush_tlb_all (void)
287 {
288         on_each_cpu((void (*)(void *))local_flush_tlb_all, NULL, 1);
289 }
290
291 void
292 smp_flush_tlb_mm (struct mm_struct *mm)
293 {
294         preempt_disable();
295         /* this happens for the common case of a single-threaded fork():  */
296         if (likely(mm == current->active_mm && atomic_read(&mm->mm_users) == 1))
297         {
298                 local_finish_flush_tlb_mm(mm);
299                 preempt_enable();
300                 return;
301         }
302
303         preempt_enable();
304         /*
305          * We could optimize this further by using mm->cpu_vm_mask to track which CPUs
306          * have been running in the address space.  It's not clear that this is worth the
307          * trouble though: to avoid races, we have to raise the IPI on the target CPU
308          * anyhow, and once a CPU is interrupted, the cost of local_flush_tlb_all() is
309          * rather trivial.
310          */
311         on_each_cpu((void (*)(void *))local_finish_flush_tlb_mm, mm, 1);
312 }
313
314 void arch_send_call_function_single_ipi(int cpu)
315 {
316         send_IPI_single(cpu, IPI_CALL_FUNC_SINGLE);
317 }
318
319 void arch_send_call_function_ipi(cpumask_t mask)
320 {
321         send_IPI_mask(mask, IPI_CALL_FUNC);
322 }
323
324 /*
325  * this function calls the 'stop' function on all other CPUs in the system.
326  */
327 void
328 smp_send_stop (void)
329 {
330         send_IPI_allbutself(IPI_CPU_STOP);
331 }
332
333 int
334 setup_profiling_timer (unsigned int multiplier)
335 {
336         return -EINVAL;
337 }