Merge git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6.git
[linux-2.6] / arch / powerpc / platforms / pseries / smp.c
1 /*
2  * SMP support for pSeries machines.
3  *
4  * Dave Engebretsen, Peter Bergner, and
5  * Mike Corrigan {engebret|bergner|mikec}@us.ibm.com
6  *
7  * Plus various changes from other IBM teams...
8  *
9  *      This program is free software; you can redistribute it and/or
10  *      modify it under the terms of the GNU General Public License
11  *      as published by the Free Software Foundation; either version
12  *      2 of the License, or (at your option) any later version.
13  */
14
15 #undef DEBUG
16
17 #include <linux/kernel.h>
18 #include <linux/module.h>
19 #include <linux/sched.h>
20 #include <linux/smp.h>
21 #include <linux/interrupt.h>
22 #include <linux/delay.h>
23 #include <linux/init.h>
24 #include <linux/spinlock.h>
25 #include <linux/cache.h>
26 #include <linux/err.h>
27 #include <linux/sysdev.h>
28 #include <linux/cpu.h>
29
30 #include <asm/ptrace.h>
31 #include <asm/atomic.h>
32 #include <asm/irq.h>
33 #include <asm/page.h>
34 #include <asm/pgtable.h>
35 #include <asm/io.h>
36 #include <asm/prom.h>
37 #include <asm/smp.h>
38 #include <asm/paca.h>
39 #include <asm/time.h>
40 #include <asm/machdep.h>
41 #include "xics.h"
42 #include <asm/cputable.h>
43 #include <asm/firmware.h>
44 #include <asm/system.h>
45 #include <asm/rtas.h>
46 #include <asm/pSeries_reconfig.h>
47 #include <asm/mpic.h>
48 #include <asm/vdso_datapage.h>
49 #include <asm/cputhreads.h>
50
51 #include "plpar_wrappers.h"
52 #include "pseries.h"
53
54 #ifdef DEBUG
55 #include <asm/udbg.h>
56 #define DBG(fmt...) udbg_printf(fmt)
57 #else
58 #define DBG(fmt...)
59 #endif
60
61 /*
62  * The primary thread of each non-boot processor is recorded here before
63  * smp init.
64  */
65 static cpumask_t of_spin_map;
66
67 extern void generic_secondary_smp_init(unsigned long);
68
69 /**
70  * smp_startup_cpu() - start the given cpu
71  *
72  * At boot time, there is nothing to do for primary threads which were
73  * started from Open Firmware.  For anything else, call RTAS with the
74  * appropriate start location.
75  *
76  * Returns:
77  *      0       - failure
78  *      1       - success
79  */
80 static inline int __devinit smp_startup_cpu(unsigned int lcpu)
81 {
82         int status;
83         unsigned long start_here = __pa((u32)*((unsigned long *)
84                                                generic_secondary_smp_init));
85         unsigned int pcpu;
86         int start_cpu;
87
88         if (cpu_isset(lcpu, of_spin_map))
89                 /* Already started by OF and sitting in spin loop */
90                 return 1;
91
92         pcpu = get_hard_smp_processor_id(lcpu);
93
94         /* Fixup atomic count: it exited inside IRQ handler. */
95         task_thread_info(paca[lcpu].__current)->preempt_count   = 0;
96
97         /* 
98          * If the RTAS start-cpu token does not exist then presume the
99          * cpu is already spinning.
100          */
101         start_cpu = rtas_token("start-cpu");
102         if (start_cpu == RTAS_UNKNOWN_SERVICE)
103                 return 1;
104
105         status = rtas_call(start_cpu, 3, 1, NULL, pcpu, start_here, pcpu);
106         if (status != 0) {
107                 printk(KERN_ERR "start-cpu failed: %i\n", status);
108                 return 0;
109         }
110
111         return 1;
112 }
113
114 #ifdef CONFIG_XICS
115 static inline void smp_xics_do_message(int cpu, int msg)
116 {
117         set_bit(msg, &xics_ipi_message[cpu].value);
118         mb();
119         xics_cause_IPI(cpu);
120 }
121
122 static void smp_xics_message_pass(int target, int msg)
123 {
124         unsigned int i;
125
126         if (target < NR_CPUS) {
127                 smp_xics_do_message(target, msg);
128         } else {
129                 for_each_online_cpu(i) {
130                         if (target == MSG_ALL_BUT_SELF
131                             && i == smp_processor_id())
132                                 continue;
133                         smp_xics_do_message(i, msg);
134                 }
135         }
136 }
137
138 static int __init smp_xics_probe(void)
139 {
140         xics_request_IPIs();
141
142         return cpus_weight(cpu_possible_map);
143 }
144
145 static void __devinit smp_xics_setup_cpu(int cpu)
146 {
147         if (cpu != boot_cpuid)
148                 xics_setup_cpu();
149
150         if (firmware_has_feature(FW_FEATURE_SPLPAR))
151                 vpa_init(cpu);
152
153         cpu_clear(cpu, of_spin_map);
154
155 }
156 #endif /* CONFIG_XICS */
157
158 static DEFINE_SPINLOCK(timebase_lock);
159 static unsigned long timebase = 0;
160
161 static void __devinit pSeries_give_timebase(void)
162 {
163         spin_lock(&timebase_lock);
164         rtas_call(rtas_token("freeze-time-base"), 0, 1, NULL);
165         timebase = get_tb();
166         spin_unlock(&timebase_lock);
167
168         while (timebase)
169                 barrier();
170         rtas_call(rtas_token("thaw-time-base"), 0, 1, NULL);
171 }
172
173 static void __devinit pSeries_take_timebase(void)
174 {
175         while (!timebase)
176                 barrier();
177         spin_lock(&timebase_lock);
178         set_tb(timebase >> 32, timebase & 0xffffffff);
179         timebase = 0;
180         spin_unlock(&timebase_lock);
181 }
182
183 static void __devinit smp_pSeries_kick_cpu(int nr)
184 {
185         BUG_ON(nr < 0 || nr >= NR_CPUS);
186
187         if (!smp_startup_cpu(nr))
188                 return;
189
190         /*
191          * The processor is currently spinning, waiting for the
192          * cpu_start field to become non-zero After we set cpu_start,
193          * the processor will continue on to secondary_start
194          */
195         paca[nr].cpu_start = 1;
196 }
197
198 static int smp_pSeries_cpu_bootable(unsigned int nr)
199 {
200         /* Special case - we inhibit secondary thread startup
201          * during boot if the user requests it.  Odd-numbered
202          * cpus are assumed to be secondary threads.
203          */
204         if (system_state < SYSTEM_RUNNING &&
205             cpu_has_feature(CPU_FTR_SMT) &&
206             !smt_enabled_at_boot && cpu_thread_in_core(nr) != 0)
207                 return 0;
208
209         return 1;
210 }
211 #ifdef CONFIG_MPIC
212 static struct smp_ops_t pSeries_mpic_smp_ops = {
213         .message_pass   = smp_mpic_message_pass,
214         .probe          = smp_mpic_probe,
215         .kick_cpu       = smp_pSeries_kick_cpu,
216         .setup_cpu      = smp_mpic_setup_cpu,
217 };
218 #endif
219 #ifdef CONFIG_XICS
220 static struct smp_ops_t pSeries_xics_smp_ops = {
221         .message_pass   = smp_xics_message_pass,
222         .probe          = smp_xics_probe,
223         .kick_cpu       = smp_pSeries_kick_cpu,
224         .setup_cpu      = smp_xics_setup_cpu,
225         .cpu_bootable   = smp_pSeries_cpu_bootable,
226 };
227 #endif
228
229 /* This is called very early */
230 static void __init smp_init_pseries(void)
231 {
232         int i;
233
234         DBG(" -> smp_init_pSeries()\n");
235
236         /* Mark threads which are still spinning in hold loops. */
237         if (cpu_has_feature(CPU_FTR_SMT)) {
238                 for_each_present_cpu(i) { 
239                         if (i % 2 == 0)
240                                 /*
241                                  * Even-numbered logical cpus correspond to
242                                  * primary threads.
243                                  */
244                                 cpu_set(i, of_spin_map);
245                 }
246         } else {
247                 of_spin_map = cpu_present_map;
248         }
249
250         cpu_clear(boot_cpuid, of_spin_map);
251
252         /* Non-lpar has additional take/give timebase */
253         if (rtas_token("freeze-time-base") != RTAS_UNKNOWN_SERVICE) {
254                 smp_ops->give_timebase = pSeries_give_timebase;
255                 smp_ops->take_timebase = pSeries_take_timebase;
256         }
257
258         DBG(" <- smp_init_pSeries()\n");
259 }
260
261 #ifdef CONFIG_MPIC
262 void __init smp_init_pseries_mpic(void)
263 {
264         smp_ops = &pSeries_mpic_smp_ops;
265
266         smp_init_pseries();
267 }
268 #endif
269
270 void __init smp_init_pseries_xics(void)
271 {
272         smp_ops = &pSeries_xics_smp_ops;
273
274         smp_init_pseries();
275 }