Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc
[linux-2.6.git] / 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
16 #include <linux/kernel.h>
17 #include <linux/module.h>
18 #include <linux/sched.h>
19 #include <linux/smp.h>
20 #include <linux/interrupt.h>
21 #include <linux/delay.h>
22 #include <linux/init.h>
23 #include <linux/spinlock.h>
24 #include <linux/cache.h>
25 #include <linux/err.h>
26 #include <linux/sysdev.h>
27 #include <linux/cpu.h>
28
29 #include <asm/ptrace.h>
30 #include <asm/atomic.h>
31 #include <asm/irq.h>
32 #include <asm/page.h>
33 #include <asm/pgtable.h>
34 #include <asm/io.h>
35 #include <asm/prom.h>
36 #include <asm/smp.h>
37 #include <asm/paca.h>
38 #include <asm/machdep.h>
39 #include <asm/cputable.h>
40 #include <asm/firmware.h>
41 #include <asm/system.h>
42 #include <asm/rtas.h>
43 #include <asm/pSeries_reconfig.h>
44 #include <asm/mpic.h>
45 #include <asm/vdso_datapage.h>
46 #include <asm/cputhreads.h>
47 #include <asm/xics.h>
48
49 #include "plpar_wrappers.h"
50 #include "pseries.h"
51 #include "offline_states.h"
52
53
54 /*
55  * The Primary thread of each non-boot processor was started from the OF client
56  * interface by prom_hold_cpus and is spinning on secondary_hold_spinloop.
57  */
58 static cpumask_var_t of_spin_mask;
59
60 /* Query where a cpu is now.  Return codes #defined in plpar_wrappers.h */
61 int smp_query_cpu_stopped(unsigned int pcpu)
62 {
63         int cpu_status, status;
64         int qcss_tok = rtas_token("query-cpu-stopped-state");
65
66         if (qcss_tok == RTAS_UNKNOWN_SERVICE) {
67                 printk_once(KERN_INFO
68                         "Firmware doesn't support query-cpu-stopped-state\n");
69                 return QCSS_HARDWARE_ERROR;
70         }
71
72         status = rtas_call(qcss_tok, 1, 2, &cpu_status, pcpu);
73         if (status != 0) {
74                 printk(KERN_ERR
75                        "RTAS query-cpu-stopped-state failed: %i\n", status);
76                 return status;
77         }
78
79         return cpu_status;
80 }
81
82 /**
83  * smp_startup_cpu() - start the given cpu
84  *
85  * At boot time, there is nothing to do for primary threads which were
86  * started from Open Firmware.  For anything else, call RTAS with the
87  * appropriate start location.
88  *
89  * Returns:
90  *      0       - failure
91  *      1       - success
92  */
93 static inline int __devinit smp_startup_cpu(unsigned int lcpu)
94 {
95         int status;
96         unsigned long start_here = __pa((u32)*((unsigned long *)
97                                                generic_secondary_smp_init));
98         unsigned int pcpu;
99         int start_cpu;
100
101         if (cpumask_test_cpu(lcpu, of_spin_mask))
102                 /* Already started by OF and sitting in spin loop */
103                 return 1;
104
105         pcpu = get_hard_smp_processor_id(lcpu);
106
107         /* Check to see if the CPU out of FW already for kexec */
108         if (smp_query_cpu_stopped(pcpu) == QCSS_NOT_STOPPED){
109                 cpumask_set_cpu(lcpu, of_spin_mask);
110                 return 1;
111         }
112
113         /* Fixup atomic count: it exited inside IRQ handler. */
114         task_thread_info(paca[lcpu].__current)->preempt_count   = 0;
115 #ifdef CONFIG_HOTPLUG_CPU
116         if (get_cpu_current_state(lcpu) == CPU_STATE_INACTIVE)
117                 goto out;
118 #endif
119         /* 
120          * If the RTAS start-cpu token does not exist then presume the
121          * cpu is already spinning.
122          */
123         start_cpu = rtas_token("start-cpu");
124         if (start_cpu == RTAS_UNKNOWN_SERVICE)
125                 return 1;
126
127         status = rtas_call(start_cpu, 3, 1, NULL, pcpu, start_here, pcpu);
128         if (status != 0) {
129                 printk(KERN_ERR "start-cpu failed: %i\n", status);
130                 return 0;
131         }
132
133 #ifdef CONFIG_HOTPLUG_CPU
134 out:
135 #endif
136         return 1;
137 }
138
139 static void __devinit smp_xics_setup_cpu(int cpu)
140 {
141         if (cpu != boot_cpuid)
142                 xics_setup_cpu();
143
144         if (firmware_has_feature(FW_FEATURE_SPLPAR))
145                 vpa_init(cpu);
146
147         cpumask_clear_cpu(cpu, of_spin_mask);
148 #ifdef CONFIG_HOTPLUG_CPU
149         set_cpu_current_state(cpu, CPU_STATE_ONLINE);
150         set_default_offline_state(cpu);
151 #endif
152 }
153
154 static int __devinit smp_pSeries_kick_cpu(int nr)
155 {
156         BUG_ON(nr < 0 || nr >= NR_CPUS);
157
158         if (!smp_startup_cpu(nr))
159                 return -ENOENT;
160
161         /*
162          * The processor is currently spinning, waiting for the
163          * cpu_start field to become non-zero After we set cpu_start,
164          * the processor will continue on to secondary_start
165          */
166         paca[nr].cpu_start = 1;
167 #ifdef CONFIG_HOTPLUG_CPU
168         set_preferred_offline_state(nr, CPU_STATE_ONLINE);
169
170         if (get_cpu_current_state(nr) == CPU_STATE_INACTIVE) {
171                 long rc;
172                 unsigned long hcpuid;
173
174                 hcpuid = get_hard_smp_processor_id(nr);
175                 rc = plpar_hcall_norets(H_PROD, hcpuid);
176                 if (rc != H_SUCCESS)
177                         printk(KERN_ERR "Error: Prod to wake up processor %d "
178                                                 "Ret= %ld\n", nr, rc);
179         }
180 #endif
181
182         return 0;
183 }
184
185 static int smp_pSeries_cpu_bootable(unsigned int nr)
186 {
187         /* Special case - we inhibit secondary thread startup
188          * during boot if the user requests it.
189          */
190         if (system_state < SYSTEM_RUNNING && cpu_has_feature(CPU_FTR_SMT)) {
191                 if (!smt_enabled_at_boot && cpu_thread_in_core(nr) != 0)
192                         return 0;
193                 if (smt_enabled_at_boot
194                     && cpu_thread_in_core(nr) >= smt_enabled_at_boot)
195                         return 0;
196         }
197
198         return 1;
199 }
200
201 static struct smp_ops_t pSeries_mpic_smp_ops = {
202         .message_pass   = smp_mpic_message_pass,
203         .probe          = smp_mpic_probe,
204         .kick_cpu       = smp_pSeries_kick_cpu,
205         .setup_cpu      = smp_mpic_setup_cpu,
206 };
207
208 static struct smp_ops_t pSeries_xics_smp_ops = {
209         .message_pass   = NULL, /* Use smp_muxed_ipi_message_pass */
210         .cause_ipi      = NULL, /* Filled at runtime by xics_smp_probe() */
211         .probe          = xics_smp_probe,
212         .kick_cpu       = smp_pSeries_kick_cpu,
213         .setup_cpu      = smp_xics_setup_cpu,
214         .cpu_bootable   = smp_pSeries_cpu_bootable,
215 };
216
217 /* This is called very early */
218 static void __init smp_init_pseries(void)
219 {
220         int i;
221
222         pr_debug(" -> smp_init_pSeries()\n");
223
224         alloc_bootmem_cpumask_var(&of_spin_mask);
225
226         /* Mark threads which are still spinning in hold loops. */
227         if (cpu_has_feature(CPU_FTR_SMT)) {
228                 for_each_present_cpu(i) { 
229                         if (cpu_thread_in_core(i) == 0)
230                                 cpumask_set_cpu(i, of_spin_mask);
231                 }
232         } else {
233                 cpumask_copy(of_spin_mask, cpu_present_mask);
234         }
235
236         cpumask_clear_cpu(boot_cpuid, of_spin_mask);
237
238         /* Non-lpar has additional take/give timebase */
239         if (rtas_token("freeze-time-base") != RTAS_UNKNOWN_SERVICE) {
240                 smp_ops->give_timebase = rtas_give_timebase;
241                 smp_ops->take_timebase = rtas_take_timebase;
242         }
243
244         pr_debug(" <- smp_init_pSeries()\n");
245 }
246
247 void __init smp_init_pseries_mpic(void)
248 {
249         smp_ops = &pSeries_mpic_smp_ops;
250
251         smp_init_pseries();
252 }
253
254 void __init smp_init_pseries_xics(void)
255 {
256         smp_ops = &pSeries_xics_smp_ops;
257
258         smp_init_pseries();
259 }