Merge branch 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git...
[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
48 #include "plpar_wrappers.h"
49 #include "pseries.h"
50 #include "xics.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_t of_spin_map;
59
60 /**
61  * smp_startup_cpu() - start the given cpu
62  *
63  * At boot time, there is nothing to do for primary threads which were
64  * started from Open Firmware.  For anything else, call RTAS with the
65  * appropriate start location.
66  *
67  * Returns:
68  *      0       - failure
69  *      1       - success
70  */
71 static inline int __devinit smp_startup_cpu(unsigned int lcpu)
72 {
73         int status;
74         unsigned long start_here = __pa((u32)*((unsigned long *)
75                                                generic_secondary_smp_init));
76         unsigned int pcpu;
77         int start_cpu;
78
79         if (cpu_isset(lcpu, of_spin_map))
80                 /* Already started by OF and sitting in spin loop */
81                 return 1;
82
83         pcpu = get_hard_smp_processor_id(lcpu);
84
85         /* Fixup atomic count: it exited inside IRQ handler. */
86         task_thread_info(paca[lcpu].__current)->preempt_count   = 0;
87
88         if (get_cpu_current_state(lcpu) == CPU_STATE_INACTIVE)
89                 goto out;
90
91         /* 
92          * If the RTAS start-cpu token does not exist then presume the
93          * cpu is already spinning.
94          */
95         start_cpu = rtas_token("start-cpu");
96         if (start_cpu == RTAS_UNKNOWN_SERVICE)
97                 return 1;
98
99         status = rtas_call(start_cpu, 3, 1, NULL, pcpu, start_here, pcpu);
100         if (status != 0) {
101                 printk(KERN_ERR "start-cpu failed: %i\n", status);
102                 return 0;
103         }
104
105 out:
106         return 1;
107 }
108
109 #ifdef CONFIG_XICS
110 static void __devinit smp_xics_setup_cpu(int cpu)
111 {
112         if (cpu != boot_cpuid)
113                 xics_setup_cpu();
114
115         if (firmware_has_feature(FW_FEATURE_SPLPAR))
116                 vpa_init(cpu);
117
118         cpu_clear(cpu, of_spin_map);
119         set_cpu_current_state(cpu, CPU_STATE_ONLINE);
120         set_default_offline_state(cpu);
121
122 }
123 #endif /* CONFIG_XICS */
124
125 static void __devinit smp_pSeries_kick_cpu(int nr)
126 {
127         long rc;
128         unsigned long hcpuid;
129         BUG_ON(nr < 0 || nr >= NR_CPUS);
130
131         if (!smp_startup_cpu(nr))
132                 return;
133
134         /*
135          * The processor is currently spinning, waiting for the
136          * cpu_start field to become non-zero After we set cpu_start,
137          * the processor will continue on to secondary_start
138          */
139         paca[nr].cpu_start = 1;
140
141         set_preferred_offline_state(nr, CPU_STATE_ONLINE);
142
143         if (get_cpu_current_state(nr) == CPU_STATE_INACTIVE) {
144                 hcpuid = get_hard_smp_processor_id(nr);
145                 rc = plpar_hcall_norets(H_PROD, hcpuid);
146                 if (rc != H_SUCCESS)
147                         panic("Error: Prod to wake up processor %d Ret= %ld\n",
148                                 nr, rc);
149         }
150 }
151
152 static int smp_pSeries_cpu_bootable(unsigned int nr)
153 {
154         /* Special case - we inhibit secondary thread startup
155          * during boot if the user requests it.
156          */
157         if (system_state < SYSTEM_RUNNING &&
158             cpu_has_feature(CPU_FTR_SMT) &&
159             !smt_enabled_at_boot && cpu_thread_in_core(nr) != 0)
160                 return 0;
161
162         return 1;
163 }
164 #ifdef CONFIG_MPIC
165 static struct smp_ops_t pSeries_mpic_smp_ops = {
166         .message_pass   = smp_mpic_message_pass,
167         .probe          = smp_mpic_probe,
168         .kick_cpu       = smp_pSeries_kick_cpu,
169         .setup_cpu      = smp_mpic_setup_cpu,
170 };
171 #endif
172 #ifdef CONFIG_XICS
173 static struct smp_ops_t pSeries_xics_smp_ops = {
174         .message_pass   = smp_xics_message_pass,
175         .probe          = smp_xics_probe,
176         .kick_cpu       = smp_pSeries_kick_cpu,
177         .setup_cpu      = smp_xics_setup_cpu,
178         .cpu_bootable   = smp_pSeries_cpu_bootable,
179 };
180 #endif
181
182 /* This is called very early */
183 static void __init smp_init_pseries(void)
184 {
185         int i;
186
187         pr_debug(" -> smp_init_pSeries()\n");
188
189         /* Mark threads which are still spinning in hold loops. */
190         if (cpu_has_feature(CPU_FTR_SMT)) {
191                 for_each_present_cpu(i) { 
192                         if (cpu_thread_in_core(i) == 0)
193                                 cpu_set(i, of_spin_map);
194                 }
195         } else {
196                 of_spin_map = cpu_present_map;
197         }
198
199         cpu_clear(boot_cpuid, of_spin_map);
200
201         /* Non-lpar has additional take/give timebase */
202         if (rtas_token("freeze-time-base") != RTAS_UNKNOWN_SERVICE) {
203                 smp_ops->give_timebase = rtas_give_timebase;
204                 smp_ops->take_timebase = rtas_take_timebase;
205         }
206
207         pr_debug(" <- smp_init_pSeries()\n");
208 }
209
210 #ifdef CONFIG_MPIC
211 void __init smp_init_pseries_mpic(void)
212 {
213         smp_ops = &pSeries_mpic_smp_ops;
214
215         smp_init_pseries();
216 }
217 #endif
218
219 void __init smp_init_pseries_xics(void)
220 {
221         smp_ops = &pSeries_xics_smp_ops;
222
223         smp_init_pseries();
224 }