2 * SMP support for pSeries machines.
4 * Dave Engebretsen, Peter Bergner, and
5 * Mike Corrigan {engebret|bergner|mikec}@us.ibm.com
7 * Plus various changes from other IBM teams...
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.
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>
30 #include <asm/ptrace.h>
31 #include <asm/atomic.h>
34 #include <asm/pgtable.h>
40 #include <asm/machdep.h>
42 #include <asm/cputable.h>
43 #include <asm/firmware.h>
44 #include <asm/system.h>
46 #include <asm/pSeries_reconfig.h>
48 #include <asm/vdso_datapage.h>
50 #include "plpar_wrappers.h"
54 #define DBG(fmt...) udbg_printf(fmt)
60 * The primary thread of each non-boot processor is recorded here before
63 static cpumask_t of_spin_map;
65 extern void generic_secondary_smp_init(unsigned long);
68 * smp_startup_cpu() - start the given cpu
70 * At boot time, there is nothing to do for primary threads which were
71 * started from Open Firmware. For anything else, call RTAS with the
72 * appropriate start location.
78 static inline int __devinit smp_startup_cpu(unsigned int lcpu)
81 unsigned long start_here = __pa((u32)*((unsigned long *)
82 generic_secondary_smp_init));
86 if (cpu_isset(lcpu, of_spin_map))
87 /* Already started by OF and sitting in spin loop */
90 pcpu = get_hard_smp_processor_id(lcpu);
92 /* Fixup atomic count: it exited inside IRQ handler. */
93 task_thread_info(paca[lcpu].__current)->preempt_count = 0;
96 * If the RTAS start-cpu token does not exist then presume the
97 * cpu is already spinning.
99 start_cpu = rtas_token("start-cpu");
100 if (start_cpu == RTAS_UNKNOWN_SERVICE)
103 status = rtas_call(start_cpu, 3, 1, NULL, pcpu, start_here, pcpu);
105 printk(KERN_ERR "start-cpu failed: %i\n", status);
113 static inline void smp_xics_do_message(int cpu, int msg)
115 set_bit(msg, &xics_ipi_message[cpu].value);
120 static void smp_xics_message_pass(int target, int msg)
124 if (target < NR_CPUS) {
125 smp_xics_do_message(target, msg);
127 for_each_online_cpu(i) {
128 if (target == MSG_ALL_BUT_SELF
129 && i == smp_processor_id())
131 smp_xics_do_message(i, msg);
136 static int __init smp_xics_probe(void)
140 return cpus_weight(cpu_possible_map);
143 static void __devinit smp_xics_setup_cpu(int cpu)
145 if (cpu != boot_cpuid)
148 if (firmware_has_feature(FW_FEATURE_SPLPAR))
151 cpu_clear(cpu, of_spin_map);
154 #endif /* CONFIG_XICS */
156 static DEFINE_SPINLOCK(timebase_lock);
157 static unsigned long timebase = 0;
159 static void __devinit pSeries_give_timebase(void)
161 spin_lock(&timebase_lock);
162 rtas_call(rtas_token("freeze-time-base"), 0, 1, NULL);
164 spin_unlock(&timebase_lock);
168 rtas_call(rtas_token("thaw-time-base"), 0, 1, NULL);
171 static void __devinit pSeries_take_timebase(void)
175 spin_lock(&timebase_lock);
176 set_tb(timebase >> 32, timebase & 0xffffffff);
178 spin_unlock(&timebase_lock);
181 static void __devinit smp_pSeries_kick_cpu(int nr)
183 BUG_ON(nr < 0 || nr >= NR_CPUS);
185 if (!smp_startup_cpu(nr))
189 * The processor is currently spinning, waiting for the
190 * cpu_start field to become non-zero After we set cpu_start,
191 * the processor will continue on to secondary_start
193 paca[nr].cpu_start = 1;
196 static int smp_pSeries_cpu_bootable(unsigned int nr)
198 /* Special case - we inhibit secondary thread startup
199 * during boot if the user requests it. Odd-numbered
200 * cpus are assumed to be secondary threads.
202 if (system_state < SYSTEM_RUNNING &&
203 cpu_has_feature(CPU_FTR_SMT) &&
204 !smt_enabled_at_boot && nr % 2 != 0)
210 static struct smp_ops_t pSeries_mpic_smp_ops = {
211 .message_pass = smp_mpic_message_pass,
212 .probe = smp_mpic_probe,
213 .kick_cpu = smp_pSeries_kick_cpu,
214 .setup_cpu = smp_mpic_setup_cpu,
218 static struct smp_ops_t pSeries_xics_smp_ops = {
219 .message_pass = smp_xics_message_pass,
220 .probe = smp_xics_probe,
221 .kick_cpu = smp_pSeries_kick_cpu,
222 .setup_cpu = smp_xics_setup_cpu,
223 .cpu_bootable = smp_pSeries_cpu_bootable,
227 /* This is called very early */
228 static void __init smp_init_pseries(void)
232 DBG(" -> smp_init_pSeries()\n");
234 /* Mark threads which are still spinning in hold loops. */
235 if (cpu_has_feature(CPU_FTR_SMT)) {
236 for_each_present_cpu(i) {
239 * Even-numbered logical cpus correspond to
242 cpu_set(i, of_spin_map);
245 of_spin_map = cpu_present_map;
248 cpu_clear(boot_cpuid, of_spin_map);
250 /* Non-lpar has additional take/give timebase */
251 if (rtas_token("freeze-time-base") != RTAS_UNKNOWN_SERVICE) {
252 smp_ops->give_timebase = pSeries_give_timebase;
253 smp_ops->take_timebase = pSeries_take_timebase;
256 DBG(" <- smp_init_pSeries()\n");
260 void __init smp_init_pseries_mpic(void)
262 smp_ops = &pSeries_mpic_smp_ops;
268 void __init smp_init_pseries_xics(void)
270 smp_ops = &pSeries_xics_smp_ops;