2 * SMP support for PowerNV machines.
4 * Copyright 2011 IBM Corp.
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
12 #include <linux/kernel.h>
13 #include <linux/module.h>
14 #include <linux/sched.h>
15 #include <linux/smp.h>
16 #include <linux/interrupt.h>
17 #include <linux/delay.h>
18 #include <linux/init.h>
19 #include <linux/spinlock.h>
20 #include <linux/cpu.h>
25 #include <asm/machdep.h>
26 #include <asm/cputable.h>
27 #include <asm/firmware.h>
29 #include <asm/vdso_datapage.h>
30 #include <asm/cputhreads.h>
33 #include <asm/runlatch.h>
34 #include <asm/code-patching.h>
35 #include <asm/dbell.h>
41 #define DBG(fmt...) udbg_printf(fmt)
46 static void pnv_smp_setup_cpu(int cpu
)
48 if (cpu
!= boot_cpuid
)
51 #ifdef CONFIG_PPC_DOORBELL
52 if (cpu_has_feature(CPU_FTR_DBELL
))
53 doorbell_setup_this_cpu();
57 static int pnv_smp_kick_cpu(int nr
)
59 unsigned int pcpu
= get_hard_smp_processor_id(nr
);
60 unsigned long start_here
=
61 __pa(ppc_function_entry(generic_secondary_smp_init
));
64 BUG_ON(nr
< 0 || nr
>= NR_CPUS
);
67 * If we already started or OPALv2 is not supported, we just
68 * kick the CPU via the PACA
70 if (paca
[nr
].cpu_start
|| !firmware_has_feature(FW_FEATURE_OPALv2
))
74 * At this point, the CPU can either be spinning on the way in
75 * from kexec or be inside OPAL waiting to be started for the
76 * first time. OPAL v3 allows us to query OPAL to know if it
77 * has the CPUs, so we do that
79 if (firmware_has_feature(FW_FEATURE_OPALv3
)) {
82 rc
= opal_query_cpu_status(pcpu
, &status
);
83 if (rc
!= OPAL_SUCCESS
) {
84 pr_warn("OPAL Error %ld querying CPU %d state\n",
90 * Already started, just kick it, probably coming from
93 if (status
== OPAL_THREAD_STARTED
)
97 * Available/inactive, let's kick it
99 if (status
== OPAL_THREAD_INACTIVE
) {
100 pr_devel("OPAL: Starting CPU %d (HW 0x%x)...\n",
102 rc
= opal_start_cpu(pcpu
, start_here
);
103 if (rc
!= OPAL_SUCCESS
) {
104 pr_warn("OPAL Error %ld starting CPU %d\n",
110 * An unavailable CPU (or any other unknown status)
111 * shouldn't be started. It should also
112 * not be in the possible map but currently it can
115 pr_devel("OPAL: CPU %d (HW 0x%x) is unavailable"
116 " (status %d)...\n", nr
, pcpu
, status
);
121 * On OPAL v2, we just kick it and hope for the best,
122 * we must not test the error from opal_start_cpu() or
123 * we would fail to get CPUs from kexec.
125 opal_start_cpu(pcpu
, start_here
);
128 return smp_generic_kick_cpu(nr
);
131 #ifdef CONFIG_HOTPLUG_CPU
133 static int pnv_smp_cpu_disable(void)
135 int cpu
= smp_processor_id();
137 /* This is identical to pSeries... might consolidate by
138 * moving migrate_irqs_away to a ppc_md with default to
139 * the generic fixup_irqs. --BenH.
141 set_cpu_online(cpu
, false);
142 vdso_data
->processorCount
--;
143 if (cpu
== boot_cpuid
)
144 boot_cpuid
= cpumask_any(cpu_online_mask
);
145 xics_migrate_irqs_away();
149 static void pnv_smp_cpu_kill_self(void)
155 /* Standard hot unplug procedure */
158 current
->active_mm
= NULL
; /* for sanity */
159 cpu
= smp_processor_id();
160 DBG("CPU%d offline\n", cpu
);
161 generic_set_cpu_dead(cpu
);
164 idle_states
= pnv_get_supported_cpuidle_states();
165 /* We don't want to take decrementer interrupts while we are offline,
166 * so clear LPCR:PECE1. We keep PECE2 enabled.
168 mtspr(SPRN_LPCR
, mfspr(SPRN_LPCR
) & ~(u64
)LPCR_PECE1
);
169 while (!generic_check_cpu_restart(cpu
)) {
171 ppc64_runlatch_off();
173 if (idle_states
& OPAL_PM_WINKLE_ENABLED
)
174 srr1
= power7_winkle();
175 else if ((idle_states
& OPAL_PM_SLEEP_ENABLED
) ||
176 (idle_states
& OPAL_PM_SLEEP_ENABLED_ER1
))
177 srr1
= power7_sleep();
179 srr1
= power7_nap(1);
184 * If the SRR1 value indicates that we woke up due to
185 * an external interrupt, then clear the interrupt.
186 * We clear the interrupt before checking for the
187 * reason, so as to avoid a race where we wake up for
188 * some other reason, find nothing and clear the interrupt
189 * just as some other cpu is sending us an interrupt.
190 * If we returned from power7_nap as a result of
191 * having finished executing in a KVM guest, then srr1
194 if ((srr1
& SRR1_WAKEMASK
) == SRR1_WAKEEE
) {
195 icp_native_flush_interrupt();
196 local_paca
->irq_happened
&= PACA_IRQ_HARD_DIS
;
200 if (cpu_core_split_required())
203 if (!generic_check_cpu_restart(cpu
))
204 DBG("CPU%d Unexpected exit while offline !\n", cpu
);
206 mtspr(SPRN_LPCR
, mfspr(SPRN_LPCR
) | LPCR_PECE1
);
207 DBG("CPU%d coming online...\n", cpu
);
210 #endif /* CONFIG_HOTPLUG_CPU */
212 static struct smp_ops_t pnv_smp_ops
= {
213 .message_pass
= smp_muxed_ipi_message_pass
,
214 .cause_ipi
= NULL
, /* Filled at runtime by xics_smp_probe() */
215 .probe
= xics_smp_probe
,
216 .kick_cpu
= pnv_smp_kick_cpu
,
217 .setup_cpu
= pnv_smp_setup_cpu
,
218 .cpu_bootable
= smp_generic_cpu_bootable
,
219 #ifdef CONFIG_HOTPLUG_CPU
220 .cpu_disable
= pnv_smp_cpu_disable
,
221 .cpu_die
= generic_cpu_die
,
222 #endif /* CONFIG_HOTPLUG_CPU */
225 /* This is called very early during platform setup_arch */
226 void __init
pnv_smp_init(void)
228 smp_ops
= &pnv_smp_ops
;
230 /* XXX We don't yet have a proper entry point from HAL, for
231 * now we rely on kexec-style entry from BML
234 #ifdef CONFIG_PPC_RTAS
235 /* Non-lpar has additional take/give timebase */
236 if (rtas_token("freeze-time-base") != RTAS_UNKNOWN_SERVICE
) {
237 smp_ops
->give_timebase
= rtas_give_timebase
;
238 smp_ops
->take_timebase
= rtas_take_timebase
;
240 #endif /* CONFIG_PPC_RTAS */
242 #ifdef CONFIG_HOTPLUG_CPU
243 ppc_md
.cpu_die
= pnv_smp_cpu_kill_self
;