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/sched/hotplug.h>
16 #include <linux/smp.h>
17 #include <linux/interrupt.h>
18 #include <linux/delay.h>
19 #include <linux/init.h>
20 #include <linux/spinlock.h>
21 #include <linux/cpu.h>
26 #include <asm/machdep.h>
27 #include <asm/cputable.h>
28 #include <asm/firmware.h>
29 #include <asm/vdso_datapage.h>
30 #include <asm/cputhreads.h>
34 #include <asm/runlatch.h>
35 #include <asm/code-patching.h>
36 #include <asm/dbell.h>
37 #include <asm/kvm_ppc.h>
38 #include <asm/ppc-opcode.h>
39 #include <asm/cpuidle.h>
45 #define DBG(fmt...) udbg_printf(fmt)
50 static void pnv_smp_setup_cpu(int cpu)
54 else if (cpu != boot_cpuid)
58 static int pnv_smp_kick_cpu(int nr)
61 unsigned long start_here =
62 __pa(ppc_function_entry(generic_secondary_smp_init));
66 if (nr < 0 || nr >= nr_cpu_ids)
69 pcpu = get_hard_smp_processor_id(nr);
71 * If we already started or OPAL is not supported, we just
72 * kick the CPU via the PACA
74 if (paca[nr].cpu_start || !firmware_has_feature(FW_FEATURE_OPAL))
78 * At this point, the CPU can either be spinning on the way in
79 * from kexec or be inside OPAL waiting to be started for the
80 * first time. OPAL v3 allows us to query OPAL to know if it
81 * has the CPUs, so we do that
83 rc = opal_query_cpu_status(pcpu, &status);
84 if (rc != OPAL_SUCCESS) {
85 pr_warn("OPAL Error %ld querying CPU %d state\n", rc, nr);
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", nr, pcpu);
101 rc = opal_start_cpu(pcpu, start_here);
102 if (rc != OPAL_SUCCESS) {
103 pr_warn("OPAL Error %ld starting CPU %d\n", rc, nr);
108 * An unavailable CPU (or any other unknown status)
109 * shouldn't be started. It should also
110 * not be in the possible map but currently it can
113 pr_devel("OPAL: CPU %d (HW 0x%x) is unavailable"
114 " (status %d)...\n", nr, pcpu, status);
119 return smp_generic_kick_cpu(nr);
122 #ifdef CONFIG_HOTPLUG_CPU
124 static int pnv_smp_cpu_disable(void)
126 int cpu = smp_processor_id();
128 /* This is identical to pSeries... might consolidate by
129 * moving migrate_irqs_away to a ppc_md with default to
130 * the generic fixup_irqs. --BenH.
132 set_cpu_online(cpu, false);
133 vdso_data->processorCount--;
134 if (cpu == boot_cpuid)
135 boot_cpuid = cpumask_any(cpu_online_mask);
137 xive_smp_disable_cpu();
139 xics_migrate_irqs_away();
143 static void pnv_smp_cpu_kill_self(void)
146 unsigned long srr1, wmask;
148 /* Standard hot unplug procedure */
150 * This hard disables local interurpts, ensuring we have no lazy
153 WARN_ON(irqs_disabled());
155 WARN_ON(lazy_irq_pending());
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 wmask = SRR1_WAKEMASK;
165 if (cpu_has_feature(CPU_FTR_ARCH_207S))
166 wmask = SRR1_WAKEMASK_P8;
168 while (!generic_check_cpu_restart(cpu)) {
170 * Clear IPI flag, since we don't handle IPIs while
171 * offline, except for those when changing micro-threading
172 * mode, which are handled explicitly below, and those
173 * for coming online, which are handled via
174 * generic_check_cpu_restart() calls.
176 kvmppc_set_host_ipi(cpu, 0);
178 srr1 = pnv_cpu_offline(cpu);
180 WARN_ON(lazy_irq_pending());
183 * If the SRR1 value indicates that we woke up due to
184 * an external interrupt, then clear the interrupt.
185 * We clear the interrupt before checking for the
186 * reason, so as to avoid a race where we wake up for
187 * some other reason, find nothing and clear the interrupt
188 * just as some other cpu is sending us an interrupt.
189 * If we returned from power7_nap as a result of
190 * having finished executing in a KVM guest, then srr1
193 if (((srr1 & wmask) == SRR1_WAKEEE) ||
194 ((srr1 & wmask) == SRR1_WAKEHVI)) {
195 if (cpu_has_feature(CPU_FTR_ARCH_300)) {
197 xive_flush_interrupt();
199 icp_opal_flush_interrupt();
201 icp_native_flush_interrupt();
202 } else if ((srr1 & wmask) == SRR1_WAKEHDBELL) {
203 unsigned long msg = PPC_DBELL_TYPE(PPC_DBELL_SERVER);
204 asm volatile(PPC_MSGCLR(%0) : : "r" (msg));
208 if (cpu_core_split_required())
211 if (srr1 && !generic_check_cpu_restart(cpu))
212 DBG("CPU%d Unexpected exit while offline srr1=%lx!\n",
217 DBG("CPU%d coming online...\n", cpu);
220 #endif /* CONFIG_HOTPLUG_CPU */
222 static int pnv_cpu_bootable(unsigned int nr)
225 * Starting with POWER8, the subcore logic relies on all threads of a
226 * core being booted so that they can participate in split mode
227 * switches. So on those machines we ignore the smt_enabled_at_boot
228 * setting (smt-enabled on the kernel command line).
230 if (cpu_has_feature(CPU_FTR_ARCH_207S))
233 return smp_generic_cpu_bootable(nr);
236 static int pnv_smp_prepare_cpu(int cpu)
239 return xive_smp_prepare_cpu(cpu);
243 /* Cause IPI as setup by the interrupt controller (xics or xive) */
244 static void (*ic_cause_ipi)(int cpu);
246 static void pnv_cause_ipi(int cpu)
248 if (doorbell_try_core_ipi(cpu))
254 static void pnv_p9_dd1_cause_ipi(int cpu)
256 int this_cpu = get_cpu();
259 * POWER9 DD1 has a global addressed msgsnd, but for now we restrict
260 * IPIs to same core, because it requires additional synchronization
261 * for inter-core doorbells which we do not implement.
263 if (cpumask_test_cpu(cpu, cpu_sibling_mask(this_cpu)))
264 doorbell_global_ipi(cpu);
271 static void __init pnv_smp_probe(void)
278 if (cpu_has_feature(CPU_FTR_DBELL)) {
279 ic_cause_ipi = smp_ops->cause_ipi;
280 WARN_ON(!ic_cause_ipi);
282 if (cpu_has_feature(CPU_FTR_ARCH_300)) {
283 if (cpu_has_feature(CPU_FTR_POWER9_DD1))
284 smp_ops->cause_ipi = pnv_p9_dd1_cause_ipi;
286 smp_ops->cause_ipi = doorbell_global_ipi;
288 smp_ops->cause_ipi = pnv_cause_ipi;
293 static struct smp_ops_t pnv_smp_ops = {
294 .message_pass = NULL, /* Use smp_muxed_ipi_message_pass */
295 .cause_ipi = NULL, /* Filled at runtime by pnv_smp_probe() */
296 .cause_nmi_ipi = NULL,
297 .probe = pnv_smp_probe,
298 .prepare_cpu = pnv_smp_prepare_cpu,
299 .kick_cpu = pnv_smp_kick_cpu,
300 .setup_cpu = pnv_smp_setup_cpu,
301 .cpu_bootable = pnv_cpu_bootable,
302 #ifdef CONFIG_HOTPLUG_CPU
303 .cpu_disable = pnv_smp_cpu_disable,
304 .cpu_die = generic_cpu_die,
305 #endif /* CONFIG_HOTPLUG_CPU */
308 /* This is called very early during platform setup_arch */
309 void __init pnv_smp_init(void)
311 smp_ops = &pnv_smp_ops;
313 #ifdef CONFIG_HOTPLUG_CPU
314 ppc_md.cpu_die = pnv_smp_cpu_kill_self;