155190f88SBenjamin Herrenschmidt /* 255190f88SBenjamin Herrenschmidt * SMP support for PowerNV machines. 355190f88SBenjamin Herrenschmidt * 455190f88SBenjamin Herrenschmidt * Copyright 2011 IBM Corp. 555190f88SBenjamin Herrenschmidt * 655190f88SBenjamin Herrenschmidt * This program is free software; you can redistribute it and/or 755190f88SBenjamin Herrenschmidt * modify it under the terms of the GNU General Public License 855190f88SBenjamin Herrenschmidt * as published by the Free Software Foundation; either version 955190f88SBenjamin Herrenschmidt * 2 of the License, or (at your option) any later version. 1055190f88SBenjamin Herrenschmidt */ 1155190f88SBenjamin Herrenschmidt 1255190f88SBenjamin Herrenschmidt #include <linux/kernel.h> 1355190f88SBenjamin Herrenschmidt #include <linux/module.h> 1455190f88SBenjamin Herrenschmidt #include <linux/sched.h> 15ef8bd77fSIngo Molnar #include <linux/sched/hotplug.h> 1655190f88SBenjamin Herrenschmidt #include <linux/smp.h> 1755190f88SBenjamin Herrenschmidt #include <linux/interrupt.h> 1855190f88SBenjamin Herrenschmidt #include <linux/delay.h> 1955190f88SBenjamin Herrenschmidt #include <linux/init.h> 2055190f88SBenjamin Herrenschmidt #include <linux/spinlock.h> 2155190f88SBenjamin Herrenschmidt #include <linux/cpu.h> 2255190f88SBenjamin Herrenschmidt 2355190f88SBenjamin Herrenschmidt #include <asm/irq.h> 2455190f88SBenjamin Herrenschmidt #include <asm/smp.h> 2555190f88SBenjamin Herrenschmidt #include <asm/paca.h> 2655190f88SBenjamin Herrenschmidt #include <asm/machdep.h> 2755190f88SBenjamin Herrenschmidt #include <asm/cputable.h> 2855190f88SBenjamin Herrenschmidt #include <asm/firmware.h> 2955190f88SBenjamin Herrenschmidt #include <asm/vdso_datapage.h> 3055190f88SBenjamin Herrenschmidt #include <asm/cputhreads.h> 3155190f88SBenjamin Herrenschmidt #include <asm/xics.h> 32243e2511SBenjamin Herrenschmidt #include <asm/xive.h> 3314a43e69SBenjamin Herrenschmidt #include <asm/opal.h> 34f2038911SPreeti U Murthy #include <asm/runlatch.h> 352751b628SAnton Blanchard #include <asm/code-patching.h> 36d4e58e59SMichael Neuling #include <asm/dbell.h> 37755563bcSPaul Mackerras #include <asm/kvm_ppc.h> 38755563bcSPaul Mackerras #include <asm/ppc-opcode.h> 39a7cd88daSGautham R. Shenoy #include <asm/cpuidle.h> 4055190f88SBenjamin Herrenschmidt 4155190f88SBenjamin Herrenschmidt #include "powernv.h" 4255190f88SBenjamin Herrenschmidt 43344eb010SBenjamin Herrenschmidt #ifdef DEBUG 44344eb010SBenjamin Herrenschmidt #include <asm/udbg.h> 45344eb010SBenjamin Herrenschmidt #define DBG(fmt...) udbg_printf(fmt) 46344eb010SBenjamin Herrenschmidt #else 47344eb010SBenjamin Herrenschmidt #define DBG(fmt...) 48344eb010SBenjamin Herrenschmidt #endif 49344eb010SBenjamin Herrenschmidt 50061d19f2SPaul Gortmaker static void pnv_smp_setup_cpu(int cpu) 5155190f88SBenjamin Herrenschmidt { 52243e2511SBenjamin Herrenschmidt if (xive_enabled()) 53243e2511SBenjamin Herrenschmidt xive_smp_setup_cpu(); 54243e2511SBenjamin Herrenschmidt else if (cpu != boot_cpuid) 5555190f88SBenjamin Herrenschmidt xics_setup_cpu(); 5655190f88SBenjamin Herrenschmidt } 5755190f88SBenjamin Herrenschmidt 58e51df2c1SAnton Blanchard static int pnv_smp_kick_cpu(int nr) 5914a43e69SBenjamin Herrenschmidt { 6014a43e69SBenjamin Herrenschmidt unsigned int pcpu = get_hard_smp_processor_id(nr); 612751b628SAnton Blanchard unsigned long start_here = 622751b628SAnton Blanchard __pa(ppc_function_entry(generic_secondary_smp_init)); 6314a43e69SBenjamin Herrenschmidt long rc; 64e4d54f71SStewart Smith uint8_t status; 6514a43e69SBenjamin Herrenschmidt 6614a43e69SBenjamin Herrenschmidt BUG_ON(nr < 0 || nr >= NR_CPUS); 6714a43e69SBenjamin Herrenschmidt 68b2b48584SBenjamin Herrenschmidt /* 69e4d54f71SStewart Smith * If we already started or OPAL is not supported, we just 70b2b48584SBenjamin Herrenschmidt * kick the CPU via the PACA 7114a43e69SBenjamin Herrenschmidt */ 72e4d54f71SStewart Smith if (paca[nr].cpu_start || !firmware_has_feature(FW_FEATURE_OPAL)) 73b2b48584SBenjamin Herrenschmidt goto kick; 74b2b48584SBenjamin Herrenschmidt 75b2b48584SBenjamin Herrenschmidt /* 76b2b48584SBenjamin Herrenschmidt * At this point, the CPU can either be spinning on the way in 77b2b48584SBenjamin Herrenschmidt * from kexec or be inside OPAL waiting to be started for the 78b2b48584SBenjamin Herrenschmidt * first time. OPAL v3 allows us to query OPAL to know if it 79b2b48584SBenjamin Herrenschmidt * has the CPUs, so we do that 80b2b48584SBenjamin Herrenschmidt */ 81b2b48584SBenjamin Herrenschmidt rc = opal_query_cpu_status(pcpu, &status); 82b2b48584SBenjamin Herrenschmidt if (rc != OPAL_SUCCESS) { 83e4d54f71SStewart Smith pr_warn("OPAL Error %ld querying CPU %d state\n", rc, nr); 84b2b48584SBenjamin Herrenschmidt return -ENODEV; 85b2b48584SBenjamin Herrenschmidt } 86b2b48584SBenjamin Herrenschmidt 87b2b48584SBenjamin Herrenschmidt /* 88b2b48584SBenjamin Herrenschmidt * Already started, just kick it, probably coming from 89b2b48584SBenjamin Herrenschmidt * kexec and spinning 90b2b48584SBenjamin Herrenschmidt */ 91b2b48584SBenjamin Herrenschmidt if (status == OPAL_THREAD_STARTED) 92b2b48584SBenjamin Herrenschmidt goto kick; 93b2b48584SBenjamin Herrenschmidt 94b2b48584SBenjamin Herrenschmidt /* 95b2b48584SBenjamin Herrenschmidt * Available/inactive, let's kick it 96b2b48584SBenjamin Herrenschmidt */ 97b2b48584SBenjamin Herrenschmidt if (status == OPAL_THREAD_INACTIVE) { 98e4d54f71SStewart Smith pr_devel("OPAL: Starting CPU %d (HW 0x%x)...\n", nr, pcpu); 9914a43e69SBenjamin Herrenschmidt rc = opal_start_cpu(pcpu, start_here); 1004ea9008bSBenjamin Herrenschmidt if (rc != OPAL_SUCCESS) { 101e4d54f71SStewart Smith pr_warn("OPAL Error %ld starting CPU %d\n", rc, nr); 1024ea9008bSBenjamin Herrenschmidt return -ENODEV; 1034ea9008bSBenjamin Herrenschmidt } 104b2b48584SBenjamin Herrenschmidt } else { 105b2b48584SBenjamin Herrenschmidt /* 106b2b48584SBenjamin Herrenschmidt * An unavailable CPU (or any other unknown status) 107b2b48584SBenjamin Herrenschmidt * shouldn't be started. It should also 108b2b48584SBenjamin Herrenschmidt * not be in the possible map but currently it can 109b2b48584SBenjamin Herrenschmidt * happen 110b2b48584SBenjamin Herrenschmidt */ 111b2b48584SBenjamin Herrenschmidt pr_devel("OPAL: CPU %d (HW 0x%x) is unavailable" 112b2b48584SBenjamin Herrenschmidt " (status %d)...\n", nr, pcpu, status); 113b2b48584SBenjamin Herrenschmidt return -ENODEV; 11414a43e69SBenjamin Herrenschmidt } 115e4d54f71SStewart Smith 116b2b48584SBenjamin Herrenschmidt kick: 11714a43e69SBenjamin Herrenschmidt return smp_generic_kick_cpu(nr); 11814a43e69SBenjamin Herrenschmidt } 11914a43e69SBenjamin Herrenschmidt 120344eb010SBenjamin Herrenschmidt #ifdef CONFIG_HOTPLUG_CPU 121344eb010SBenjamin Herrenschmidt 122344eb010SBenjamin Herrenschmidt static int pnv_smp_cpu_disable(void) 123344eb010SBenjamin Herrenschmidt { 124344eb010SBenjamin Herrenschmidt int cpu = smp_processor_id(); 125344eb010SBenjamin Herrenschmidt 126344eb010SBenjamin Herrenschmidt /* This is identical to pSeries... might consolidate by 127344eb010SBenjamin Herrenschmidt * moving migrate_irqs_away to a ppc_md with default to 128344eb010SBenjamin Herrenschmidt * the generic fixup_irqs. --BenH. 129344eb010SBenjamin Herrenschmidt */ 130344eb010SBenjamin Herrenschmidt set_cpu_online(cpu, false); 131344eb010SBenjamin Herrenschmidt vdso_data->processorCount--; 132344eb010SBenjamin Herrenschmidt if (cpu == boot_cpuid) 133344eb010SBenjamin Herrenschmidt boot_cpuid = cpumask_any(cpu_online_mask); 134243e2511SBenjamin Herrenschmidt if (xive_enabled()) 135243e2511SBenjamin Herrenschmidt xive_smp_disable_cpu(); 136243e2511SBenjamin Herrenschmidt else 137344eb010SBenjamin Herrenschmidt xics_migrate_irqs_away(); 138344eb010SBenjamin Herrenschmidt return 0; 139344eb010SBenjamin Herrenschmidt } 140344eb010SBenjamin Herrenschmidt 141344eb010SBenjamin Herrenschmidt static void pnv_smp_cpu_kill_self(void) 142344eb010SBenjamin Herrenschmidt { 143344eb010SBenjamin Herrenschmidt unsigned int cpu; 144755563bcSPaul Mackerras unsigned long srr1, wmask; 145344eb010SBenjamin Herrenschmidt 146344eb010SBenjamin Herrenschmidt /* Standard hot unplug procedure */ 147344eb010SBenjamin Herrenschmidt local_irq_disable(); 148344eb010SBenjamin Herrenschmidt idle_task_exit(); 149344eb010SBenjamin Herrenschmidt current->active_mm = NULL; /* for sanity */ 150344eb010SBenjamin Herrenschmidt cpu = smp_processor_id(); 151344eb010SBenjamin Herrenschmidt DBG("CPU%d offline\n", cpu); 152344eb010SBenjamin Herrenschmidt generic_set_cpu_dead(cpu); 153344eb010SBenjamin Herrenschmidt smp_wmb(); 154344eb010SBenjamin Herrenschmidt 155755563bcSPaul Mackerras wmask = SRR1_WAKEMASK; 156755563bcSPaul Mackerras if (cpu_has_feature(CPU_FTR_ARCH_207S)) 157755563bcSPaul Mackerras wmask = SRR1_WAKEMASK_P8; 158755563bcSPaul Mackerras 159344eb010SBenjamin Herrenschmidt /* We don't want to take decrementer interrupts while we are offline, 1609b256714SBenjamin Herrenschmidt * so clear LPCR:PECE1. We keep PECE2 (and LPCR_PECE_HVEE on P9) 1619b256714SBenjamin Herrenschmidt * enabled as to let IPIs in. 162344eb010SBenjamin Herrenschmidt */ 163344eb010SBenjamin Herrenschmidt mtspr(SPRN_LPCR, mfspr(SPRN_LPCR) & ~(u64)LPCR_PECE1); 16453c656c4SPaul Mackerras 16553c656c4SPaul Mackerras /* 16653c656c4SPaul Mackerras * Hard-disable interrupts, and then clear irq_happened flags 16753c656c4SPaul Mackerras * that we can safely ignore while off-line, since they 16853c656c4SPaul Mackerras * are for things for which we do no processing when off-line 16953c656c4SPaul Mackerras * (or in the case of HMI, all the processing we need to do 17053c656c4SPaul Mackerras * is done in lower-level real-mode code). 17153c656c4SPaul Mackerras */ 17253c656c4SPaul Mackerras hard_irq_disable(); 17353c656c4SPaul Mackerras local_paca->irq_happened &= ~(PACA_IRQ_DEC | PACA_IRQ_HMI); 17453c656c4SPaul Mackerras 175344eb010SBenjamin Herrenschmidt while (!generic_check_cpu_restart(cpu)) { 17653c656c4SPaul Mackerras /* 17753c656c4SPaul Mackerras * Clear IPI flag, since we don't handle IPIs while 17853c656c4SPaul Mackerras * offline, except for those when changing micro-threading 17953c656c4SPaul Mackerras * mode, which are handled explicitly below, and those 18053c656c4SPaul Mackerras * for coming online, which are handled via 18153c656c4SPaul Mackerras * generic_check_cpu_restart() calls. 18253c656c4SPaul Mackerras */ 18353c656c4SPaul Mackerras kvmppc_set_host_ipi(cpu, 0); 18477b54e9fSShreyas B. Prabhu 185f2038911SPreeti U Murthy ppc64_runlatch_off(); 186a7cd88daSGautham R. Shenoy srr1 = pnv_cpu_offline(cpu); 187f2038911SPreeti U Murthy ppc64_runlatch_on(); 188e2186023SMichael Ellerman 18956548fc0SPaul Mackerras /* 19056548fc0SPaul Mackerras * If the SRR1 value indicates that we woke up due to 19156548fc0SPaul Mackerras * an external interrupt, then clear the interrupt. 19256548fc0SPaul Mackerras * We clear the interrupt before checking for the 19356548fc0SPaul Mackerras * reason, so as to avoid a race where we wake up for 19456548fc0SPaul Mackerras * some other reason, find nothing and clear the interrupt 19556548fc0SPaul Mackerras * just as some other cpu is sending us an interrupt. 19656548fc0SPaul Mackerras * If we returned from power7_nap as a result of 19756548fc0SPaul Mackerras * having finished executing in a KVM guest, then srr1 19856548fc0SPaul Mackerras * contains 0. 19956548fc0SPaul Mackerras */ 20053c656c4SPaul Mackerras if (((srr1 & wmask) == SRR1_WAKEEE) || 2019b256714SBenjamin Herrenschmidt ((srr1 & wmask) == SRR1_WAKEHVI) || 20253c656c4SPaul Mackerras (local_paca->irq_happened & PACA_IRQ_EE)) { 203243e2511SBenjamin Herrenschmidt if (cpu_has_feature(CPU_FTR_ARCH_300)) { 204243e2511SBenjamin Herrenschmidt if (xive_enabled()) 205243e2511SBenjamin Herrenschmidt xive_flush_interrupt(); 2069b256714SBenjamin Herrenschmidt else 207243e2511SBenjamin Herrenschmidt icp_opal_flush_interrupt(); 208243e2511SBenjamin Herrenschmidt } else 209d6a4f709SPaul Mackerras icp_native_flush_interrupt(); 210755563bcSPaul Mackerras } else if ((srr1 & wmask) == SRR1_WAKEHDBELL) { 211755563bcSPaul Mackerras unsigned long msg = PPC_DBELL_TYPE(PPC_DBELL_SERVER); 212755563bcSPaul Mackerras asm volatile(PPC_MSGCLR(%0) : : "r" (msg)); 21356548fc0SPaul Mackerras } 21453c656c4SPaul Mackerras local_paca->irq_happened &= ~(PACA_IRQ_EE | PACA_IRQ_DBELL); 21553c656c4SPaul Mackerras smp_mb(); 216e2186023SMichael Ellerman 217e2186023SMichael Ellerman if (cpu_core_split_required()) 218e2186023SMichael Ellerman continue; 219e2186023SMichael Ellerman 22053c656c4SPaul Mackerras if (srr1 && !generic_check_cpu_restart(cpu)) 221e2186023SMichael Ellerman DBG("CPU%d Unexpected exit while offline !\n", cpu); 222344eb010SBenjamin Herrenschmidt } 2239b256714SBenjamin Herrenschmidt 2249b256714SBenjamin Herrenschmidt /* Re-enable decrementer interrupts */ 225344eb010SBenjamin Herrenschmidt mtspr(SPRN_LPCR, mfspr(SPRN_LPCR) | LPCR_PECE1); 226344eb010SBenjamin Herrenschmidt DBG("CPU%d coming online...\n", cpu); 227344eb010SBenjamin Herrenschmidt } 228344eb010SBenjamin Herrenschmidt 229344eb010SBenjamin Herrenschmidt #endif /* CONFIG_HOTPLUG_CPU */ 230344eb010SBenjamin Herrenschmidt 231d70a54e2SGreg Kurz static int pnv_cpu_bootable(unsigned int nr) 232d70a54e2SGreg Kurz { 233d70a54e2SGreg Kurz /* 234d70a54e2SGreg Kurz * Starting with POWER8, the subcore logic relies on all threads of a 235d70a54e2SGreg Kurz * core being booted so that they can participate in split mode 236d70a54e2SGreg Kurz * switches. So on those machines we ignore the smt_enabled_at_boot 237d70a54e2SGreg Kurz * setting (smt-enabled on the kernel command line). 238d70a54e2SGreg Kurz */ 239d70a54e2SGreg Kurz if (cpu_has_feature(CPU_FTR_ARCH_207S)) 240d70a54e2SGreg Kurz return 1; 241d70a54e2SGreg Kurz 242d70a54e2SGreg Kurz return smp_generic_cpu_bootable(nr); 243d70a54e2SGreg Kurz } 244d70a54e2SGreg Kurz 245243e2511SBenjamin Herrenschmidt static int pnv_smp_prepare_cpu(int cpu) 246243e2511SBenjamin Herrenschmidt { 247243e2511SBenjamin Herrenschmidt if (xive_enabled()) 248243e2511SBenjamin Herrenschmidt return xive_smp_prepare_cpu(cpu); 249243e2511SBenjamin Herrenschmidt return 0; 250243e2511SBenjamin Herrenschmidt } 251243e2511SBenjamin Herrenschmidt 252b866cc21SNicholas Piggin static void pnv_cause_ipi(int cpu) 253b866cc21SNicholas Piggin { 254b866cc21SNicholas Piggin if (doorbell_try_core_ipi(cpu)) 255b866cc21SNicholas Piggin return; 256b866cc21SNicholas Piggin 257b866cc21SNicholas Piggin icp_ops->cause_ipi(cpu); 258b866cc21SNicholas Piggin } 259b866cc21SNicholas Piggin 260243e2511SBenjamin Herrenschmidt static void __init pnv_smp_probe(void) 261243e2511SBenjamin Herrenschmidt { 262243e2511SBenjamin Herrenschmidt if (xive_enabled()) 263243e2511SBenjamin Herrenschmidt xive_smp_probe(); 264243e2511SBenjamin Herrenschmidt else 265243e2511SBenjamin Herrenschmidt xics_smp_probe(); 266b866cc21SNicholas Piggin 267b866cc21SNicholas Piggin if (cpu_has_feature(CPU_FTR_DBELL) && !cpu_has_feature(CPU_FTR_ARCH_300)) { 268b866cc21SNicholas Piggin smp_ops->cause_ipi = pnv_cause_ipi; 269b866cc21SNicholas Piggin } else { 270b866cc21SNicholas Piggin smp_ops->cause_ipi = icp_ops->cause_ipi; 271b866cc21SNicholas Piggin } 272243e2511SBenjamin Herrenschmidt } 273243e2511SBenjamin Herrenschmidt 27455190f88SBenjamin Herrenschmidt static struct smp_ops_t pnv_smp_ops = { 275b866cc21SNicholas Piggin .message_pass = NULL, /* Use smp_muxed_ipi_message_pass */ 276b866cc21SNicholas Piggin .cause_ipi = NULL, /* Filled at runtime by pnv_smp_probe() */ 277243e2511SBenjamin Herrenschmidt .probe = pnv_smp_probe, 278243e2511SBenjamin Herrenschmidt .prepare_cpu = pnv_smp_prepare_cpu, 27914a43e69SBenjamin Herrenschmidt .kick_cpu = pnv_smp_kick_cpu, 28055190f88SBenjamin Herrenschmidt .setup_cpu = pnv_smp_setup_cpu, 281d70a54e2SGreg Kurz .cpu_bootable = pnv_cpu_bootable, 282344eb010SBenjamin Herrenschmidt #ifdef CONFIG_HOTPLUG_CPU 283344eb010SBenjamin Herrenschmidt .cpu_disable = pnv_smp_cpu_disable, 284344eb010SBenjamin Herrenschmidt .cpu_die = generic_cpu_die, 285344eb010SBenjamin Herrenschmidt #endif /* CONFIG_HOTPLUG_CPU */ 28655190f88SBenjamin Herrenschmidt }; 28755190f88SBenjamin Herrenschmidt 28855190f88SBenjamin Herrenschmidt /* This is called very early during platform setup_arch */ 28955190f88SBenjamin Herrenschmidt void __init pnv_smp_init(void) 29055190f88SBenjamin Herrenschmidt { 29155190f88SBenjamin Herrenschmidt smp_ops = &pnv_smp_ops; 29255190f88SBenjamin Herrenschmidt 293344eb010SBenjamin Herrenschmidt #ifdef CONFIG_HOTPLUG_CPU 294344eb010SBenjamin Herrenschmidt ppc_md.cpu_die = pnv_smp_cpu_kill_self; 295344eb010SBenjamin Herrenschmidt #endif 29655190f88SBenjamin Herrenschmidt } 297