/* * SMP support for PowerNV machines. * * Copyright 2011 IBM Corp. * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version * 2 of the License, or (at your option) any later version. */ #include <linux/kernel.h> #include <linux/module.h> #include <linux/sched.h> #include <linux/smp.h> #include <linux/interrupt.h> #include <linux/delay.h> #include <linux/init.h> #include <linux/spinlock.h> #include <linux/cpu.h> #include <asm/irq.h> #include <asm/smp.h> #include <asm/paca.h> #include <asm/machdep.h> #include <asm/cputable.h> #include <asm/firmware.h> #include <asm/vdso_datapage.h> #include <asm/cputhreads.h> #include <asm/xics.h> #include <asm/opal.h> #include <asm/runlatch.h> #include <asm/code-patching.h> #include <asm/dbell.h> #include <asm/kvm_ppc.h> #include <asm/ppc-opcode.h> #include "powernv.h" #ifdef DEBUG #include <asm/udbg.h> #define DBG(fmt...) udbg_printf(fmt) #else #define DBG(fmt...) #endif static void pnv_smp_setup_cpu(int cpu) { if (cpu != boot_cpuid) xics_setup_cpu(); #ifdef CONFIG_PPC_DOORBELL if (cpu_has_feature(CPU_FTR_DBELL)) doorbell_setup_this_cpu(); #endif } static int pnv_smp_kick_cpu(int nr) { unsigned int pcpu = get_hard_smp_processor_id(nr); unsigned long start_here = __pa(ppc_function_entry(generic_secondary_smp_init)); long rc; BUG_ON(nr < 0 || nr >= NR_CPUS); /* * If we already started or OPALv2 is not supported, we just * kick the CPU via the PACA */ if (paca[nr].cpu_start || !firmware_has_feature(FW_FEATURE_OPALv2)) goto kick; /* * At this point, the CPU can either be spinning on the way in * from kexec or be inside OPAL waiting to be started for the * first time. OPAL v3 allows us to query OPAL to know if it * has the CPUs, so we do that */ if (firmware_has_feature(FW_FEATURE_OPALv3)) { uint8_t status; rc = opal_query_cpu_status(pcpu, &status); if (rc != OPAL_SUCCESS) { pr_warn("OPAL Error %ld querying CPU %d state\n", rc, nr); return -ENODEV; } /* * Already started, just kick it, probably coming from * kexec and spinning */ if (status == OPAL_THREAD_STARTED) goto kick; /* * Available/inactive, let's kick it */ if (status == OPAL_THREAD_INACTIVE) { pr_devel("OPAL: Starting CPU %d (HW 0x%x)...\n", nr, pcpu); rc = opal_start_cpu(pcpu, start_here); if (rc != OPAL_SUCCESS) { pr_warn("OPAL Error %ld starting CPU %d\n", rc, nr); return -ENODEV; } } else { /* * An unavailable CPU (or any other unknown status) * shouldn't be started. It should also * not be in the possible map but currently it can * happen */ pr_devel("OPAL: CPU %d (HW 0x%x) is unavailable" " (status %d)...\n", nr, pcpu, status); return -ENODEV; } } else { /* * On OPAL v2, we just kick it and hope for the best, * we must not test the error from opal_start_cpu() or * we would fail to get CPUs from kexec. */ opal_start_cpu(pcpu, start_here); } kick: return smp_generic_kick_cpu(nr); } #ifdef CONFIG_HOTPLUG_CPU static int pnv_smp_cpu_disable(void) { int cpu = smp_processor_id(); /* This is identical to pSeries... might consolidate by * moving migrate_irqs_away to a ppc_md with default to * the generic fixup_irqs. --BenH. */ set_cpu_online(cpu, false); vdso_data->processorCount--; if (cpu == boot_cpuid) boot_cpuid = cpumask_any(cpu_online_mask); xics_migrate_irqs_away(); return 0; } static void pnv_smp_cpu_kill_self(void) { unsigned int cpu; unsigned long srr1, wmask; u32 idle_states; /* Standard hot unplug procedure */ local_irq_disable(); idle_task_exit(); current->active_mm = NULL; /* for sanity */ cpu = smp_processor_id(); DBG("CPU%d offline\n", cpu); generic_set_cpu_dead(cpu); smp_wmb(); wmask = SRR1_WAKEMASK; if (cpu_has_feature(CPU_FTR_ARCH_207S)) wmask = SRR1_WAKEMASK_P8; idle_states = pnv_get_supported_cpuidle_states(); /* We don't want to take decrementer interrupts while we are offline, * so clear LPCR:PECE1. We keep PECE2 enabled. */ mtspr(SPRN_LPCR, mfspr(SPRN_LPCR) & ~(u64)LPCR_PECE1); while (!generic_check_cpu_restart(cpu)) { ppc64_runlatch_off(); if (idle_states & OPAL_PM_WINKLE_ENABLED) srr1 = power7_winkle(); else if ((idle_states & OPAL_PM_SLEEP_ENABLED) || (idle_states & OPAL_PM_SLEEP_ENABLED_ER1)) srr1 = power7_sleep(); else srr1 = power7_nap(1); ppc64_runlatch_on(); /* * If the SRR1 value indicates that we woke up due to * an external interrupt, then clear the interrupt. * We clear the interrupt before checking for the * reason, so as to avoid a race where we wake up for * some other reason, find nothing and clear the interrupt * just as some other cpu is sending us an interrupt. * If we returned from power7_nap as a result of * having finished executing in a KVM guest, then srr1 * contains 0. */ if ((srr1 & wmask) == SRR1_WAKEEE) { icp_native_flush_interrupt(); local_paca->irq_happened &= PACA_IRQ_HARD_DIS; smp_mb(); } else if ((srr1 & wmask) == SRR1_WAKEHDBELL) { unsigned long msg = PPC_DBELL_TYPE(PPC_DBELL_SERVER); asm volatile(PPC_MSGCLR(%0) : : "r" (msg)); kvmppc_set_host_ipi(cpu, 0); } if (cpu_core_split_required()) continue; if (!generic_check_cpu_restart(cpu)) DBG("CPU%d Unexpected exit while offline !\n", cpu); } mtspr(SPRN_LPCR, mfspr(SPRN_LPCR) | LPCR_PECE1); DBG("CPU%d coming online...\n", cpu); } #endif /* CONFIG_HOTPLUG_CPU */ static int pnv_cpu_bootable(unsigned int nr) { /* * Starting with POWER8, the subcore logic relies on all threads of a * core being booted so that they can participate in split mode * switches. So on those machines we ignore the smt_enabled_at_boot * setting (smt-enabled on the kernel command line). */ if (cpu_has_feature(CPU_FTR_ARCH_207S)) return 1; return smp_generic_cpu_bootable(nr); } static struct smp_ops_t pnv_smp_ops = { .message_pass = smp_muxed_ipi_message_pass, .cause_ipi = NULL, /* Filled at runtime by xics_smp_probe() */ .probe = xics_smp_probe, .kick_cpu = pnv_smp_kick_cpu, .setup_cpu = pnv_smp_setup_cpu, .cpu_bootable = pnv_cpu_bootable, #ifdef CONFIG_HOTPLUG_CPU .cpu_disable = pnv_smp_cpu_disable, .cpu_die = generic_cpu_die, #endif /* CONFIG_HOTPLUG_CPU */ }; /* This is called very early during platform setup_arch */ void __init pnv_smp_init(void) { smp_ops = &pnv_smp_ops; #ifdef CONFIG_HOTPLUG_CPU ppc_md.cpu_die = pnv_smp_cpu_kill_self; #endif }