| // SPDX-License-Identifier: GPL-2.0-or-later |
| /* |
| * SMP support for PowerNV machines. |
| * |
| * Copyright 2011 IBM Corp. |
| */ |
| |
| #include <linux/kernel.h> |
| #include <linux/module.h> |
| #include <linux/sched.h> |
| #include <linux/sched/hotplug.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/xive.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 <asm/cpuidle.h> |
| #include <asm/kexec.h> |
| #include <asm/reg.h> |
| #include <asm/powernv.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) |
| { |
| /* |
| * P9 workaround for CI vector load (see traps.c), |
| * enable the corresponding HMI interrupt |
| */ |
| if (pvr_version_is(PVR_POWER9)) |
| mtspr(SPRN_HMEER, mfspr(SPRN_HMEER) | PPC_BIT(17)); |
| |
| if (xive_enabled()) |
| xive_smp_setup_cpu(); |
| else if (cpu != boot_cpuid) |
| xics_setup_cpu(); |
| } |
| |
| static int pnv_smp_kick_cpu(int nr) |
| { |
| unsigned int pcpu; |
| unsigned long start_here = |
| __pa(ppc_function_entry(generic_secondary_smp_init)); |
| long rc; |
| uint8_t status; |
| |
| if (nr < 0 || nr >= nr_cpu_ids) |
| return -EINVAL; |
| |
| pcpu = get_hard_smp_processor_id(nr); |
| /* |
| * If we already started or OPAL is not supported, we just |
| * kick the CPU via the PACA |
| */ |
| if (paca_ptrs[nr]->cpu_start || !firmware_has_feature(FW_FEATURE_OPAL)) |
| 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 |
| */ |
| 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; |
| } |
| |
| 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); |
| if (xive_enabled()) |
| xive_smp_disable_cpu(); |
| else |
| xics_migrate_irqs_away(); |
| return 0; |
| } |
| |
| static void pnv_smp_cpu_kill_self(void) |
| { |
| unsigned int cpu; |
| unsigned long srr1, wmask; |
| u64 lpcr_val; |
| |
| /* Standard hot unplug procedure */ |
| /* |
| * This hard disables local interurpts, ensuring we have no lazy |
| * irqs pending. |
| */ |
| WARN_ON(irqs_disabled()); |
| hard_irq_disable(); |
| WARN_ON(lazy_irq_pending()); |
| |
| 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; |
| |
| /* |
| * We don't want to take decrementer interrupts while we are |
| * offline, so clear LPCR:PECE1. We keep PECE2 (and |
| * LPCR_PECE_HVEE on P9) enabled so as to let IPIs in. |
| * |
| * If the CPU gets woken up by a special wakeup, ensure that |
| * the SLW engine sets LPCR with decrementer bit cleared, else |
| * the CPU will come back to the kernel due to a spurious |
| * wakeup. |
| */ |
| lpcr_val = mfspr(SPRN_LPCR) & ~(u64)LPCR_PECE1; |
| pnv_program_cpu_hotplug_lpcr(cpu, lpcr_val); |
| |
| while (!generic_check_cpu_restart(cpu)) { |
| /* |
| * Clear IPI flag, since we don't handle IPIs while |
| * offline, except for those when changing micro-threading |
| * mode, which are handled explicitly below, and those |
| * for coming online, which are handled via |
| * generic_check_cpu_restart() calls. |
| */ |
| kvmppc_set_host_ipi(cpu, 0); |
| |
| srr1 = pnv_cpu_offline(cpu); |
| |
| WARN_ON(lazy_irq_pending()); |
| |
| /* |
| * 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) || |
| ((srr1 & wmask) == SRR1_WAKEHVI)) { |
| if (cpu_has_feature(CPU_FTR_ARCH_300)) { |
| if (xive_enabled()) |
| xive_flush_interrupt(); |
| else |
| icp_opal_flush_interrupt(); |
| } else |
| icp_native_flush_interrupt(); |
| } else if ((srr1 & wmask) == SRR1_WAKEHDBELL) { |
| unsigned long msg = PPC_DBELL_TYPE(PPC_DBELL_SERVER); |
| asm volatile(PPC_MSGCLR(%0) : : "r" (msg)); |
| } else if ((srr1 & wmask) == SRR1_WAKERESET) { |
| irq_set_pending_from_srr1(srr1); |
| /* Does not return */ |
| } |
| |
| smp_mb(); |
| |
| /* |
| * For kdump kernels, we process the ipi and jump to |
| * crash_ipi_callback |
| */ |
| if (kdump_in_progress()) { |
| /* |
| * If we got to this point, we've not used |
| * NMI's, otherwise we would have gone |
| * via the SRR1_WAKERESET path. We are |
| * using regular IPI's for waking up offline |
| * threads. |
| */ |
| struct pt_regs regs; |
| |
| ppc_save_regs(®s); |
| crash_ipi_callback(®s); |
| /* Does not return */ |
| } |
| |
| if (cpu_core_split_required()) |
| continue; |
| |
| if (srr1 && !generic_check_cpu_restart(cpu)) |
| DBG("CPU%d Unexpected exit while offline srr1=%lx!\n", |
| cpu, srr1); |
| |
| } |
| |
| /* |
| * Re-enable decrementer interrupts in LPCR. |
| * |
| * Further, we want stop states to be woken up by decrementer |
| * for non-hotplug cases. So program the LPCR via stop api as |
| * well. |
| */ |
| lpcr_val = mfspr(SPRN_LPCR) | (u64)LPCR_PECE1; |
| pnv_program_cpu_hotplug_lpcr(cpu, lpcr_val); |
| |
| 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 int pnv_smp_prepare_cpu(int cpu) |
| { |
| if (xive_enabled()) |
| return xive_smp_prepare_cpu(cpu); |
| return 0; |
| } |
| |
| /* Cause IPI as setup by the interrupt controller (xics or xive) */ |
| static void (*ic_cause_ipi)(int cpu); |
| |
| static void pnv_cause_ipi(int cpu) |
| { |
| if (doorbell_try_core_ipi(cpu)) |
| return; |
| |
| ic_cause_ipi(cpu); |
| } |
| |
| static void __init pnv_smp_probe(void) |
| { |
| if (xive_enabled()) |
| xive_smp_probe(); |
| else |
| xics_smp_probe(); |
| |
| if (cpu_has_feature(CPU_FTR_DBELL)) { |
| ic_cause_ipi = smp_ops->cause_ipi; |
| WARN_ON(!ic_cause_ipi); |
| |
| if (cpu_has_feature(CPU_FTR_ARCH_300)) |
| smp_ops->cause_ipi = doorbell_global_ipi; |
| else |
| smp_ops->cause_ipi = pnv_cause_ipi; |
| } |
| } |
| |
| static int pnv_system_reset_exception(struct pt_regs *regs) |
| { |
| if (smp_handle_nmi_ipi(regs)) |
| return 1; |
| return 0; |
| } |
| |
| static int pnv_cause_nmi_ipi(int cpu) |
| { |
| int64_t rc; |
| |
| if (cpu >= 0) { |
| int h = get_hard_smp_processor_id(cpu); |
| |
| if (opal_check_token(OPAL_QUIESCE)) |
| opal_quiesce(QUIESCE_HOLD, h); |
| |
| rc = opal_signal_system_reset(h); |
| |
| if (opal_check_token(OPAL_QUIESCE)) |
| opal_quiesce(QUIESCE_RESUME, h); |
| |
| if (rc != OPAL_SUCCESS) |
| return 0; |
| return 1; |
| |
| } else if (cpu == NMI_IPI_ALL_OTHERS) { |
| bool success = true; |
| int c; |
| |
| if (opal_check_token(OPAL_QUIESCE)) |
| opal_quiesce(QUIESCE_HOLD, -1); |
| |
| /* |
| * We do not use broadcasts (yet), because it's not clear |
| * exactly what semantics Linux wants or the firmware should |
| * provide. |
| */ |
| for_each_online_cpu(c) { |
| if (c == smp_processor_id()) |
| continue; |
| |
| rc = opal_signal_system_reset( |
| get_hard_smp_processor_id(c)); |
| if (rc != OPAL_SUCCESS) |
| success = false; |
| } |
| |
| if (opal_check_token(OPAL_QUIESCE)) |
| opal_quiesce(QUIESCE_RESUME, -1); |
| |
| if (success) |
| return 1; |
| |
| /* |
| * Caller will fall back to doorbells, which may pick |
| * up the remainders. |
| */ |
| } |
| |
| return 0; |
| } |
| |
| static struct smp_ops_t pnv_smp_ops = { |
| .message_pass = NULL, /* Use smp_muxed_ipi_message_pass */ |
| .cause_ipi = NULL, /* Filled at runtime by pnv_smp_probe() */ |
| .cause_nmi_ipi = NULL, |
| .probe = pnv_smp_probe, |
| .prepare_cpu = pnv_smp_prepare_cpu, |
| .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) |
| { |
| if (opal_check_token(OPAL_SIGNAL_SYSTEM_RESET)) { |
| ppc_md.system_reset_exception = pnv_system_reset_exception; |
| pnv_smp_ops.cause_nmi_ipi = pnv_cause_nmi_ipi; |
| } |
| smp_ops = &pnv_smp_ops; |
| |
| #ifdef CONFIG_HOTPLUG_CPU |
| ppc_md.cpu_die = pnv_smp_cpu_kill_self; |
| #ifdef CONFIG_KEXEC_CORE |
| crash_wake_offline = 1; |
| #endif |
| #endif |
| } |