/* * SMP support for pSeries machines. * * Dave Engebretsen, Peter Bergner, and * Mike Corrigan {engebret|bergner|mikec}@us.ibm.com * * Plus various changes from other IBM teams... * * 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/sched.h> #include <linux/smp.h> #include <linux/interrupt.h> #include <linux/delay.h> #include <linux/init.h> #include <linux/spinlock.h> #include <linux/cache.h> #include <linux/err.h> #include <linux/device.h> #include <linux/cpu.h> #include <asm/ptrace.h> #include <linux/atomic.h> #include <asm/irq.h> #include <asm/page.h> #include <asm/pgtable.h> #include <asm/io.h> #include <asm/prom.h> #include <asm/smp.h> #include <asm/paca.h> #include <asm/machdep.h> #include <asm/cputable.h> #include <asm/firmware.h> #include <asm/rtas.h> #include <asm/mpic.h> #include <asm/vdso_datapage.h> #include <asm/cputhreads.h> #include <asm/xics.h> #include <asm/dbell.h> #include <asm/plpar_wrappers.h> #include <asm/code-patching.h> #include "pseries.h" #include "offline_states.h" /* * The Primary thread of each non-boot processor was started from the OF client * interface by prom_hold_cpus and is spinning on secondary_hold_spinloop. */ static cpumask_var_t of_spin_mask; /* * If we multiplex IPI mechanisms, store the appropriate XICS IPI mechanism here */ static void (*xics_cause_ipi)(int cpu, unsigned long data); /* Query where a cpu is now. Return codes #defined in plpar_wrappers.h */ int smp_query_cpu_stopped(unsigned int pcpu) { int cpu_status, status; int qcss_tok = rtas_token("query-cpu-stopped-state"); if (qcss_tok == RTAS_UNKNOWN_SERVICE) { printk_once(KERN_INFO "Firmware doesn't support query-cpu-stopped-state\n"); return QCSS_HARDWARE_ERROR; } status = rtas_call(qcss_tok, 1, 2, &cpu_status, pcpu); if (status != 0) { printk(KERN_ERR "RTAS query-cpu-stopped-state failed: %i\n", status); return status; } return cpu_status; } /** * smp_startup_cpu() - start the given cpu * * At boot time, there is nothing to do for primary threads which were * started from Open Firmware. For anything else, call RTAS with the * appropriate start location. * * Returns: * 0 - failure * 1 - success */ static inline int smp_startup_cpu(unsigned int lcpu) { int status; unsigned long start_here = __pa(ppc_function_entry(generic_secondary_smp_init)); unsigned int pcpu; int start_cpu; if (cpumask_test_cpu(lcpu, of_spin_mask)) /* Already started by OF and sitting in spin loop */ return 1; pcpu = get_hard_smp_processor_id(lcpu); /* Check to see if the CPU out of FW already for kexec */ if (smp_query_cpu_stopped(pcpu) == QCSS_NOT_STOPPED){ cpumask_set_cpu(lcpu, of_spin_mask); return 1; } /* Fixup atomic count: it exited inside IRQ handler. */ task_thread_info(paca[lcpu].__current)->preempt_count = 0; #ifdef CONFIG_HOTPLUG_CPU if (get_cpu_current_state(lcpu) == CPU_STATE_INACTIVE) goto out; #endif /* * If the RTAS start-cpu token does not exist then presume the * cpu is already spinning. */ start_cpu = rtas_token("start-cpu"); if (start_cpu == RTAS_UNKNOWN_SERVICE) return 1; status = rtas_call(start_cpu, 3, 1, NULL, pcpu, start_here, pcpu); if (status != 0) { printk(KERN_ERR "start-cpu failed: %i\n", status); return 0; } #ifdef CONFIG_HOTPLUG_CPU out: #endif return 1; } static void smp_xics_setup_cpu(int cpu) { if (cpu != boot_cpuid) xics_setup_cpu(); if (cpu_has_feature(CPU_FTR_DBELL)) doorbell_setup_this_cpu(); if (firmware_has_feature(FW_FEATURE_SPLPAR)) vpa_init(cpu); cpumask_clear_cpu(cpu, of_spin_mask); #ifdef CONFIG_HOTPLUG_CPU set_cpu_current_state(cpu, CPU_STATE_ONLINE); set_default_offline_state(cpu); #endif } static int smp_pSeries_kick_cpu(int nr) { BUG_ON(nr < 0 || nr >= NR_CPUS); if (!smp_startup_cpu(nr)) return -ENOENT; /* * The processor is currently spinning, waiting for the * cpu_start field to become non-zero After we set cpu_start, * the processor will continue on to secondary_start */ paca[nr].cpu_start = 1; #ifdef CONFIG_HOTPLUG_CPU set_preferred_offline_state(nr, CPU_STATE_ONLINE); if (get_cpu_current_state(nr) == CPU_STATE_INACTIVE) { long rc; unsigned long hcpuid; hcpuid = get_hard_smp_processor_id(nr); rc = plpar_hcall_norets(H_PROD, hcpuid); if (rc != H_SUCCESS) printk(KERN_ERR "Error: Prod to wake up processor %d " "Ret= %ld\n", nr, rc); } #endif return 0; } /* Only used on systems that support multiple IPI mechanisms */ static void pSeries_cause_ipi_mux(int cpu, unsigned long data) { if (cpumask_test_cpu(cpu, cpu_sibling_mask(smp_processor_id()))) doorbell_cause_ipi(cpu, data); else xics_cause_ipi(cpu, data); } static __init int pSeries_smp_probe(void) { int ret = xics_smp_probe(); if (cpu_has_feature(CPU_FTR_DBELL)) { xics_cause_ipi = smp_ops->cause_ipi; smp_ops->cause_ipi = pSeries_cause_ipi_mux; } return ret; } static struct smp_ops_t pSeries_mpic_smp_ops = { .message_pass = smp_mpic_message_pass, .probe = smp_mpic_probe, .kick_cpu = smp_pSeries_kick_cpu, .setup_cpu = smp_mpic_setup_cpu, }; static struct smp_ops_t pSeries_xics_smp_ops = { .message_pass = NULL, /* Use smp_muxed_ipi_message_pass */ .cause_ipi = NULL, /* Filled at runtime by pSeries_smp_probe() */ .probe = pSeries_smp_probe, .kick_cpu = smp_pSeries_kick_cpu, .setup_cpu = smp_xics_setup_cpu, .cpu_bootable = smp_generic_cpu_bootable, }; /* This is called very early */ static void __init smp_init_pseries(void) { int i; pr_debug(" -> smp_init_pSeries()\n"); alloc_bootmem_cpumask_var(&of_spin_mask); /* * Mark threads which are still spinning in hold loops * * We know prom_init will not have started them if RTAS supports * query-cpu-stopped-state. */ if (rtas_token("query-cpu-stopped-state") == RTAS_UNKNOWN_SERVICE) { if (cpu_has_feature(CPU_FTR_SMT)) { for_each_present_cpu(i) { if (cpu_thread_in_core(i) == 0) cpumask_set_cpu(i, of_spin_mask); } } else cpumask_copy(of_spin_mask, cpu_present_mask); cpumask_clear_cpu(boot_cpuid, of_spin_mask); } /* Non-lpar has additional take/give timebase */ if (rtas_token("freeze-time-base") != RTAS_UNKNOWN_SERVICE) { smp_ops->give_timebase = rtas_give_timebase; smp_ops->take_timebase = rtas_take_timebase; } pr_debug(" <- smp_init_pSeries()\n"); } void __init smp_init_pseries_mpic(void) { smp_ops = &pSeries_mpic_smp_ops; smp_init_pseries(); } void __init smp_init_pseries_xics(void) { smp_ops = &pSeries_xics_smp_ops; smp_init_pseries(); }