diff options
Diffstat (limited to 'kernel/arch/powerpc/platforms/pseries/smp.c')
-rw-r--r-- | kernel/arch/powerpc/platforms/pseries/smp.c | 274 |
1 files changed, 274 insertions, 0 deletions
diff --git a/kernel/arch/powerpc/platforms/pseries/smp.c b/kernel/arch/powerpc/platforms/pseries/smp.c new file mode 100644 index 000000000..6932ea803 --- /dev/null +++ b/kernel/arch/powerpc/platforms/pseries/smp.c @@ -0,0 +1,274 @@ +/* + * 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 void pSeries_smp_probe(void) +{ + 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; + } +} + +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(); +} |