arch/powerpc/platforms/pseries/smp.c

   1 /*
   2  * SMP support for pSeries machines.
   3  *
   4  * Dave Engebretsen, Peter Bergner, and
   5  * Mike Corrigan {engebret|bergner|mikec}@us.ibm.com
   6  *
   7  * Plus various changes from other IBM teams...
   8  *
   9  *      This program is free software; you can redistribute it and/or
  10  *      modify it under the terms of the GNU General Public License
  11  *      as published by the Free Software Foundation; either version
  12  *      2 of the License, or (at your option) any later version.
  13  */
  14
  15
  16 #include <linux/kernel.h>
  17 #include <linux/module.h>
  18 #include <linux/sched.h>
  19 #include <linux/smp.h>
  20 #include <linux/interrupt.h>
  21 #include <linux/delay.h>
  22 #include <linux/init.h>
  23 #include <linux/spinlock.h>
  24 #include <linux/cache.h>
  25 #include <linux/err.h>
  26 #include <linux/sysdev.h>
  27 #include <linux/cpu.h>
  28
  29 #include <asm/ptrace.h>
  30 #include <asm/atomic.h>
  31 #include <asm/irq.h>
  32 #include <asm/page.h>
  33 #include <asm/pgtable.h>
  34 #include <asm/io.h>
  35 #include <asm/prom.h>
  36 #include <asm/smp.h>
  37 #include <asm/paca.h>
  38 #include <asm/machdep.h>
  39 #include <asm/cputable.h>
  40 #include <asm/firmware.h>
  41 #include <asm/system.h>
  42 #include <asm/rtas.h>
  43 #include <asm/pSeries_reconfig.h>
  44 #include <asm/mpic.h>
  45 #include <asm/vdso_datapage.h>
  46 #include <asm/cputhreads.h>
  47
  48 #include "plpar_wrappers.h"
  49 #include "pseries.h"
  50 #include "xics.h"
  51 #include "offline_states.h"
  52
  53
  54 /*
  55  * The Primary thread of each non-boot processor was started from the OF client
  56  * interface by prom_hold_cpus and is spinning on secondary_hold_spinloop.
  57  */
  58 static cpumask_t of_spin_map;
  59
  60 /**
  61  * smp_startup_cpu() - start the given cpu
  62  *
  63  * At boot time, there is nothing to do for primary threads which were
  64  * started from Open Firmware.  For anything else, call RTAS with the
  65  * appropriate start location.
  66  *
  67  * Returns:
  68  *      0       - failure
  69  *      1       - success
  70  */
  71 static inline int __devinit smp_startup_cpu(unsigned int lcpu)
  72 {
  73         int status;
  74         unsigned long start_here = __pa((u32)*((unsigned long *)
  75                                                generic_secondary_smp_init));
  76         unsigned int pcpu;
  77         int start_cpu;
  78
  79         if (cpu_isset(lcpu, of_spin_map))
  80                 /* Already started by OF and sitting in spin loop */
  81                 return 1;
  82
  83         pcpu = get_hard_smp_processor_id(lcpu);
  84
  85         /* Fixup atomic count: it exited inside IRQ handler. */
  86         task_thread_info(paca[lcpu].__current)->preempt_count   = 0;
  87
  88         if (get_cpu_current_state(lcpu) == CPU_STATE_INACTIVE)
  89                 goto out;
  90
  91         /*
  92          * If the RTAS start-cpu token does not exist then presume the
  93          * cpu is already spinning.
  94          */
  95         start_cpu = rtas_token("start-cpu");
  96         if (start_cpu == RTAS_UNKNOWN_SERVICE)
  97                 return 1;
  98
  99         status = rtas_call(start_cpu, 3, 1, NULL, pcpu, start_here, pcpu);
 100         if (status != 0) {
 101                 printk(KERN_ERR "start-cpu failed: %i\n", status);
 102                 return 0;
 103         }
 104
 105 out:
 106         return 1;
 107 }
 108
 109 #ifdef CONFIG_XICS
 110 static void __devinit smp_xics_setup_cpu(int cpu)
 111 {
 112         if (cpu != boot_cpuid)
 113                 xics_setup_cpu();
 114
 115         if (firmware_has_feature(FW_FEATURE_SPLPAR))
 116                 vpa_init(cpu);
 117
 118         cpu_clear(cpu, of_spin_map);
 119         set_cpu_current_state(cpu, CPU_STATE_ONLINE);
 120         set_default_offline_state(cpu);
 121
 122 }
 123 #endif /* CONFIG_XICS */
 124
 125 static void __devinit smp_pSeries_kick_cpu(int nr)
 126 {
 127         long rc;
 128         unsigned long hcpuid;
 129         BUG_ON(nr < 0 || nr >= NR_CPUS);
 130
 131         if (!smp_startup_cpu(nr))
 132                 return;
 133
 134         /*
 135          * The processor is currently spinning, waiting for the
 136          * cpu_start field to become non-zero After we set cpu_start,
 137          * the processor will continue on to secondary_start
 138          */
 139         paca[nr].cpu_start = 1;
 140
 141         set_preferred_offline_state(nr, CPU_STATE_ONLINE);
 142
 143         if (get_cpu_current_state(nr) == CPU_STATE_INACTIVE) {
 144                 hcpuid = get_hard_smp_processor_id(nr);
 145                 rc = plpar_hcall_norets(H_PROD, hcpuid);
 146                 if (rc != H_SUCCESS)
 147                         printk(KERN_ERR "Error: Prod to wake up processor %d\
 148                                                 Ret= %ld\n", nr, rc);
 149         }
 150 }
 151
 152 static int smp_pSeries_cpu_bootable(unsigned int nr)
 153 {
 154         /* Special case - we inhibit secondary thread startup
 155          * during boot if the user requests it.
 156          */
 157         if (system_state < SYSTEM_RUNNING &&
 158             cpu_has_feature(CPU_FTR_SMT) &&
 159             !smt_enabled_at_boot && cpu_thread_in_core(nr) != 0)
 160                 return 0;
 161
 162         return 1;
 163 }
 164 #ifdef CONFIG_MPIC
 165 static struct smp_ops_t pSeries_mpic_smp_ops = {
 166         .message_pass   = smp_mpic_message_pass,
 167         .probe          = smp_mpic_probe,
 168         .kick_cpu       = smp_pSeries_kick_cpu,
 169         .setup_cpu      = smp_mpic_setup_cpu,
 170 };
 171 #endif
 172 #ifdef CONFIG_XICS
 173 static struct smp_ops_t pSeries_xics_smp_ops = {
 174         .message_pass   = smp_xics_message_pass,
 175         .probe          = smp_xics_probe,
 176         .kick_cpu       = smp_pSeries_kick_cpu,
 177         .setup_cpu      = smp_xics_setup_cpu,
 178         .cpu_bootable   = smp_pSeries_cpu_bootable,
 179 };
 180 #endif
 181
 182 /* This is called very early */
 183 static void __init smp_init_pseries(void)
 184 {
 185         int i;
 186
 187         pr_debug(" -> smp_init_pSeries()\n");
 188
 189         /* Mark threads which are still spinning in hold loops. */
 190         if (cpu_has_feature(CPU_FTR_SMT)) {
 191                 for_each_present_cpu(i) {
 192                         if (cpu_thread_in_core(i) == 0)
 193                                 cpu_set(i, of_spin_map);
 194                 }
 195         } else {
 196                 of_spin_map = cpu_present_map;
 197         }
 198
 199         cpu_clear(boot_cpuid, of_spin_map);
 200
 201         /* Non-lpar has additional take/give timebase */
 202         if (rtas_token("freeze-time-base") != RTAS_UNKNOWN_SERVICE) {
 203                 smp_ops->give_timebase = rtas_give_timebase;
 204                 smp_ops->take_timebase = rtas_take_timebase;
 205         }
 206
 207         pr_debug(" <- smp_init_pSeries()\n");
 208 }
 209
 210 #ifdef CONFIG_MPIC
 211 void __init smp_init_pseries_mpic(void)
 212 {
 213         smp_ops = &pSeries_mpic_smp_ops;
 214
 215         smp_init_pseries();
 216 }
 217 #endif
 218
 219 void __init smp_init_pseries_xics(void)
 220 {
 221         smp_ops = &pSeries_xics_smp_ops;
 222
 223         smp_init_pseries();
 224 }