SAFE public projects git trees. - safe/jmp/linux-2.6/blob - 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 #undef DEBUG
  16
  17 #include <linux/kernel.h>
  18 #include <linux/module.h>
  19 #include <linux/sched.h>
  20 #include <linux/smp.h>
  21 #include <linux/interrupt.h>
  22 #include <linux/delay.h>
  23 #include <linux/init.h>
  24 #include <linux/spinlock.h>
  25 #include <linux/cache.h>
  26 #include <linux/err.h>
  27 #include <linux/sysdev.h>
  28 #include <linux/cpu.h>
  29
  30 #include <asm/ptrace.h>
  31 #include <asm/atomic.h>
  32 #include <asm/irq.h>
  33 #include <asm/page.h>
  34 #include <asm/pgtable.h>
  35 #include <asm/io.h>
  36 #include <asm/prom.h>
  37 #include <asm/smp.h>
  38 #include <asm/paca.h>
  39 #include <asm/time.h>
  40 #include <asm/machdep.h>
  41 #include "xics.h"
  42 #include <asm/cputable.h>
  43 #include <asm/firmware.h>
  44 #include <asm/system.h>
  45 #include <asm/rtas.h>
  46 #include <asm/pSeries_reconfig.h>
  47 #include <asm/mpic.h>
  48 #include <asm/vdso_datapage.h>
  49 #include <asm/cputhreads.h>
  50
  51 #include "plpar_wrappers.h"
  52 #include "pseries.h"
  53
  54
  55 /*
  56  * The primary thread of each non-boot processor is recorded here before
  57  * smp init.
  58  */
  59 static cpumask_t of_spin_map;
  60
  61 extern void generic_secondary_smp_init(unsigned long);
  62
  63 /**
  64  * smp_startup_cpu() - start the given cpu
  65  *
  66  * At boot time, there is nothing to do for primary threads which were
  67  * started from Open Firmware.  For anything else, call RTAS with the
  68  * appropriate start location.
  69  *
  70  * Returns:
  71  *      0       - failure
  72  *      1       - success
  73  */
  74 static inline int __devinit smp_startup_cpu(unsigned int lcpu)
  75 {
  76         int status;
  77         unsigned long start_here = __pa((u32)*((unsigned long *)
  78                                                generic_secondary_smp_init));
  79         unsigned int pcpu;
  80         int start_cpu;
  81
  82         if (cpu_isset(lcpu, of_spin_map))
  83                 /* Already started by OF and sitting in spin loop */
  84                 return 1;
  85
  86         pcpu = get_hard_smp_processor_id(lcpu);
  87
  88         /* Fixup atomic count: it exited inside IRQ handler. */
  89         task_thread_info(paca[lcpu].__current)->preempt_count   = 0;
  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         return 1;
 106 }
 107
 108 #ifdef CONFIG_XICS
 109 static inline void smp_xics_do_message(int cpu, int msg)
 110 {
 111         set_bit(msg, &xics_ipi_message[cpu].value);
 112         mb();
 113         xics_cause_IPI(cpu);
 114 }
 115
 116 static void smp_xics_message_pass(int target, int msg)
 117 {
 118         unsigned int i;
 119
 120         if (target < NR_CPUS) {
 121                 smp_xics_do_message(target, msg);
 122         } else {
 123                 for_each_online_cpu(i) {
 124                         if (target == MSG_ALL_BUT_SELF
 125                             && i == smp_processor_id())
 126                                 continue;
 127                         smp_xics_do_message(i, msg);
 128                 }
 129         }
 130 }
 131
 132 static int __init smp_xics_probe(void)
 133 {
 134         xics_request_IPIs();
 135
 136         return cpus_weight(cpu_possible_map);
 137 }
 138
 139 static void __devinit smp_xics_setup_cpu(int cpu)
 140 {
 141         if (cpu != boot_cpuid)
 142                 xics_setup_cpu();
 143
 144         if (firmware_has_feature(FW_FEATURE_SPLPAR))
 145                 vpa_init(cpu);
 146
 147         cpu_clear(cpu, of_spin_map);
 148
 149 }
 150 #endif /* CONFIG_XICS */
 151
 152 static DEFINE_SPINLOCK(timebase_lock);
 153 static unsigned long timebase = 0;
 154
 155 static void __devinit pSeries_give_timebase(void)
 156 {
 157         spin_lock(&timebase_lock);
 158         rtas_call(rtas_token("freeze-time-base"), 0, 1, NULL);
 159         timebase = get_tb();
 160         spin_unlock(&timebase_lock);
 161
 162         while (timebase)
 163                 barrier();
 164         rtas_call(rtas_token("thaw-time-base"), 0, 1, NULL);
 165 }
 166
 167 static void __devinit pSeries_take_timebase(void)
 168 {
 169         while (!timebase)
 170                 barrier();
 171         spin_lock(&timebase_lock);
 172         set_tb(timebase >> 32, timebase & 0xffffffff);
 173         timebase = 0;
 174         spin_unlock(&timebase_lock);
 175 }
 176
 177 static void __devinit smp_pSeries_kick_cpu(int nr)
 178 {
 179         BUG_ON(nr < 0 || nr >= NR_CPUS);
 180
 181         if (!smp_startup_cpu(nr))
 182                 return;
 183
 184         /*
 185          * The processor is currently spinning, waiting for the
 186          * cpu_start field to become non-zero After we set cpu_start,
 187          * the processor will continue on to secondary_start
 188          */
 189         paca[nr].cpu_start = 1;
 190 }
 191
 192 static int smp_pSeries_cpu_bootable(unsigned int nr)
 193 {
 194         /* Special case - we inhibit secondary thread startup
 195          * during boot if the user requests it.  Odd-numbered
 196          * cpus are assumed to be secondary threads.
 197          */
 198         if (system_state < SYSTEM_RUNNING &&
 199             cpu_has_feature(CPU_FTR_SMT) &&
 200             !smt_enabled_at_boot && cpu_thread_in_core(nr) != 0)
 201                 return 0;
 202
 203         return 1;
 204 }
 205 #ifdef CONFIG_MPIC
 206 static struct smp_ops_t pSeries_mpic_smp_ops = {
 207         .message_pass   = smp_mpic_message_pass,
 208         .probe          = smp_mpic_probe,
 209         .kick_cpu       = smp_pSeries_kick_cpu,
 210         .setup_cpu      = smp_mpic_setup_cpu,
 211 };
 212 #endif
 213 #ifdef CONFIG_XICS
 214 static struct smp_ops_t pSeries_xics_smp_ops = {
 215         .message_pass   = smp_xics_message_pass,
 216         .probe          = smp_xics_probe,
 217         .kick_cpu       = smp_pSeries_kick_cpu,
 218         .setup_cpu      = smp_xics_setup_cpu,
 219         .cpu_bootable   = smp_pSeries_cpu_bootable,
 220 };
 221 #endif
 222
 223 /* This is called very early */
 224 static void __init smp_init_pseries(void)
 225 {
 226         int i;
 227
 228         pr_debug(" -> smp_init_pSeries()\n");
 229
 230         /* Mark threads which are still spinning in hold loops. */
 231         if (cpu_has_feature(CPU_FTR_SMT)) {
 232                 for_each_present_cpu(i) {
 233                         if (i % 2 == 0)
 234                                 /*
 235                                  * Even-numbered logical cpus correspond to
 236                                  * primary threads.
 237                                  */
 238                                 cpu_set(i, of_spin_map);
 239                 }
 240         } else {
 241                 of_spin_map = cpu_present_map;
 242         }
 243
 244         cpu_clear(boot_cpuid, of_spin_map);
 245
 246         /* Non-lpar has additional take/give timebase */
 247         if (rtas_token("freeze-time-base") != RTAS_UNKNOWN_SERVICE) {
 248                 smp_ops->give_timebase = pSeries_give_timebase;
 249                 smp_ops->take_timebase = pSeries_take_timebase;
 250         }
 251
 252         pr_debug(" <- smp_init_pSeries()\n");
 253 }
 254
 255 #ifdef CONFIG_MPIC
 256 void __init smp_init_pseries_mpic(void)
 257 {
 258         smp_ops = &pSeries_mpic_smp_ops;
 259
 260         smp_init_pseries();
 261 }
 262 #endif
 263
 264 void __init smp_init_pseries_xics(void)
 265 {
 266         smp_ops = &pSeries_xics_smp_ops;
 267
 268         smp_init_pseries();
 269 }