arch/ia64/kernel/smp.c

   1 /*
   2  * SMP Support
   3  *
   4  * Copyright (C) 1999 Walt Drummond <drummond@valinux.com>
   5  * Copyright (C) 1999, 2001, 2003 David Mosberger-Tang <davidm@hpl.hp.com>
   6  *
   7  * Lots of stuff stolen from arch/alpha/kernel/smp.c
   8  *
   9  * 01/05/16 Rohit Seth <rohit.seth@intel.com>  IA64-SMP functions. Reorganized
  10  * the existing code (on the lines of x86 port).
  11  * 00/09/11 David Mosberger <davidm@hpl.hp.com> Do loops_per_jiffy
  12  * calibration on each CPU.
  13  * 00/08/23 Asit Mallick <asit.k.mallick@intel.com> fixed logical processor id
  14  * 00/03/31 Rohit Seth <rohit.seth@intel.com>   Fixes for Bootstrap Processor
  15  * & cpu_online_map now gets done here (instead of setup.c)
  16  * 99/10/05 davidm      Update to bring it in sync with new command-line processing
  17  *  scheme.
  18  * 10/13/00 Goutham Rao <goutham.rao@intel.com> Updated smp_call_function and
  19  *              smp_call_function_single to resend IPI on timeouts
  20  */
  21 #include <linux/module.h>
  22 #include <linux/kernel.h>
  23 #include <linux/sched.h>
  24 #include <linux/init.h>
  25 #include <linux/interrupt.h>
  26 #include <linux/smp.h>
  27 #include <linux/kernel_stat.h>
  28 #include <linux/mm.h>
  29 #include <linux/cache.h>
  30 #include <linux/delay.h>
  31 #include <linux/efi.h>
  32 #include <linux/bitops.h>
  33 #include <linux/kexec.h>
  34
  35 #include <asm/atomic.h>
  36 #include <asm/current.h>
  37 #include <asm/delay.h>
  38 #include <asm/machvec.h>
  39 #include <asm/io.h>
  40 #include <asm/irq.h>
  41 #include <asm/page.h>
  42 #include <asm/pgalloc.h>
  43 #include <asm/pgtable.h>
  44 #include <asm/processor.h>
  45 #include <asm/ptrace.h>
  46 #include <asm/sal.h>
  47 #include <asm/system.h>
  48 #include <asm/tlbflush.h>
  49 #include <asm/unistd.h>
  50 #include <asm/mca.h>
  51
  52 /*
  53  * Note: alignment of 4 entries/cacheline was empirically determined
  54  * to be a good tradeoff between hot cachelines & spreading the array
  55  * across too many cacheline.
  56  */
  57 static struct local_tlb_flush_counts {
  58         unsigned int count;
  59 } __attribute__((__aligned__(32))) local_tlb_flush_counts[NR_CPUS];
  60
  61 static DEFINE_PER_CPU_SHARED_ALIGNED(unsigned short [NR_CPUS],
  62                                      shadow_flush_counts);
  63
  64 #define IPI_CALL_FUNC           0
  65 #define IPI_CPU_STOP            1
  66 #define IPI_CALL_FUNC_SINGLE    2
  67 #define IPI_KDUMP_CPU_STOP      3
  68
  69 /* This needs to be cacheline aligned because it is written to by *other* CPUs.  */
  70 static DEFINE_PER_CPU_SHARED_ALIGNED(unsigned long, ipi_operation);
  71
  72 extern void cpu_halt (void);
  73
  74 static void
  75 stop_this_cpu(void)
  76 {
  77         /*
  78          * Remove this CPU:
  79          */
  80         cpu_clear(smp_processor_id(), cpu_online_map);
  81         max_xtp();
  82         local_irq_disable();
  83         cpu_halt();
  84 }
  85
  86 void
  87 cpu_die(void)
  88 {
  89         max_xtp();
  90         local_irq_disable();
  91         cpu_halt();
  92         /* Should never be here */
  93         BUG();
  94         for (;;);
  95 }
  96
  97 irqreturn_t
  98 handle_IPI (int irq, void *dev_id)
  99 {
 100         int this_cpu = get_cpu();
 101         unsigned long *pending_ipis = &__ia64_per_cpu_var(ipi_operation);
 102         unsigned long ops;
 103
 104         mb();   /* Order interrupt and bit testing. */
 105         while ((ops = xchg(pending_ipis, 0)) != 0) {
 106                 mb();   /* Order bit clearing and data access. */
 107                 do {
 108                         unsigned long which;
 109
 110                         which = ffz(~ops);
 111                         ops &= ~(1 << which);
 112
 113                         switch (which) {
 114                         case IPI_CPU_STOP:
 115                                 stop_this_cpu();
 116                                 break;
 117                         case IPI_CALL_FUNC:
 118                                 generic_smp_call_function_interrupt();
 119                                 break;
 120                         case IPI_CALL_FUNC_SINGLE:
 121                                 generic_smp_call_function_single_interrupt();
 122                                 break;
 123 #ifdef CONFIG_KEXEC
 124                         case IPI_KDUMP_CPU_STOP:
 125                                 unw_init_running(kdump_cpu_freeze, NULL);
 126                                 break;
 127 #endif
 128                         default:
 129                                 printk(KERN_CRIT "Unknown IPI on CPU %d: %lu\n",
 130                                                 this_cpu, which);
 131                                 break;
 132                         }
 133                 } while (ops);
 134                 mb();   /* Order data access and bit testing. */
 135         }
 136         put_cpu();
 137         return IRQ_HANDLED;
 138 }
 139
 140
 141
 142 /*
 143  * Called with preemption disabled.
 144  */
 145 static inline void
 146 send_IPI_single (int dest_cpu, int op)
 147 {
 148         set_bit(op, &per_cpu(ipi_operation, dest_cpu));
 149         platform_send_ipi(dest_cpu, IA64_IPI_VECTOR, IA64_IPI_DM_INT, 0);
 150 }
 151
 152 /*
 153  * Called with preemption disabled.
 154  */
 155 static inline void
 156 send_IPI_allbutself (int op)
 157 {
 158         unsigned int i;
 159
 160         for_each_online_cpu(i) {
 161                 if (i != smp_processor_id())
 162                         send_IPI_single(i, op);
 163         }
 164 }
 165
 166 /*
 167  * Called with preemption disabled.
 168  */
 169 static inline void
 170 send_IPI_mask(const struct cpumask *mask, int op)
 171 {
 172         unsigned int cpu;
 173
 174         for_each_cpu(cpu, mask) {
 175                         send_IPI_single(cpu, op);
 176         }
 177 }
 178
 179 /*
 180  * Called with preemption disabled.
 181  */
 182 static inline void
 183 send_IPI_all (int op)
 184 {
 185         int i;
 186
 187         for_each_online_cpu(i) {
 188                 send_IPI_single(i, op);
 189         }
 190 }
 191
 192 /*
 193  * Called with preemption disabled.
 194  */
 195 static inline void
 196 send_IPI_self (int op)
 197 {
 198         send_IPI_single(smp_processor_id(), op);
 199 }
 200
 201 #ifdef CONFIG_KEXEC
 202 void
 203 kdump_smp_send_stop(void)
 204 {
 205         send_IPI_allbutself(IPI_KDUMP_CPU_STOP);
 206 }
 207
 208 void
 209 kdump_smp_send_init(void)
 210 {
 211         unsigned int cpu, self_cpu;
 212         self_cpu = smp_processor_id();
 213         for_each_online_cpu(cpu) {
 214                 if (cpu != self_cpu) {
 215                         if(kdump_status[cpu] == 0)
 216                                 platform_send_ipi(cpu, 0, IA64_IPI_DM_INIT, 0);
 217                 }
 218         }
 219 }
 220 #endif
 221 /*
 222  * Called with preemption disabled.
 223  */
 224 void
 225 smp_send_reschedule (int cpu)
 226 {
 227         platform_send_ipi(cpu, IA64_IPI_RESCHEDULE, IA64_IPI_DM_INT, 0);
 228 }
 229 EXPORT_SYMBOL_GPL(smp_send_reschedule);
 230
 231 /*
 232  * Called with preemption disabled.
 233  */
 234 static void
 235 smp_send_local_flush_tlb (int cpu)
 236 {
 237         platform_send_ipi(cpu, IA64_IPI_LOCAL_TLB_FLUSH, IA64_IPI_DM_INT, 0);
 238 }
 239
 240 void
 241 smp_local_flush_tlb(void)
 242 {
 243         /*
 244          * Use atomic ops. Otherwise, the load/increment/store sequence from
 245          * a "++" operation can have the line stolen between the load & store.
 246          * The overhead of the atomic op in negligible in this case & offers
 247          * significant benefit for the brief periods where lots of cpus
 248          * are simultaneously flushing TLBs.
 249          */
 250         ia64_fetchadd(1, &local_tlb_flush_counts[smp_processor_id()].count, acq);
 251         local_flush_tlb_all();
 252 }
 253
 254 #define FLUSH_DELAY     5 /* Usec backoff to eliminate excessive cacheline bouncing */
 255
 256 void
 257 smp_flush_tlb_cpumask(cpumask_t xcpumask)
 258 {
 259         unsigned short *counts = __ia64_per_cpu_var(shadow_flush_counts);
 260         cpumask_t cpumask = xcpumask;
 261         int mycpu, cpu, flush_mycpu = 0;
 262
 263         preempt_disable();
 264         mycpu = smp_processor_id();
 265
 266         for_each_cpu_mask(cpu, cpumask)
 267                 counts[cpu] = local_tlb_flush_counts[cpu].count & 0xffff;
 268
 269         mb();
 270         for_each_cpu_mask(cpu, cpumask) {
 271                 if (cpu == mycpu)
 272                         flush_mycpu = 1;
 273                 else
 274                         smp_send_local_flush_tlb(cpu);
 275         }
 276
 277         if (flush_mycpu)
 278                 smp_local_flush_tlb();
 279
 280         for_each_cpu_mask(cpu, cpumask)
 281                 while(counts[cpu] == (local_tlb_flush_counts[cpu].count & 0xffff))
 282                         udelay(FLUSH_DELAY);
 283
 284         preempt_enable();
 285 }
 286
 287 void
 288 smp_flush_tlb_all (void)
 289 {
 290         on_each_cpu((void (*)(void *))local_flush_tlb_all, NULL, 1);
 291 }
 292
 293 void
 294 smp_flush_tlb_mm (struct mm_struct *mm)
 295 {
 296         preempt_disable();
 297         /* this happens for the common case of a single-threaded fork():  */
 298         if (likely(mm == current->active_mm && atomic_read(&mm->mm_users) == 1))
 299         {
 300                 local_finish_flush_tlb_mm(mm);
 301                 preempt_enable();
 302                 return;
 303         }
 304
 305         smp_call_function_many(mm_cpumask(mm),
 306                 (void (*)(void *))local_finish_flush_tlb_mm, mm, 1);
 307         local_irq_disable();
 308         local_finish_flush_tlb_mm(mm);
 309         local_irq_enable();
 310         preempt_enable();
 311 }
 312
 313 void arch_send_call_function_single_ipi(int cpu)
 314 {
 315         send_IPI_single(cpu, IPI_CALL_FUNC_SINGLE);
 316 }
 317
 318 void arch_send_call_function_ipi_mask(const struct cpumask *mask)
 319 {
 320         send_IPI_mask(mask, IPI_CALL_FUNC);
 321 }
 322
 323 /*
 324  * this function calls the 'stop' function on all other CPUs in the system.
 325  */
 326 void
 327 smp_send_stop (void)
 328 {
 329         send_IPI_allbutself(IPI_CPU_STOP);
 330 }
 331
 332 int
 333 setup_profiling_timer (unsigned int multiplier)
 334 {
 335         return -EINVAL;
 336 }