arch/cris/arch-v32/kernel/smp.c

   1 #include <linux/types.h>
   2 #include <asm/delay.h>
   3 #include <irq.h>
   4 #include <hwregs/intr_vect.h>
   5 #include <hwregs/intr_vect_defs.h>
   6 #include <asm/tlbflush.h>
   7 #include <asm/mmu_context.h>
   8 #include <hwregs/asm/mmu_defs_asm.h>
   9 #include <hwregs/supp_reg.h>
  10 #include <linux/atomic.h>
  11
  12 #include <linux/err.h>
  13 #include <linux/init.h>
  14 #include <linux/timex.h>
  15 #include <linux/sched.h>
  16 #include <linux/kernel.h>
  17 #include <linux/cpumask.h>
  18 #include <linux/interrupt.h>
  19 #include <linux/module.h>
  20
  21 #define IPI_SCHEDULE 1
  22 #define IPI_CALL 2
  23 #define IPI_FLUSH_TLB 4
  24 #define IPI_BOOT 8
  25
  26 #define FLUSH_ALL (void*)0xffffffff
  27
  28 /* Vector of locks used for various atomic operations */
  29 spinlock_t cris_atomic_locks[] = {
  30         [0 ... LOCK_COUNT - 1] = __SPIN_LOCK_UNLOCKED(cris_atomic_locks)
  31 };
  32
  33 /* CPU masks */
  34 cpumask_t phys_cpu_present_map = CPU_MASK_NONE;
  35 EXPORT_SYMBOL(phys_cpu_present_map);
  36
  37 /* Variables used during SMP boot */
  38 volatile int cpu_now_booting = 0;
  39 volatile struct thread_info *smp_init_current_idle_thread;
  40
  41 /* Variables used during IPI */
  42 static DEFINE_SPINLOCK(call_lock);
  43 static DEFINE_SPINLOCK(tlbstate_lock);
  44
  45 struct call_data_struct {
  46         void (*func) (void *info);
  47         void *info;
  48         int wait;
  49 };
  50
  51 static struct call_data_struct * call_data;
  52
  53 static struct mm_struct* flush_mm;
  54 static struct vm_area_struct* flush_vma;
  55 static unsigned long flush_addr;
  56
  57 /* Mode registers */
  58 static unsigned long irq_regs[NR_CPUS] = {
  59   regi_irq,
  60   regi_irq2
  61 };
  62
  63 static irqreturn_t crisv32_ipi_interrupt(int irq, void *dev_id);
  64 static int send_ipi(int vector, int wait, cpumask_t cpu_mask);
  65 static struct irqaction irq_ipi  = {
  66         .handler = crisv32_ipi_interrupt,
  67         .flags = IRQF_DISABLED,
  68         .name = "ipi",
  69 };
  70
  71 extern void cris_mmu_init(void);
  72 extern void cris_timer_init(void);
  73
  74 /* SMP initialization */
  75 void __init smp_prepare_cpus(unsigned int max_cpus)
  76 {
  77         int i;
  78
  79         /* From now on we can expect IPIs so set them up */
  80         setup_irq(IPI_INTR_VECT, &irq_ipi);
  81
  82         /* Mark all possible CPUs as present */
  83         for (i = 0; i < max_cpus; i++)
  84                 cpumask_set_cpu(i, &phys_cpu_present_map);
  85 }
  86
  87 void smp_prepare_boot_cpu(void)
  88 {
  89         /* PGD pointer has moved after per_cpu initialization so
  90          * update the MMU.
  91          */
  92         pgd_t **pgd;
  93         pgd = (pgd_t**)&per_cpu(current_pgd, smp_processor_id());
  94
  95         SUPP_BANK_SEL(1);
  96         SUPP_REG_WR(RW_MM_TLB_PGD, pgd);
  97         SUPP_BANK_SEL(2);
  98         SUPP_REG_WR(RW_MM_TLB_PGD, pgd);
  99
 100         set_cpu_online(0, true);
 101         cpumask_set_cpu(0, &phys_cpu_present_map);
 102         set_cpu_possible(0, true);
 103 }
 104
 105 void __init smp_cpus_done(unsigned int max_cpus)
 106 {
 107 }
 108
 109 /* Bring one cpu online.*/
 110 static int __init
 111 smp_boot_one_cpu(int cpuid, struct task_struct idle)
 112 {
 113         unsigned timeout;
 114         cpumask_t cpu_mask;
 115
 116         cpumask_clear(&cpu_mask);
 117         task_thread_info(idle)->cpu = cpuid;
 118
 119         /* Information to the CPU that is about to boot */
 120         smp_init_current_idle_thread = task_thread_info(idle);
 121         cpu_now_booting = cpuid;
 122
 123         /* Kick it */
 124         set_cpu_online(cpuid, true);
 125         cpumask_set_cpu(cpuid, &cpu_mask);
 126         send_ipi(IPI_BOOT, 0, cpu_mask);
 127         set_cpu_online(cpuid, false);
 128
 129         /* Wait for CPU to come online */
 130         for (timeout = 0; timeout < 10000; timeout++) {
 131                 if(cpu_online(cpuid)) {
 132                         cpu_now_booting = 0;
 133                         smp_init_current_idle_thread = NULL;
 134                         return 0; /* CPU online */
 135                 }
 136                 udelay(100);
 137                 barrier();
 138         }
 139
 140         printk(KERN_CRIT "SMP: CPU:%d is stuck.\n", cpuid);
 141         return -1;
 142 }
 143
 144 /* Secondary CPUs starts using C here. Here we need to setup CPU
 145  * specific stuff such as the local timer and the MMU. */
 146 void __init smp_callin(void)
 147 {
 148         int cpu = cpu_now_booting;
 149         reg_intr_vect_rw_mask vect_mask = {0};
 150
 151         /* Initialise the idle task for this CPU */
 152         atomic_inc(&init_mm.mm_count);
 153         current->active_mm = &init_mm;
 154
 155         /* Set up MMU */
 156         cris_mmu_init();
 157         __flush_tlb_all();
 158
 159         /* Setup local timer. */
 160         cris_timer_init();
 161
 162         /* Enable IRQ and idle */
 163         REG_WR(intr_vect, irq_regs[cpu], rw_mask, vect_mask);
 164         crisv32_unmask_irq(IPI_INTR_VECT);
 165         crisv32_unmask_irq(TIMER0_INTR_VECT);
 166         preempt_disable();
 167         notify_cpu_starting(cpu);
 168         local_irq_enable();
 169
 170         set_cpu_online(cpu, true);
 171         cpu_startup_entry(CPUHP_ONLINE);
 172 }
 173
 174 /* Stop execution on this CPU.*/
 175 void stop_this_cpu(void* dummy)
 176 {
 177         local_irq_disable();
 178         asm volatile("halt");
 179 }
 180
 181 /* Other calls */
 182 void smp_send_stop(void)
 183 {
 184         smp_call_function(stop_this_cpu, NULL, 0);
 185 }
 186
 187 int setup_profiling_timer(unsigned int multiplier)
 188 {
 189         return -EINVAL;
 190 }
 191
 192
 193 /* cache_decay_ticks is used by the scheduler to decide if a process
 194  * is "hot" on one CPU. A higher value means a higher penalty to move
 195  * a process to another CPU. Our cache is rather small so we report
 196  * 1 tick.
 197  */
 198 unsigned long cache_decay_ticks = 1;
 199
 200 int __cpuinit __cpu_up(unsigned int cpu, struct task_struct *tidle)
 201 {
 202         smp_boot_one_cpu(cpu, tidle);
 203         return cpu_online(cpu) ? 0 : -ENOSYS;
 204 }
 205
 206 void smp_send_reschedule(int cpu)
 207 {
 208         cpumask_t cpu_mask;
 209         cpumask_clear(&cpu_mask);
 210         cpumask_set_cpu(cpu, &cpu_mask);
 211         send_ipi(IPI_SCHEDULE, 0, cpu_mask);
 212 }
 213
 214 /* TLB flushing
 215  *
 216  * Flush needs to be done on the local CPU and on any other CPU that
 217  * may have the same mapping. The mm->cpu_vm_mask is used to keep track
 218  * of which CPUs that a specific process has been executed on.
 219  */
 220 void flush_tlb_common(struct mm_struct* mm, struct vm_area_struct* vma, unsigned long addr)
 221 {
 222         unsigned long flags;
 223         cpumask_t cpu_mask;
 224
 225         spin_lock_irqsave(&tlbstate_lock, flags);
 226         cpu_mask = (mm == FLUSH_ALL ? cpu_all_mask : *mm_cpumask(mm));
 227         cpumask_clear_cpu(smp_processor_id(), &cpu_mask);
 228         flush_mm = mm;
 229         flush_vma = vma;
 230         flush_addr = addr;
 231         send_ipi(IPI_FLUSH_TLB, 1, cpu_mask);
 232         spin_unlock_irqrestore(&tlbstate_lock, flags);
 233 }
 234
 235 void flush_tlb_all(void)
 236 {
 237         __flush_tlb_all();
 238         flush_tlb_common(FLUSH_ALL, FLUSH_ALL, 0);
 239 }
 240
 241 void flush_tlb_mm(struct mm_struct *mm)
 242 {
 243         __flush_tlb_mm(mm);
 244         flush_tlb_common(mm, FLUSH_ALL, 0);
 245         /* No more mappings in other CPUs */
 246         cpumask_clear(mm_cpumask(mm));
 247         cpumask_set_cpu(smp_processor_id(), mm_cpumask(mm));
 248 }
 249
 250 void flush_tlb_page(struct vm_area_struct *vma,
 251                            unsigned long addr)
 252 {
 253         __flush_tlb_page(vma, addr);
 254         flush_tlb_common(vma->vm_mm, vma, addr);
 255 }
 256
 257 /* Inter processor interrupts
 258  *
 259  * The IPIs are used for:
 260  *   * Force a schedule on a CPU
 261  *   * FLush TLB on other CPUs
 262  *   * Call a function on other CPUs
 263  */
 264
 265 int send_ipi(int vector, int wait, cpumask_t cpu_mask)
 266 {
 267         int i = 0;
 268         reg_intr_vect_rw_ipi ipi = REG_RD(intr_vect, irq_regs[i], rw_ipi);
 269         int ret = 0;
 270
 271         /* Calculate CPUs to send to. */
 272         cpumask_and(&cpu_mask, &cpu_mask, cpu_online_mask);
 273
 274         /* Send the IPI. */
 275         for_each_cpu(i, &cpu_mask)
 276         {
 277                 ipi.vector |= vector;
 278                 REG_WR(intr_vect, irq_regs[i], rw_ipi, ipi);
 279         }
 280
 281         /* Wait for IPI to finish on other CPUS */
 282         if (wait) {
 283                 for_each_cpu(i, &cpu_mask) {
 284                         int j;
 285                         for (j = 0 ; j < 1000; j++) {
 286                                 ipi = REG_RD(intr_vect, irq_regs[i], rw_ipi);
 287                                 if (!ipi.vector)
 288                                         break;
 289                                 udelay(100);
 290                         }
 291
 292                         /* Timeout? */
 293                         if (ipi.vector) {
 294                                 printk("SMP call timeout from %d to %d\n", smp_processor_id(), i);
 295                                 ret = -ETIMEDOUT;
 296                                 dump_stack();
 297                         }
 298                 }
 299         }
 300         return ret;
 301 }
 302
 303 /*
 304  * You must not call this function with disabled interrupts or from a
 305  * hardware interrupt handler or from a bottom half handler.
 306  */
 307 int smp_call_function(void (*func)(void *info), void *info, int wait)
 308 {
 309         cpumask_t cpu_mask;
 310         struct call_data_struct data;
 311         int ret;
 312
 313         cpumask_setall(&cpu_mask);
 314         cpumask_clear_cpu(smp_processor_id(), &cpu_mask);
 315
 316         WARN_ON(irqs_disabled());
 317
 318         data.func = func;
 319         data.info = info;
 320         data.wait = wait;
 321
 322         spin_lock(&call_lock);
 323         call_data = &data;
 324         ret = send_ipi(IPI_CALL, wait, cpu_mask);
 325         spin_unlock(&call_lock);
 326
 327         return ret;
 328 }
 329
 330 irqreturn_t crisv32_ipi_interrupt(int irq, void *dev_id)
 331 {
 332         void (*func) (void *info) = call_data->func;
 333         void *info = call_data->info;
 334         reg_intr_vect_rw_ipi ipi;
 335
 336         ipi = REG_RD(intr_vect, irq_regs[smp_processor_id()], rw_ipi);
 337
 338         if (ipi.vector & IPI_SCHEDULE) {
 339                 scheduler_ipi();
 340         }
 341         if (ipi.vector & IPI_CALL) {
 342                 func(info);
 343         }
 344         if (ipi.vector & IPI_FLUSH_TLB) {
 345                 if (flush_mm == FLUSH_ALL)
 346                         __flush_tlb_all();
 347                 else if (flush_vma == FLUSH_ALL)
 348                         __flush_tlb_mm(flush_mm);
 349                 else
 350                         __flush_tlb_page(flush_vma, flush_addr);
 351         }
 352
 353         ipi.vector = 0;
 354         REG_WR(intr_vect, irq_regs[smp_processor_id()], rw_ipi, ipi);
 355
 356         return IRQ_HANDLED;
 357 }
 358