kernel/arch/i386/arch_smp.c

   1 /* This file contains essentially the MP handling code of the Minix kernel.
   2  *
   3  * Changes:
   4  *   Apr 1,  2008     Added SMP support.
   5  */
   6
   7 #define _SMP
   8
   9 #include "kernel/kernel.h"
  10 #include "arch_proto.h"
  11 #include <unistd.h>
  12 #include <assert.h>
  13 #include <stdlib.h>
  14 #include <string.h>
  15 #include <machine/archtypes.h>
  16 #include <archconst.h>
  17 #include <machine/cmos.h>
  18 #include <machine/bios.h>
  19 #include <minix/portio.h>
  20
  21 #include "kernel/spinlock.h"
  22 #include "kernel/smp.h"
  23 #include "apic.h"
  24 #include "acpi.h"
  25 #include "clock.h"
  26
  27 #include "glo.h"
  28
  29 void trampoline(void);
  30
  31 /*
  32  * arguments for trampoline. We need to pass the logical cpu id, gdt and idt.
  33  * They have to be in location which is reachable using absolute addressing in
  34  * 16-bit mode
  35  */
  36 extern volatile u32_t __ap_id, __ap_pt;
  37 extern volatile struct desctableptr_s __ap_gdt, __ap_idt;
  38 extern u32_t __ap_gdt_tab, __ap_idt_tab;
  39 extern void * __trampoline_end;
  40
  41 extern u32_t busclock[CONFIG_MAX_CPUS];
  42 extern int panicking;
  43
  44 static int volatile ap_cpu_ready;
  45 static int volatile cpu_down;
  46
  47 /* there can be at most 255 local APIC ids, each fits in 8 bits */
  48 static unsigned char apicid2cpuid[255];
  49 unsigned char cpuid2apicid[CONFIG_MAX_CPUS];
  50
  51 SPINLOCK_DEFINE(smp_cpu_lock)
  52 SPINLOCK_DEFINE(dispq_lock)
  53
  54 static void smp_reinit_vars(void);
  55
  56 /* These are initialized in protect.c */
  57 extern struct segdesc_s gdt[GDT_SIZE];
  58 extern struct gatedesc_s idt[IDT_SIZE];
  59 extern struct tss_s tss[CONFIG_MAX_CPUS];
  60 extern int prot_init_done;      /* Indicates they are ready */
  61
  62 static phys_bytes trampoline_base;
  63
  64 static u32_t ap_lin_addr(void *vaddr)
  65 {
  66         assert(trampoline_base);
  67         return (u32_t) vaddr - (u32_t) &trampoline + trampoline_base;
  68 }
  69
  70 /*
  71  * copies the 16-bit AP trampoline code to the first 1M of memory
  72  */
  73 void copy_trampoline(void)
  74 {
  75         unsigned tramp_size, tramp_start = (unsigned)&trampoline;;
  76
  77         /* The trampoline code/data is made to be page-aligned. */
  78         assert(!(tramp_start % I386_PAGE_SIZE));
  79
  80         tramp_size = (unsigned) &__trampoline_end - tramp_start;
  81         trampoline_base = alloc_lowest(&kinfo, tramp_size);
  82
  83         /* The memory allocator finds the lowest available memory..
  84          * Verify it's low enough
  85          */
  86         assert(trampoline_base + tramp_size < (1 << 20));
  87
  88         /* prepare gdt and idt for the new cpus; make copies
  89          * of both the tables and the descriptors of them
  90          * in their boot addressing environment.
  91          */
  92         assert(prot_init_done);
  93         memcpy(&__ap_gdt_tab, gdt, sizeof(gdt));
  94         memcpy(&__ap_idt_tab, gdt, sizeof(idt));
  95         __ap_gdt.base = ap_lin_addr(&__ap_gdt_tab);
  96         __ap_gdt.limit = sizeof(gdt)-1;
  97         __ap_idt.base = ap_lin_addr(&__ap_idt_tab);
  98         __ap_idt.limit = sizeof(idt)-1;
  99
 100         phys_copy((phys_bytes) trampoline, trampoline_base, tramp_size);
 101 }
 102
 103 extern int booting_cpu; /* tell protect.c what to do */
 104
 105 static void smp_start_aps(void)
 106 {
 107         unsigned cpu;
 108         u32_t biosresetvector;
 109         phys_bytes __ap_id_phys;
 110         struct proc *bootstrap_pt = get_cpulocal_var(ptproc);
 111
 112         /* TODO hack around the alignment problem */
 113
 114         phys_copy(0x467, (phys_bytes) &biosresetvector, sizeof(u32_t));
 115
 116         /* set the bios shutdown code to 0xA */
 117         outb(RTC_INDEX, 0xF);
 118         outb(RTC_IO, 0xA);
 119
 120         assert(bootstrap_pt);
 121         assert(bootstrap_pt->p_seg.p_cr3);
 122         __ap_pt  = bootstrap_pt->p_seg.p_cr3;
 123         assert(__ap_pt);
 124
 125         copy_trampoline();
 126
 127         /* New locations for cpu id, pagetable root */
 128         __ap_id_phys = trampoline_base +
 129                 (phys_bytes) &__ap_id - (phys_bytes)&trampoline;
 130
 131         /* setup the warm reset vector */
 132         phys_copy((phys_bytes) &trampoline_base, 0x467, sizeof(u32_t));
 133
 134         /* okay, we're ready to go.  boot all of the ap's now.  we loop through
 135          * using the processor's apic id values.
 136          */
 137         for (cpu = 0; cpu < ncpus; cpu++) {
 138                 ap_cpu_ready = -1;
 139                 /* Don't send INIT/SIPI to boot cpu.  */
 140                 if((apicid() == cpuid2apicid[cpu]) &&
 141                                 (apicid() == bsp_lapic_id)) {
 142                         continue;
 143                 }
 144
 145                 __ap_id = booting_cpu = cpu;
 146                 phys_copy((phys_bytes) &__ap_id, __ap_id_phys, sizeof(__ap_id));
 147                 mfence();
 148                 if (apic_send_init_ipi(cpu, trampoline_base) ||
 149                                 apic_send_startup_ipi(cpu, trampoline_base)) {
 150                         printf("WARNING cannot boot cpu %d\n", cpu);
 151                         continue;
 152                 }
 153
 154                 /* wait for 5 secs for the processors to boot */
 155                 lapic_set_timer_one_shot(5000000);
 156
 157                 while (lapic_read(LAPIC_TIMER_CCR)) {
 158                         if (ap_cpu_ready == cpu) {
 159                                 cpu_set_flag(cpu, CPU_IS_READY);
 160                                 break;
 161                         }
 162                 }
 163                 if (ap_cpu_ready == -1) {
 164                         printf("WARNING : CPU %d didn't boot\n", cpu);
 165                 }
 166         }
 167
 168         phys_copy((phys_bytes) &biosresetvector, 0x467, sizeof(u32_t));
 169
 170         outb(RTC_INDEX, 0xF);
 171         outb(RTC_IO, 0);
 172
 173         bsp_finish_booting();
 174         NOT_REACHABLE;
 175 }
 176
 177 void smp_halt_cpu (void)
 178 {
 179         NOT_IMPLEMENTED;
 180 }
 181
 182 void smp_shutdown_aps(void)
 183 {
 184         unsigned cpu;
 185
 186         if (ncpus == 1)
 187                 goto exit_shutdown_aps;
 188
 189         /* we must let the other cpus enter the kernel mode */
 190         BKL_UNLOCK();
 191
 192         for (cpu = 0; cpu < ncpus; cpu++) {
 193                 if (cpu == cpuid)
 194                         continue;
 195                 if (!cpu_test_flag(cpu, CPU_IS_READY)) {
 196                         printf("CPU %d didn't boot\n", cpu);
 197                         continue;
 198                 }
 199
 200                 cpu_down = -1;
 201                 barrier();
 202                 apic_send_ipi(APIC_SMP_CPU_HALT_VECTOR, cpu, APIC_IPI_DEST);
 203                 /* wait for the cpu to be down */
 204                 while (cpu_down != cpu);
 205                 printf("CPU %d is down\n", cpu);
 206                 cpu_clear_flag(cpu, CPU_IS_READY);
 207         }
 208
 209 exit_shutdown_aps:
 210         ioapic_disable_all();
 211
 212         lapic_disable();
 213
 214         ncpus = 1; /* hopefully !!! */
 215         lapic_addr = lapic_eoi_addr = 0;
 216         return;
 217 }
 218
 219 static void ap_finish_booting(void)
 220 {
 221         unsigned cpu = cpuid;
 222
 223         /* inform the world of our presence. */
 224         ap_cpu_ready = cpu;
 225
 226         /*
 227          * Finish processor initialisation.  CPUs must be excluded from running.
 228          * lapic timer calibration locks and unlocks the BKL because of the
 229          * nested interrupts used for calibration. Therefore BKL is not good
 230          * enough, the boot_lock must be held.
 231          */
 232         spinlock_lock(&boot_lock);
 233         BKL_LOCK();
 234
 235         printf("CPU %d is up\n", cpu);
 236
 237         cpu_identify();
 238
 239         lapic_enable(cpu);
 240         fpu_init();
 241
 242         if (app_cpu_init_timer(system_hz)) {
 243                 panic("FATAL : failed to initialize timer interrupts CPU %d, "
 244                                 "cannot continue without any clock source!", cpu);
 245         }
 246
 247         /* FIXME assign CPU local idle structure */
 248         get_cpulocal_var(proc_ptr) = get_cpulocal_var_ptr(idle_proc);
 249         get_cpulocal_var(bill_ptr) = get_cpulocal_var_ptr(idle_proc);
 250
 251         ap_boot_finished(cpu);
 252         spinlock_unlock(&boot_lock);
 253
 254         switch_to_user();
 255         NOT_REACHABLE;
 256 }
 257
 258 void smp_ap_boot(void)
 259 {
 260         switch_k_stack((char *)get_k_stack_top(__ap_id) -
 261                         X86_STACK_TOP_RESERVED, ap_finish_booting);
 262 }
 263
 264 static void smp_reinit_vars(void)
 265 {
 266         lapic_addr = lapic_eoi_addr = 0;
 267         ioapic_enabled = 0;
 268
 269         ncpus = 1;
 270 }
 271
 272 static void tss_init_all(void)
 273 {
 274         unsigned cpu;
 275
 276         for(cpu = 0; cpu < ncpus ; cpu++)
 277                 tss_init(cpu, get_k_stack_top(cpu));
 278 }
 279
 280 static int discover_cpus(void)
 281 {
 282         struct acpi_madt_lapic * cpu;
 283
 284         while (ncpus < CONFIG_MAX_CPUS && (cpu = acpi_get_lapic_next())) {
 285                 apicid2cpuid[cpu->apic_id] = ncpus;
 286                 cpuid2apicid[ncpus] = cpu->apic_id;
 287                 printf("CPU %3d local APIC id %3d\n", ncpus, cpu->apic_id);
 288                 ncpus++;
 289         }
 290
 291         return ncpus;
 292 }
 293
 294 void smp_init (void)
 295 {
 296         /* read the MP configuration */
 297         if (!discover_cpus()) {
 298                 ncpus = 1;
 299                 goto uniproc_fallback;
 300         }
 301
 302         lapic_addr = LOCAL_APIC_DEF_ADDR;
 303         ioapic_enabled = 0;
 304
 305         tss_init_all();
 306
 307         /*
 308          * we still run on the boot stack and we cannot use cpuid as its value
 309          * wasn't set yet. apicid2cpuid initialized in mps_init()
 310          */
 311         bsp_cpu_id = apicid2cpuid[apicid()];
 312
 313         if (!lapic_enable(bsp_cpu_id)) {
 314                 printf("ERROR : failed to initialize BSP Local APIC\n");
 315                 goto uniproc_fallback;
 316         }
 317
 318         bsp_lapic_id = apicid();
 319
 320         acpi_init();
 321
 322         if (!detect_ioapics()) {
 323                 lapic_disable();
 324                 lapic_addr = 0x0;
 325                 goto uniproc_fallback;
 326         }
 327
 328         ioapic_enable_all();
 329
 330         if (ioapic_enabled)
 331                 machine.apic_enabled = 1;
 332
 333         /* set smp idt entries. */
 334         apic_idt_init(0); /* Not a reset ! */
 335         idt_reload();
 336
 337         BOOT_VERBOSE(printf("SMP initialized\n"));
 338
 339         switch_k_stack((char *)get_k_stack_top(bsp_cpu_id) -
 340                         X86_STACK_TOP_RESERVED, smp_start_aps);
 341
 342         return;
 343
 344 uniproc_fallback:
 345         apic_idt_init(1); /* Reset to PIC idt ! */
 346         idt_reload();
 347         smp_reinit_vars (); /* revert to a single proc system. */
 348         intr_init(0); /* no auto eoi */
 349         printf("WARNING : SMP initialization failed\n");
 350 }
 351
 352 void arch_smp_halt_cpu(void)
 353 {
 354         /* say that we are down */
 355         cpu_down = cpuid;
 356         barrier();
 357         /* unlock the BKL and don't continue */
 358         BKL_UNLOCK();
 359         for(;;);
 360 }
 361
 362 void arch_send_smp_schedule_ipi(unsigned cpu)
 363 {
 364         apic_send_ipi(APIC_SMP_SCHED_PROC_VECTOR, cpu, APIC_IPI_DEST);
 365 }