minix/kernel/arch/i386/arch_smp.c

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/* This file contains essentially the MP handling code of the Minix kernel.
*
* Changes:
* Apr 1, 2008 Added SMP support.
*/
#define _SMP
#include "kernel/kernel.h"
#include "kernel/proc.h"
#include "arch_proto.h"
#include "kernel/glo.h"
#include <unistd.h>
#include <stdlib.h>
#include <machine/cmos.h>
#include <machine/bios.h>
#include <minix/portio.h>
#include "kernel/spinlock.h"
#include "kernel/smp.h"
#include "apic.h"
#include "acpi.h"
#include "clock.h"
#include "glo.h"
void trampoline(void);
/*
* arguments for trampoline. We need to pass the logical cpu id, gdt and idt.
* They have to be in location which is reachable using absolute addressing in
* 16-bit mode
*/
extern volatile u32_t __ap_id;
extern volatile struct segdesc_s __ap_gdt, __ap_idt;
extern void * __trampoline_end;
extern u32_t busclock[CONFIG_MAX_CPUS];
extern int panicking;
static int volatile ap_cpu_ready;
static int volatile cpu_down;
/* there can be at most 255 local APIC ids, each fits in 8 bits */
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static unsigned char apicid2cpuid[255];
unsigned char cpuid2apicid[CONFIG_MAX_CPUS];
SPINLOCK_DEFINE(smp_cpu_lock)
SPINLOCK_DEFINE(dispq_lock)
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static void smp_reinit_vars(void);
/*
* copies the 16-bit AP trampoline code to the first 1M of memory
*/
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static phys_bytes copy_trampoline(void)
{
char * s, *end;
phys_bytes tramp_base = 0;
unsigned tramp_size;
tramp_size = (unsigned) &__trampoline_end - (unsigned)&trampoline;
s = env_get("memory");
if (!s)
return 0;
while (*s != 0) {
phys_bytes base = 0xfffffff;
unsigned size;
/* Read fresh base and expect colon as next char. */
base = strtoul(s, &end, 0x10); /* get number */
if (end != s && *end == ':')
s = ++end; /* skip ':' */
else
*s=0;
/* Read fresh size and expect comma or assume end. */
size = strtoul(s, &end, 0x10); /* get number */
if (end != s && *end == ',')
s = ++end; /* skip ',' */
tramp_base = (base + 0xfff) & ~(0xfff);
/* the address must be less than 1M */
if (tramp_base >= (1 << 20))
continue;
if (size - (tramp_base - base) < tramp_size)
continue;
break;
}
phys_copy(vir2phys(trampoline), tramp_base, tramp_size);
return tramp_base;
}
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static void smp_start_aps(void)
{
/*
* Find an address and align it to a 4k boundary.
*/
unsigned cpu;
u32_t biosresetvector;
phys_bytes trampoline_base, __ap_id_phys;
/* TODO hack around the alignment problem */
phys_copy (0x467, vir2phys(&biosresetvector), sizeof(u32_t));
/* set the bios shutdown code to 0xA */
outb(RTC_INDEX, 0xF);
outb(RTC_IO, 0xA);
/* prepare gdt and idt for the new cpus */
__ap_gdt = gdt[GDT_INDEX];
__ap_idt = gdt[IDT_INDEX];
if (!(trampoline_base = copy_trampoline())) {
printf("Copying trampoline code failed, cannot boot SMP\n");
ncpus = 1;
}
__ap_id_phys = trampoline_base +
(phys_bytes) &__ap_id - (phys_bytes)&trampoline;
/* setup the warm reset vector */
phys_copy(vir2phys(&trampoline_base), 0x467, sizeof(u32_t));
/* okay, we're ready to go. boot all of the ap's now. we loop through
* using the processor's apic id values.
*/
for (cpu = 0; cpu < ncpus; cpu++) {
ap_cpu_ready = -1;
/* Don't send INIT/SIPI to boot cpu. */
if((apicid() == cpuid2apicid[cpu]) &&
(apicid() == bsp_lapic_id)) {
continue;
}
__ap_id = cpu;
phys_copy(vir2phys(__ap_id), __ap_id_phys, sizeof(__ap_id));
mfence();
if (apic_send_init_ipi(cpu, trampoline_base) ||
apic_send_startup_ipi(cpu, trampoline_base)) {
printf("WARNING cannot boot cpu %d\n", cpu);
continue;
}
/* wait for 5 secs for the processors to boot */
lapic_set_timer_one_shot(5000000);
while (lapic_read(LAPIC_TIMER_CCR)) {
if (ap_cpu_ready == cpu) {
cpu_set_flag(cpu, CPU_IS_READY);
break;
}
}
if (ap_cpu_ready == -1) {
printf("WARNING : CPU %d didn't boot\n", cpu);
}
}
phys_copy(vir2phys(&biosresetvector),(phys_bytes)0x467,sizeof(u32_t));
outb(RTC_INDEX, 0xF);
outb(RTC_IO, 0);
bsp_finish_booting();
NOT_REACHABLE;
}
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void smp_halt_cpu (void)
{
NOT_IMPLEMENTED;
}
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void smp_shutdown_aps(void)
{
unsigned cpu;
if (ncpus == 1)
goto exit_shutdown_aps;
/* we must let the other cpus enter the kernel mode */
BKL_UNLOCK();
for (cpu = 0; cpu < ncpus; cpu++) {
if (cpu == cpuid)
continue;
if (!cpu_test_flag(cpu, CPU_IS_READY)) {
printf("CPU %d didn't boot\n", cpu);
continue;
}
cpu_down = -1;
barrier();
apic_send_ipi(APIC_SMP_CPU_HALT_VECTOR, cpu, APIC_IPI_DEST);
/* wait for the cpu to be down */
while (cpu_down != cpu);
printf("CPU %d is down\n", cpu);
cpu_clear_flag(cpu, CPU_IS_READY);
}
exit_shutdown_aps:
ioapic_disable_all();
lapic_disable();
ncpus = 1; /* hopefully !!! */
lapic_addr = lapic_eoi_addr = 0;
return;
}
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static void ap_finish_booting(void)
{
unsigned cpu = cpuid;
/* inform the world of our presence. */
ap_cpu_ready = cpu;
while(!i386_paging_enabled)
arch_pause();
/*
* Finish processor initialisation. CPUs must be excluded from running.
* lapic timer calibration locks and unlocks the BKL because of the
* nested interrupts used for calibration. Therefore BKL is not good
* enough, the boot_lock must be held.
*/
spinlock_lock(&boot_lock);
BKL_LOCK();
/*
* we must load some page tables befre we turn paging on. As VM is
* always present we use those
*/
segmentation2paging(proc_addr(VM_PROC_NR));
printf("CPU %d paging is on\n", cpu);
cpu_identify();
lapic_enable(cpu);
fpu_init();
if (app_cpu_init_timer(system_hz)) {
panic("FATAL : failed to initialize timer interrupts CPU %d, "
"cannot continue without any clock source!", cpu);
}
/* FIXME assign CPU local idle structure */
get_cpulocal_var(proc_ptr) = get_cpulocal_var_ptr(idle_proc);
get_cpulocal_var(bill_ptr) = get_cpulocal_var_ptr(idle_proc);
ap_boot_finished(cpu);
spinlock_unlock(&boot_lock);
switch_to_user();
NOT_REACHABLE;
}
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void smp_ap_boot(void)
{
switch_k_stack((char *)get_k_stack_top(__ap_id) -
X86_STACK_TOP_RESERVED, ap_finish_booting);
}
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static void smp_reinit_vars(void)
{
lapic_addr = lapic_eoi_addr = 0;
ioapic_enabled = 0;
ncpus = 1;
}
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static void tss_init_all(void)
{
unsigned cpu;
for(cpu = 0; cpu < ncpus ; cpu++)
tss_init(cpu, get_k_stack_top(cpu));
}
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static int discover_cpus(void)
{
struct acpi_madt_lapic * cpu;
while (ncpus < CONFIG_MAX_CPUS && (cpu = acpi_get_lapic_next())) {
apicid2cpuid[cpu->apic_id] = ncpus;
cpuid2apicid[ncpus] = cpu->apic_id;
printf("CPU %3d local APIC id %3d\n", ncpus, cpu->apic_id);
ncpus++;
}
return ncpus;
}
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void smp_init (void)
{
/* read the MP configuration */
if (!discover_cpus()) {
ncpus = 1;
goto uniproc_fallback;
}
lapic_addr = phys2vir(LOCAL_APIC_DEF_ADDR);
ioapic_enabled = 0;
tss_init_all();
/*
* we still run on the boot stack and we cannot use cpuid as its value
* wasn't set yet. apicid2cpuid initialized in mps_init()
*/
bsp_cpu_id = apicid2cpuid[apicid()];
if (!lapic_enable(bsp_cpu_id)) {
printf("ERROR : failed to initialize BSP Local APIC\n");
goto uniproc_fallback;
}
bsp_lapic_id = apicid();
acpi_init();
if (!detect_ioapics()) {
lapic_disable();
lapic_addr = 0x0;
goto uniproc_fallback;
}
ioapic_enable_all();
if (ioapic_enabled)
machine.apic_enabled = 1;
/* set smp idt entries. */
apic_idt_init(0); /* Not a reset ! */
idt_reload();
BOOT_VERBOSE(printf("SMP initialized\n"));
switch_k_stack((char *)get_k_stack_top(bsp_cpu_id) -
X86_STACK_TOP_RESERVED, smp_start_aps);
return;
uniproc_fallback:
apic_idt_init(1); /* Reset to PIC idt ! */
idt_reload();
smp_reinit_vars (); /* revert to a single proc system. */
intr_init (INTS_MINIX, 0); /* no auto eoi */
printf("WARNING : SMP initialization failed\n");
}
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void arch_smp_halt_cpu(void)
{
/* say that we are down */
cpu_down = cpuid;
barrier();
/* unlock the BKL and don't continue */
BKL_UNLOCK();
for(;;);
}
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void arch_send_smp_schedule_ipi(unsigned cpu)
{
apic_send_ipi(APIC_SMP_SCHED_PROC_VECTOR, cpu, APIC_IPI_DEST);
}