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smp.c
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smp.c
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/* Functionality for symetrical multi-processors */
/*
** Copyright 2001-2002, Travis Geiselbrecht. All rights reserved.
** Distributed under the terms of the NewOS License.
*/
#include <kernel.h>
#include <thread.h>
#include <console.h>
#include <debug.h>
#include <int.h>
#include <arch/int.h>
#include <smp_priv.h>
#include <smp.h>
#include <memheap.h>
#include <Errors.h>
#include <atomic.h>
#include <cpu.h>
#include <arch/cpu.h>
#include <arch/smp.h>
//#include <arch/pmap.h>
#include <string.h>
#define MSG_POOL_SIZE (SMP_MAX_CPUS * 4)
struct smp_msg {
struct smp_msg *next;
int message;
unsigned long data;
unsigned long data2;
unsigned long data3;
void *data_ptr;
int flags;
int ref_count;
volatile bool done;
unsigned int proc_bitmap;
int lock;
};
#define MAILBOX_LOCAL 1
#define MAILBOX_BCAST 2
static spinlock_t boot_cpu_spin[SMP_MAX_CPUS] = { 0, };
static struct smp_msg *free_msgs = NULL;
static volatile int free_msg_count = 0;
static spinlock_t free_msg_spinlock = 0;
static struct smp_msg *smp_msgs[SMP_MAX_CPUS] = { NULL, };
static spinlock_t cpu_msg_spinlock[SMP_MAX_CPUS] = { 0, };
static struct smp_msg *smp_broadcast_msgs = NULL;
static spinlock_t broadcast_msg_spinlock = 0;
static bool ici_enabled = false;
static int smp_num_cpus = 1;
static int smp_process_pending_ici(int curr_cpu);
void acquire_spinlock(spinlock_t *lock)
{
if(smp_num_cpus > 1) {
int curr_cpu = smp_get_current_cpu();
if(int_is_interrupts_enabled())
panic("acquire_spinlock: attempt to acquire lock %p with interrupts enabled\n", lock);
while(1) {
while(*lock != 0)
smp_process_pending_ici(curr_cpu);
if(atomic_set(lock, 1) == 0)
break;
}
}
}
static void acquire_spinlock_nocheck(spinlock_t *lock)
{
if(smp_num_cpus > 1) {
while(1) {
while(*lock != 0)
;
if(atomic_set(lock, 1) == 0)
break;
}
}
}
void release_spinlock(spinlock_t *lock)
{
*lock = 0;
}
// finds a free message and gets it
// NOTE: has side effect of disabling interrupts
// return value is interrupt state
static int find_free_message(struct smp_msg **msg)
{
int state;
// dprintf("find_free_message: entry\n");
retry:
while(free_msg_count <= 0)
;
state = int_disable_interrupts();
acquire_spinlock(&free_msg_spinlock);
if(free_msg_count <= 0) {
// someone grabbed one while we were getting the lock,
// go back to waiting for it
release_spinlock(&free_msg_spinlock);
int_restore_interrupts(state);
goto retry;
}
*msg = free_msgs;
free_msgs = (*msg)->next;
free_msg_count--;
release_spinlock(&free_msg_spinlock);
// dprintf("find_free_message: returning msg 0x%x\n", *msg);
return state;
}
static void return_free_message(struct smp_msg *msg)
{
// dprintf("return_free_message: returning msg 0x%x\n", msg);
acquire_spinlock_nocheck(&free_msg_spinlock);
msg->next = free_msgs;
free_msgs = msg;
free_msg_count++;
release_spinlock(&free_msg_spinlock);
}
static struct smp_msg *smp_check_for_message(int curr_cpu, int *source_mailbox)
{
struct smp_msg *msg;
acquire_spinlock_nocheck(&cpu_msg_spinlock[curr_cpu]);
msg = smp_msgs[curr_cpu];
if(msg != NULL) {
smp_msgs[curr_cpu] = msg->next;
release_spinlock(&cpu_msg_spinlock[curr_cpu]);
// dprintf(" found msg 0x%x in cpu mailbox\n", msg);
*source_mailbox = MAILBOX_LOCAL;
} else {
// try getting one from the broadcast mailbox
release_spinlock(&cpu_msg_spinlock[curr_cpu]);
acquire_spinlock_nocheck(&broadcast_msg_spinlock);
msg = smp_broadcast_msgs;
while(msg != NULL) {
if(CHECK_BIT(msg->proc_bitmap, curr_cpu) != 0) {
// we have handled this one already
msg = msg->next;
continue;
}
// mark it so we wont try to process this one again
msg->proc_bitmap = SET_BIT(msg->proc_bitmap, curr_cpu);
*source_mailbox = MAILBOX_BCAST;
break;
}
release_spinlock(&broadcast_msg_spinlock);
// dprintf(" found msg 0x%x in broadcast mailbox\n", msg);
}
return msg;
}
static void smp_finish_message_processing(int curr_cpu, struct smp_msg *msg, int source_mailbox)
{
int old_refcount;
old_refcount = atomic_add(&msg->ref_count, -1);
if(old_refcount == 1) {
// we were the last one to decrement the ref_count
// it's our job to remove it from the list & possibly clean it up
struct smp_msg **mbox = NULL;
spinlock_t *spinlock = NULL;
// clean up the message from one of the mailboxes
switch(source_mailbox) {
case MAILBOX_BCAST:
mbox = &smp_broadcast_msgs;
spinlock = &broadcast_msg_spinlock;
break;
case MAILBOX_LOCAL:
mbox = &smp_msgs[curr_cpu];
spinlock = &cpu_msg_spinlock[curr_cpu];
break;
}
acquire_spinlock_nocheck(spinlock);
// dprintf("cleaning up message 0x%x\n", msg);
if(msg == *mbox) {
(*mbox) = msg->next;
} else {
// we need to walk to find the message in the list.
// we can't use any data found when previously walking through
// the list, since the list may have changed. But, we are guaranteed
// to at least have msg in it.
struct smp_msg *last = NULL;
struct smp_msg *msg1;
msg1 = *mbox;
while(msg1 != NULL && msg1 != msg) {
last = msg1;
msg1 = msg1->next;
}
// by definition, last must be something
if(msg1 == msg && last != NULL) {
last->next = msg->next;
} else {
dprintf("last == NULL or msg != msg1!!!\n");
}
}
release_spinlock(spinlock);
if(msg->data_ptr != NULL)
kfree(msg->data_ptr);
if(msg->flags == SMP_MSG_FLAG_SYNC) {
msg->done = true;
// the caller cpu should now free the message
} else {
// in the !SYNC case, we get to free the message
return_free_message(msg);
}
}
}
static int smp_process_pending_ici(int curr_cpu)
{
struct smp_msg *msg;
bool halt = false;
int source_mailbox = 0;
int retval = INT_NO_RESCHEDULE;
msg = smp_check_for_message(curr_cpu, &source_mailbox);
if(msg == NULL)
return retval;
// dprintf(" message = %d\n", msg->message);
switch(msg->message) {
case SMP_MSG_INVL_PAGE_RANGE:
arch_cpu_invalidate_TLB_range((addr)msg->data, (addr)msg->data2);
break;
case SMP_MSG_INVL_PAGE_LIST:
arch_cpu_invalidate_TLB_list((addr *)msg->data, (int)msg->data2);
break;
case SMP_MSG_GLOBAL_INVL_PAGE:
arch_cpu_global_TLB_invalidate();
break;
case SMP_MSG_RESCHEDULE:
retval = INT_RESCHEDULE;
break;
case SMP_MSG_CPU_HALT:
halt = true;
dprintf("cpu %d halted!\n", curr_cpu);
break;
case SMP_MSG_1:
default:
dprintf("smp_intercpu_int_handler: got unknown message %d\n", msg->message);
}
// finish dealing with this message, possibly removing it from the list
smp_finish_message_processing(curr_cpu, msg, source_mailbox);
// special case for the halt message
// we otherwise wouldn't have gotten the opportunity to clean up
if(halt) {
int_disable_interrupts();
for(;;);
}
return retval;
}
int smp_intercpu_int_handler(void)
{
int retval;
int curr_cpu = smp_get_current_cpu();
// dprintf("smp_intercpu_int_handler: entry on cpu %d\n", curr_cpu);
retval = smp_process_pending_ici(curr_cpu);
// dprintf("smp_intercpu_int_handler: done\n");
return retval;
}
void smp_send_ici(int target_cpu, int message, unsigned long data, unsigned long data2, unsigned long data3, void *data_ptr, int flags)
{
struct smp_msg *msg;
// dprintf("smp_send_ici: target 0x%x, mess 0x%x, data 0x%x, data2 0x%x, data3 0x%x, ptr 0x%x, flags 0x%x\n",
// target_cpu, message, data, data2, data3, data_ptr, flags);
if(ici_enabled) {
int state;
int curr_cpu;
// find_free_message leaves interrupts disabled
state = find_free_message(&msg);
curr_cpu = smp_get_current_cpu();
if(target_cpu == curr_cpu) {
return_free_message(msg);
int_restore_interrupts(state);
return; // nope, cant do that
}
// set up the message
msg->message = message;
msg->data = data;
msg->data = data2;
msg->data = data3;
msg->data_ptr = data_ptr;
msg->ref_count = 1;
msg->flags = flags;
msg->done = false;
// stick it in the appropriate cpu's mailbox
acquire_spinlock_nocheck(&cpu_msg_spinlock[target_cpu]);
msg->next = smp_msgs[target_cpu];
smp_msgs[target_cpu] = msg;
release_spinlock(&cpu_msg_spinlock[target_cpu]);
arch_smp_send_ici(target_cpu);
if(flags == SMP_MSG_FLAG_SYNC) {
// wait for the other cpu to finish processing it
// the interrupt handler will ref count it to <0
// if the message is sync after it has removed it from the mailbox
while(msg->done == false)
smp_process_pending_ici(curr_cpu);
// for SYNC messages, it's our responsibility to put it
// back into the free list
return_free_message(msg);
}
int_restore_interrupts(state);
}
}
void smp_send_broadcast_ici(int message, unsigned long data, unsigned long data2, unsigned long data3, void *data_ptr, int flags)
{
struct smp_msg *msg;
// dprintf("smp_send_broadcast_ici: cpu %d mess 0x%x, data 0x%x, data2 0x%x, data3 0x%x, ptr 0x%x, flags 0x%x\n",
// smp_get_current_cpu(), message, data, data2, data3, data_ptr, flags);
if(ici_enabled) {
int state;
int curr_cpu;
// find_free_message leaves interrupts disabled
state = find_free_message(&msg);
curr_cpu = smp_get_current_cpu();
msg->message = message;
msg->data = data;
msg->data2 = data2;
msg->data3 = data3;
msg->data_ptr = data_ptr;
msg->ref_count = smp_num_cpus - 1;
msg->flags = flags;
msg->proc_bitmap = SET_BIT(0, curr_cpu);
msg->done = false;
// dprintf("smp_send_broadcast_ici%d: inserting msg 0x%x into broadcast mbox\n", smp_get_current_cpu(), msg);
// stick it in the appropriate cpu's mailbox
acquire_spinlock_nocheck(&broadcast_msg_spinlock);
msg->next = smp_broadcast_msgs;
smp_broadcast_msgs = msg;
release_spinlock(&broadcast_msg_spinlock);
arch_smp_send_broadcast_ici();
// dprintf("smp_send_broadcast_ici: sent interrupt\n");
if(flags == SMP_MSG_FLAG_SYNC) {
// wait for the other cpus to finish processing it
// the interrupt handler will ref count it to <0
// if the message is sync after it has removed it from the mailbox
// dprintf("smp_send_broadcast_ici: waiting for ack\n");
while(msg->done == false)
smp_process_pending_ici(curr_cpu);
// dprintf("smp_send_broadcast_ici: returning message to free list\n");
// for SYNC messages, it's our responsibility to put it
// back into the free list
return_free_message(msg);
}
int_restore_interrupts(state);
}
// dprintf("smp_send_broadcast_ici: done\n");
}
int smp_trap_non_boot_cpus(kernel_args *ka, int cpu)
{
if(cpu > 0) {
boot_cpu_spin[cpu] = 1;
acquire_spinlock(&boot_cpu_spin[cpu]);
return 1;
} else {
return 0;
}
}
void smp_wake_up_all_non_boot_cpus()
{
int i;
for(i=1; i < smp_num_cpus; i++) {
release_spinlock(&boot_cpu_spin[i]);
}
}
void smp_wait_for_ap_cpus(kernel_args *ka)
{
unsigned int i;
int retry;
do {
retry = 0;
for(i=1; i < ka->num_cpus; i++) {
if(boot_cpu_spin[i] != 1)
retry = 1;
}
} while(retry == 1);
}
int smp_init(kernel_args *ka)
{
struct smp_msg *msg;
int i;
dprintf("smp_init: entry\n");
if(ka->num_cpus > 1) {
free_msgs = NULL;
free_msg_count = 0;
for(i=0; i<MSG_POOL_SIZE; i++) {
msg = (struct smp_msg *)kmalloc(sizeof(struct smp_msg));
if(msg == NULL) {
panic("error creating smp mailboxes\n");
return ERR_GENERAL;
}
memset(msg, 0, sizeof(struct smp_msg));
msg->next = free_msgs;
free_msgs = msg;
free_msg_count++;
}
smp_num_cpus = ka->num_cpus;
}
dprintf("smp_init: calling arch_smp_init\n");
return arch_smp_init(ka);
}
void smp_set_num_cpus(int num_cpus)
{
smp_num_cpus = num_cpus;
}
int smp_get_num_cpus()
{
return smp_num_cpus;
}
int smp_get_current_cpu(void)
{
struct thread *t = thread_get_current_thread();
if(t)
return t->cpu->info.cpu_num;
else
return 0;
}
int smp_enable_ici()
{
if(smp_num_cpus > 1) // dont actually do it if we only have one cpu
ici_enabled = true;
return B_NO_ERROR;
}
int smp_disable_ici()
{
ici_enabled = false;
return B_NO_ERROR;
}