neptune/start.c

69 lines
1.9 KiB
C

#include <config.h>
#include <ispinlock.h>
#include <kalloc.h>
#include <memory.h>
#include <proc.h>
#include <riscv.h>
#include <types.h>
#include <uart.h>
/**
* Allocate one stack per CPU (hart).
* Each stack is 4096 bytes, aligned to 16 bytes for safety and performance.
* The entry assembly code will calculate the proper stack address for the
* current hart. For more info, read up on stack pointers and see: entry.S
*/
char stack0[4096 * NCPU] __attribute__((aligned(16)));
/* Keep this here and sync on it until we have synchronized printf */
spinlock_t sl = {0};
volatile int hold = 1;
volatile int max_hart = 0;
/* This is where entry.S drops us of. All cores land here */
void start() {
// Do this first
__sync_fetch_and_add(&max_hart, 1);
__sync_synchronize();
u64 id = read_mhartid();
// Keep each CPU's hartid in its tp (thread pointer) register, for cpuid().
// This can then be retrieved with r_wp or cpuid(). It is used to index the
// cpus[] array in mycpu(), which in turn holds state for each individual
// cpu (struct Cpu).
write_tp(id);
if (id == 0) {
/* Here we will do a bunch of initialization steps */
kalloc_init();
uart_puts("Hello Neptune!\n");
spinlock_init(&sl);
hold = 0;
} else {
while (hold);
}
// spin_lock(&sl);
//
// uart_puts("Hart number: ");
// uart_putc(id + '0');
// uart_putc('\n');
//
// spin_unlock(&sl);
if (id == 0) {
spin_lock(&sl);
uart_puts("Core count: ");
uart_putc(max_hart + '0');
uart_putc('\n');
if (max_hart == NCPU) {
uart_puts("All cores up!");
uart_putc('\n');
}
spin_unlock(&sl);
}
// We should not arrive here, but if we do, hang in a while on wfi.
while (1) __asm__ volatile("wfi"); // (Wait For Interrupt)
}