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#include "kernel/spinlock.h"
#include "kernel/riscv.h"
#include "kernel/proc.h"
#include "drivers/uart.h"
#include "common/types.h"
#define NCPU 8
namespace Spinlock
{
int g_noff[NCPU];
int g_intena[NCPU];
int cpuid()
{
return r_tp();
}
void init(struct spinlock *lk, char* name)
{
lk->name = name;
lk->locked = 0;
lk->cpu_id = -1;
}
void push_off()
{
int old = intr_get();
intr_off();
int id = cpuid();
if (g_noff[id] == 0)
{
g_intena[id] = old;
}
g_noff[id] += 1;
}
void pop_off()
{
int id = cpuid();
if (intr_get())
Drivers::uart_puts("pop_off - interruptible\n");
if (g_noff[id] < 1)
Drivers::uart_puts("pop_off - count error\n");
g_noff[id] -= 1;
if (g_noff[id] == 0 && g_intena[id])
{
intr_on();
}
}
int holding(struct spinlock *lk)
{
int r;
push_off();
r = (lk->locked && lk->cpu_id == cpuid());
pop_off();
return r;
}
void acquire(struct spinlock *lk)
{
push_off();
if(holding(lk))
{
Drivers::uart_puts("acquire: panic - recursive lock ");
Drivers::uart_puts(lk->name);
Drivers::uart_puts("\n");
while (1)
;
}
while (__sync_lock_test_and_set(&lk->locked, 1) != 0)
{
// 自旋等待
}
__sync_synchronize();
lk->cpu_id = cpuid();
}
void release(struct spinlock *lk)
{
if (!holding(lk))
{
Drivers::uart_puts("release: panic - not holding\n");
while (1)
;
}
lk->cpu_id = -1;
__sync_synchronize();
__sync_lock_release(&lk->locked);
pop_off();
}
} // namespace Spinlock
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