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bugfix: spinlock操作时，产生的内存写入越界问题。

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This commit is contained in:
fslongjin 2022-08-20 17:11:13 +08:00
parent 05ae8dea67
commit 5747e4c8cc
1 changed files with 9 additions and 9 deletions
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18
kernel/common/spinlock.h
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@ -19,7 +19,7 @@
typedef struct
{
int8_t lock; // 1:unlocked 0:locked
} spinlock_t;
}spinlock_t;
/**
@ -30,11 +30,11 @@ typedef struct
void spin_lock(spinlock_t *lock)
{
__asm__ __volatile__("1: \n\t"
"lock decq %0 \n\t" // 尝试-1
"lock decb %0 \n\t" // 尝试-1
"jns 3f \n\t" // 加锁成功，跳转到步骤3
"2: \n\t" // 加锁失败，稍后再试
"pause \n\t"
"cmpq $0, %0 \n\t"
"cmpb $0, %0 \n\t"
"jle 2b \n\t" // 若锁被占用，则继续重试
"jmp 1b \n\t" // 尝试加锁
"3:"
@ -50,7 +50,7 @@ void spin_lock(spinlock_t *lock)
void spin_unlock(spinlock_t *lock)
{
preempt_enable();
__asm__ __volatile__("movq $1, %0 \n\t"
__asm__ __volatile__("movb $1, %0 \n\t"
: "=m"(lock->lock)::"memory");
}
@ -74,11 +74,11 @@ void spin_init(spinlock_t *lock)
void spin_lock_no_preempt(spinlock_t *lock)
{
__asm__ __volatile__("1: \n\t"
"lock decq %0 \n\t" // 尝试-1
"lock decb %0 \n\t" // 尝试-1
"jns 3f \n\t" // 加锁成功，跳转到步骤3
"2: \n\t" // 加锁失败，稍后再试
"pause \n\t"
"cmpq $0, %0 \n\t"
"cmpb $0, %0 \n\t"
"jle 2b \n\t" // 若锁被占用，则继续重试
"jmp 1b \n\t" // 尝试加锁
"3:"
@ -91,7 +91,7 @@ void spin_lock_no_preempt(spinlock_t *lock)
*/
void spin_unlock_no_preempt(spinlock_t *lock)
{
__asm__ __volatile__("movq $1, %0 \n\t"
__asm__ __volatile__("movb $1, %0 \n\t"
: "=m"(lock->lock)::"memory");
}
@ -106,9 +106,9 @@ long spin_trylock(spinlock_t *lock)
uint64_t tmp_val = 0;
preempt_disable();
// 交换tmp_val和lock的值，若tmp_val==1则证明加锁成功
asm volatile("lock xchgq %0, %1 \n\t" // 确保只有1个进程能得到锁
asm volatile("lock xchg %%bx, %1 \n\t" // 确保只有1个进程能得到锁
: "=q"(tmp_val), "=m"(lock->lock)
: "0"(0)
: "b"(0)
: "memory");
if (!tmp_val)
preempt_enable();