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原帖由 new_learner 于 2009-4-21 23:24 发表
感觉有道理。。。。
多谢!
明天我再验证一下:)
写了一段kernel module和 userspace program来验证:
kernel module: my_spin_lock.c
- #include <linux/kernel.h>
- #include <linux/init.h>
- #include <linux/module.h>
- #include <linux/spinlock.h>
- #define IF_MASK 0x00000200
- static spinlock_t my_spinlock;
- static unsigned int is_interrupt_enable()
- {
- unsigned long my_eflags;
- asm volatile ("pushfl \n\t"
- "popl %0"
- :"=a"(my_eflags));
- return (((my_eflags & IF_MASK) == 0) ? 0 : 1);
- }
- static int __init init_test()
- {
- unsigned long flags;
- spin_lock_init(&my_spinlock);
- spin_lock_irqsave(&my_spinlock, flags);
- printk("from kernelspace init: interrupt was enable : %d\n", is_interrupt_enable());
- return 0;
- }
- static void __exit init_exit()
- {
- return;
- }
- MODULE_LICENSE("GPL");
- module_init(init_test);
- module_exit(init_exit);
复制代码
编译以后生成my_spin_lock.ko
然后再写一段userspace program : test.c
- #include <stdio.h>
- #include <stdlib.h>
- #define IF_MASK 0x00000200
- #define CMD_LEN 100
- unsigned int is_interrupt_enable()
- {
- unsigned long my_eflags;
- asm volatile ("pushfl \n\t"
- "popl %0 \n\t"
- :"=a"(my_eflags));
-
- return (((my_eflags & IF_MASK) == 0) ? 0 : 1);
- }
- int main (int argc, char *argv[])
- {
- if (argc != 2)
- {
- printf("usersage: insmod your_kernel_module\n");
- return 0;
- }
- char cmd[CMD_LEN];
- memset(cmd, 0, sizeof(cmd));
- sprintf(cmd, "insmod %s", argv[1]);
- printf("from userspace, before insmod, inerrput is enable : %d\n", is_interrupt_enable());
- system(cmd); /*insmod kernel module*/
- printf("from userspace, after insmod, interrupt is enable : %d\n", is_interrupt_enable());
- memset(cmd, 0, sizeof(cmd));
- sprintf(cmd, "rmmod %s", argv[1]);
- system(cmd); /*rmmod kernel module*/
-
-
- return 0;
- }
复制代码
编译以后生成test二进制文件
然后下命令:
运行结果:
from userspace, before insmod, interrupt is enable : 1
from kernelspace init: interrupt was enable : 0
from userspace, after insmod, interrupt is enable: 1
可见,运行了kernel module的init函数以后,interrupt确实被禁止了。然后返回到用户态,interrupt被打开了。
[ 本帖最后由 new_learner 于 2009-4-22 16:22 编辑 ] |
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