1 #include <linux/version.h>
2 #if (LINUX_VERSION_CODE < KERNEL_VERSION(2,6,17))
3 #include <linux/config.h>
6 #if defined(MODVERSIONS)
7 #include <linux/modversions.h>
9 #include <linux/kernel.h>
10 #include <linux/sched.h>
12 #if (LINUX_VERSION_CODE < KERNEL_VERSION(2,5,40))
13 #include <linux/tqueue.h>
15 #if (LINUX_VERSION_CODE < KERNEL_VERSION(2,6,17))
16 #include <linux/devfs_fs_kernel.h>
20 #include <linux/wait.h>
21 #include <linux/signal.h>
22 #include <linux/interrupt.h>
24 #if (LINUX_VERSION_CODE < KERNEL_VERSION(2,6,27))
25 #include <asm/semaphore.h>
27 #include <linux/semaphore.h>
30 #include <linux/smp_lock.h>
32 #include "../include/kthread.h"
34 /* private functions */
35 #if (LINUX_VERSION_CODE < KERNEL_VERSION(2,5,40))
36 static void kthread_launcher(void *data)
38 static void kthread_launcher(unsigned long data)
41 kthread_t *kthread = (kthread_t *)data;
43 kernel_thread((int (*)(void *))kthread->function, (void *)kthread, 0);
46 /* public functions */
48 /* create a new kernel thread. Called by the creator. */
49 void start_kthread(void (*func)(kthread_t *), kthread_t *kthread)
51 /* initialize the semaphore:
52 we start with the semaphore locked. The new kernel
53 thread will setup its stuff and unlock it. This
54 control flow (the one that creates the thread) blocks
55 in the down operation below until the thread has reached
58 sema_init(&kthread->startstop_sem, 0);
60 /* store the function to be executed in the data passed to
62 kthread->function=func;
64 /* create the new thread my running a task through keventd */
66 #if (LINUX_VERSION_CODE < KERNEL_VERSION(2,5,40))
68 /* initialize the task queue structure */
70 INIT_LIST_HEAD(&kthread->tq.list);
71 kthread->tq.routine = kthread_launcher;
72 kthread->tq.data = kthread;
74 /* and schedule it for execution */
75 schedule_task(&kthread->tq);
77 /* initialize tasklet */
78 tasklet_init(&kthread->tq, kthread_launcher, (unsigned long)kthread);
79 /* and schedule it for execution */
80 tasklet_schedule(&kthread->tq);
83 /* wait till it has reached the setup_thread routine */
84 down(&kthread->startstop_sem);
87 /* stop a kernel thread. Called by the removing instance */
88 void stop_kthread(kthread_t *kthread)
90 if (kthread->thread == NULL)
92 printk("stop_kthread: killing non existing thread!\n");
96 /* this function needs to be protected with the big
97 kernel lock (lock_kernel()). The lock must be
98 grabbed before changing the terminate
99 flag and released after the down() call. */
102 /* initialize the semaphore. We lock it here, the
103 leave_thread call of the thread to be terminated
104 will unlock it. As soon as we see the semaphore
105 unlocked, we know that the thread has exited.
107 sema_init(&kthread->startstop_sem,0);
109 /* We need to do a memory barrier here to be sure that
110 the flags are visible on all CPUs.
114 /* set flag to request thread termination */
115 kthread->terminate = 1;
117 /* We need to do a memory barrier here to be sure that
118 the flags are visible on all CPUs.
121 #warning The local code for kernel thread support is not more needed for recent 2.6 kernels
122 #warning and code should be modified to emulate same interface for older kernels
123 #if (LINUX_VERSION_CODE < KERNEL_VERSION(2,6,20))
124 kill_proc(kthread->thread->pid, SIGKILL, 1);
125 #else /* >= 2,6,20 */
126 send_sig(SIGKILL, kthread->thread, 1);
127 #endif /* >= 2,6,20 */
129 /* block till thread terminated */
130 down(&kthread->startstop_sem);
132 /* release the big kernel lock */
135 /* now we are sure the thread is in zombie state. We
136 notify keventd to clean the process up.
138 #if (LINUX_VERSION_CODE < KERNEL_VERSION(2,6,20))
139 kill_proc(2, SIGCHLD, 1);
140 #endif /* >= 2,6,20 */
144 /* initialize new created thread. Called by the new thread. */
145 void init_kthread(kthread_t *kthread, char *name)
147 /* fill in thread structure */
148 kthread->thread = current;
150 /* initialise termination flag */
151 kthread->terminate = 0;
153 /* initialise wait queue */
154 init_waitqueue_head(&kthread->queue);
156 #if (LINUX_VERSION_CODE < KERNEL_VERSION(2,5,40))
157 /* lock the kernel. A new kernel thread starts without
158 the big kernel lock, regardless of the lock state
159 of the creator (the lock level is *not* inheritated)
164 /* set signal mask to what we want to respond */
165 siginitsetinv(¤t->blocked, sigmask(SIGKILL)|sigmask(SIGINT)|sigmask(SIGTERM));
167 /* set name of this process (max 15 chars + 0 !) */
168 sprintf(current->comm, name);
177 /* tell the creator that we are ready and let him continue */
178 up(&kthread->startstop_sem);
181 /* cleanup of thread. Called by the exiting thread. */
182 void exit_kthread(kthread_t *kthread)
184 /* we are terminating */
186 /* lock the kernel, the exit will unlock it */
188 kthread->thread = NULL;
191 /* notify the stop_kthread() routine that we are terminating. */
192 up(&kthread->startstop_sem);
193 /* the kernel_thread that called clone() does a do_exit here. */
195 /* there is no race here between execution of the "killer" and real termination
196 of the thread (race window between up and do_exit), since both the
197 thread and the "killer" function are running with the kernel lock held.
198 The kernel lock will be freed after the thread exited, so the code
199 is really not executed anymore as soon as the unload functions gets
200 the kernel lock back.
201 The init process may not have made the cleanup of the process here,
202 but the cleanup can be done safely with the module unloaded.