mirror of
https://github.com/cirosantilli/linux-kernel-module-cheat.git
synced 2026-01-22 17:55:57 +01:00
56738a1c70
Unsquashed version at v2-rc-unsquashed, but that cannot be merged as it breaks bisects at several points. All bugs will not bisect to this humongous change. It all started with a conversion of the Bash scripts to Python, mainly because I couldn't stand not being able to properly use --options for run which has a million options. Then since that required a full testing, I decided to do all the refactorings that I had in mind at once, and so I did and it became v2-rc. This is the largest patch I have ever done! OMG a few weeks of extra time. I'm never writing a Bash script for anything that starts getting big again. Some of the features are: * separate build-qemu and build-gem5 commands * common: convert scripts to python. Add --option for everything * rename build to build-buildroot now that we are splitting all the build commands, Linux kernel to follow * move all git submodules to submodules/ and all buildroot packages to packages/ * refactor the out/ structure. Keep projects on toplevel, because guest projects separate archs and host ones don't, making a toplevel arch wrong * do-release: rename to just release https://stackoverflow.com/questions/16174992/cant-get-argparse-to-read-quoted-string-with-dashes-in-it * run: add --terminal and explain gem5 pdb * just track the lvimrc * store CLI kernel config fragment inside buildlroot to avoid conflicts * gem5: document m5 initparam * readme: make a bunch of things awesomer * readme: fix broken refs * parsec-benchmark: update to 75d55ac446a43c47efb1044844a108c6c330184c Could not fetch otherwise. * gem5: M5_OVERRIDE_PY_SOURCE
85 lines
2.2 KiB
C
85 lines
2.2 KiB
C
/* https://github.com/cirosantilli/linux-kernel-module-cheat#poll */
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#include <linux/debugfs.h>
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#include <linux/delay.h> /* usleep_range */
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#include <linux/errno.h> /* EFAULT */
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#include <linux/fs.h>
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#include <linux/jiffies.h>
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#include <linux/kernel.h> /* min */
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#include <linux/kthread.h>
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#include <linux/module.h>
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#include <linux/poll.h>
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#include <linux/printk.h> /* printk */
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#include <linux/uaccess.h> /* copy_from_user, copy_to_user */
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#include <linux/wait.h> /* wait_queue_head_t, wait_event_interruptible, wake_up_interruptible */
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#include <uapi/linux/stat.h> /* S_IRUSR */
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static char readbuf[1024];
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static size_t readbuflen;
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static struct dentry *debugfs_file;
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static struct task_struct *kthread;
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static wait_queue_head_t waitqueue;
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static ssize_t read(struct file *filp, char __user *buf, size_t len, loff_t *off)
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{
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ssize_t ret;
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if (copy_to_user(buf, readbuf, readbuflen)) {
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ret = -EFAULT;
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} else {
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ret = readbuflen;
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}
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/* This is normal pipe behaviour: data gets drained once a reader reads from it. */
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/* https://stackoverflow.com/questions/1634580/named-pipes-fifos-on-unix-with-multiple-readers */
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readbuflen = 0;
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return ret;
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}
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/* If you return 0 here, then the kernel will sleep until an event happens in the queue.
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*
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* This gets called again every time an event happens in the wait queue.
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*/
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unsigned int poll(struct file *filp, struct poll_table_struct *wait)
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{
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poll_wait(filp, &waitqueue, wait);
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if (readbuflen)
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return POLLIN;
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else
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return 0;
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}
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static int kthread_func(void *data)
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{
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while (!kthread_should_stop()) {
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readbuflen = snprintf(readbuf, sizeof(readbuf), "%llu", (unsigned long long)jiffies);
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usleep_range(1000000, 1000001);
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wake_up(&waitqueue);
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}
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return 0;
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}
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static const struct file_operations fops = {
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.owner = THIS_MODULE,
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.read = read,
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.poll = poll
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};
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static int myinit(void)
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{
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debugfs_file = debugfs_create_file(
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"lkmc_poll", S_IRUSR | S_IWUSR, NULL, NULL, &fops);
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init_waitqueue_head(&waitqueue);
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kthread = kthread_create(kthread_func, NULL, "mykthread");
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wake_up_process(kthread);
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return 0;
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}
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static void myexit(void)
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{
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kthread_stop(kthread);
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debugfs_remove(debugfs_file);
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}
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module_init(myinit)
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module_exit(myexit)
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MODULE_LICENSE("GPL");
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