cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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led.c (3258B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2#include <linux/kernel.h>
      3#include <linux/module.h>
      4#include <linux/init.h>
      5#include <linux/proc_fs.h>
      6#include <linux/seq_file.h>
      7#include <linux/slab.h>
      8#include <linux/string.h>
      9#include <linux/jiffies.h>
     10#include <linux/timer.h>
     11#include <linux/uaccess.h>
     12#include <linux/sched/loadavg.h>
     13
     14#include <asm/auxio.h>
     15
     16#define LED_MAX_LENGTH 8 /* maximum chars written to proc file */
     17
     18static inline void led_toggle(void)
     19{
     20	unsigned char val = get_auxio();
     21	unsigned char on, off;
     22
     23	if (val & AUXIO_LED) {
     24		on = 0;
     25		off = AUXIO_LED;
     26	} else {
     27		on = AUXIO_LED;
     28		off = 0;
     29	}
     30
     31	set_auxio(on, off);
     32}
     33
     34static struct timer_list led_blink_timer;
     35static unsigned long led_blink_timer_timeout;
     36
     37static void led_blink(struct timer_list *unused)
     38{
     39	unsigned long timeout = led_blink_timer_timeout;
     40
     41	led_toggle();
     42
     43	/* reschedule */
     44	if (!timeout) { /* blink according to load */
     45		led_blink_timer.expires = jiffies +
     46			((1 + (avenrun[0] >> FSHIFT)) * HZ);
     47	} else { /* blink at user specified interval */
     48		led_blink_timer.expires = jiffies + (timeout * HZ);
     49	}
     50	add_timer(&led_blink_timer);
     51}
     52
     53#ifdef CONFIG_PROC_FS
     54static int led_proc_show(struct seq_file *m, void *v)
     55{
     56	if (get_auxio() & AUXIO_LED)
     57		seq_puts(m, "on\n");
     58	else
     59		seq_puts(m, "off\n");
     60	return 0;
     61}
     62
     63static int led_proc_open(struct inode *inode, struct file *file)
     64{
     65	return single_open(file, led_proc_show, NULL);
     66}
     67
     68static ssize_t led_proc_write(struct file *file, const char __user *buffer,
     69			      size_t count, loff_t *ppos)
     70{
     71	char *buf = NULL;
     72
     73	if (count > LED_MAX_LENGTH)
     74		count = LED_MAX_LENGTH;
     75
     76	buf = memdup_user_nul(buffer, count);
     77	if (IS_ERR(buf))
     78		return PTR_ERR(buf);
     79
     80	/* work around \n when echo'ing into proc */
     81	if (buf[count - 1] == '\n')
     82		buf[count - 1] = '\0';
     83
     84	/* before we change anything we want to stop any running timers,
     85	 * otherwise calls such as on will have no persistent effect
     86	 */
     87	del_timer_sync(&led_blink_timer);
     88
     89	if (!strcmp(buf, "on")) {
     90		auxio_set_led(AUXIO_LED_ON);
     91	} else if (!strcmp(buf, "toggle")) {
     92		led_toggle();
     93	} else if ((*buf > '0') && (*buf <= '9')) {
     94		led_blink_timer_timeout = simple_strtoul(buf, NULL, 10);
     95		led_blink(&led_blink_timer);
     96	} else if (!strcmp(buf, "load")) {
     97		led_blink_timer_timeout = 0;
     98		led_blink(&led_blink_timer);
     99	} else {
    100		auxio_set_led(AUXIO_LED_OFF);
    101	}
    102
    103	kfree(buf);
    104
    105	return count;
    106}
    107
    108static const struct proc_ops led_proc_ops = {
    109	.proc_open	= led_proc_open,
    110	.proc_read	= seq_read,
    111	.proc_lseek	= seq_lseek,
    112	.proc_release	= single_release,
    113	.proc_write	= led_proc_write,
    114};
    115#endif
    116
    117#define LED_VERSION	"0.1"
    118
    119static int __init led_init(void)
    120{
    121	timer_setup(&led_blink_timer, led_blink, 0);
    122
    123#ifdef CONFIG_PROC_FS
    124	if (!proc_create("led", 0, NULL, &led_proc_ops))
    125		return -ENOMEM;
    126#endif
    127	printk(KERN_INFO
    128	       "led: version %s, Lars Kotthoff <metalhead@metalhead.ws>\n",
    129	       LED_VERSION);
    130
    131	return 0;
    132}
    133
    134static void __exit led_exit(void)
    135{
    136	remove_proc_entry("led", NULL);
    137	del_timer_sync(&led_blink_timer);
    138}
    139
    140module_init(led_init);
    141module_exit(led_exit);
    142
    143MODULE_AUTHOR("Lars Kotthoff <metalhead@metalhead.ws>");
    144MODULE_DESCRIPTION("Provides control of the front LED on SPARC systems.");
    145MODULE_LICENSE("GPL");
    146MODULE_VERSION(LED_VERSION);