135728b82SThomas Gleixner // SPDX-License-Identifier: GPL-2.0+ 20606f422SRichard Cochran /* 358c5fc2bSThomas Gleixner * Support for dynamic clock devices 40606f422SRichard Cochran * 50606f422SRichard Cochran * Copyright (C) 2010 OMICRON electronics GmbH 60606f422SRichard Cochran * 70606f422SRichard Cochran * This program is free software; you can redistribute it and/or modify 80606f422SRichard Cochran * it under the terms of the GNU General Public License as published by 90606f422SRichard Cochran * the Free Software Foundation; either version 2 of the License, or 100606f422SRichard Cochran * (at your option) any later version. 110606f422SRichard Cochran * 120606f422SRichard Cochran * This program is distributed in the hope that it will be useful, 130606f422SRichard Cochran * but WITHOUT ANY WARRANTY; without even the implied warranty of 140606f422SRichard Cochran * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 150606f422SRichard Cochran * GNU General Public License for more details. 160606f422SRichard Cochran * 170606f422SRichard Cochran * You should have received a copy of the GNU General Public License 180606f422SRichard Cochran * along with this program; if not, write to the Free Software 190606f422SRichard Cochran * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 200606f422SRichard Cochran */ 210606f422SRichard Cochran #include <linux/device.h> 226e5fdeedSPaul Gortmaker #include <linux/export.h> 230606f422SRichard Cochran #include <linux/file.h> 240606f422SRichard Cochran #include <linux/posix-clock.h> 250606f422SRichard Cochran #include <linux/slab.h> 260606f422SRichard Cochran #include <linux/syscalls.h> 270606f422SRichard Cochran #include <linux/uaccess.h> 280606f422SRichard Cochran 29bab0aae9SThomas Gleixner #include "posix-timers.h" 30bab0aae9SThomas Gleixner 310606f422SRichard Cochran static void delete_clock(struct kref *kref); 320606f422SRichard Cochran 330606f422SRichard Cochran /* 340606f422SRichard Cochran * Returns NULL if the posix_clock instance attached to 'fp' is old and stale. 350606f422SRichard Cochran */ 360606f422SRichard Cochran static struct posix_clock *get_posix_clock(struct file *fp) 370606f422SRichard Cochran { 380606f422SRichard Cochran struct posix_clock *clk = fp->private_data; 390606f422SRichard Cochran 401791f881SRichard Cochran down_read(&clk->rwsem); 410606f422SRichard Cochran 420606f422SRichard Cochran if (!clk->zombie) 430606f422SRichard Cochran return clk; 440606f422SRichard Cochran 451791f881SRichard Cochran up_read(&clk->rwsem); 460606f422SRichard Cochran 470606f422SRichard Cochran return NULL; 480606f422SRichard Cochran } 490606f422SRichard Cochran 500606f422SRichard Cochran static void put_posix_clock(struct posix_clock *clk) 510606f422SRichard Cochran { 521791f881SRichard Cochran up_read(&clk->rwsem); 530606f422SRichard Cochran } 540606f422SRichard Cochran 550606f422SRichard Cochran static ssize_t posix_clock_read(struct file *fp, char __user *buf, 560606f422SRichard Cochran size_t count, loff_t *ppos) 570606f422SRichard Cochran { 580606f422SRichard Cochran struct posix_clock *clk = get_posix_clock(fp); 590606f422SRichard Cochran int err = -EINVAL; 600606f422SRichard Cochran 610606f422SRichard Cochran if (!clk) 620606f422SRichard Cochran return -ENODEV; 630606f422SRichard Cochran 640606f422SRichard Cochran if (clk->ops.read) 650606f422SRichard Cochran err = clk->ops.read(clk, fp->f_flags, buf, count); 660606f422SRichard Cochran 670606f422SRichard Cochran put_posix_clock(clk); 680606f422SRichard Cochran 690606f422SRichard Cochran return err; 700606f422SRichard Cochran } 710606f422SRichard Cochran 729dd95748SAl Viro static __poll_t posix_clock_poll(struct file *fp, poll_table *wait) 730606f422SRichard Cochran { 740606f422SRichard Cochran struct posix_clock *clk = get_posix_clock(fp); 759dd95748SAl Viro __poll_t result = 0; 760606f422SRichard Cochran 770606f422SRichard Cochran if (!clk) 78a9a08845SLinus Torvalds return EPOLLERR; 790606f422SRichard Cochran 800606f422SRichard Cochran if (clk->ops.poll) 810606f422SRichard Cochran result = clk->ops.poll(clk, fp, wait); 820606f422SRichard Cochran 830606f422SRichard Cochran put_posix_clock(clk); 840606f422SRichard Cochran 850606f422SRichard Cochran return result; 860606f422SRichard Cochran } 870606f422SRichard Cochran 880606f422SRichard Cochran static long posix_clock_ioctl(struct file *fp, 890606f422SRichard Cochran unsigned int cmd, unsigned long arg) 900606f422SRichard Cochran { 910606f422SRichard Cochran struct posix_clock *clk = get_posix_clock(fp); 920606f422SRichard Cochran int err = -ENOTTY; 930606f422SRichard Cochran 940606f422SRichard Cochran if (!clk) 950606f422SRichard Cochran return -ENODEV; 960606f422SRichard Cochran 970606f422SRichard Cochran if (clk->ops.ioctl) 980606f422SRichard Cochran err = clk->ops.ioctl(clk, cmd, arg); 990606f422SRichard Cochran 1000606f422SRichard Cochran put_posix_clock(clk); 1010606f422SRichard Cochran 1020606f422SRichard Cochran return err; 1030606f422SRichard Cochran } 1040606f422SRichard Cochran 1050606f422SRichard Cochran #ifdef CONFIG_COMPAT 1060606f422SRichard Cochran static long posix_clock_compat_ioctl(struct file *fp, 1070606f422SRichard Cochran unsigned int cmd, unsigned long arg) 1080606f422SRichard Cochran { 1090606f422SRichard Cochran struct posix_clock *clk = get_posix_clock(fp); 1100606f422SRichard Cochran int err = -ENOTTY; 1110606f422SRichard Cochran 1120606f422SRichard Cochran if (!clk) 1130606f422SRichard Cochran return -ENODEV; 1140606f422SRichard Cochran 1150606f422SRichard Cochran if (clk->ops.ioctl) 1160606f422SRichard Cochran err = clk->ops.ioctl(clk, cmd, arg); 1170606f422SRichard Cochran 1180606f422SRichard Cochran put_posix_clock(clk); 1190606f422SRichard Cochran 1200606f422SRichard Cochran return err; 1210606f422SRichard Cochran } 1220606f422SRichard Cochran #endif 1230606f422SRichard Cochran 1240606f422SRichard Cochran static int posix_clock_open(struct inode *inode, struct file *fp) 1250606f422SRichard Cochran { 1260606f422SRichard Cochran int err; 1270606f422SRichard Cochran struct posix_clock *clk = 1280606f422SRichard Cochran container_of(inode->i_cdev, struct posix_clock, cdev); 1290606f422SRichard Cochran 1301791f881SRichard Cochran down_read(&clk->rwsem); 1310606f422SRichard Cochran 1320606f422SRichard Cochran if (clk->zombie) { 1330606f422SRichard Cochran err = -ENODEV; 1340606f422SRichard Cochran goto out; 1350606f422SRichard Cochran } 1360606f422SRichard Cochran if (clk->ops.open) 1370606f422SRichard Cochran err = clk->ops.open(clk, fp->f_mode); 1380606f422SRichard Cochran else 1390606f422SRichard Cochran err = 0; 1400606f422SRichard Cochran 1410606f422SRichard Cochran if (!err) { 1420606f422SRichard Cochran kref_get(&clk->kref); 1430606f422SRichard Cochran fp->private_data = clk; 1440606f422SRichard Cochran } 1450606f422SRichard Cochran out: 1461791f881SRichard Cochran up_read(&clk->rwsem); 1470606f422SRichard Cochran return err; 1480606f422SRichard Cochran } 1490606f422SRichard Cochran 1500606f422SRichard Cochran static int posix_clock_release(struct inode *inode, struct file *fp) 1510606f422SRichard Cochran { 1520606f422SRichard Cochran struct posix_clock *clk = fp->private_data; 1530606f422SRichard Cochran int err = 0; 1540606f422SRichard Cochran 1550606f422SRichard Cochran if (clk->ops.release) 1560606f422SRichard Cochran err = clk->ops.release(clk); 1570606f422SRichard Cochran 1580606f422SRichard Cochran kref_put(&clk->kref, delete_clock); 1590606f422SRichard Cochran 1600606f422SRichard Cochran fp->private_data = NULL; 1610606f422SRichard Cochran 1620606f422SRichard Cochran return err; 1630606f422SRichard Cochran } 1640606f422SRichard Cochran 1650606f422SRichard Cochran static const struct file_operations posix_clock_file_operations = { 1660606f422SRichard Cochran .owner = THIS_MODULE, 1670606f422SRichard Cochran .llseek = no_llseek, 1680606f422SRichard Cochran .read = posix_clock_read, 1690606f422SRichard Cochran .poll = posix_clock_poll, 1700606f422SRichard Cochran .unlocked_ioctl = posix_clock_ioctl, 1710606f422SRichard Cochran .open = posix_clock_open, 1720606f422SRichard Cochran .release = posix_clock_release, 1730606f422SRichard Cochran #ifdef CONFIG_COMPAT 1740606f422SRichard Cochran .compat_ioctl = posix_clock_compat_ioctl, 1750606f422SRichard Cochran #endif 1760606f422SRichard Cochran }; 1770606f422SRichard Cochran 1780606f422SRichard Cochran int posix_clock_register(struct posix_clock *clk, dev_t devid) 1790606f422SRichard Cochran { 1800606f422SRichard Cochran int err; 1810606f422SRichard Cochran 1820606f422SRichard Cochran kref_init(&clk->kref); 1831791f881SRichard Cochran init_rwsem(&clk->rwsem); 1840606f422SRichard Cochran 1850606f422SRichard Cochran cdev_init(&clk->cdev, &posix_clock_file_operations); 1860606f422SRichard Cochran clk->cdev.owner = clk->ops.owner; 1870606f422SRichard Cochran err = cdev_add(&clk->cdev, devid, 1); 1880606f422SRichard Cochran 1890606f422SRichard Cochran return err; 1900606f422SRichard Cochran } 1910606f422SRichard Cochran EXPORT_SYMBOL_GPL(posix_clock_register); 1920606f422SRichard Cochran 1930606f422SRichard Cochran static void delete_clock(struct kref *kref) 1940606f422SRichard Cochran { 1950606f422SRichard Cochran struct posix_clock *clk = container_of(kref, struct posix_clock, kref); 1961791f881SRichard Cochran 1970606f422SRichard Cochran if (clk->release) 1980606f422SRichard Cochran clk->release(clk); 1990606f422SRichard Cochran } 2000606f422SRichard Cochran 2010606f422SRichard Cochran void posix_clock_unregister(struct posix_clock *clk) 2020606f422SRichard Cochran { 2030606f422SRichard Cochran cdev_del(&clk->cdev); 2040606f422SRichard Cochran 2051791f881SRichard Cochran down_write(&clk->rwsem); 2060606f422SRichard Cochran clk->zombie = true; 2071791f881SRichard Cochran up_write(&clk->rwsem); 2080606f422SRichard Cochran 2090606f422SRichard Cochran kref_put(&clk->kref, delete_clock); 2100606f422SRichard Cochran } 2110606f422SRichard Cochran EXPORT_SYMBOL_GPL(posix_clock_unregister); 2120606f422SRichard Cochran 2130606f422SRichard Cochran struct posix_clock_desc { 2140606f422SRichard Cochran struct file *fp; 2150606f422SRichard Cochran struct posix_clock *clk; 2160606f422SRichard Cochran }; 2170606f422SRichard Cochran 2180606f422SRichard Cochran static int get_clock_desc(const clockid_t id, struct posix_clock_desc *cd) 2190606f422SRichard Cochran { 22029f1b2b0SNick Desaulniers struct file *fp = fget(clockid_to_fd(id)); 2210606f422SRichard Cochran int err = -EINVAL; 2220606f422SRichard Cochran 2230606f422SRichard Cochran if (!fp) 2240606f422SRichard Cochran return err; 2250606f422SRichard Cochran 2260606f422SRichard Cochran if (fp->f_op->open != posix_clock_open || !fp->private_data) 2270606f422SRichard Cochran goto out; 2280606f422SRichard Cochran 2290606f422SRichard Cochran cd->fp = fp; 2300606f422SRichard Cochran cd->clk = get_posix_clock(fp); 2310606f422SRichard Cochran 2320606f422SRichard Cochran err = cd->clk ? 0 : -ENODEV; 2330606f422SRichard Cochran out: 2340606f422SRichard Cochran if (err) 2350606f422SRichard Cochran fput(fp); 2360606f422SRichard Cochran return err; 2370606f422SRichard Cochran } 2380606f422SRichard Cochran 2390606f422SRichard Cochran static void put_clock_desc(struct posix_clock_desc *cd) 2400606f422SRichard Cochran { 2410606f422SRichard Cochran put_posix_clock(cd->clk); 2420606f422SRichard Cochran fput(cd->fp); 2430606f422SRichard Cochran } 2440606f422SRichard Cochran 2450606f422SRichard Cochran static int pc_clock_adjtime(clockid_t id, struct timex *tx) 2460606f422SRichard Cochran { 2470606f422SRichard Cochran struct posix_clock_desc cd; 2480606f422SRichard Cochran int err; 2490606f422SRichard Cochran 2500606f422SRichard Cochran err = get_clock_desc(id, &cd); 2510606f422SRichard Cochran if (err) 2520606f422SRichard Cochran return err; 2530606f422SRichard Cochran 2546e6823d1STorben Hohn if ((cd.fp->f_mode & FMODE_WRITE) == 0) { 2556e6823d1STorben Hohn err = -EACCES; 2566e6823d1STorben Hohn goto out; 2576e6823d1STorben Hohn } 2586e6823d1STorben Hohn 2590606f422SRichard Cochran if (cd.clk->ops.clock_adjtime) 2600606f422SRichard Cochran err = cd.clk->ops.clock_adjtime(cd.clk, tx); 2610606f422SRichard Cochran else 2620606f422SRichard Cochran err = -EOPNOTSUPP; 2636e6823d1STorben Hohn out: 2640606f422SRichard Cochran put_clock_desc(&cd); 2650606f422SRichard Cochran 2660606f422SRichard Cochran return err; 2670606f422SRichard Cochran } 2680606f422SRichard Cochran 2693c9c12f4SDeepa Dinamani static int pc_clock_gettime(clockid_t id, struct timespec64 *ts) 2700606f422SRichard Cochran { 2710606f422SRichard Cochran struct posix_clock_desc cd; 2720606f422SRichard Cochran int err; 2730606f422SRichard Cochran 2740606f422SRichard Cochran err = get_clock_desc(id, &cd); 2750606f422SRichard Cochran if (err) 2760606f422SRichard Cochran return err; 2770606f422SRichard Cochran 2783c9c12f4SDeepa Dinamani if (cd.clk->ops.clock_gettime) 2793c9c12f4SDeepa Dinamani err = cd.clk->ops.clock_gettime(cd.clk, ts); 2800606f422SRichard Cochran else 2810606f422SRichard Cochran err = -EOPNOTSUPP; 2820606f422SRichard Cochran 2830606f422SRichard Cochran put_clock_desc(&cd); 2840606f422SRichard Cochran 2850606f422SRichard Cochran return err; 2860606f422SRichard Cochran } 2870606f422SRichard Cochran 288d2e3e0caSDeepa Dinamani static int pc_clock_getres(clockid_t id, struct timespec64 *ts) 2890606f422SRichard Cochran { 2900606f422SRichard Cochran struct posix_clock_desc cd; 2910606f422SRichard Cochran int err; 2920606f422SRichard Cochran 2930606f422SRichard Cochran err = get_clock_desc(id, &cd); 2940606f422SRichard Cochran if (err) 2950606f422SRichard Cochran return err; 2960606f422SRichard Cochran 297d2e3e0caSDeepa Dinamani if (cd.clk->ops.clock_getres) 298d2e3e0caSDeepa Dinamani err = cd.clk->ops.clock_getres(cd.clk, ts); 2990606f422SRichard Cochran else 3000606f422SRichard Cochran err = -EOPNOTSUPP; 3010606f422SRichard Cochran 3020606f422SRichard Cochran put_clock_desc(&cd); 3030606f422SRichard Cochran 3040606f422SRichard Cochran return err; 3050606f422SRichard Cochran } 3060606f422SRichard Cochran 3070fe6afe3SDeepa Dinamani static int pc_clock_settime(clockid_t id, const struct timespec64 *ts) 3080606f422SRichard Cochran { 3090606f422SRichard Cochran struct posix_clock_desc cd; 3100606f422SRichard Cochran int err; 3110606f422SRichard Cochran 3120606f422SRichard Cochran err = get_clock_desc(id, &cd); 3130606f422SRichard Cochran if (err) 3140606f422SRichard Cochran return err; 3150606f422SRichard Cochran 3166e6823d1STorben Hohn if ((cd.fp->f_mode & FMODE_WRITE) == 0) { 3176e6823d1STorben Hohn err = -EACCES; 3186e6823d1STorben Hohn goto out; 3196e6823d1STorben Hohn } 3206e6823d1STorben Hohn 3210606f422SRichard Cochran if (cd.clk->ops.clock_settime) 3220fe6afe3SDeepa Dinamani err = cd.clk->ops.clock_settime(cd.clk, ts); 3230606f422SRichard Cochran else 3240606f422SRichard Cochran err = -EOPNOTSUPP; 3256e6823d1STorben Hohn out: 3260606f422SRichard Cochran put_clock_desc(&cd); 3270606f422SRichard Cochran 3280606f422SRichard Cochran return err; 3290606f422SRichard Cochran } 3300606f422SRichard Cochran 331d3ba5a9aSChristoph Hellwig const struct k_clock clock_posix_dynamic = { 3320606f422SRichard Cochran .clock_getres = pc_clock_getres, 3330606f422SRichard Cochran .clock_set = pc_clock_settime, 3340606f422SRichard Cochran .clock_get = pc_clock_gettime, 3350606f422SRichard Cochran .clock_adj = pc_clock_adjtime, 3360606f422SRichard Cochran }; 337