Minki/linux
1
0
Fork 1
mirror of https://github.com/torvalds/linux.git synced 2024-11-18 01:51:53 +00:00
Code Issues Packages Projects Releases Wiki Activity
50dd154ed7
linux/drivers/ptp/ptp_chardev.c
Richard Cochran 62582a7ee7 ptp: Avoid deadlocks in the programmable pin code. 
The PTP Hardware Clock (PHC) subsystem offers an API for configuring
programmable pins.  User space sets or gets the settings using ioctls,
and drivers verify dialed settings via a callback.  Drivers may also
query pin settings by calling the ptp_find_pin() method.

Although the core subsystem protects concurrent access to the pin
settings, the implementation places illogical restrictions on how
drivers may call ptp_find_pin().  When enabling an auxiliary function
via the .enable(on=1) callback, drivers may invoke the pin finding
method, but when disabling with .enable(on=0) drivers are not
permitted to do so.  With the exception of the mv88e6xxx, all of the
PHC drivers do respect this restriction, but still the locking pattern
is both confusing and unnecessary.

This patch changes the locking implementation to allow PHC drivers to
freely call ptp_find_pin() from their .enable() and .verify()
callbacks.

V2 ChangeLog:
- fixed spelling in the kernel doc
- add Vladimir's tested by tag

Signed-off-by: Richard Cochran <richardcochran@gmail.com>
Reported-by: Yangbo Lu <yangbo.lu@nxp.com>
Tested-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-03-30 11:16:38 -07:00

471 lines
11 KiB
C
Raw Blame History

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* PTP 1588 clock support - character device implementation.
*
* Copyright (C) 2010 OMICRON electronics GmbH
*/
#include <linux/module.h>
#include <linux/posix-clock.h>
#include <linux/poll.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/timekeeping.h>
#include <linux/nospec.h>
#include "ptp_private.h"
static int ptp_disable_pinfunc(struct ptp_clock_info *ops,
enum ptp_pin_function func, unsigned int chan)
{
struct ptp_clock_request rq;
int err = 0;
memset(&rq, 0, sizeof(rq));
switch (func) {
case PTP_PF_NONE:
break;
case PTP_PF_EXTTS:
rq.type = PTP_CLK_REQ_EXTTS;
rq.extts.index = chan;
err = ops->enable(ops, &rq, 0);
break;
case PTP_PF_PEROUT:
rq.type = PTP_CLK_REQ_PEROUT;
rq.perout.index = chan;
err = ops->enable(ops, &rq, 0);
break;
case PTP_PF_PHYSYNC:
break;
default:
return -EINVAL;
}
return err;
}
int ptp_set_pinfunc(struct ptp_clock *ptp, unsigned int pin,
enum ptp_pin_function func, unsigned int chan)
{
struct ptp_clock_info *info = ptp->info;
struct ptp_pin_desc *pin1 = NULL, *pin2 = &info->pin_config[pin];
unsigned int i;
/* Check to see if any other pin previously had this function. */
for (i = 0; i < info->n_pins; i++) {
if (info->pin_config[i].func == func &&
info->pin_config[i].chan == chan) {
pin1 = &info->pin_config[i];
break;
}
}
if (pin1 && i == pin)
return 0;
/* Check the desired function and channel. */
switch (func) {
case PTP_PF_NONE:
break;
case PTP_PF_EXTTS:
if (chan >= info->n_ext_ts)
return -EINVAL;
break;
case PTP_PF_PEROUT:
if (chan >= info->n_per_out)
return -EINVAL;
break;
case PTP_PF_PHYSYNC:
if (chan != 0)
return -EINVAL;
break;
default:
return -EINVAL;
}
if (info->verify(info, pin, func, chan)) {
pr_err("driver cannot use function %u on pin %u\n", func, chan);
return -EOPNOTSUPP;
}
/* Disable whatever function was previously assigned. */
if (pin1) {
ptp_disable_pinfunc(info, func, chan);
pin1->func = PTP_PF_NONE;
pin1->chan = 0;
}
ptp_disable_pinfunc(info, pin2->func, pin2->chan);
pin2->func = func;
pin2->chan = chan;
return 0;
}
int ptp_open(struct posix_clock *pc, fmode_t fmode)
{
return 0;
}
long ptp_ioctl(struct posix_clock *pc, unsigned int cmd, unsigned long arg)
{
struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
struct ptp_sys_offset_extended *extoff = NULL;
struct ptp_sys_offset_precise precise_offset;
struct system_device_crosststamp xtstamp;
struct ptp_clock_info *ops = ptp->info;
struct ptp_sys_offset *sysoff = NULL;
struct ptp_system_timestamp sts;
struct ptp_clock_request req;
struct ptp_clock_caps caps;
struct ptp_clock_time *pct;
unsigned int i, pin_index;
struct ptp_pin_desc pd;
struct timespec64 ts;
int enable, err = 0;
switch (cmd) {
case PTP_CLOCK_GETCAPS:
case PTP_CLOCK_GETCAPS2:
memset(&caps, 0, sizeof(caps));
caps.max_adj = ptp->info->max_adj;
caps.n_alarm = ptp->info->n_alarm;
caps.n_ext_ts = ptp->info->n_ext_ts;
caps.n_per_out = ptp->info->n_per_out;
caps.pps = ptp->info->pps;
caps.n_pins = ptp->info->n_pins;
caps.cross_timestamping = ptp->info->getcrosststamp != NULL;
if (copy_to_user((void __user *)arg, &caps, sizeof(caps)))
err = -EFAULT;
break;
case PTP_EXTTS_REQUEST:
case PTP_EXTTS_REQUEST2:
memset(&req, 0, sizeof(req));
if (copy_from_user(&req.extts, (void __user *)arg,
sizeof(req.extts))) {
err = -EFAULT;
break;
}
if (cmd == PTP_EXTTS_REQUEST2) {
/* Tell the drivers to check the flags carefully. */
req.extts.flags |= PTP_STRICT_FLAGS;
/* Make sure no reserved bit is set. */
if ((req.extts.flags & ~PTP_EXTTS_VALID_FLAGS) ||
req.extts.rsv[0] || req.extts.rsv[1]) {
err = -EINVAL;
break;
}
/* Ensure one of the rising/falling edge bits is set. */
if ((req.extts.flags & PTP_ENABLE_FEATURE) &&
(req.extts.flags & PTP_EXTTS_EDGES) == 0) {
err = -EINVAL;
break;
}
} else if (cmd == PTP_EXTTS_REQUEST) {
req.extts.flags &= PTP_EXTTS_V1_VALID_FLAGS;
req.extts.rsv[0] = 0;
req.extts.rsv[1] = 0;
}
if (req.extts.index >= ops->n_ext_ts) {
err = -EINVAL;
break;
}
req.type = PTP_CLK_REQ_EXTTS;
enable = req.extts.flags & PTP_ENABLE_FEATURE ? 1 : 0;
if (mutex_lock_interruptible(&ptp->pincfg_mux))
return -ERESTARTSYS;
err = ops->enable(ops, &req, enable);
mutex_unlock(&ptp->pincfg_mux);
break;
case PTP_PEROUT_REQUEST:
case PTP_PEROUT_REQUEST2:
memset(&req, 0, sizeof(req));
if (copy_from_user(&req.perout, (void __user *)arg,
sizeof(req.perout))) {
err = -EFAULT;
break;
}
if (((req.perout.flags & ~PTP_PEROUT_VALID_FLAGS) ||
req.perout.rsv[0] || req.perout.rsv[1] ||
req.perout.rsv[2] || req.perout.rsv[3]) &&
cmd == PTP_PEROUT_REQUEST2) {
err = -EINVAL;
break;
} else if (cmd == PTP_PEROUT_REQUEST) {
req.perout.flags &= PTP_PEROUT_V1_VALID_FLAGS;
req.perout.rsv[0] = 0;
req.perout.rsv[1] = 0;
req.perout.rsv[2] = 0;
req.perout.rsv[3] = 0;
}
if (req.perout.index >= ops->n_per_out) {
err = -EINVAL;
break;
}
req.type = PTP_CLK_REQ_PEROUT;
enable = req.perout.period.sec || req.perout.period.nsec;
if (mutex_lock_interruptible(&ptp->pincfg_mux))
return -ERESTARTSYS;
err = ops->enable(ops, &req, enable);
mutex_unlock(&ptp->pincfg_mux);
break;
case PTP_ENABLE_PPS:
case PTP_ENABLE_PPS2:
memset(&req, 0, sizeof(req));
if (!capable(CAP_SYS_TIME))
return -EPERM;
req.type = PTP_CLK_REQ_PPS;
enable = arg ? 1 : 0;
if (mutex_lock_interruptible(&ptp->pincfg_mux))
return -ERESTARTSYS;
err = ops->enable(ops, &req, enable);
mutex_unlock(&ptp->pincfg_mux);
break;
case PTP_SYS_OFFSET_PRECISE:
case PTP_SYS_OFFSET_PRECISE2:
if (!ptp->info->getcrosststamp) {
err = -EOPNOTSUPP;
break;
}
err = ptp->info->getcrosststamp(ptp->info, &xtstamp);
if (err)
break;
memset(&precise_offset, 0, sizeof(precise_offset));
ts = ktime_to_timespec64(xtstamp.device);
precise_offset.device.sec = ts.tv_sec;
precise_offset.device.nsec = ts.tv_nsec;
ts = ktime_to_timespec64(xtstamp.sys_realtime);
precise_offset.sys_realtime.sec = ts.tv_sec;
precise_offset.sys_realtime.nsec = ts.tv_nsec;
ts = ktime_to_timespec64(xtstamp.sys_monoraw);
precise_offset.sys_monoraw.sec = ts.tv_sec;
precise_offset.sys_monoraw.nsec = ts.tv_nsec;
if (copy_to_user((void __user *)arg, &precise_offset,
sizeof(precise_offset)))
err = -EFAULT;
break;
case PTP_SYS_OFFSET_EXTENDED:
case PTP_SYS_OFFSET_EXTENDED2:
if (!ptp->info->gettimex64) {
err = -EOPNOTSUPP;
break;
}
extoff = memdup_user((void __user *)arg, sizeof(*extoff));
if (IS_ERR(extoff)) {
err = PTR_ERR(extoff);
extoff = NULL;
break;
}
if (extoff->n_samples > PTP_MAX_SAMPLES
|| extoff->rsv[0] || extoff->rsv[1] || extoff->rsv[2]) {
err = -EINVAL;
break;
}
for (i = 0; i < extoff->n_samples; i++) {
err = ptp->info->gettimex64(ptp->info, &ts, &sts);
if (err)
goto out;
extoff->ts[i][0].sec = sts.pre_ts.tv_sec;
extoff->ts[i][0].nsec = sts.pre_ts.tv_nsec;
extoff->ts[i][1].sec = ts.tv_sec;
extoff->ts[i][1].nsec = ts.tv_nsec;
extoff->ts[i][2].sec = sts.post_ts.tv_sec;
extoff->ts[i][2].nsec = sts.post_ts.tv_nsec;
}
if (copy_to_user((void __user *)arg, extoff, sizeof(*extoff)))
err = -EFAULT;
break;
case PTP_SYS_OFFSET:
case PTP_SYS_OFFSET2:
sysoff = memdup_user((void __user *)arg, sizeof(*sysoff));
if (IS_ERR(sysoff)) {
err = PTR_ERR(sysoff);
sysoff = NULL;
break;
}
if (sysoff->n_samples > PTP_MAX_SAMPLES) {
err = -EINVAL;
break;
}
pct = &sysoff->ts[0];
for (i = 0; i < sysoff->n_samples; i++) {
ktime_get_real_ts64(&ts);
pct->sec = ts.tv_sec;
pct->nsec = ts.tv_nsec;
pct++;
if (ops->gettimex64)
err = ops->gettimex64(ops, &ts, NULL);
else
err = ops->gettime64(ops, &ts);
if (err)
goto out;
pct->sec = ts.tv_sec;
pct->nsec = ts.tv_nsec;
pct++;
}
ktime_get_real_ts64(&ts);
pct->sec = ts.tv_sec;
pct->nsec = ts.tv_nsec;
if (copy_to_user((void __user *)arg, sysoff, sizeof(*sysoff)))
err = -EFAULT;
break;
case PTP_PIN_GETFUNC:
case PTP_PIN_GETFUNC2:
if (copy_from_user(&pd, (void __user *)arg, sizeof(pd))) {
err = -EFAULT;
break;
}
if ((pd.rsv[0] || pd.rsv[1] || pd.rsv[2]
|| pd.rsv[3] || pd.rsv[4])
&& cmd == PTP_PIN_GETFUNC2) {
err = -EINVAL;
break;
} else if (cmd == PTP_PIN_GETFUNC) {
pd.rsv[0] = 0;
pd.rsv[1] = 0;
pd.rsv[2] = 0;
pd.rsv[3] = 0;
pd.rsv[4] = 0;
}
pin_index = pd.index;
if (pin_index >= ops->n_pins) {
err = -EINVAL;
break;
}
pin_index = array_index_nospec(pin_index, ops->n_pins);
if (mutex_lock_interruptible(&ptp->pincfg_mux))
return -ERESTARTSYS;
pd = ops->pin_config[pin_index];
mutex_unlock(&ptp->pincfg_mux);
if (!err && copy_to_user((void __user *)arg, &pd, sizeof(pd)))
err = -EFAULT;
break;
case PTP_PIN_SETFUNC:
case PTP_PIN_SETFUNC2:
if (copy_from_user(&pd, (void __user *)arg, sizeof(pd))) {
err = -EFAULT;
break;
}
if ((pd.rsv[0] || pd.rsv[1] || pd.rsv[2]
|| pd.rsv[3] || pd.rsv[4])
&& cmd == PTP_PIN_SETFUNC2) {
err = -EINVAL;
break;
} else if (cmd == PTP_PIN_SETFUNC) {
pd.rsv[0] = 0;
pd.rsv[1] = 0;
pd.rsv[2] = 0;
pd.rsv[3] = 0;
pd.rsv[4] = 0;
}
pin_index = pd.index;
if (pin_index >= ops->n_pins) {
err = -EINVAL;
break;
}
pin_index = array_index_nospec(pin_index, ops->n_pins);
if (mutex_lock_interruptible(&ptp->pincfg_mux))
return -ERESTARTSYS;
err = ptp_set_pinfunc(ptp, pin_index, pd.func, pd.chan);
mutex_unlock(&ptp->pincfg_mux);
break;
default:
err = -ENOTTY;
break;
}
out:
kfree(extoff);
kfree(sysoff);
return err;
}
__poll_t ptp_poll(struct posix_clock *pc, struct file *fp, poll_table *wait)
{
struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
poll_wait(fp, &ptp->tsev_wq, wait);
return queue_cnt(&ptp->tsevq) ? EPOLLIN : 0;
}
#define EXTTS_BUFSIZE (PTP_BUF_TIMESTAMPS * sizeof(struct ptp_extts_event))
ssize_t ptp_read(struct posix_clock *pc,
uint rdflags, char __user *buf, size_t cnt)
{
struct ptp_clock *ptp = container_of(pc, struct ptp_clock, clock);
struct timestamp_event_queue *queue = &ptp->tsevq;
struct ptp_extts_event *event;
unsigned long flags;
size_t qcnt, i;
int result;
if (cnt % sizeof(struct ptp_extts_event) != 0)
return -EINVAL;
if (cnt > EXTTS_BUFSIZE)
cnt = EXTTS_BUFSIZE;
cnt = cnt / sizeof(struct ptp_extts_event);
if (mutex_lock_interruptible(&ptp->tsevq_mux))
return -ERESTARTSYS;
if (wait_event_interruptible(ptp->tsev_wq,
ptp->defunct || queue_cnt(queue))) {
mutex_unlock(&ptp->tsevq_mux);
return -ERESTARTSYS;
}
if (ptp->defunct) {
mutex_unlock(&ptp->tsevq_mux);
return -ENODEV;
}
event = kmalloc(EXTTS_BUFSIZE, GFP_KERNEL);
if (!event) {
mutex_unlock(&ptp->tsevq_mux);
return -ENOMEM;
}
spin_lock_irqsave(&queue->lock, flags);
qcnt = queue_cnt(queue);
if (cnt > qcnt)
cnt = qcnt;
for (i = 0; i < cnt; i++) {
event[i] = queue->buf[queue->head];
queue->head = (queue->head + 1) % PTP_MAX_TIMESTAMPS;
}
spin_unlock_irqrestore(&queue->lock, flags);
cnt = cnt * sizeof(struct ptp_extts_event);
mutex_unlock(&ptp->tsevq_mux);
result = cnt;
if (copy_to_user(buf, event, cnt))
result = -EFAULT;
kfree(event);
return result;
}
Reference in New Issue View Git Blame Copy Permalink