compat_ioctl: move rtc handling into drivers/rtc/dev.c

We no longer need the rtc compat handling to be in common code, now that
all drivers are either moved to the rtc-class framework, or (rarely)
exist in drivers/char for architectures without compat mode (m68k,
alpha and ia64, respectively).

I checked the list of ioctl commands in drivers, and the ones that are
not already handled are all compatible, again with the one exception of
m68k driver, which implements RTC_PLL_GET and RTC_PLL_SET, but has no
compat mode.

Unlike earlier versions of this patch, I'm now adding a separate
compat_ioctl handler that takes care of RTC_IRQP_READ32/RTC_IRQP_SET32
and treats all other commands as compatible, leaving the native
behavior unchanged.

The old conversion handler also deals with RTC_EPOCH_READ and
RTC_EPOCH_SET, which are not handled in rtc-dev.c but only in a single
device driver (rtc-vr41xx), so I'm adding the compat version in the same
place. I don't expect other drivers to need those commands in the future.

Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Reviewed-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
v4: handle RTC_EPOCH_SET32 in rtc_dev_compat_ioctl
v3: handle RTC_IRQP_READ32/RTC_IRQP_SET32 in rtc_dev_compat_ioctl
v2: merge compat handler into ioctl function to avoid the
    compat_alloc_user_space() roundtrip, based on feedback
    from Al Viro.
This commit is contained in:
Arnd Bergmann 2018-08-24 00:11:19 +02:00
parent 18bd6caaef
commit 076ff65862
3 changed files with 40 additions and 54 deletions

View File

@ -10,6 +10,7 @@
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/compat.h>
#include <linux/module.h>
#include <linux/rtc.h>
#include <linux/sched/signal.h>
@ -360,7 +361,6 @@ static long rtc_dev_ioctl(struct file *file,
case RTC_IRQP_SET:
err = rtc_irq_set_freq(rtc, arg);
break;
case RTC_IRQP_READ:
err = put_user(rtc->irq_freq, (unsigned long __user *)uarg);
break;
@ -399,6 +399,34 @@ static long rtc_dev_ioctl(struct file *file,
return err;
}
#ifdef CONFIG_COMPAT
#define RTC_IRQP_SET32 _IOW('p', 0x0c, __u32)
#define RTC_IRQP_READ32 _IOR('p', 0x0b, __u32)
#define RTC_EPOCH_SET32 _IOW('p', 0x0e, __u32)
static long rtc_dev_compat_ioctl(struct file *file,
unsigned int cmd, unsigned long arg)
{
struct rtc_device *rtc = file->private_data;
void __user *uarg = compat_ptr(arg);
switch (cmd) {
case RTC_IRQP_READ32:
return put_user(rtc->irq_freq, (__u32 __user *)uarg);
case RTC_IRQP_SET32:
/* arg is a plain integer, not pointer */
return rtc_dev_ioctl(file, RTC_IRQP_SET, arg);
case RTC_EPOCH_SET32:
/* arg is a plain integer, not pointer */
return rtc_dev_ioctl(file, RTC_EPOCH_SET, arg);
}
return rtc_dev_ioctl(file, cmd, (unsigned long)uarg);
}
#endif
static int rtc_dev_fasync(int fd, struct file *file, int on)
{
struct rtc_device *rtc = file->private_data;
@ -434,6 +462,9 @@ static const struct file_operations rtc_dev_fops = {
.read = rtc_dev_read,
.poll = rtc_dev_poll,
.unlocked_ioctl = rtc_dev_ioctl,
#ifdef CONFIG_COMPAT
.compat_ioctl = rtc_dev_compat_ioctl,
#endif
.open = rtc_dev_open,
.release = rtc_dev_release,
.fasync = rtc_dev_fasync,

View File

@ -4,6 +4,7 @@
*
* Copyright (C) 2003-2008 Yoichi Yuasa <yuasa@linux-mips.org>
*/
#include <linux/compat.h>
#include <linux/err.h>
#include <linux/fs.h>
#include <linux/init.h>
@ -66,6 +67,9 @@ static void __iomem *rtc2_base;
#define rtc2_read(offset) readw(rtc2_base + (offset))
#define rtc2_write(offset, value) writew((value), rtc2_base + (offset))
/* 32-bit compat for ioctls that nobody else uses */
#define RTC_EPOCH_READ32 _IOR('p', 0x0d, __u32)
static unsigned long epoch = 1970; /* Jan 1 1970 00:00:00 */
static DEFINE_SPINLOCK(rtc_lock);
@ -179,6 +183,10 @@ static int vr41xx_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long
switch (cmd) {
case RTC_EPOCH_READ:
return put_user(epoch, (unsigned long __user *)arg);
#ifdef CONFIG_64BIT
case RTC_EPOCH_READ32:
return put_user(epoch, (unsigned int __user *)arg);
#endif
case RTC_EPOCH_SET:
/* Doesn't support before 1900 */
if (arg < 1900)

View File

@ -32,7 +32,6 @@
#include <linux/vt_kern.h>
#include <linux/raw.h>
#include <linux/blkdev.h>
#include <linux/rtc.h>
#include <linux/pci.h>
#include <linux/serial.h>
#include <linux/ctype.h>
@ -436,37 +435,6 @@ static int mt_ioctl_trans(struct file *file,
#define HCIUARTSETFLAGS _IOW('U', 203, int)
#define HCIUARTGETFLAGS _IOR('U', 204, int)
#define RTC_IRQP_READ32 _IOR('p', 0x0b, compat_ulong_t)
#define RTC_IRQP_SET32 _IOW('p', 0x0c, compat_ulong_t)
#define RTC_EPOCH_READ32 _IOR('p', 0x0d, compat_ulong_t)
#define RTC_EPOCH_SET32 _IOW('p', 0x0e, compat_ulong_t)
static int rtc_ioctl(struct file *file,
unsigned cmd, void __user *argp)
{
unsigned long __user *valp = compat_alloc_user_space(sizeof(*valp));
int ret;
if (valp == NULL)
return -EFAULT;
switch (cmd) {
case RTC_IRQP_READ32:
case RTC_EPOCH_READ32:
ret = do_ioctl(file, (cmd == RTC_IRQP_READ32) ?
RTC_IRQP_READ : RTC_EPOCH_READ,
(unsigned long)valp);
if (ret)
return ret;
return convert_in_user(valp, (unsigned int __user *)argp);
case RTC_IRQP_SET32:
return do_ioctl(file, RTC_IRQP_SET, (unsigned long)argp);
case RTC_EPOCH_SET32:
return do_ioctl(file, RTC_EPOCH_SET, (unsigned long)argp);
}
return -ENOIOCTLCMD;
}
/*
* simple reversible transform to make our table more evenly
* distributed after sorting.
@ -503,21 +471,6 @@ COMPATIBLE_IOCTL(SCSI_IOCTL_GET_PCI)
/* Big V (don't complain on serial console) */
IGNORE_IOCTL(VT_OPENQRY)
IGNORE_IOCTL(VT_GETMODE)
/* Little p (/dev/rtc, /dev/envctrl, etc.) */
COMPATIBLE_IOCTL(RTC_AIE_ON)
COMPATIBLE_IOCTL(RTC_AIE_OFF)
COMPATIBLE_IOCTL(RTC_UIE_ON)
COMPATIBLE_IOCTL(RTC_UIE_OFF)
COMPATIBLE_IOCTL(RTC_PIE_ON)
COMPATIBLE_IOCTL(RTC_PIE_OFF)
COMPATIBLE_IOCTL(RTC_WIE_ON)
COMPATIBLE_IOCTL(RTC_WIE_OFF)
COMPATIBLE_IOCTL(RTC_ALM_SET)
COMPATIBLE_IOCTL(RTC_ALM_READ)
COMPATIBLE_IOCTL(RTC_RD_TIME)
COMPATIBLE_IOCTL(RTC_SET_TIME)
COMPATIBLE_IOCTL(RTC_WKALM_SET)
COMPATIBLE_IOCTL(RTC_WKALM_RD)
/*
* These two are only for the sbus rtc driver, but
* hwclock tries them on every rtc device first when
@ -897,12 +850,6 @@ static long do_ioctl_trans(unsigned int cmd,
case MTIOCPOS32:
return mt_ioctl_trans(file, cmd, argp);
#endif
/* Not implemented in the native kernel */
case RTC_IRQP_READ32:
case RTC_IRQP_SET32:
case RTC_EPOCH_READ32:
case RTC_EPOCH_SET32:
return rtc_ioctl(file, cmd, argp);
}
/*