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

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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
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33
drivers/rtc/dev.c
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 @@ done:
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,