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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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8
drivers/rtc/rtc-vr41xx.c
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@@ -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)