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.

diff --git a/drivers/rtc/dev.c b/drivers/rtc/dev.c
index 84feb25..5b8ebe8 100644 (file)
--- a/drivers/rtc/dev.c
+++ b/drivers/rtc/dev.c
@@ -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,

diff --git a/drivers/rtc/rtc-vr41xx.c b/drivers/rtc/rtc-vr41xx.c
index c752305..c367104 100644 (file)
--- a/drivers/rtc/rtc-vr41xx.c
+++ b/drivers/rtc/rtc-vr41xx.c
@@ -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)

diff --git a/fs/compat_ioctl.c b/fs/compat_ioctl.c
index cec3ec0..47da220 100644 (file)
--- a/fs/compat_ioctl.c
+++ b/fs/compat_ioctl.c
@@ -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);
        }
 
        /*