[RFC PATCH v2 1/4] y2038: add 64bit time_t support in timeval for 32bit architecture

[Bamvor Zhang Jian <bamvor.zhangjian@linaro.org>]

Add timeval64 structure and copy_(from)|(to)_user functions. Add
__kernel_timeval for syscalls.

This changes follow the similar way in the followings commit:
361a3bf time64: Add time64.h header and define struct timespec64
49cd6f8 time: More core infrastructure for timespec64
ca2c9c5 y2038: introduce struct __kernel_timespec[1].

[1] http://git.kernel.org/cgit/linux/kernel/git/arnd/playground.git/commit/?h=y2038-syscalls&id=9005d4f4a44fc56bd0a1fe7c08e8e3f13eb75de7

Signed-off-by: Bamvor Zhang Jian <bamvor.zhangjian@linaro.org>
---
 include/linux/time64.h    | 20 ++++++++++++++++++--
 include/uapi/linux/time.h | 10 ++++++++++
 kernel/time/time.c        | 36 ++++++++++++++++++++++++++++++++++++
 3 files changed, 64 insertions(+), 2 deletions(-)

diff --git a/include/linux/time64.h b/include/linux/time64.h
index 77b5df2..2ca4f85 100644
--- a/include/linux/time64.h
+++ b/include/linux/time64.h
@@ -1,24 +1,35 @@
 #ifndef _LINUX_TIME64_H
 #define _LINUX_TIME64_H
 
-#include <uapi/linux/time.h>
-#include <linux/math64.h>
 
 typedef __s64 time64_t;
 
+#ifndef CONFIG_COMPAT_TIME
+# define __kernel_timeval timeval
+#endif
+
 /*
  * This wants to go into uapi/linux/time.h once we agreed about the
  * userspace interfaces.
  */
 #if __BITS_PER_LONG == 64
 # define timespec64 timespec
+# define timeval64 timeval
 #else
 struct timespec64 {
 	time64_t	tv_sec;			/* seconds */
 	long		tv_nsec;		/* nanoseconds */
 };
+
+struct timeval64 {
+	time64_t		tv_sec;		/* seconds */
+	__kernel_suseconds_t	tv_usec;	/* microseconds */
+};
 #endif
 
+#include <uapi/linux/time.h>
+#include <linux/math64.h>
+
 /* Parameters used to convert the timespec values: */
 #define MSEC_PER_SEC	1000L
 #define USEC_PER_MSEC	1000L
@@ -189,4 +200,9 @@ static __always_inline void timespec64_add_ns(struct timespec64 *a, u64 ns)
 
 #endif
 
+extern int get_timeval64(struct timeval64 *tv,
+                         const struct __kernel_timeval __user *utv);
+extern int put_timeval64(const struct timeval64 *tv,
+                         struct __kernel_timeval __user *utv);
+
 #endif /* _LINUX_TIME64_H */
diff --git a/include/uapi/linux/time.h b/include/uapi/linux/time.h
index e75e1b6..2ca6a31 100644
--- a/include/uapi/linux/time.h
+++ b/include/uapi/linux/time.h
@@ -66,4 +66,14 @@ struct itimerval {
  */
 #define TIMER_ABSTIME			0x01
 
+/* types based on 64-bit time_t */
+#ifndef __kernel_timeval
+typedef __s64 __kernel_time64_t;
+
+struct __kernel_timeval {
+       __kernel_time64_t       tv_sec;
+       __s64                   tv_usec;
+};
+#endif
+
 #endif /* _UAPI_LINUX_TIME_H */
diff --git a/kernel/time/time.c b/kernel/time/time.c
index 85d5bb1..adf0455 100644
--- a/kernel/time/time.c
+++ b/kernel/time/time.c
@@ -37,6 +37,7 @@
 #include <linux/fs.h>
 #include <linux/math64.h>
 #include <linux/ptrace.h>
+#include <linux/time64.h>
 
 #include <asm/uaccess.h>
 #include <asm/unistd.h>
@@ -759,3 +760,38 @@ struct timespec timespec_add_safe(const struct timespec lhs,
 
 	return res;
 }
+
+int get_timeval64(struct timeval64 *tv,
+                  const struct __kernel_timeval __user *utv)
+{
+       struct __kernel_timeval ktv;
+       int ret;
+
+       ret = copy_from_user(&ktv, utv, sizeof(ktv));
+       if (ret)
+               return -EFAULT;
+
+       tv->tv_sec = ktv.tv_sec;
+       if (!IS_ENABLED(CONFIG_64BIT)
+#ifdef CONFIG_COMPAT
+	   || is_compat_task()
+#endif
+	   )
+               ktv.tv_usec &= 0xfffffffful;
+       tv->tv_usec = ktv.tv_usec;
+
+       return 0;
+}
+EXPORT_SYMBOL_GPL(get_timeval64);
+
+int put_timeval64(const struct timeval64 *tv,
+                  struct __kernel_timeval __user *utv)
+{
+       struct __kernel_timeval ktv = {
+               .tv_sec = tv->tv_sec,
+               .tv_usec = tv->tv_usec
+       };
+       return copy_to_user(utv, &utv, sizeof(ktv)) ? -EFAULT : 0;
+}
+EXPORT_SYMBOL_GPL(put_timeval64);
+
-- 
2.1.4