[PATCH v3 0/7] Introduce struct __kernel_timex

[PATCH v3 0/7] Introduce struct __kernel_timex

[Deepa Dinamani]

The series introduces struct __kernel_timex as a substitute for
the non y2038 safe struct timex.

The series is based on the original series posted by Arnd Bergmann
in [1].

The overview of the series is as below:
1. Prepare for the compat timex interfaces to be used unconditionally.
2. Introduce struct __kernel_timex.
3. Use struct __kernel_timex in place of struct timex.
4. Switch syscalls to use struct __kernel_timex.

[1] https://sourceware.org/ml/libc-alpha/2015-05/msg00070.html

Changes since v2:
* Use only generic compat.h for riscv
Changes since v1:
* Fix riscv asm/compat.h to pick up generic compat types

Deepa Dinamani (7):
  arm64: Make basic compat_* types always available
  sparc: Make thread_info.h available directly
  riscv: Delete asm/compat.h
  timex: prepare compat helpers for y2038 changes
  time: Add struct __kernel_timex
  timex: use __kernel_timex internally
  timex: change syscalls to use struct __kernel_timex

 arch/alpha/kernel/osf_sys.c     |  2 +-
 arch/arm64/include/asm/compat.h | 22 ++++-----
 arch/riscv/include/asm/Kbuild   |  1 +
 arch/riscv/include/asm/compat.h | 29 ------------
 arch/sparc/include/asm/compat.h |  2 +
 drivers/ptp/ptp_clock.c         |  2 +-
 include/asm-generic/compat.h    |  8 +++-
 include/linux/compat.h          | 33 --------------
 include/linux/compat_time.h     | 34 ++++++++++++++
 include/linux/posix-clock.h     |  2 +-
 include/linux/syscalls.h        |  5 +--
 include/linux/timex.h           |  9 +++-
 include/uapi/linux/timex.h      | 41 +++++++++++++++++
 kernel/compat.c                 | 63 --------------------------
 kernel/time/ntp.c               | 12 ++---
 kernel/time/ntp_internal.h      |  2 +-
 kernel/time/posix-clock.c       |  2 +-
 kernel/time/posix-timers.c      | 14 ++----
 kernel/time/posix-timers.h      |  2 +-
 kernel/time/time.c              | 80 ++++++++++++++++++++++++++++++---
 kernel/time/timekeeping.c       |  4 +-
 21 files changed, 199 insertions(+), 170 deletions(-)
 delete mode 100644 arch/riscv/include/asm/compat.h


base-commit: 526674536360a4c508e84f67314c2028e45e1bf2
-- 
2.17.1

Cc: catalin.marinas@arm.com
Cc: davem@davemloft.net
Cc: linux-alpha@vger.kernel.org
Cc: linux-api@vger.kernel.org
Cc: linux-arch@vger.kernel.org
Cc: linux-riscv@lists.infradead.org
Cc: netdev@vger.kernel.org
Cc: palmer@sifive.com
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[PATCH v3 7/7] timex: change syscalls to use struct __kernel_timex

[Deepa Dinamani]

struct timex is not y2038 safe.
Switch all the syscall apis to use y2038 safe __kernel_timex.

Note that sys_adjtimex() does not have a y2038 safe solution.
The api is meant to be deprecated on 32 bit machines after y2038.

Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
Cc: linux-api@vger.kernel.org
---
 include/linux/syscalls.h   |  5 ++---
 kernel/time/posix-timers.c | 10 +---------
 kernel/time/time.c         |  9 +++++++--
 3 files changed, 10 insertions(+), 14 deletions(-)

diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 3ee3b3f1302f..54688c7b4dae 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -54,7 +54,6 @@ struct __sysctl_args;
 struct sysinfo;
 struct timespec;
 struct timeval;
-struct timex;
 struct timezone;
 struct tms;
 struct utimbuf;
@@ -677,7 +676,7 @@ asmlinkage long sys_gettimeofday(struct timeval __user *tv,
 				struct timezone __user *tz);
 asmlinkage long sys_settimeofday(struct timeval __user *tv,
 				struct timezone __user *tz);
-asmlinkage long sys_adjtimex(struct timex __user *txc_p);
+asmlinkage long sys_adjtimex(struct __kernel_timex __user *txc_p);
 
 /* kernel/timer.c */
 asmlinkage long sys_getpid(void);
@@ -846,7 +845,7 @@ asmlinkage long sys_open_by_handle_at(int mountdirfd,
 				      struct file_handle __user *handle,
 				      int flags);
 asmlinkage long sys_clock_adjtime(clockid_t which_clock,
-				struct timex __user *tx);
+				struct __kernel_timex __user *tx);
 asmlinkage long sys_syncfs(int fd);
 asmlinkage long sys_setns(int fd, int nstype);
 asmlinkage long sys_sendmmsg(int fd, struct mmsghdr __user *msg,
diff --git a/kernel/time/posix-timers.c b/kernel/time/posix-timers.c
index a2595cb0cb16..1b485422f9f3 100644
--- a/kernel/time/posix-timers.c
+++ b/kernel/time/posix-timers.c
@@ -1084,7 +1084,7 @@ SYSCALL_DEFINE2(clock_gettime, const clockid_t, which_clock,
 }
 
 SYSCALL_DEFINE2(clock_adjtime, const clockid_t, which_clock,
-		struct timex __user *, utx)
+		struct __kernel_timex __user *, utx)
 {
 	const struct k_clock *kc = clockid_to_kclock(which_clock);
 	struct __kernel_timex ktx;
@@ -1159,10 +1159,6 @@ COMPAT_SYSCALL_DEFINE2(clock_gettime, clockid_t, which_clock,
 	return err;
 }
 
-#endif
-
-#ifdef CONFIG_COMPAT
-
 COMPAT_SYSCALL_DEFINE2(clock_adjtime, clockid_t, which_clock,
 		       struct compat_timex __user *, utp)
 {
@@ -1187,10 +1183,6 @@ COMPAT_SYSCALL_DEFINE2(clock_adjtime, clockid_t, which_clock,
 	return err;
 }
 
-#endif
-
-#ifdef CONFIG_COMPAT_32BIT_TIME
-
 COMPAT_SYSCALL_DEFINE2(clock_getres, clockid_t, which_clock,
 		       struct compat_timespec __user *, tp)
 {
diff --git a/kernel/time/time.c b/kernel/time/time.c
index 2c5afb008b14..a374fdbb368b 100644
--- a/kernel/time/time.c
+++ b/kernel/time/time.c
@@ -263,7 +263,10 @@ COMPAT_SYSCALL_DEFINE2(settimeofday, struct compat_timeval __user *, tv,
 }
 #endif
 
-SYSCALL_DEFINE1(adjtimex, struct timex __user *, txc_p)
+
+#if !defined(CONFIG_64BIT_TIME) || defined(CONFIG_64BIT)
+
+SYSCALL_DEFINE1(adjtimex, struct __kernel_timex __user *, txc_p)
 {
 	struct __kernel_timex txc;		/* Local copy of parameter */
 	int ret;
@@ -278,7 +281,9 @@ SYSCALL_DEFINE1(adjtimex, struct timex __user *, txc_p)
 	return copy_to_user(txc_p, &txc, sizeof(struct __kernel_timex)) ? -EFAULT : ret;
 }
 
-#ifdef CONFIG_COMPAT
+#endif
+
+#ifdef CONFIG_COMPAT_32BIT_TIME
 
 COMPAT_SYSCALL_DEFINE1(adjtimex, struct compat_timex __user *, utp)
 {
-- 
2.17.1

Re: [PATCH v3 7/7] timex: change syscalls to use struct __kernel_timex

[Christoph Hellwig]

On Fri, Jul 06, 2018 at 10:42:47PM -0700, Deepa Dinamani wrote:
> struct timex is not y2038 safe.
> Switch all the syscall apis to use y2038 safe __kernel_timex.

So you switch existing syscalls to use a different structure.
If this actually happens to be safe it needs a big explanation
in the commit log.

> -#ifdef CONFIG_COMPAT
> -
>  COMPAT_SYSCALL_DEFINE2(clock_adjtime, clockid_t, which_clock,
>  		       struct compat_timex __user *, utp)
>  {
> @@ -1187,10 +1183,6 @@ COMPAT_SYSCALL_DEFINE2(clock_adjtime, clockid_t, which_clock,
>  	return err;
>  }
>  
> -#endif

And this unconditionally defines clock_adjtime, but doesn't actually
seem to add callers, which looks rather odd.  Same for other bits
in the patch.

Re: [PATCH v3 7/7] timex: change syscalls to use struct __kernel_timex

[Arnd Bergmann]

On Thu, Jul 12, 2018 at 10:29 AM, Christoph Hellwig <hch@infradead.org> wrote:
> On Fri, Jul 06, 2018 at 10:42:47PM -0700, Deepa Dinamani wrote:
>
>> -#ifdef CONFIG_COMPAT
>> -
>>  COMPAT_SYSCALL_DEFINE2(clock_adjtime, clockid_t, which_clock,
>>                      struct compat_timex __user *, utp)
>>  {
>> @@ -1187,10 +1183,6 @@ COMPAT_SYSCALL_DEFINE2(clock_adjtime, clockid_t, which_clock,
>>       return err;
>>  }
>>
>> -#endif
>
> And this unconditionally defines clock_adjtime, but doesn't actually
> seem to add callers, which looks rather odd.  Same for other bits
> in the patch.

It really just moves compat_sys_clock_adjtime() into the same
#ifdef CONFIG_COMPAT_32BIT_TIME that hides the surrounding
functions.

Currently CONFIG_COMPAT_32BIT_TIME is used only as a subset
of CONFIG_COMPAT, and the plan was to have 32-bit architectures
enable it later so they could get access to all the functions
implementing 32-bit time with a patch similar to what I'm testing
with, see https://pastebin.com/F3QZdyin for the current draft that
I use for testing.

We already spent several review rounds coming just discussing the
naming of the macros etc before we decided on the
CONFIG_64BIT_TIME and CONFIG_COMPAT_32BIT_TIME
symbol, but if you have a better suggestion (as part of moving
away from the compat_ naming), we can change all that again.

      Arnd