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From: Arnd Bergmann <arnd@arndb.de>
To: y2038@lists.linaro.org, linux-kernel@vger.kernel.org
Cc: Arnd Bergmann <arnd@arndb.de>,
	linux-api@vger.kernel.org, linux-arch@vger.kernel.org,
	libc-alpha@sourceware.org, tglx@linutronix.de,
	deepa.kernel@gmail.com, viro@zeniv.linux.org.uk,
	ebiederm@xmission.com, albert.aribaud@3adev.fr,
	linux-s390@vger.kernel.org, schwidefsky@de.ibm.com,
	x86@kernel.org, catalin.marinas@arm.com, will.deacon@arm.com,
	linux-mips@linux-mips.org, jhogan@kernel.org,
	ralf@linux-mips.org, linuxppc-dev@lists.ozlabs.org,
	sparclinux@vger.kernel.org
Subject: [PATCH v3 06/17] y2038: mips: Extend sysvipc data structures
Date: Thu, 19 Apr 2018 16:37:26 +0200	[thread overview]
Message-ID: <20180419143737.606138-7-arnd@arndb.de> (raw)
In-Reply-To: <20180419143737.606138-1-arnd@arndb.de>

MIPS is the weirdest case for sysvipc, because each of the
three data structures is done differently:

* msqid64_ds has padding in the right place so we could in theory
  extend this one to just have 64-bit values instead of time_t.
  As this does not work for most of the other combinations,
  we just handle it in the common manner though.

* semid64_ds has no padding for 64-bit time_t, but has two reserved
  'long' fields, which are sufficient to extend the sem_otime
  and sem_ctime fields to 64 bit. In order to do this, the libc
  implementation will have to copy the data into another structure
  that has the fields in a different order. MIPS is the only
  architecture with this problem, so this is best done in MIPS
  specific libc code.

* shmid64_ds is slightly worse than that, because it has three
  time_t fields but only two unused 32-bit words. As a workaround,
  we extend each field only by 16 bits, ending up with 48-bit
  timestamps that user space again has to work around by itself.

The compat versions of the data structures are changed in the
same way.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 arch/mips/include/asm/compat.h      | 40 ++++++++++++++------------
 arch/mips/include/uapi/asm/msgbuf.h | 57 ++++++++++++++++++++++++-------------
 arch/mips/include/uapi/asm/sembuf.h | 15 ++++++++--
 arch/mips/include/uapi/asm/shmbuf.h | 23 +++++++++++++--
 4 files changed, 94 insertions(+), 41 deletions(-)

diff --git a/arch/mips/include/asm/compat.h b/arch/mips/include/asm/compat.h
index 3e548ee99a2f..78675f19440f 100644
--- a/arch/mips/include/asm/compat.h
+++ b/arch/mips/include/asm/compat.h
@@ -37,9 +37,11 @@ typedef struct {
 typedef s32		compat_timer_t;
 typedef s32		compat_key_t;
 
+typedef s16		compat_short_t;
 typedef s32		compat_int_t;
 typedef s32		compat_long_t;
 typedef s64		compat_s64;
+typedef u16		compat_ushort_t;
 typedef u32		compat_uint_t;
 typedef u32		compat_ulong_t;
 typedef u64		compat_u64;
@@ -157,35 +159,35 @@ struct compat_ipc64_perm {
 
 struct compat_semid64_ds {
 	struct compat_ipc64_perm sem_perm;
-	compat_time_t	sem_otime;
-	compat_time_t	sem_ctime;
+	compat_ulong_t	sem_otime;
+	compat_ulong_t	sem_ctime;
 	compat_ulong_t	sem_nsems;
-	compat_ulong_t	__unused1;
-	compat_ulong_t	__unused2;
+	compat_ulong_t	sem_otime_high;
+	compat_ulong_t	sem_ctime_high;
 };
 
 struct compat_msqid64_ds {
 	struct compat_ipc64_perm msg_perm;
 #ifndef CONFIG_CPU_LITTLE_ENDIAN
-	compat_ulong_t	__unused1;
+	compat_ulong_t	msg_stime_high;
 #endif
-	compat_time_t	msg_stime;
+	compat_ulong_t	msg_stime;
 #ifdef CONFIG_CPU_LITTLE_ENDIAN
-	compat_ulong_t	__unused1;
+	compat_ulong_t	msg_stime_high;
 #endif
 #ifndef CONFIG_CPU_LITTLE_ENDIAN
-	compat_ulong_t	__unused2;
+	compat_ulong_t	msg_rtime_high;
 #endif
-	compat_time_t	msg_rtime;
+	compat_ulong_t	msg_rtime;
 #ifdef CONFIG_CPU_LITTLE_ENDIAN
-	compat_ulong_t	__unused2;
+	compat_ulong_t	msg_rtime_high;
 #endif
 #ifndef CONFIG_CPU_LITTLE_ENDIAN
-	compat_ulong_t	__unused3;
+	compat_ulong_t	msg_ctime_high;
 #endif
-	compat_time_t	msg_ctime;
+	compat_ulong_t	msg_ctime;
 #ifdef CONFIG_CPU_LITTLE_ENDIAN
-	compat_ulong_t	__unused3;
+	compat_ulong_t	msg_ctime_high;
 #endif
 	compat_ulong_t	msg_cbytes;
 	compat_ulong_t	msg_qnum;
@@ -199,14 +201,16 @@ struct compat_msqid64_ds {
 struct compat_shmid64_ds {
 	struct compat_ipc64_perm shm_perm;
 	compat_size_t	shm_segsz;
-	compat_time_t	shm_atime;
-	compat_time_t	shm_dtime;
-	compat_time_t	shm_ctime;
+	compat_ulong_t	shm_atime;
+	compat_ulong_t	shm_dtime;
+	compat_ulong_t	shm_ctime;
 	compat_pid_t	shm_cpid;
 	compat_pid_t	shm_lpid;
 	compat_ulong_t	shm_nattch;
-	compat_ulong_t	__unused1;
-	compat_ulong_t	__unused2;
+	compat_ushort_t	shm_atime_high;
+	compat_ushort_t	shm_dtime_high;
+	compat_ushort_t	shm_ctime_high;
+	compat_ushort_t	__unused2;
 };
 
 /* MIPS has unusual order of fields in stack_t */
diff --git a/arch/mips/include/uapi/asm/msgbuf.h b/arch/mips/include/uapi/asm/msgbuf.h
index eb4d0f9d7364..46aa15b13e4e 100644
--- a/arch/mips/include/uapi/asm/msgbuf.h
+++ b/arch/mips/include/uapi/asm/msgbuf.h
@@ -9,33 +9,15 @@
  * between kernel and user space.
  *
  * Pad space is left for:
- * - extension of time_t to 64-bit on 32-bitsystem to solve the y2038 problem
  * - 2 miscellaneous unsigned long values
  */
 
+#if defined(__mips64)
 struct msqid64_ds {
 	struct ipc64_perm msg_perm;
-#if !defined(__mips64) && defined(__MIPSEB__)
-	unsigned long	__unused1;
-#endif
 	__kernel_time_t msg_stime;	/* last msgsnd time */
-#if !defined(__mips64) && defined(__MIPSEL__)
-	unsigned long	__unused1;
-#endif
-#if !defined(__mips64) && defined(__MIPSEB__)
-	unsigned long	__unused2;
-#endif
 	__kernel_time_t msg_rtime;	/* last msgrcv time */
-#if !defined(__mips64) && defined(__MIPSEL__)
-	unsigned long	__unused2;
-#endif
-#if !defined(__mips64) && defined(__MIPSEB__)
-	unsigned long	__unused3;
-#endif
 	__kernel_time_t msg_ctime;	/* last change time */
-#if !defined(__mips64) && defined(__MIPSEL__)
-	unsigned long	__unused3;
-#endif
 	unsigned long  msg_cbytes;	/* current number of bytes on queue */
 	unsigned long  msg_qnum;	/* number of messages in queue */
 	unsigned long  msg_qbytes;	/* max number of bytes on queue */
@@ -44,5 +26,42 @@ struct msqid64_ds {
 	unsigned long  __unused4;
 	unsigned long  __unused5;
 };
+#elif defined (__MIPSEB__)
+struct msqid64_ds {
+	struct ipc64_perm msg_perm;
+	unsigned long  msg_stime_high;
+	unsigned long  msg_stime;	/* last msgsnd time */
+	unsigned long  msg_rtime_high;
+	unsigned long  msg_rtime;	/* last msgrcv time */
+	unsigned long  msg_ctime_high;
+	unsigned long  msg_ctime;	/* last change time */
+	unsigned long  msg_cbytes;	/* current number of bytes on queue */
+	unsigned long  msg_qnum;	/* number of messages in queue */
+	unsigned long  msg_qbytes;	/* max number of bytes on queue */
+	__kernel_pid_t msg_lspid;	/* pid of last msgsnd */
+	__kernel_pid_t msg_lrpid;	/* last receive pid */
+	unsigned long  __unused4;
+	unsigned long  __unused5;
+};
+#elif defined (__MIPSEL__)
+struct msqid64_ds {
+	struct ipc64_perm msg_perm;
+	unsigned long  msg_stime;	/* last msgsnd time */
+	unsigned long  msg_stime_high;
+	unsigned long  msg_rtime;	/* last msgrcv time */
+	unsigned long  msg_rtime_high;
+	unsigned long  msg_ctime;	/* last change time */
+	unsigned long  msg_ctime_high;
+	unsigned long  msg_cbytes;	/* current number of bytes on queue */
+	unsigned long  msg_qnum;	/* number of messages in queue */
+	unsigned long  msg_qbytes;	/* max number of bytes on queue */
+	__kernel_pid_t msg_lspid;	/* pid of last msgsnd */
+	__kernel_pid_t msg_lrpid;	/* last receive pid */
+	unsigned long  __unused4;
+	unsigned long  __unused5;
+};
+#else
+#warning no endianess set
+#endif
 
 #endif /* _ASM_MSGBUF_H */
diff --git a/arch/mips/include/uapi/asm/sembuf.h b/arch/mips/include/uapi/asm/sembuf.h
index 2c0f507ab7d1..60c89e6cb25b 100644
--- a/arch/mips/include/uapi/asm/sembuf.h
+++ b/arch/mips/include/uapi/asm/sembuf.h
@@ -7,10 +7,11 @@
  * Note extra padding because this structure is passed back and forth
  * between kernel and user space.
  *
- * Pad space is left for:
- * - 2 miscellaneous 64-bit values
+ * Pad space is left for 2 miscellaneous 64-bit values on mips64,
+ * but used for the upper 32 bit of the time values on mips32.
  */
 
+#ifdef __mips64
 struct semid64_ds {
 	struct ipc64_perm sem_perm;		/* permissions .. see ipc.h */
 	__kernel_time_t sem_otime;		/* last semop time */
@@ -19,5 +20,15 @@ struct semid64_ds {
 	unsigned long	__unused1;
 	unsigned long	__unused2;
 };
+#else
+struct semid64_ds {
+	struct ipc64_perm sem_perm;		/* permissions .. see ipc.h */
+	unsigned long   sem_otime;		/* last semop time */
+	unsigned long   sem_ctime;		/* last change time */
+	unsigned long	sem_nsems;		/* no. of semaphores in array */
+	unsigned long	sem_otime_high;
+	unsigned long	sem_ctime_high;
+};
+#endif
 
 #endif /* _ASM_SEMBUF_H */
diff --git a/arch/mips/include/uapi/asm/shmbuf.h b/arch/mips/include/uapi/asm/shmbuf.h
index 379e6bca518b..9b9bba3401f2 100644
--- a/arch/mips/include/uapi/asm/shmbuf.h
+++ b/arch/mips/include/uapi/asm/shmbuf.h
@@ -7,10 +7,13 @@
  * Note extra padding because this structure is passed back and forth
  * between kernel and user space.
  *
- * Pad space is left for:
- * - 2 miscellaneous 32-bit rsp. 64-bit values
+ * As MIPS was lacking proper padding after shm_?time, we use 48 bits
+ * of the padding at the end to store a few additional bits of the time.
+ * libc implementations need to take care to convert this into a proper
+ * data structure when moving to 64-bit time_t.
  */
 
+#ifdef __mips64
 struct shmid64_ds {
 	struct ipc64_perm	shm_perm;	/* operation perms */
 	size_t			shm_segsz;	/* size of segment (bytes) */
@@ -23,6 +26,22 @@ struct shmid64_ds {
 	unsigned long		__unused1;
 	unsigned long		__unused2;
 };
+#else
+struct shmid64_ds {
+	struct ipc64_perm	shm_perm;	/* operation perms */
+	size_t			shm_segsz;	/* size of segment (bytes) */
+	unsigned long		shm_atime;	/* last attach time */
+	unsigned long		shm_dtime;	/* last detach time */
+	unsigned long		shm_ctime;	/* last change time */
+	__kernel_pid_t		shm_cpid;	/* pid of creator */
+	__kernel_pid_t		shm_lpid;	/* pid of last operator */
+	unsigned long		shm_nattch;	/* no. of current attaches */
+	unsigned short		shm_atime_high;
+	unsigned short		shm_dtime_high;
+	unsigned short		shm_ctime_high;
+	unsigned short		__unused1;
+};
+#endif
 
 struct shminfo64 {
 	unsigned long	shmmax;
-- 
2.9.0


  parent reply	other threads:[~2018-04-19 14:39 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-04-19 14:37 [PATCH v3 00/17] y2038: Convert IPC syscalls Arnd Bergmann
2018-04-19 14:37 ` [PATCH v3 01/17] y2038: asm-generic: Extend sysvipc data structures Arnd Bergmann
2018-04-19 14:59   ` Eric W. Biederman
2018-04-19 15:20     ` Arnd Bergmann
2018-04-19 21:24       ` Arnd Bergmann
2018-04-19 22:12         ` Eric W. Biederman
2018-04-20  8:54           ` Arnd Bergmann
2018-04-20 13:03             ` [PATCH] x86: ipc: fix x32 version of shmid64_ds and msqid64_ds Arnd Bergmann
2018-04-20 13:53               ` Jeffrey Walton
2018-04-20 14:38                 ` Arnd Bergmann
2018-04-22 12:38                   ` H.J. Lu
2018-04-22 20:17                     ` Arnd Bergmann
2018-04-19 15:30   ` [PATCH v3 01/17] y2038: asm-generic: Extend sysvipc data structures Zack Weinberg
2018-04-19 15:51     ` Arnd Bergmann
2018-04-19 14:37 ` [PATCH v3 02/17] y2038: alpha: Remove unneeded ipc uapi header files Arnd Bergmann
2018-04-19 14:37 ` [PATCH v3 03/17] y2038: ia64: " Arnd Bergmann
2018-04-19 14:37 ` [PATCH v3 04/17] y2038: s390: " Arnd Bergmann
2018-04-20  7:54   ` Heiko Carstens
2018-04-20  7:58     ` Arnd Bergmann
2018-04-19 14:37 ` [PATCH v3 05/17] y2038: arm64: Extend sysvipc compat data structures Arnd Bergmann
2018-04-19 14:37 ` Arnd Bergmann [this message]
2018-04-19 14:37 ` [PATCH v3 07/17] y2038: x86: Extend sysvipc " Arnd Bergmann
2018-04-19 14:37 ` [PATCH v3 08/17] y2038: parisc: " Arnd Bergmann
2018-04-19 14:37 ` [PATCH v3 09/17] y2038: sparc: " Arnd Bergmann
2018-04-19 14:37 ` [PATCH v3 10/17] y2038: powerpc: " Arnd Bergmann
2018-04-19 14:37 ` [PATCH v3 11/17] y2038: xtensa: " Arnd Bergmann
2018-04-19 14:37 ` [PATCH v3 12/17] y2038: ipc: Use ktime_get_real_seconds consistently Arnd Bergmann
2018-04-19 14:37 ` [PATCH v3 13/17] y2038: ipc: Report long times to user space Arnd Bergmann
2018-04-19 14:37 ` [PATCH v3 14/17] y2038: ipc: Use __kernel_timespec Arnd Bergmann
2018-04-19 14:37 ` [PATCH v3 15/17] y2038: ipc: Enable COMPAT_32BIT_TIME Arnd Bergmann
2018-04-19 14:37 ` [PATCH v3 16/17] y2038: ipc: Redirect ipc(SEMTIMEDOP, ...) to compat_ksys_semtimedop Arnd Bergmann
2018-04-19 14:37 ` [PATCH v3 17/17] y2038: compat: Move common compat types to asm-generic/compat.h Arnd Bergmann

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