asm-generic: add generic sysv ipc headers

The ipc64 data structures were originally meant to
be architecture specific so that each architecture
could add their own optimizations for padding.

In the end, most of them just copied the x86 version,
and most got that wrong. UClibc expects the x86 anyway,
so we might just declare that the default and get
rid of the extra copies.

Signed-off-by: Remis Lima Baima <remis.developer@googlemail.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

1 files changed, 38 insertions, 0 deletions

diff --git a/include/asm-generic/sembuf.h b/include/asm-generic/sembuf.h
new file mode 100644
index 000000000000..4cb2c13e5090
--- /dev/null
+++ b/include/asm-generic/sembuf.h
@@ -0,0 +1,38 @@
+#ifndef __ASM_GENERIC_SEMBUF_H
+#define __ASM_GENERIC_SEMBUF_H
+
+#include <asm/bitsperlong.h>
+
+/*
+ * The semid64_ds structure for x86 architecture.
+ * Note extra padding because this structure is passed back and forth
+ * between kernel and user space.
+ *
+ * semid64_ds was originally meant to be architecture specific, but
+ * everyone just ended up making identical copies without specific
+ * optimizations, so we may just as well all use the same one.
+ *
+ * 64 bit architectures typically define a 64 bit __kernel_time_t,
+ * so they do not need the first two padding words.
+ * On big-endian systems, the padding is in the wrong place.
+ *
+ * Pad space is left for:
+ * - 64-bit time_t to solve y2038 problem
+ * - 2 miscellaneous 32-bit values
+ */
+struct semid64_ds {
+        struct ipc64_perm sem_perm;     /* permissions .. see ipc.h */
+        __kernel_time_t sem_otime;      /* last semop time */
+#if __BITS_PER_LONG != 64
+        unsigned long   __unused1;
+#endif
+        __kernel_time_t sem_ctime;      /* last change time */
+#if __BITS_PER_LONG != 64
+        unsigned long   __unused2;
+#endif
+        unsigned long   sem_nsems;      /* no. of semaphores in array */
+        unsigned long   __unused3;
+        unsigned long   __unused4;
+};
+
+#endif /* __ASM_GENERIC_SEMBUF_H */