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author | Arnd Bergmann <arnd@arndb.de> | 2015-05-05 22:53:12 +0200 |
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committer | Arnd Bergmann <arnd@arndb.de> | 2018-04-20 16:20:04 +0200 |
commit | 3f3a4b3fbf2f2bede531b0c9a3ba2baed87cf420 (patch) | |
tree | b52accbaa5f0b35a1ba0ec50cbfca88524e47892 /arch/mips/include/uapi/asm/shmbuf.h | |
parent | y2038: arm64: Extend sysvipc compat data structures (diff) | |
download | linux-dev-3f3a4b3fbf2f2bede531b0c9a3ba2baed87cf420.tar.xz linux-dev-3f3a4b3fbf2f2bede531b0c9a3ba2baed87cf420.zip |
y2038: mips: Extend sysvipc data structures
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>
Diffstat (limited to '')
-rw-r--r-- | arch/mips/include/uapi/asm/shmbuf.h | 23 |
1 files changed, 21 insertions, 2 deletions
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; |