linux_dsm_epyc7002/arch/mips/include/uapi/asm/shmbuf.h
Arnd Bergmann 3f3a4b3fbf 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>
2018-04-20 16:20:04 +02:00

59 lines
1.9 KiB
C

/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
#ifndef _ASM_SHMBUF_H
#define _ASM_SHMBUF_H
/*
* The shmid64_ds structure for the MIPS architecture.
* Note extra padding because this structure is passed back and forth
* between kernel and user space.
*
* 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) */
__kernel_time_t shm_atime; /* last attach time */
__kernel_time_t shm_dtime; /* last detach time */
__kernel_time_t 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 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;
unsigned long shmmin;
unsigned long shmmni;
unsigned long shmseg;
unsigned long shmall;
unsigned long __unused1;
unsigned long __unused2;
unsigned long __unused3;
unsigned long __unused4;
};
#endif /* _ASM_SHMBUF_H */