[PATCH v8 0/2] Support semctl_syscall() for __TIMESIZE==64

[Vineet Gupta]

On 5/13/20 8:22 AM, Alistair Francis via Libc-alpha wrote:
> This series supports the semctl calls on a system with __TIMESIZE==64
> and __WORDSIZE==32 while not breaking current architectures. This is a
> step towards full y2038 support, but does not get us there yet.
> 
> See: https://sourceware.org/pipermail/libc-alpha/2020-May/113774.html
> for more details on what is still required.

Reviewers ping !

FWIW ARC port is also dependent on this patchset !

> 
> This series adds a new __semid_ds32 that is passed to the kernel
> (as part of a union) when running on 32-bit systems. If we are doing an
> IPC_STAT/SEM_STAT command then the 32-bit sem_{c,o}time{_high} values
> are combined to create a 64-bit value.
> 
> The semctl_syscall() function passes a union semun to the kernel. The
> union includes struct semid_ds as a member. On 32-bit architectures the
> Linux kernel provides a *_high version of the 32-bit sem_otime and
> sem_ctime values. These can be combined to get a 64-bit version of the
> time.
> 
> This patch adjusts the struct semid_ds to support the *_high versions
> of sem_otime and sem_ctime. For 32-bit systems with a 64-bit time_t
> this can be used to get a 64-bit time from the two 32-bit values.
> 
> This series was tested by running:
>   ./scripts/build-many-glibcs.py ... compilers
>   ./scripts/build-many-glibcs.py ... glibcs
> on my x86_64 machine.
> 
> I also ran make check on RV32 and I only see a total of 9 test failures.
> 
> v8:
>  - Revert back to v6-ish and only support __TIMESIZE==64
> v7:
>  - Re-write based on code from Adhemerval.
> v6:
>  - Update the 3rd patch to pass a temp buffer to the kernel
> v5:
>  - Address v4 review comments
>  - Set the semid_ds struct from a temp struct
> v4:
>  - Remove the __IPC_TIME64 macro
>     - It was only used once and doesn't work if __IPC_64 is 0 (which is
>       usually is)
>  - Address failures pointed out by Vineet Gupta
> 
> Alistair Francis (2):
>   sysv: linux: Define the __semid_ds32 struct
>   sysv: linux: Pass 64-bit version of semctl syscall
> 
>  .../unix/sysv/linux/hppa/struct__semid_ds32.h | 30 +++++++++++
>  sysdeps/unix/sysv/linux/ipc_priv.h            |  4 ++
>  .../unix/sysv/linux/mips/struct__semid_ds32.h | 28 +++++++++++
>  .../sysv/linux/powerpc/struct__semid_ds32.h   | 30 +++++++++++
>  sysdeps/unix/sysv/linux/semctl.c              | 50 +++++++++++++++++--
>  .../sysv/linux/sparc/struct__semid_ds32.h     | 30 +++++++++++
>  sysdeps/unix/sysv/linux/struct__semid_ds32.h  | 30 +++++++++++
>  .../unix/sysv/linux/x86/struct__semid_ds32.h  | 30 +++++++++++
>  8 files changed, 228 insertions(+), 4 deletions(-)
>  create mode 100644 sysdeps/unix/sysv/linux/hppa/struct__semid_ds32.h
>  create mode 100644 sysdeps/unix/sysv/linux/mips/struct__semid_ds32.h
>  create mode 100644 sysdeps/unix/sysv/linux/powerpc/struct__semid_ds32.h
>  create mode 100644 sysdeps/unix/sysv/linux/sparc/struct__semid_ds32.h
>  create mode 100644 sysdeps/unix/sysv/linux/struct__semid_ds32.h
>  create mode 100644 sysdeps/unix/sysv/linux/x86/struct__semid_ds32.h
>