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author | Adhemerval Zanella <adhemerval.zanella@linaro.org> | 2020-06-29 13:35:50 -0300 |
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committer | Adhemerval Zanella <adhemerval.zanella@linaro.org> | 2020-07-09 12:05:35 -0300 |
commit | dba950e3174a5210b900a26a7d2f361cadea2834 (patch) | |
tree | e2cf866c106f5361fbb5880820d0fb9701d1977a /sysdeps/unix/sysv/linux/sparc/bits/typesizes.h | |
parent | ffb17e7ba3a5ba9632cee97330b325072fbe41dd (diff) | |
download | glibc-dba950e3174a5210b900a26a7d2f361cadea2834.tar.gz glibc-dba950e3174a5210b900a26a7d2f361cadea2834.tar.xz glibc-dba950e3174a5210b900a26a7d2f361cadea2834.zip |
sysv: linux: Add 64-bit time_t variant for semctl
Different than others 64-bit time_t syscalls, the SysIPC interface does not provide a new set of syscall for y2038 safeness. Instead it uses unused fields in semid_ds structure to return the high bits for the timestamps. To provide a y2038 safe interface a new symbol __semctl64 is added and __semctl is change to call it instead (it adds some extra buffer copying for the 32 bit time_t implementation). Two new structures are added: 1. kernel_semid64_ds: used internally only on 32-bit architectures to issue the syscall. A handful of architectures (hppa, i386, mips, powerpc32, sparc32) require specific implementations due their kernel ABI. 2. semid_ds64: this is only for __TIMESIZE != 64 to use along with the 64-bit semctl. It is different than the kernel struct because the exported 64-bit time_t might require different alignment depending on the architecture ABI. So the resulting implementation does: 1. For 64-bit architectures it assumes semid_ds already contains 64-bit time_t fields and will result in just the __semctl symbol using the __semctl64 code. The semid_ds argument is passed as-is to the syscall. 2. For 32-bit architectures with default 64-bit time_t (newer ABIs such riscv32 or arc), it will also result in only one exported symbol but with the required high/low handling. It might be possible to optimize it further to avoid the kernel_semid64_ds to semun transformation if the exported ABI for the architectures matches the expected kernel ABI, but the implementation is already complex enough and don't think this should be a hotspot in any case. 3. Finally for 32-bit architecture with both 32-bit and 64-bit time_t support we follow the already set way to provide one symbol with 64-bit time_t support and implement the 32-bit time_t support using the 64-bit one. The default 32-bit symbol will allocate and copy the semid_ds over multiple buffers, but this should be deprecated in favor of the __semctl64 anyway. Checked on i686-linux-gnu and x86_64-linux-gnu. I also did some sniff tests on powerpc, powerpc64, mips, mips64, armhf, sparcv9, and sparc64. Reviewed-by: Alistair Francis <alistair.francis@wdc.com> Tested-by: Alistair Francis <alistair.francis@wdc.com> Tested-by: Vineet Gupta <vgupta@synopsys.com> Reviewed-by: Carlos O'Donell <carlos@redhat.com> Tested-by: Carlos O'Donell <carlos@redhat.com>
Diffstat (limited to 'sysdeps/unix/sysv/linux/sparc/bits/typesizes.h')
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