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dba950e317
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>
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| .. | ||
| bits | ||
| mips32 | ||
| mips64 | ||
| sys | ||
| ____longjmp_chk.c | ||
| _test_and_set.c | ||
| brk.c | ||
| clone.S | ||
| configure | ||
| configure.ac | ||
| dl-cache.h | ||
| dl-static.c | ||
| errlist-compat.c | ||
| getcontext.S | ||
| getrlimit64.c | ||
| getsysstats.c | ||
| Implies | ||
| kernel_rt_sigframe.h | ||
| kernel_sigaction.h | ||
| kernel_stat.h | ||
| kernel_termios.h | ||
| kernel-features.h | ||
| ldsodefs.h | ||
| libc-abis | ||
| makecontext.S | ||
| Makefile | ||
| mmap_info.h | ||
| pipe.S | ||
| readelflib.c | ||
| register-dump.h | ||
| setcontext.S | ||
| setrlimit64.c | ||
| shlib-versions | ||
| sigcontextinfo.h | ||
| struct_kernel_semid64_ds.h | ||
| swapcontext.S | ||
| syscalls.list | ||
| sysdep.h | ||
| ucontext_i.sym | ||
| unwind-arch.h | ||
| ustat.c | ||
| Versions | ||
| vfork.S | ||
| xstatconv.c | ||