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2a4b25fad8
sysdeps/unix/sysv/linux/bits/shm.h has padding after time fields in struct shmid_ds unconditionally, and thus is only suitable for 32-bit architectures (no 64-bit configurations use this file); sysdeps/unix/sysv/linux/generic/bits/shm.h is substantively the same, except that the padding is conditioned on __WORDSIZE == 32, and so it can be used for 64-bit architectures as well. This patch adds the conditionals to sysdeps/unix/sysv/linux/bits/shm.h. The linux/generic/ version is then no longer needed and so is removed, as are the alpha and s390 versions which are also no longer needed. The other architecture-specific versions have different padding, layout, types or SHMLBA definitions and so are still needed after this change. This is essentially the same change for bits/shm.h as the bits/msq.h patch and the bits/sem.h patch. However, the details of the padding variations for the architectures that aren't changed are not all the same between msqid_ds, shmid_ds and semid_ds. Tested with build-many-glibcs.py. * sysdeps/unix/sysv/linux/bits/shm.h: Include <bits/wordsize.h>. (struct shmid_ds): Condition padding after time fields on [__WORDSIZE == 32]. * sysdeps/unix/sysv/linux/alpha/bits/shm.h: Remove file. * sysdeps/unix/sysv/linux/generic/bits/shm.h: Likewise. * sysdeps/unix/sysv/linux/s390/bits/shm.h: Likewise.
This hierarchy supports Linux systems using the new asm-generic/unistd.h, which removes many familiar old syscalls. For example, to implement open(), newer Linux architectures require glibc to invoke the __NR_openat syscall with AT_FDCWD. This hierarchy provides all those implementations. It also provides support for 32-bit platforms using the 64-bit kernel syscall APIs, as the 32-bit ones are no longer provided. Note that newer ILP32 environments (x32 or AArch64:ILP32, for example) are converting to use more 64-bit types in kernel syscalls, so that aspect of this support is in more flux as of this writing.