88499a87ce
This patch consolidates the pause Linux implementation on sysdeps/unix/sysv/linux/pause.c. If defined the pause syscall (__NR_pause) will be used, other ppoll with 0 arguments will be used instead. It has the small advantage of generic pause implementation with uses rt_sigprocmask plus rt_sigsuspend because it requires only one syscall and the pause is done atomically regarding signal handling (for instance, pause may not be interrupted if the signal arrives between the rt_sigprocmask and rt_sigsuspend syscall). Checked on i686-linux-gnu, x86_64-linux-gnu, x86_64-linux-gnux32, arch64-linux-gnu, arm-linux-gnueabihf, powerpc64le-linux-gnu, sparc64-linux-gnu, and sparcv9-linux-gnu. * sysdeps/unix/sysv/linux/generic/pause.c: Remove file. * sysdeps/unix/sysv/linux/sparc/sparc64/pause.c: Likewise. * sysdeps/unix/sysv/linux/sparc/kernel-features.h [__arch64__] (__NR_pause): Undefine. * sysdeps/unix/sysv/linux/pause.c: New file. * sysdeps/unix/sysv/linux/syscalls.list: Remove pause from auto-generation list.
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.