On 32 bit mips the kernel uses -1UL/2 to mark RLIM_INFINITY (and this is the definition in the userspace api), but since it is in the middle of the valid range of limits and limits are often compared with relational operators, various kernel side logic is broken if larger than -1UL/2 limits are used. So we truncate the limits to -1UL/2 in get/setrlimit and prlimit. Even if the kernel side logic consistently treated -1UL/2 as greater than any other limit value, there wouldn't be any clean workaround that allowed using large limits: * using -1UL/2 as RLIM_INFINITY in userspace would mean different infinity value for get/setrlimt and prlimit (where infinity is always -1ULL) and userspace logic could break easily (just like the kernel is broken now) and more special case code would be needed for mips. * translating -1UL/2 kernel side value to -1ULL in userspace would mean that -1UL/2 limit cannot be set (eg. -1UL/2+1 had to be passed to the kernel instead).
such archs are expected to omit definitions of the SYS_* macros for syscalls their kernels lack from arch/$ARCH/bits/syscall.h. the preprocessor is then able to select the an appropriate implementation for affected functions. two basic strategies are used on a case-by-case basis: where the old syscalls correspond to deprecated library-level functions, the deprecated functions have been converted to wrappers for the modern function, and the modern function has fallback code (omitted at the preprocessor level on new archs) to make use of the old syscalls if the new syscall fails with ENOSYS. this also improves functionality on older kernels and eliminates the incentive to program with deprecated library-level functions for the sake of compatibility with older kernels. in other situations where the old syscalls correspond to library-level functions which are not deprecated but merely lack some new features, such as the *at functions, the old syscalls are still used on archs which support them. this may change at some point in the future if or when fallback code is added to the new functions to make them usable (possibly with reduced functionality) on old kernels.
it will be needed to implement some things in sysconf, and the syscall can't easily be used directly because the x32 syscall uses the wrong structure layout. the l (uncreative, for "linux") prefix is used since the symbol name __sysinfo is already taken for AT_SYSINFO from the aux vector. the way the x32 override of this function works is also changed to be simpler and avoid the useless jump instruction.
the kernel uses long longs in the struct, but the documentation says they're long. so we need to fixup the mismatch between the userspace and kernelspace structs. since the struct offers a mem_unit member, we can avoid truncation by adjusting that value.
The architecture-specific assembly versions of clone did not set errno on failure, which is inconsistent with glibc. __clone still returns the error via its return value, and clone is now a wrapper that sets errno as needed. The public clone has also been moved to src/linux, as it's not directly related to the pthreads API. __clone is called by pthread_create, which does not report errors via errno. Though not strictly necessary, it's nice to avoid clobbering errno here.
it's unclear what the historical signature for this function was, but semantically, the argument should be a pointer to const, and this is what glibc uses. correct programs should not be using this function anyway, so it's unlikely to matter.
both the kernel and glibc agree that this argument is unsigned; the incorrect type ssize_t came from erroneous man pages.
this was wrong since the original commit adding inotify, and I don't see any explanation for it. not even the man pages have it wrong. it was most likely a copy-and-paste error.