On Tue, Jul 24, 2018 at 08:39:57PM +0300, Yury Norov wrote: > Hi all, > > + Pavel Machek, Palmer Dabbelt, Wookey. > > On Wed, May 16, 2018 at 11:18:45AM +0300, Yury Norov wrote: > > This series enables AARCH64 with ILP32 mode. > > > > As supporting work, it introduces ARCH_32BIT_OFF_T configuration > > option that is enabled for existing 32-bit architectures but disabled > > for new arches (so 64-bit off_t userspace type is used by new userspace). > > Also it deprecates getrlimit and setrlimit syscalls prior to prlimit64. > > > > Based on kernel v4.16. Tested with LTP, glibc testsuite, trinity, lmbench, > > CPUSpec. > This is the update of the series based on 4.17 kernel > https://github.com/norov/linux/tree/ilp32-4.17 Hello. I have some questions regarding AArch64 ILP32 implementation for which I failed to find an answer myself: * How ptrace() tracer is supposed to distinguish between ILP32 and LP64 tracees? For MIPS N32 and x32 this is possible based on syscall number, but for AArch64 ILP32 I do not see such a sign. There's also ARM_ip is employed for signalling entering/exiting, I wonder whether it's possible to employ it also for signalling tracee's personality. * What's the reasoning behind capping syscall arguments to 32 bit? x32 and MIPS N32 do not have such a restriction (and do not need special wrappers for syscalls that pass 64-bit values as a result, except when they do, as it is the case for preadv2 on x32); moreover, that would lead to insurmountable difficulties for AArch64 ILP32 tracers that try to trace LP64 tracees, as it would be impossible to pass 64-bit addresses to process_vm_{read,write} or ptrace PEEK/POKE. Thank you.
