The removal of generic syscall(), and introduction of pinsyscalls() which registers the precise entry location of every system call used by a program, makes me think of some kernel-level ABI issues that Linux has.
In particular, kernel ABI is the main stable interface that Linux exposes - and all applications can just use syscalls directly without having to interface with the libc at all. However, that means that kernel must not change its ABI lest it risks breaking compatibility, and each functionality that isn't implemented inside of the kernel (e.g. GUI stuff) cannot be implemented completely portably.
However, using pinsyscalls(), a kernel can make sure that syscalls can only be called from the libc - therefore, making the libc de-facto ABI! Which allows for much more freedom in changing kernel ABI, as long as the libc follows through. Perhaps this way the system can go away from the syscall-level ABI and move over to the libc ABI / shared library ABI?
In particular, kernel ABI is the main stable interface that Linux exposes - and all applications can just use syscalls directly without having to interface with the libc at all. However, that means that kernel must not change its ABI lest it risks breaking compatibility, and each functionality that isn't implemented inside of the kernel (e.g. GUI stuff) cannot be implemented completely portably.
However, using pinsyscalls(), a kernel can make sure that syscalls can only be called from the libc - therefore, making the libc de-facto ABI! Which allows for much more freedom in changing kernel ABI, as long as the libc follows through. Perhaps this way the system can go away from the syscall-level ABI and move over to the libc ABI / shared library ABI?