Re: [RFC v2 PATCH 7/7] x86/entry: use int for syscall number; handle all invalid syscall nrs

From: H. Peter Anvin
Date: Thu May 13 2021 - 20:39:00 EST

On 5/12/21 3:22 PM, Thomas Gleixner wrote:

As far as this being a user ABI change, this is actually a revert to the
original x86-64 ABI; see my message to Ingo.

I'm not against that change, but it has to be well justified and the
reasoning wants to be in the changelog. You know the drill :)


So in the process of breaking up and better document this patch, I have looked at the syscall_numbering_64 (and have rewritten it to be more complete.)

I found that running it under strace fails, as strace (possibly ptrace, possibly the strace binary) causes %rax = 2^32 to be clobbered to zero already...

More motivation, I guess.