status of Linux ptrace on amd64?

[Alexander Nasonov <alnsn%yandex.ru@localhost>]

Hi,

While trying to make some Linux instrumentation tool work on -current
amd64 I noticed that ptrace support in compat_linux and compat_linux32
have some notable differences and compat_linux32 has a better support.
For instance, I can debug 32bit Linux binaries with NetBSD's gdb but
any attempt to set a breakpoint on 64bit Linux results in SIGTRAP.

Neither compat_linux32 nor compat_linux work for that particular tool
because they don't support LIUNX_PEEKUSER.

So, I wonder how much work it is to improve ptrace in compat_linux and
compat_linux32?

Alex