Re: tprof(8) ABI

[Martin Husemann <martin%duskware.de@localhost>]

On Sun, Apr 19, 2026 at 05:54:23PM -0700, Kevin Bowling wrote:
> Hi Nick,
> 
> My understanding is we are trying to capture a 64-bit PC from the
> kernel into a structure that n32 userland reads. If we sign extend a
> 32-bit value read from the kernel, I'm not sure if we'd have the right
> value in every case but I don't fully grasp the sign extension.  I
> suppose we'd need to understand some other cases like x86 user on
> amd64 or sparc on sparc64 too, and KASLR?

Why is the kernel PC relevant here? I thought this would sample the
userland PC as observed by the kernel, and for 32bit userland processes
this can always only be a 32bit value (on sparc and i386 zero extended,
on mips and riscv probably sign extended).

Martin