Re: [PATCH 3/6] linux-user: Add code for PR_GET/SET_UNALIGN

[Richard Henderson]

On 1/9/24 04:15, Philippe Mathieu-Daudé wrote:
> > +/*
> > + * This can't go in hw/core/cpu.c because that file is compiled only
> > + * once for both user-mode and system builds.
> > + */
> >   static Property cpu_common_props[] = {
> > -#ifndef CONFIG_USER_ONLY
> > +#ifdef CONFIG_USER_ONLY
> >       /*
> > -     * Create a memory property for softmmu CPU object,
> > -     * so users can wire up its memory. (This can't go in hw/core/cpu.c
> > -     * because that file is compiled only once for both user-mode
> > -     * and system builds.) The default if no link is set up is to use
> > +     * Create a property for the user-only object, so users can
> > +     * adjust prctl(PR_SET_UNALIGN) from the command-line.
>
> How can I test this per-thread property?

-cpu foo,prctl-unalign-sigbus=true


> Shouldn't this be an accel (TCG/user) property, for all threads?

There is always one cpu at user-only startup, and it is copied on clone.

Logically it would be a kernel property, since it's something the kernel does, not the 
cpu.  But cpu vs accel makes no difference to me; it was just easy here.

IIRC, this is simply a proxy for not really being able to inherit this bit across 
fork+exec like you can with the real kernel.


r~