Re: [PATCH v2 4/8] linux-user/arm: Report SIGBUS and SIGSEGV correctly

[Richard Henderson]

On 8/26/21 6:31 AM, Peter Maydell wrote:
> > +                si_signo = TARGET_SIGSEGV;
> > +                si_code = TARGET_SEGV_ACCERR;
> > +                break;
> > +            case 0x5: /* Translation fault, level 1 */
> > +            case 0x7: /* Translation fault, level 2 */
> > +                si_signo = TARGET_SIGSEGV;
> > +                si_code = TARGET_SEGV_MAPERR;
> > +                break;
>
> Side note: for cases like this where we can tell MAPERR from
> ACCERR based on info the exception handler passes to us, should
> we prefer that or the "check the page flags" approach that
> force_sigsegv_for_addr() takes ?

FYI, the v3 version of the sigsegv+siginfo patch set makes is vastly easier on the target 
code.  For the most part the target code goes away entirely.  For the specific case of Arm 
(both a32 and a64), we retain it because we are supposed to report the ESR and FAR as part 
of the signal frame.

I'll note that a64 isn't filling in the esr_context and far_context structures.  The 
latter was invented for MTE, I believe, where the normal si_addr is untagged.  I should 
have a double-check around those at some point...


r~