Re: [Gcl-devel] Re: siginfo fault addresses now apprently working on hppa

[Camm Maguire]

Greetings, and thanks for your feedback!  I notice sarti has the same
kernel.  I'll change to si_addr, but this will mean that the
autobuilders will turn off SGC with my new patch on maxima/acl2/axiom.
Users running the binaries on working kernels could reenable it if
they knew how (i.e. (si:;sgc-on t)).  Any idea of what Debian hppa
users are likely to run?  In any case, the code will be ready when the
kernels catch up.

Carlos O'Donell <address@hidden> writes:

> Cam,
> 
> > > a. siginfo_t is properly delivered to 32-bit userspace from a 32-bit
> > >    kernel. If it doesn't, please show me the example code, kernel config,
> > >    and hardware used to run the test. This has always worked.
> > > 
> > 
> > Well, I'm not sure how long is meant by always, but lets forget about
> > the past for the moment.  Right now on paer I can get the address in
> >  ((siginfo_t *)code)->si_ptr
> > where the handler is defined as
> > void
> > memprotect_handler(int sig, long code, void *scp, char *addr)
> > and setup with SA_RESTART and SA_SIGINFO.  On most machines its under 
> >  ((siginfo_t *)code)->si_addr
> > but not on paer.  I can show you a gdb trace if you need.
> 
> si_ptr is only valid for POSIX real-time signals, don't use that.
> paer is a 64-bit box running 2.4.23-pa5, and thus does not have the
> fixes required. The fact that si_ptr works is a *complete* fluke, the
> kernel has shifted all values in the structure. You are really reading a
> 64-bit version of the structure.
> 
> Please apply pressure to have paer updated to a new 2.6.x kernel :)
>  
> > Thanks for this jog.  This has been on my todo list for sometime now.
> > I've just implemented a runtime test for the fault recovery
> > mechanism.  I'm not checking kernel versions per se, just the compile
> > time determined code snippet for recovering the fault address on the
> > runtime kernel.  Here's the outline:
> 
> It looks fine, you just can't run that code on a 64-bit box without a
> 2.6.1 or newer kernel from cvs.parisc-linux.org.

I think the code will run, discover the fault address is wrong, and
disable the feature.  That's the idea anyway.

Take care,

> 
> c.
> 
> 
> 
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> 
> 
> 

-- 
Camm Maguire                                            address@hidden
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