PPC / Unwinding non-call exceptions

[Andrew Haley]

Richard Henderson writes:
 > On Thu, May 17, 2001 at 05:18:37PM +0100, Andrew Haley wrote:
 > > 	* config/rs6000/linux.h (MD_FALLBACK_FRAME_STATE_FOR): New.
 > 
 > Ok.
 > 
 > > +    /* The unwinder expects the IP to point to the following insn,	\
 > > +       whereas the kernel returns the address of the actual		\
 > > +       faulting insn.  */						\
 > > +    sc_->regs->nip += 4;  						\
 > 
 > Always?  For instance on Alpha, SIGSEGV/SIGBUS point to the
 > faulting insn, while SIGFPE/SIGILL point to the following insn.

"For all program exceptions except floating-point enabled exceptions
when operating in imprecise mode, SRR0 contains the EA of the
excepting instruction."

I haven't tried all the possibilites, but as far as I can tell the
kernel doesn't adjust SRR0 before passing the IP value to user code.

Andrew.