[patch] sigaltstack fixes for hppa-linux

[Andrew Cagney]

> This patch fixes sigaltstack handling on hppa. It requires one arch-indep 
> change in frame.c: on hppa (stack-grows-up), the relationship of the 
> sigaltstack can be that it is not "inner" to the signal frame, if the 
> sigaltstack resides in a caller's stack frame (as is true in gdb's testcase.)

The current code handles the transition:

stk 1: caller (this_frame)
stk 2: trampoline (this_frame->next)
stk 2: handler

are you saying that the transition:

stk 1: caller
stk 1: trampoline (this_frame)
stk 2: handler (this_frame->next)

is also possible?

Perhaphs the test should be just:

    if (this_frame->type == NORMAL_FRAME
        && this_frame->next->type == NORMAL_FRAME
        && frame_id_inner (get_frame_id (this_frame),
  			 get_frame_id (this_frame->next)))

Andrew

> ok to apply?