- In the initial description of si_addr, do not claim that it is
always the faulting instruction.
- For si_addr, document that it is generally set to the PC for
synchronous signals, but that it can be set to the the address of
the faulting memory reference for some signals including SIGSEGV and
SIGBUS. In particular, while SIGSEGV generally sets si_addr to the
faulting memory reference, SIGBUS can vary. On some platforms, some
SIGBUS signals set si_addr to the PC and other SIGBUS signals set
si_addr to the faulting address depending on the specific hardware
exception.
- For si_trapno, synchronous signals should set this to some value.
Reviewed by: kib
Sponsored by: DARPA
Differential Revision: https://reviews.freebsd.org/D25777
