- Assume a permission fault is always the result of an attempted
write, so no need to disassemble the opcode.
(as discussed with Richard Earnshaw/Jason Thorpe a week or two ago)
- Split out non-MMU data aborts into separate functions, and deal
correctly with XScale imprecise aborts. Specifically, the old code
made no attempt to handle the double abort faults which can occur
as a result of two consecutive external (imprecise) aborts. This
was easy to provoke by read(2)ing from a /dev/mem offset which caused
an external abort. With the old code, this would bring the system
down instantly, with little clue as to why. (hint: tf_spsr held
PSR_ABT32_MODE...)
- Re-write badaddr_read() to use pcb_onfault instead of adding extra
overhead to data_abort_handler(). A side effect of this is that it
now benefits from the XScale double abort recovery.
- Invoke the cpu-specific prefetch/data abort fixup routines only if
the host cpu actually needs it. On other cpus, the code is optimised
away.
- Sprinkle __predict_{false,true} in all the right places.
- G/C some excess debugging baggage.
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