6 Jan
2015
6 Jan
'15
11 p.m.
Right - that's how the kernel set up the page tables for the user processes.
On Tue, Jan 6, 2015 at 4:57 PM, Ronald Natalie <ron(a)ronnatalie.com> wrote:
On Jan 6, 2015, at 3:33 PM, random832(a)fastmail.us
wrote:
Was it possible to read/write to the instruction space, or execute the
data space?
In split I/D mode (411) magic number. It is imposible to execute in D
space or use regular data access instructions to access i-space. The
addresses are in completely different spaces (i.e, 0 in data is mapped to
different memory than 0 in instruction space). Some access at the kernel
level can be done with MFPI and MPFD instructions.
In write protected, non-split more (410 magic), you could read the I space
and you could jump in to D space. You were prohibited to write the i
space.
In non protected mode (407 magic) everything was fair game.
_______________________________________________
TUHS mailing list
TUHS(a)minnie.tuhs.org
https://minnie.tuhs.org/mailman/listinfo/tuhs