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antonblanchard.microwatt/execute1.vhdl
Paul Mackerras d47fbf88d1 Implement access permission checks
This adds logic to the dcache to check the permissions encoded in
the PTE that it gets from the dTLB.  The bits that are checked are:

R must be 1
C must be 1 for a store
EAA(0) - if this is 1, MSR[PR] must be 0
EAA(2) must be 1 for a store
EAA(1) | EAA(2) must be 1 for a load

In addition, ATT(0) is used to indicate a cache-inhibited access.

This now implements DSISR bits 36, 38 and 45.

(Bit numbers above correspond to the ISA, i.e. using big-endian
numbering.)

MSR[PR] is now conveyed to loadstore1 for use in permission checking.

Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
2020-05-08 12:12:01 +10:00

35 KiB