Sun Microelectronics
59
6. MMU Internal Architecture
E
:
Reports the side-effect bit (E) associated with the faulting data access or
FLUSH instruction. Set by FLUSH or translating ASI accesses (see Section
8.3, “Alternate Address Spaces,” on page 146) mapped by the TLB with
the E bit set and ASI_PHYS_BYPASS_EC_WITH_EBIT{_LITTLE} ASIs
(15
16
and 1D
16
). Other cases that update the SFSR (including bypass or
internal ASI accesses) set the E bit to 0. It always reads as 0 in the I-MMU.
CT
:
Context register selection, as described in the following table. The context
is set to 11
2
when the access does not have a translating ASI (see Section
8.3, “Alternate Address Spaces,” on page 146).
PR
:
Privilege. Set if the faulting access occurred while in Privileged mode.
This field is valid for all traps in which the Fault Valid (FV) bit is set.
W
:
Write. Set if the faulting access indicated a data write operation (a store
or atomic load/store instruction). Always reads as 0 in the I-MMU SFSR.
OW
:
Overwrite. Set to one when the MMU detects a fault, if the Fault Valid bit
has not been cleared from a previous fault; otherwise, it is set to zero.
Table 6-11
MMU Synchronous Fault Status Register FT (Fault Type) Field
FT<6:0>
Fault Type
01
16
Privilege violation
02
16
Speculative Load or Flush instruction to page marked with E-bit. This bit is zero for internal
ASI accesses.
04
16
Atomic (including 128-bit atomic load) to page marked uncacheable. This bit is zero for
internal ASI accesses, except for atomics to DTLB_DATA_ACCESS_REG (5D
16
), which
update according to the TLB entry accessed.
08
16
Illegal LDA/STA ASI value, VA, RW, or size. Excludes cases where 02
16
and 04
16
are set.
10
16
Access other than non-faulting load to page marked NFO. This bit is zero for internal ASI
accesses.
20
16
VA out of range (D-MMU and I-MMU branch, CALL, sequential)
40
16
VA out of range (I-MMU JMPL or RETURN)
Table 6-12
MMU SFSR Context ID Field Description
Context ID
I-MMU Context
D-MMU Context
00
Primary
Primary
01
Reserved
Secondary
10
Nucleus
Nucleus
11
Reserved
Reserved
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