Intel Xeon E5502 80602E5502 User Manual

Product codes
80602E5502
Page of 130
Intel® Xeon® Processor 5500 Series Datasheet, Volume 2
59
Register Description
2.7.3
SAD_HEN
Register for legacy Hole Enable.
2.7.4
SAD_SMRAM
Register for legacy 9Dh address space. Note both IOH and non-core have this now.
Device:
0
Function: 1
Offset:
48h
Access as a Dword
Bit
Type
Reset
Value
Description
7
RW
0
HEN. This field enables a memory hole in DRAM space. The DRAM that lies 
"behind" this space is not remapped.
0: No Memory hole.
1: Memory hole from 15 MB to 16MB.
Device:
0
Function: 1
Offset:
4Ch
Access as a Dword
Bit
Type
Reset
Value
Description
14
RW
0
SMM Space Open (D_OPEN). When D_OPEN=1 and D_LCK=0, the SMM 
space DRAM is made visible even when SMM decode is not active. This is 
intended to help BIOS initialize SMM space. Software should ensure that 
D_OPEN=1 and D_CLS=1 are not set at the same time.
13
RW
0
SMM Space Closed (D_CLS). When D_CLS = 1 SMM space DRAM is not 
accessible to data references, even if SMM decode is active. Code references 
may still access SMM space DRAM. This will allow SMM software to reference 
through SMM space to update the display even when SMM is mapped over 
the VGA range. Software should ensure that D_OPEN=1 and D_CLS=1 are 
not set at the same time.
12
RW1S
0
SMM Space Locked (D_LCK). When D_LCK is set to 1 then D_OPEN is 
reset to 0 and D_LCK, D_OPEN, C_BASE_SEG, G_SMRAME, PCIEXBAR, 
(DRAM_RULEs and INTERLEAVE_LISTs) become read only. D_LCK can be set 
to 1 via a normal configuration space write but can only be cleared by a 
Reset. The combination of D_LCK and D_OPEN provide convenience with 
security. The BIOS can use the D_OPEN function to initialize SMM space and 
then use D_LCK to "lock down" SMM space in the future so that no 
application software (or BIOS itself) can violate the integrity of SMM space, 
even if the program has knowledge of the D_OPEN function. Note that TAD 
does not implement this lock.
11
RW
0
Global SMRAM Enable (G_SMRAME). If set to a 1, then Compatible 
SMRAM functions are enabled, providing 128 KB of DRAM accessible at the 
A0000h address while in SMM (ADSB with SMM decode). To enable Extended 
SMRAM function this bit has to be set to 1. Once D_LCK is set, this bit 
becomes read only. 
10:8
RO
-
Compatible SMM Space Base Segment (C_BASE_SEG). This field 
indicates the location of SMM space. SMM DRAM is not remapped. It is simply 
made visible if the conditions are right to access SMM space, otherwise the 
access is forwarded to HI. Only SMM space between A0000 and BFFFF is 
supported so this field is hardwired to 010.