Open aswaterman opened 10 months ago
@aswaterman is there a position defined for this bit.
I'm pretty swamped right now. Can you make a proposal (and a PR once we an agree)?
Will do.
Bits that are presently defined in xstateen0
.
fcsr
for Zfinx and related extensionsjvt
CSR for Zcmthcontext
CSRstopei
and vstopei
siselect
, sireg
, vsiselect
, and vsireg
sstateen0
and hstateen0
This issue proposes to define a single xstateen0
bit - bit 55 - to govern new state introduced by Priv-1.14-era extensions.
The state of the following extensions is expected to be governed by the bit 55:
srmcfg
(holds QoS identifiers)stvt
, snxti
, sintstatus
, sintthresh
, sscratchcsw
, and sscratchcswl
(S-mode CLIC extensions)siselect
/vsiselect
value of 0x200 through 0x2FF (Control transfer records extension)The bit 56 was initially intended for use by the counter delegation extension but was not pursued/approved. The updated definition is as follows:
An architecture decisions shall be made, per 1.14-era extensions, to determine if the extension should be governed by the bit provided in xstateen0
for the 1.14-era extensions or the extension should be governed by an extension specific bit. This determination is pending for Ssclic and Ssctr.
Bit 56 in CSR xstateen0
is defined to govern new state introduced by Priv-1.14-era extensions. Access to the CSR srmcfg
introduced by the Ssqosid extension shall be governed by the bit 56 of CSR mstateen0
.
Agreed.
Bit 56 in CSR mstateen0
controls access to CSR henvcfgh
.
Bit 55 in CSR mstateen0
is defined to control access to new state introduced by the following small extensions of Priv-1.14-era:
srmcfg
introduced by the forthcoming Ssqosid extension.
Going forward, we'd like to allocate only a single stateen bit for small extensions defined between priv-spec releases, rather than allocating a bit for every small extension. This isn't an absolute rule; it's just an attempt to cut down on stateen bit count when practical.
The plan is that the qosid register will be controlled by the priv-1.13 stateen bit, and possibly other registers will, too.