On Fri, Jun 11, 2010 at 06:07:52AM -0700, Richard Henderson wrote: > On 06/11/2010 01:06 AM, Aurelien Jarno wrote: > > What's the difference between FACILITY_ZARCH and FACILITY_ZARCH_ACTIVE, > > as both are actually flagged together. My guess is that > > FACILITY_ZARCH_ACTIVE is needed in 64-bit mode, why FACILITY_ZARCH is > > only needed for a possible future 32-bit mode. Is it correct? > > Loosely, > > ZARCH is set when the system is 64-bit capable, whether or not it is active. > The OS would check this bit at startup if it wanted to change modes. This > bit isn't really interesting to us in userspace. > > ZARCH_ACTIVE is set when the system is in 64-bit mode, i.e. you've booted > with a 64-bit kernel. Note that this says nothing about the address > decoding mode -- this bit can be set while the PSW is set for 31-bit > address translation, e.g. running a 32-bit program on a 64-bit kernel. >
So in short we never use ZARCH in QEMU, so we probably don't want to have this #define, nor add it at the same time as FACILITY_ZARCH_ACTIVE. -- Aurelien Jarno GPG: 1024D/F1BCDB73 aurel...@aurel32.net http://www.aurel32.net
