On Mon, 12 May 2008, lunight wrote: > Hi all, > do any body knows what the solaris does when a context/address switch > happens? > since the entity of solaris schedule is kernel thread , and not like > linux , solaris separates user address space and kernel address, so when a > thread make a syscall, there will be a address space changing ..my question > is :how the kernel make this happens? I know there is an ASI register in > SPARC, it is said ASI has something to do with this procedure, anybody knows > how to use it? another question is :is there any register like the cr3(x86) > in sparc ? how to use it? > > I want to know these answers for so long..thx for your help.
Hmm, seen there's still no answer - so here we go ;-) Unlike x86, where there is only _one_ MMU context register (%cr3), SPARC has different MMU contexts depending on the CPU state. In other words, the CPU switches the default MMU context when it switches privileges. That's simplified, but close. Think of it a bit like the x86 architecture switches %esp/%rsp when switching privileges - that's something done implicitly there, based on the TSS settings for the various stacks. On SPARC, that needs to be done explicitly. It's the other way round with the MMU context, where x86 requires an explicit switch (if you'd want one), while on SPARC(v9) it's explicit. There are two MMU contexts - ASI_PRIMARY and ASI_SECONDARY, and a change in processor state (such as a trap) changes which one is used by default. The rules (and involved registers / ASIs) are given in the sparcv9 joint programming specification, appendix F.5, see there for a summary: http://www.fujitsu.com/downloads/PRMPWR/JPS1-R1.0.4-Common-pub.pdf Best regards, FrankH. _______________________________________________ opensolaris-code mailing list [email protected] http://mail.opensolaris.org/mailman/listinfo/opensolaris-code
