Several changes related to all pmaps having their own level 1
page table: - Update the current hwpcb pointer in the SWITCH_CONTEXT macro, so that we know it's always correct. - Optimize cpu_switch(): if we're switching to ourselves, skip the actual context swap. - Clean up some comments and remove some code rendered obsolete by the fact that address spaces are now selected by switching to a new level 1 page table.
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thorpej
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cb6972d4d3
commit
5d56ce57ba
@ -1,4 +1,4 @@
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/* $NetBSD: locore.s,v 1.40 1998/02/24 07:38:01 thorpej Exp $ */
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/* $NetBSD: locore.s,v 1.41 1998/02/27 03:53:49 thorpej Exp $ */
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/*
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* Copyright (c) 1994, 1995, 1996 Carnegie-Mellon University.
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@ -33,7 +33,7 @@
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#include <machine/asm.h>
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__KERNEL_RCSID(0, "$NetBSD: locore.s,v 1.40 1998/02/24 07:38:01 thorpej Exp $");
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__KERNEL_RCSID(0, "$NetBSD: locore.s,v 1.41 1998/02/27 03:53:49 thorpej Exp $");
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#ifndef EVCNT_COUNTERS
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#include <machine/intrcnt.h>
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@ -42,15 +42,26 @@ __KERNEL_RCSID(0, "$NetBSD: locore.s,v 1.40 1998/02/24 07:38:01 thorpej Exp $");
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.stabs __FILE__,132,0,0,kernel_text
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/*
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* The physical address of the current HWPCB.
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*/
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BSS(curpcb, 8)
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/*
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* Perform actions necessary to switch to a new context. The
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* hwpcb should be in a0.
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*/
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#define SWITCH_CONTEXT \
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/* Make a note of the context we're running on. */ \
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stq a0, curpcb ; \
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\
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/* Swap in the new context. */ \
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call_pal PAL_OSF1_swpctx ; \
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\
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/* Flush out the entire TLB. (XXX only user side?) */ \
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/* \
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* Invalidate the TLB. \
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* XXX Should use ASNs, and not have to invalidate. \
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*/ \
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ldiq a0, -2 ; \
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call_pal PAL_OSF1_tbi ; \
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call_pal PAL_imb
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@ -589,8 +600,6 @@ Lsavectx1: LDGP(pv)
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/**************************************************************************/
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BSS(curpcb, 8)
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IMPORT(whichqs, 4)
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IMPORT(want_resched, 8)
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IMPORT(Lev1map, 8)
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@ -618,7 +627,6 @@ Lidle2:
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/*
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* cpu_switch()
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* Find the highest priority process and resume it.
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* XXX should optimiize, and not do the switch if switching to curproc
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*/
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LEAF(cpu_switch, 0)
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LDGP(pv)
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@ -684,23 +692,26 @@ Lcs4:
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stl t3, whichqs
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Lcs5:
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/*
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* Switch to the new context
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*/
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/* mark the new curproc, and other globals */
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stq zero, want_resched /* we've rescheduled */
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stq t4, curproc /* curproc = p */
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ldq t5, P_MD_PCBPADDR(t4) /* t5 = p->p_md.md_pcbpaddr */
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stq t5, curpcb /* and store it in curpcb */
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mov t4, s2 /* save new proc */
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ldq s3, P_MD_PCBPADDR(s2) /* save new pcbpaddr */
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/*
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* Do the context swap, and invalidate old TLB entries.
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* XXX should do the ASN thing, and therefore not have to invalidate.
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* Check to see if we're switching to ourself. If we are,
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* don't bother loading the new context.
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*
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* Note that even if we re-enter cpu_switch() from idle(),
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* s0 will still contain the old curproc value because any
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* users of that register between then and now must have
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* saved it. Also note that switch_exit() ensures that
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* s0 is clear before jumping here to find a new process.
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*/
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cmpeq s0, t4, t0 /* oldproc == newproc? */
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bne t0, Lcs6 /* Yes! Skip! */
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mov t4, s2 /* save new curproc */
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mov t5, s3 /* save new pcbpaddr */
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/*
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* Activate the new process's address space and perform
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* the actual context swap.
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*/
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mov s2, a0 /* pmap_activate(p) */
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CALL(pmap_activate)
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@ -708,15 +719,18 @@ Lcs5:
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mov s3, a0 /* swap the context */
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SWITCH_CONTEXT
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#ifdef NEW_PMAP
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mov s0, a0 /* pmap_deactivate(oldproc) */
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CALL(pmap_deactivate)
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#else
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Lcs6:
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/*
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* Utah-derived pmap_deactivate() is a noop, so don't bother with
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* the call.
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* Now that the switch is done, update curproc and other
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* globals. We must do this even if switching to ourselves
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* because we might have re-entered cpu_switch() from idle(),
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* in which case curproc would be NULL.
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*/
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#endif
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stq s2, curproc /* curproc = p */
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stq zero, want_resched /* we've rescheduled */
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/*
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* Now running on the new u struct.
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@ -773,22 +787,10 @@ LEAF(switch_exit, 1)
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/* Switch to proc0. */
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lda t4, proc0 /* t4 = &proc0 */
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ldq t5, P_MD_PCBPADDR(t4) /* t5 = p->p_md.md_pcbpaddr */
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stq t5, curpcb /* and store it in curpcb */
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#ifndef NEW_PMAP
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mov t4, s0
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ldq s1, P_ADDR(t4)
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#endif
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/*
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* Do the context swap, and invalidate old TLB entries.
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* XXX should do the ASN thing, and therefore not have to invalidate.
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* Do the actual context swap.
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*/
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#ifndef NEW_PMAP
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ldq t2, P_VMSPACE(t4) /* t2 = p->p_vmspace */
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ldq a0, VM_MAP_PMAP(t2) /* a0 = ... ->vm_map.pmap */
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CALL(_pmap_activate)
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#endif
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mov t5, a0
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SWITCH_CONTEXT
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@ -807,10 +809,13 @@ LEAF(switch_exit, 1)
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CALL(kmem_free)
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#endif
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/* and jump into the middle of cpu_switch. */
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#ifdef NEW_PMAP
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/* XXX XXX LOSE */
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#endif
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/*
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* Now jump back into the middle of cpu_switch(). Note that
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* we must clear s0 to guarantee that the check for switching
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* to ourselves in cpu_switch() will fail. This is safe since
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* s0 will be restored when a new process is resumed.
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*/
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mov zero, s0
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jmp zero, sw1
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END(switch_exit)
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