[src/trunk]: src/sys/arch/vax/vax Change Swtch so that the old process contex...

[ragge <ragge%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/7c8f8c398c91
branches:  trunk
changeset: 510456:7c8f8c398c91
user:      ragge <ragge%NetBSD.org@localhost>
date:      Tue May 29 21:25:11 2001 +0000

description:
Change Swtch so that the old process context is stored directly and the
idle loop is on the interrupt stack instead of the last running process'
stack. This is needed to work in a multiprocessor environment.

diffstat:

 sys/arch/vax/vax/subr.s |  55 ++++++++++++++++++------------------------------
 1 files changed, 21 insertions(+), 34 deletions(-)

diffs (116 lines):

diff -r a6f407c4ca65 -r 7c8f8c398c91 sys/arch/vax/vax/subr.s
--- a/sys/arch/vax/vax/subr.s   Tue May 29 20:22:05 2001 +0000
+++ b/sys/arch/vax/vax/subr.s   Tue May 29 21:25:11 2001 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: subr.s,v 1.58 2001/05/27 19:33:20 ragge Exp $     */
+/*     $NetBSD: subr.s,v 1.59 2001/05/29 21:25:11 ragge Exp $     */
 
 /*
  * Copyright (c) 1994 Ludd, University of Lule}, Sweden.
@@ -317,14 +317,11 @@
 #elif defined(MULTIPROCESSOR)
        clrl    _C_LABEL(sched_lock)    # release sched lock
 #endif
-       mtpr    $IPL_NONE,$PR_IPL       # Enable all types of interrupts
-1:
-#if 0
-       tstl    _C_LABEL(uvm)+UVM_PAGE_IDLE_ZERO
-       beql    2f
-       calls   $0,_C_LABEL(uvm_pageidlezero)
-#endif
-2:     tstl    _C_LABEL(sched_whichqs) # Anything ready to run?
+       mtpr    $1,$PR_IPL              # IPL cannot be 0 because we are
+                                       # running on the interrupt stack
+                                       # and may get interrupts
+
+1:     tstl    _C_LABEL(sched_whichqs) # Anything ready to run?
        beql    1b                      # no, run the idle loop again.
 /* Now try the test the long way */
        mtpr    $IPL_HIGH,$PR_IPL       # block all types of interrupts
@@ -333,9 +330,7 @@
 #elif defined(MULTIPROCESSOR)
 3:     bbssi   $0,_C_LABEL(sched_lock),3b      # acquire sched lock
 #endif
-       tstl    _C_LABEL(sched_whichqs) # Anything ready to run?
-       beql    idle                    # Yes, goto switch again.
-       brb     Swtch                   # nope, continue to idlely loop
+       brb     lp                      # check sched_whichqs again
 
 #
 # cpu_switch, cpu_exit and the idle loop implemented in assembler 
@@ -346,7 +341,12 @@
 JSBENTRY(Swtch)
        mfpr    $PR_SSP,r1              # Get ptr to this cpu_info struct
        clrl    CI_CURPROC(r1)          # Stop process accounting
-       ffs     $0,$32,_C_LABEL(sched_whichqs),r3 # Search for bit set
+       svpctx                          # Save context if another CPU
+                                       # get control first (must be on
+                                       # the interrupt stack when idling)
+
+
+lp:    ffs     $0,$32,_C_LABEL(sched_whichqs),r3 # Search for bit set
        beql    idle                    # no bit set, go to idle loop
 
        movaq   _C_LABEL(sched_qs)[r3],r1       # get address of queue head
@@ -356,14 +356,8 @@
        bvc     1f                      # check if something on queue
        pushab  noque
        calls   $1,_C_LABEL(panic)
-#ifdef __ELF__
-       .section        .rodata
 #endif
-noque: .asciz  "swtch"
-#ifdef __ELF__
-       .text
-#endif
-#endif
+
 1:     bneq    2f                      # more processes on queue?
        bbsc    r3,_C_LABEL(sched_whichqs),2f   # no, clear bit in whichqs
 2:     clrl    P_BACK(r2)              # clear proc backpointer
@@ -375,15 +369,7 @@
        movb    $SONPROC,P_STAT(r2)     # p->p_stat = SONPROC;
        movl    r2,CI_CURPROC(r1)       # set new process running
        clrl    CI_WANT_RESCHED(r1)     # we are now changing process
-       cmpl    r6,r2                   # Same process?
-       bneq    1f                      # No, continue
-#if defined(LOCKDEBUG)
-       calls   $0,_C_LABEL(sched_unlock_idle)
-#elif defined(MULTIPROCESSOR)
-       clrl    _C_LABEL(sched_lock)    # clear sched lock
-#endif
-       rsb
-1:     movl    P_ADDR(r2),r0           # Get pointer to new pcb.
+       movl    P_ADDR(r2),r0           # Get pointer to new pcb.
        addl3   r0,$IFTRAP,r1           # Save for copy* functions.
        mtpr    r1,$PR_ESP              # Use ESP as CPU-specific pointer
        movl    r1,ESP(r0)              # Must save in PCB also.
@@ -396,11 +382,6 @@
        extzv   $9,$21,r0,r1            # extract offset
        ashl    $9,*_C_LABEL(Sysmap)[r1],r3
 
-#
-# Do the actual process switch. pc + psl are already on stack, from
-# the calling routine.
-#
-       svpctx
        mtpr    r3,$PR_PCBB
        ldpctx
 #if defined(LOCKDEBUG)
@@ -411,6 +392,7 @@
        rei
 
 #if defined(MULTIPROCESSOR)
+       .align 2
        .globl  _C_LABEL(tramp) # used to kick off multiprocessor systems.
 _C_LABEL(tramp):
        ldpctx
@@ -613,3 +595,8 @@
        .globl _C_LABEL(memtest)
 _C_LABEL(memtest):             # memory test in progress
        .long 0
+
+#ifdef __ELF__
+       .section        .rodata
+#endif
+noque: .asciz  "swtch"