From e9e45e17eb015267aa9db69deecf26d07fa12011 Mon Sep 17 00:00:00 2001 From: cinap_lenrek Date: Mon, 30 Mar 2015 00:26:33 +0200 Subject: sgi: preserve R27 in setregisters(), use setregisters() in noted() GEVector() saves the exception return PC in Ureg.r27 which needs to be preserved. there should be no reason for the user to change the status register from noted() eigther, so we now just use setregisters() in noted() to restore previous general purpose registers. this means that CU1 will always be off after noted() because notify() has disabled the FPU on entry and set fpstatus to FPinactive if it was on. once user starts using FPU again, it will trap and restore fpu registers. --- sys/src/9/sgi/trap.c | 31 +++++-------------------------- 1 file changed, 5 insertions(+), 26 deletions(-) diff --git a/sys/src/9/sgi/trap.c b/sys/src/9/sgi/trap.c index d9a6ae204..4c59730f6 100644 --- a/sys/src/9/sgi/trap.c +++ b/sys/src/9/sgi/trap.c @@ -575,22 +575,6 @@ notify(Ureg *ur) return 1; } -/* - * Check that status is OK to return from note. - */ -int -validstatus(ulong kstatus, ulong ustatus) -{ -// if((kstatus & (INTMASK|KX|SX|UX)) != (ustatus & (INTMASK|KX|SX|UX))) - if((kstatus & INTMASK) != (ustatus & INTMASK)) - return 0; - if((ustatus&(KSU|ERL|EXL|IE)) != (KUSER|EXL|IE)) - return 0; - if(ustatus & (0xFFFF0000&~CU1)) /* no CU3, CU2, CU0, RP, FR, RE, DS */ - return 0; - return 1; -} - /* * Return user to state before notify(); called from user's handler. */ @@ -613,20 +597,13 @@ noted(Ureg *kur, ulong arg0) nur = up->ureg; oureg = (ulong)nur; - if((oureg & (BY2WD-1)) - || !okaddr((ulong)oureg-BY2WD, BY2WD+sizeof(Ureg), 0)){ + if((oureg & (BY2WD-1)) || !okaddr((ulong)oureg-BY2WD, BY2WD+sizeof(Ureg), 0)){ pprint("bad up->ureg in noted or call to noted() when not notified\n"); qunlock(&up->debug); pexit("Suicide", 0); } - if(0 && !validstatus(kur->status, nur->status)) { - qunlock(&up->debug); - pprint("bad noted ureg status %#lux\n", nur->status); - pexit("Suicide", 0); - } - - memmove(kur, up->ureg, sizeof(Ureg)); + setregisters(kur, (char*)kur, (char*)up->ureg, sizeof(Ureg)); switch(arg0) { case NCONT: case NRSTR: /* only used by APE */ @@ -873,10 +850,12 @@ userpc(void) void setregisters(Ureg *xp, char *pureg, char *uva, int n) { - ulong status; + ulong status, r27; + r27 = xp->r27; /* return PC for GEVector() */ status = xp->status; memmove(pureg, uva, n); + xp->r27 = r27; xp->status = status; } -- cgit v1.2.3