+/* vmproc.c 2.2 1/21/80 */
+
+#include "../h/param.h"
+#include "../h/systm.h"
+#include "../h/dir.h"
+#include "../h/user.h"
+#include "../h/proc.h"
+#include "../h/mtpr.h"
+#include "../h/pte.h"
+#include "../h/map.h"
+#include "../h/cmap.h"
+#include "../h/text.h"
+#include "../h/vm.h"
+
+/*
+ * Begin to get virtual memory resources for a new process.
+ * Called by exec with the new text data and stack sizes.
+ *
+ * NOTE: should free extra page table pages here or somewhere.
+ */
+vgetvm(ts, ds, ss)
+ int ts, ds, ss;
+{
+#ifdef UNTESTED
+ register int szpt = clrnd(ctopt(ts+ds+ss));
+ register int freeptp = u.u_procp.p_szpt - szpt;
+ register int i;
+ int a;
+
+ a = btokmx(u.u_pcb.pcb_p0br);
+ if (freeptp > 0) {
+ memfree(&Usrptmap[a + szpt], freeptp, 1);
+ mfree(kernelmap, freeptp, a + szpt);
+ u.u_pcb.pcb_szpt = szpt;
+ u.u_procp->p_szpt = szpt;
+ u.u_pcb.pcb_p1br = kmxtob(a + szpt);
+ mtpr(P1BR, u.u_pcb.pcb_p1br);
+ mtpr(TBIA, 1);
+ }
+ for (i = 0; i < u.u_pcb.pcb_szpt; i++)
+ clearseg(Usrptmap[a + i].pg_pfnum);
+#endif
+ mtpr(P0LR, ts);
+ u.u_pcb.pcb_p0lr = ts | AST;
+ mtpr(P1LR, P1TOP);
+ u.u_pcb.pcb_p1lr = P1TOP;
+ u.u_procp->p_tsize = ts;
+ u.u_tsize = ts;
+ expand((int)ss, P1BR);
+ expand((int)ds, P0BR);
+}
+
+/*
+ * Release the virtual memory resources (memory
+ * pages, and swap area) associated with the current process.
+ * Used at exit or execl.
+ */
+vrelvm()
+{
+ register struct proc *p = u.u_procp;
+ register int n;
+
+ xfree();
+ p->p_rssize -= vmemfree(dptopte(p, 0), p->p_dsize);
+ p->p_rssize -= vmemfree(sptopte(p, p->p_ssize - 1), p->p_ssize);
+ if (p->p_rssize != 0)
+ panic("vrelvm rss");
+ p->p_swrss = 0;
+ while (p->p_poip)
+ sleep((caddr_t)&p->p_poip, PSWP+1);
+ VOID vsexpand(0, &u.u_dmap);
+ VOID vsexpand(0, &u.u_smap);
+ p->p_tsize = 0;
+ p->p_dsize = 0;
+ p->p_ssize = 0;
+ u.u_tsize = 0;
+ u.u_dsize = 0;
+ u.u_ssize = 0;
+ for (n = 0; n < NOFILE; n++)
+ if (u.u_vrpages[n])
+ panic("vrelvm vrpages");
+}
+
+/*
+ * Pass virtual memory resources from p to q.
+ * P's u. area is up, q's is uq. Used internally
+ * when starting/ending a vfork().
+ */
+vpassvm(p, q, up, uq)
+ register struct proc *p, *q;
+ register struct user *up, *uq;
+{
+
+ vpasspt(p, q, up, uq);
+
+ uq->u_tsize = q->p_tsize = p->p_tsize; up->u_tsize = p->p_tsize = 0;
+ uq->u_dsize = q->p_dsize = p->p_dsize; up->u_dsize = p->p_dsize = 0;
+ uq->u_ssize = q->p_ssize = p->p_ssize; up->u_ssize = p->p_ssize = 0;
+
+ q->p_swrss = p->p_swrss; p->p_swrss = 0;
+ q->p_rssize = p->p_rssize; p->p_rssize = 0;
+ q->p_poip = p->p_poip; p->p_poip = 0;
+
+ q->p_textp = p->p_textp;
+ xrepl(p, q);
+ p->p_textp = 0;
+
+ uq->u_dmap = up->u_dmap; up->u_dmap = zdmap;
+ uq->u_smap = up->u_smap; up->u_smap = zdmap;
+ uq->u_outime = up->u_outime; up->u_outime = 0;
+ uq->u_majorflt = up->u_majorflt; up->u_majorflt = 0;
+ uq->u_minorflt = up->u_minorflt; up->u_minorflt = 0;
+}
+
+/*
+ * Change the size of the data+stack regions of the process.
+ * If the size is shrinking, it's easy-- just release virtual memory.
+ * If it's growing, initalize new page table entries as
+ * 'zero fill on demand' pages.
+ */
+expand(change, region)
+{
+ register struct proc *p;
+ register struct pte *base, *p0, *p1;
+ struct pte proto;
+ int a0, a1;
+
+ p = u.u_procp;
+ if (change == 0)
+ return;
+ if (change % CLSIZE)
+ panic("expand");
+
+
+#ifdef ERNIE
+ vmsizmon();
+#endif
+
+ /*
+ * Update the sizes to reflect the change. Note that we may
+ * swap as a result of a ptexpand, but this will work, because
+ * the routines which swap out will get the current text and data
+ * sizes from the arguments they are passed, and when the process
+ * resumes the lengths in the proc structure are used to
+ * build the new page tables.
+ */
+ if (region == P0BR) {
+ p->p_dsize += change;
+ u.u_dsize += change;
+ } else {
+ p->p_ssize += change;
+ u.u_ssize += change;
+ }
+
+ /*
+ * Compute the end of the text+data regions and the beginning
+ * of the stack region in the page tables,
+ * and expand the page tables if necessary.
+ */
+ p0 = (struct pte *)mfpr(P0BR) + mfpr(P0LR);
+ p1 = (struct pte *)mfpr(P1BR) + mfpr(P1LR);
+ if (change > p1 - p0)
+ ptexpand(clrnd(ctopt(change - (p1 - p0))));
+ /* PTEXPAND SHOULD GIVE BACK EXCESS PAGE TABLE PAGES */
+
+ /*
+ * Compute the base of the allocated/freed region.
+ */
+ if (region == P0BR) {
+ base = (struct pte *)mfpr(P0BR);
+ base += (a0 = mfpr(P0LR)) + (change > 0 ? 0 : change);
+ } else {
+ base = (struct pte *)mfpr(P1BR);
+ base += (a1 = mfpr(P1LR)) - (change > 0 ? change : 0);
+ }
+
+ /*
+ * If we shrunk, give back the virtual memory.
+ * This code should happen earlier in this routine.
+ */
+ if (change < 0)
+ p->p_rssize -= vmemfree(base, -change);
+
+ /*
+ * Update the processor length registers and words in the pcb.
+ */
+ if (region == P0BR) {
+ mtpr(P0LR,a0 + change);
+ u.u_pcb.pcb_p0lr = a0 + change | AST;
+ } else {
+ mtpr(P1LR,a1 - change);
+ u.u_pcb.pcb_p1lr = a1 - change;
+ }
+
+ /*
+ * If shrinking, clear pte's, otherwise
+ * initialize zero fill on demand pte's.
+ */
+ *(int *)&proto = PG_UW;
+ if (change < 0)
+ change = -change;
+ else {
+ proto.pg_fod = 1;
+ ((struct fpte *)&proto)->pg_fileno = PG_FZERO;
+ cnt.v_nzfod += change;
+ }
+ while (--change >= 0)
+ *base++ = proto;
+
+ mtpr(TBIA,0); /* conservative */
+}
+
+/*
+ * Create a duplicate copy of the current process
+ * in process slot p, which has been partially initialized
+ * by newproc().
+ */
+procdup(p, isvfork)
+ register struct proc *p;
+{
+ register int n;
+
+ /*
+ * There is an extremely unlikely possible deadlock here.
+ * It can only happen if two very large processes grab
+ * their page tables and then each gets part of his UPAGES
+ * and then they have consumed all the available memory.
+ * This can only happen when
+ * USRPTSIZE + UPAGES * NPROC > maxmem
+ * and this is almost never true, except on systems
+ * with incredibly tiny real memories. In practice
+ * such large processes will not fork() but vfork() where
+ * there is no problem.
+ */
+ if (isvfork == 0)
+ while (vgetpt(p, vmemall) == 0) {
+ kmapwnt++;
+ sleep((caddr_t)kernelmap, PSWP+4);
+ }
+ VOID vgetu(p, vmemall, Forkmap, &forkutl, &u);
+ if (isvfork) {
+ vpassvm(u.u_procp, p, &u, &forkutl);
+ for (n = 0; n < NOFILE; n++)
+ if (forkutl.u_vrpages[n] != 0)
+ forkutl.u_vrpages[n]++;
+ return;
+ }
+ forkutl.u_majorflt = 0;
+ forkutl.u_minorflt = 0;
+ forkutl.u_dmap = u.u_cdmap;
+ forkutl.u_smap = u.u_csmap;
+ forkutl.u_outime = 0;
+ if (p->p_textp) {
+ p->p_textp->x_count++;
+ xlink(p);
+ }
+
+ vmdup(p, dptopte(p, 0), dptov(p, 0), p->p_dsize, MDATA);
+ vmdup(p, sptopte(p, p->p_ssize - 1), sptov(p, p->p_ssize - 1), p->p_ssize, MSTACK);
+}
+
+vmdup(p, pte, v, count, type)
+ struct proc *p;
+ register struct pte *pte;
+ register unsigned v;
+ register int count;
+ int type;
+{
+ register struct pte *opte = vtopte(u.u_procp, v);
+ register int i;
+
+ while (count != 0) {
+ count -= CLSIZE;
+ if (opte->pg_fod) {
+ v += CLSIZE;
+ for (i = 0; i < CLSIZE; i++)
+ *(int *)pte++ = *(int *)opte++;
+ continue;
+ }
+ opte += CLSIZE;
+ VOID vmemall(pte, CLSIZE, p, type);
+ p->p_rssize += CLSIZE;
+ for (i = 0; i < CLSIZE; i++) {
+ copyseg((caddr_t)ctob(v+i), (pte+i)->pg_pfnum);
+ *(int *)(pte+i) |= (PG_V|PG_M) + PG_UW;
+ }
+ v += CLSIZE;
+ munlock(pte->pg_pfnum);
+ pte += CLSIZE;
+ }
+}
+
+/*
+ * Check that a process will not be too large.
+ */
+chksize(ts, ds, ss)
+ size_t ts, ds, ss;
+{
+
+ if (ts>MAXTSIZ || ds>MAXDSIZ || ss>MAXSSIZ) {
+ u.u_error = ENOMEM;
+ return(1);
+ }
+ return(0);
+}
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