usr/src/sys/pmax/pmax/vm_machdep.c

/*
 * Copyright (c) 1988 University of Utah.
 * Copyright (c) 1992 The Regents of the University of California.
 * All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * the Systems Programming Group of the University of Utah Computer
 * Science Department and Ralph Campbell.
 *
 * %sccs.include.redist.c%
 *
 * from: Utah $Hdr: vm_machdep.c 1.21 91/04/06$
 *
 *      @(#)vm_machdep.c        7.7 (Berkeley) %G%
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/malloc.h>
#include <sys/buf.h>
#include <sys/vnode.h>
#include <sys/user.h>

#include <vm/vm.h>
#include <vm/vm_kern.h>
#include <vm/vm_page.h>

#include <machine/pte.h>

/*
 * Finish a fork operation, with process p2 nearly set up.
 * Copy and update the kernel stack and pcb, making the child
 * ready to run, and marking it so that it can return differently
 * than the parent.  Returns 1 in the child process, 0 in the parent.
 * We currently double-map the user area so that the stack is at the same
 * address in each process; in the future we will probably relocate
 * the frame pointers on the stack after copying.
 */
cpu_fork(p1, p2)
        register struct proc *p1, *p2;
{
        register struct user *up = p2->p_addr;
        register pt_entry_t *pte;
        register int i;
        extern struct proc *machFPCurProcPtr;

        p2->p_md.md_regs = up->u_pcb.pcb_regs;
        p2->p_md.md_flags = p1->p_md.md_flags & (MDP_FPUSED | MDP_ULTRIX);

        /*
         * Convert the user struct virtual address to a physical one
         * and cache it in the proc struct. Note: if the phyical address
         * can change (due to memory compaction in kmem_alloc?),
         * we will have to update things.
         */
        pte = kvtopte(up);
        for (i = 0; i < UPAGES; i++) {
                p2->p_md.md_upte[i] = pte->pt_entry & ~PG_G;
                pte++;
        }

        /*
         * Copy floating point state from the FP chip if this process
         * has state stored there.
         */
        if (p1 == machFPCurProcPtr)
                MachSaveCurFPState(p1);

        /*
         * Copy pcb and stack from proc p1 to p2.
         * We do this as cheaply as possible, copying only the active
         * part of the stack.  The stack and pcb need to agree;
         */
        p2->p_addr->u_pcb = p1->p_addr->u_pcb;
        /* cache segtab for ULTBMiss() */
        p2->p_addr->u_pcb.pcb_segtab = (void *)p2->p_vmspace->vm_pmap.pm_segtab;

        /*
         * Arrange for a non-local goto when the new process
         * is started, to resume here, returning nonzero from setjmp.
         */
#ifdef DIAGNOSTIC
        if (p1 != curproc)
                panic("cpu_fork: curproc");
#endif
        if (copykstack(up)) {
                /*
                 * Return 1 in child.
                 */
                return (1);
        }
        return (0);
}

/*
 * cpu_exit is called as the last action during exit.
 * We release the address space and machine-dependent resources,
 * including the memory for the user structure and kernel stack.
 * Once finished, we call swtch_exit, which switches to a temporary
 * pcb and stack and never returns.  We block memory allocation
 * until swtch_exit has made things safe again.
 */
cpu_exit(p)
        struct proc *p;
{
        extern struct proc *machFPCurProcPtr;

        if (machFPCurProcPtr == p)
                machFPCurProcPtr = (struct proc *)0;

        vmspace_free(p->p_vmspace);

        (void) splhigh();
        kmem_free(kernel_map, (vm_offset_t)p->p_addr, ctob(UPAGES));
        swtch_exit();
        /* NOTREACHED */
}

/*
 * Dump the machine specific header information at the start of a core dump.
 */
cpu_coredump(p, vp, cred)
        struct proc *p;
        struct vnode *vp;
        struct ucred *cred;
{
        extern struct proc *machFPCurProcPtr;

        /*
         * Copy floating point state from the FP chip if this process
         * has state stored there.
         */
        if (p == machFPCurProcPtr)
                MachSaveCurFPState(p);

        return (vn_rdwr(UIO_WRITE, vp, (caddr_t)p->p_addr, ctob(UPAGES),
            (off_t)0, UIO_SYSSPACE, IO_NODELOCKED|IO_UNIT, cred, (int *)NULL,
            p));
}

/*
 * Move pages from one kernel virtual address to another.
 * Both addresses are assumed to reside in the Sysmap,
 * and size must be a multiple of CLSIZE.
 */
pagemove(from, to, size)
        register caddr_t from, to;
        int size;
{
        register pt_entry_t *fpte, *tpte;

        if (size % CLBYTES)
                panic("pagemove");
        fpte = kvtopte(from);
        tpte = kvtopte(to);
        while (size > 0) {
                MachTLBFlushAddr(from);
                MachTLBUpdate(to, *fpte);
                *tpte++ = *fpte;
                fpte->pt_entry = 0;
                fpte++;
                size -= NBPG;
                from += NBPG;
                to += NBPG;
        }
}

extern vm_map_t phys_map;

/*
 * Map an IO request into kernel virtual address space.  Requests fall into
 * one of five catagories:
 *
 *      B_PHYS|B_UAREA: User u-area swap.
 *                      Address is relative to start of u-area (p_addr).
 *      B_PHYS|B_PAGET: User page table swap.
 *                      Address is a kernel VA in usrpt (Usrptmap).
 *      B_PHYS|B_DIRTY: Dirty page push.
 *                      Address is a VA in proc2's address space.
 *      B_PHYS|B_PGIN:  Kernel pagein of user pages.
 *                      Address is VA in user's address space.
 *      B_PHYS:         User "raw" IO request.
 *                      Address is VA in user's address space.
 *
 * All requests are (re)mapped into kernel VA space via the phys_map
 */
vmapbuf(bp)
        register struct buf *bp;
{
        register caddr_t addr;
        register vm_size_t sz;
        struct proc *p;
        int off;
        vm_offset_t kva;
        register vm_offset_t pa;

        if ((bp->b_flags & B_PHYS) == 0)
                panic("vmapbuf");
        addr = bp->b_saveaddr = bp->b_un.b_addr;
        off = (int)addr & PGOFSET;
        p = bp->b_proc;
        sz = round_page(bp->b_bcount + off);
        kva = kmem_alloc_wait(phys_map, sz);
        bp->b_un.b_addr = (caddr_t) (kva + off);
        sz = atop(sz);
        while (sz--) {
                pa = pmap_extract(vm_map_pmap(&p->p_vmspace->vm_map),
                        (vm_offset_t)addr);
                if (pa == 0)
                        panic("vmapbuf: null page frame");
                pmap_enter(vm_map_pmap(phys_map), kva, trunc_page(pa),
                        VM_PROT_READ|VM_PROT_WRITE, TRUE);
                addr += PAGE_SIZE;
                kva += PAGE_SIZE;
        }
}

/*
 * Free the io map PTEs associated with this IO operation.
 * We also invalidate the TLB entries and restore the original b_addr.
 */
vunmapbuf(bp)
        register struct buf *bp;
{
        register caddr_t addr = bp->b_un.b_addr;
        register vm_size_t sz;
        vm_offset_t kva;

        if ((bp->b_flags & B_PHYS) == 0)
                panic("vunmapbuf");
        sz = round_page(bp->b_bcount + ((int)addr & PGOFSET));
        kva = (vm_offset_t)((int)addr & ~PGOFSET);
        kmem_free_wakeup(phys_map, kva, sz);
        bp->b_un.b_addr = bp->b_saveaddr;
        bp->b_saveaddr = NULL;
}