usr/src/sys/luna68k/luna68k/vm_machdep.c

/*
 * Copyright (c) 1988 University of Utah.
 * Copyright (c) 1992 OMRON Corporation.
 * Copyright (c) 1982, 1986, 1990 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.
 *
 * %sccs.include.redist.c%
 *
 * from: Utah $Hdr: vm_machdep.c 1.21 91/04/06$
 * from: hp300/hp300/vm_machdep.c       7.14 (Berkeley) 12/27/92
 *
 *      @(#)vm_machdep.c        7.5 (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 <machine/cpu.h>

#include <vm/vm.h>
#include <vm/vm_kern.h>
#include <luna68k/luna68k/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;
        int offset;
        extern caddr_t getsp();
        extern char kstack[];

        p2->p_md.md_regs = p1->p_md.md_regs;
        p2->p_md.md_flags = (p1->p_md.md_flags & ~(MDP_AST|MDP_HPUXTRACE));

        /*
         * 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;
         * this is tricky, as the final pcb is constructed by savectx,
         * but its frame isn't yet on the stack when the stack is copied.
         * swtch compensates for this when the child eventually runs.
         * This should be done differently, with a single call
         * that copies and updates the pcb+stack,
         * replacing the bcopy and savectx.
         */
        p2->p_addr->u_pcb = p1->p_addr->u_pcb;
        offset = getsp() - kstack;
        bcopy((caddr_t)kstack + offset, (caddr_t)p2->p_addr + offset,
            (unsigned) ctob(UPAGES) - offset);

        PMAP_ACTIVATE(&p2->p_vmspace->vm_pmap, &up->u_pcb, 0);

        /*
         * Arrange for a non-local goto when the new process
         * is started, to resume here, returning nonzero from setjmp.
         */
        if (savectx(up, 1)) {
                /*
                 * 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;
{

        vmspace_free(p->p_vmspace);

        (void) splimp();
        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;
{
        int error;

        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 struct pte *fpte, *tpte;

        if (size % CLBYTES)
                panic("pagemove");
        fpte = kvtopte(from);
        tpte = kvtopte(to);
        while (size > 0) {
                *tpte++ = *fpte;
                *(int *)fpte++ = PG_NV;
                TBIS(from);
                TBIS(to);
                from += NBPG;
                to += NBPG;
                size -= NBPG;
        }
#ifdef LUNA2
        DCIS();
#endif
}

/*
 * Map `size' bytes of physical memory starting at `paddr' into
 * kernel VA space at `vaddr'.  Read/write and cache-inhibit status
 * are specified by `prot'.
 */
physaccess(vaddr, paddr, size, prot)
        caddr_t vaddr, paddr;
        register int size, prot;
{
        register struct pte *pte;
        register u_int page;

        pte = kvtopte(vaddr);
        page = (u_int)paddr & PG_FRAME;
        for (size = btoc(size); size; size--) {
                *(int *)pte++ = PG_V | prot | page;
                page += NBPG;
        }
        TBIAS();
}

physunaccess(vaddr, size)
        caddr_t vaddr;
        register int size;
{
        register struct pte *pte;

        pte = kvtopte(vaddr);
        for (size = btoc(size); size; size--)
                *(int *)pte++ = PG_NV;
        TBIAS();
}

/*
 * Set a red zone in the kernel stack after the u. area.
 * We don't support a redzone right now.  It really isn't clear
 * that it is a good idea since, if the kernel stack were to roll
 * into a write protected page, the processor would lock up (since
 * it cannot create an exception frame) and we would get no useful
 * post-mortem info.  Currently, under the DEBUG option, we just
 * check at every clock interrupt to see if the current k-stack has
 * gone too far (i.e. into the "redzone" page) and if so, panic.
 * Look at _lev6intr in locore.s for more details.
 */
/*ARGSUSED*/
setredzone(pte, vaddr)
        struct pte *pte;
        caddr_t vaddr;
{
}

/*
 * Convert kernel VA to physical address
 */
kvtop(addr)
        register caddr_t addr;
{
        vm_offset_t va;

        va = pmap_extract(kernel_pmap, (vm_offset_t)addr);
        if (va == 0)
                panic("kvtop: zero page frame");
        return((int)va);
}

extern vm_map_t phys_map;

/*
 * Map an IO request into kernel virtual address space.
 *
 * XXX we allocate KVA space by using kmem_alloc_wait which we know
 * allocates space without backing physical memory.  This implementation
 * is a total crock, the multiple mappings of these physical pages should
 * be reflected in the higher-level VM structures to avoid problems.
 */
vmapbuf(bp)
        register struct buf *bp;
{
        register int npf;
        register caddr_t addr;
        register long flags = bp->b_flags;
        struct proc *p;
        int off;
        vm_offset_t kva;
        register vm_offset_t pa;

        if ((flags & B_PHYS) == 0)
                panic("vmapbuf");
        addr = bp->b_saveaddr = bp->b_un.b_addr;
        off = (int)addr & PGOFSET;
        p = bp->b_proc;
        npf = btoc(round_page(bp->b_bcount + off));
        kva = kmem_alloc_wait(phys_map, ctob(npf));
        bp->b_un.b_addr = (caddr_t) (kva + off);
        while (npf--) {
                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.
 */
vunmapbuf(bp)
        register struct buf *bp;
{
        register int npf;
        register caddr_t addr = bp->b_un.b_addr;
        vm_offset_t kva;

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