4.4BSD/usr/src/sys/i386/i386/vm_machdep.c
/*-
* Copyright (c) 1982, 1986, 1993
* The Regents of the University of California. All rights reserved.
* 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 William Jolitz.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)vm_machdep.c 8.1 (Berkeley) 6/11/93
* Utah $Hdr: vm_machdep.c 1.16.1.1 89/06/23$
*/
#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>
/*
* 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 foo, offset, addr, i;
extern char kstack[];
extern int mvesp();
/*
* 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 = mvesp() - (int)kstack;
bcopy((caddr_t)kstack + offset, (caddr_t)p2->p_addr + offset,
(unsigned) ctob(UPAGES) - offset);
p2->p_md.md_regs = p1->p_md.md_regs;
/*
* Wire top of address space of child to it's u.
* First, fault in a page of pte's to map it.
*/
addr = trunc_page((u_int)vtopte(kstack));
(void)vm_map_pageable(&p2->p_vmspace->vm_map, addr, addr+NBPG, FALSE);
for (i=0; i < UPAGES; i++)
pmap_enter(&p2->p_vmspace->vm_pmap, (vm_offset_t)kstack+i*NBPG,
pmap_extract(kernel_pmap, ((int)p2->p_addr)+i*NBPG),
VM_PROT_READ, 1);
pmap_activate(&p2->p_vmspace->vm_pmap, &up->u_pcb);
/*
*
* 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);
}
#include "npx.h"
#if NNPX > 0
extern struct proc *npxproc;
#endif
#ifdef notyet
/*
* cpu_exit is called as the last action during exit.
*
* We change to an inactive address space and a "safe" stack,
* passing thru an argument to the new stack. Now, safely isolated
* from the resources we're shedding, we release the address space
* and any remaining machine-dependent resources, including the
* memory for the user structure and kernel stack.
*
* Next, we assign a dummy context to be written over by swtch,
* calling it to send this process off to oblivion.
* [The nullpcb allows us to minimize cost in swtch() by not having
* a special case].
*/
struct proc *swtch_to_inactive();
cpu_exit(p)
register struct proc *p;
{
static struct pcb nullpcb; /* pcb to overwrite on last swtch */
#if NNPX > 0
/* free cporcessor (if we have it) */
if( p == npxproc) npxproc =0;
#endif
/* move to inactive space and stack, passing arg accross */
p = swtch_to_inactive(p);
/* drop per-process resources */
vmspace_free(p->p_vmspace);
kmem_free(kernel_map, (vm_offset_t)p->p_addr, ctob(UPAGES));
p->p_addr = (struct user *) &nullpcb;
swtch();
/* NOTREACHED */
}
#else
cpu_exit(p)
register struct proc *p;
{
/* free coprocessor (if we have it) */
#if NNPX > 0
if( p == npxproc) npxproc =0;
#endif
curproc = p;
swtch();
}
cpu_wait(p) struct proc *p; {
/* drop per-process resources */
vmspace_free(p->p_vmspace);
kmem_free(kernel_map, (vm_offset_t)p->p_addr, ctob(UPAGES));
}
#endif
/*
* 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;
{
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));
}
/*
* Set a red zone in the kernel stack after the u. area.
*/
setredzone(pte, vaddr)
u_short *pte;
caddr_t vaddr;
{
/* eventually do this by setting up an expand-down stack segment
for ss0: selector, allowing stack access down to top of u.
this means though that protection violations need to be handled
thru a double fault exception that must do an integral task
switch to a known good context, within which a dump can be
taken. a sensible scheme might be to save the initial context
used by sched (that has physical memory mapped 1:1 at bottom)
and take the dump while still in mapped mode */
}
/*
* 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++ = 0;
from += NBPG;
to += NBPG;
size -= NBPG;
}
tlbflush();
}
/*
* 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);
}
#ifdef notdef
/*
* The probe[rw] routines should probably be redone in assembler
* for efficiency.
*/
prober(addr)
register u_int addr;
{
register int page;
register struct proc *p;
if (addr >= USRSTACK)
return(0);
p = u.u_procp;
page = btop(addr);
if (page < dptov(p, p->p_dsize) || page > sptov(p, p->p_ssize))
return(1);
return(0);
}
probew(addr)
register u_int addr;
{
register int page;
register struct proc *p;
if (addr >= USRSTACK)
return(0);
p = u.u_procp;
page = btop(addr);
if (page < dptov(p, p->p_dsize) || page > sptov(p, p->p_ssize))
return((*(int *)vtopte(p, page) & PG_PROT) == PG_UW);
return(0);
}
/*
* NB: assumes a physically contiguous kernel page table
* (makes life a LOT simpler).
*/
kernacc(addr, count, rw)
register u_int addr;
int count, rw;
{
register struct pde *pde;
register struct pte *pte;
register int ix, cnt;
extern long Syssize;
if (count <= 0)
return(0);
pde = (struct pde *)((u_int)u.u_procp->p_p0br + u.u_procp->p_szpt * NBPG);
ix = (addr & PD_MASK) >> PD_SHIFT;
cnt = ((addr + count + (1 << PD_SHIFT) - 1) & PD_MASK) >> PD_SHIFT;
cnt -= ix;
for (pde += ix; cnt; cnt--, pde++)
if (pde->pd_v == 0)
return(0);
ix = btop(addr-0xfe000000);
cnt = btop(addr-0xfe000000+count+NBPG-1);
if (cnt > (int)&Syssize)
return(0);
cnt -= ix;
for (pte = &Sysmap[ix]; cnt; cnt--, pte++)
if (pte->pg_v == 0 /*|| (rw == B_WRITE && pte->pg_prot == 1)*/)
return(0);
return(1);
}
useracc(addr, count, rw)
register u_int addr;
int count, rw;
{
register int (*func)();
register u_int addr2;
extern int prober(), probew();
if (count <= 0)
return(0);
addr2 = addr;
addr += count;
func = (rw == B_READ) ? prober : probew;
do {
if ((*func)(addr2) == 0)
return(0);
addr2 = (addr2 + NBPG) & ~PGOFSET;
} while (addr2 < addr);
return(1);
}
#endif
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 useriomap
* (a name with only slightly more meaning than "kernelmap")
*/
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(&p->p_vmspace->vm_pmap, (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 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;
}