pmap.c

基于组件方式开发操作系统的OSKIT源代码

	simple_unlock(&pmap->pm_obj.vmobjlock);

	if (old_ldt != NULL)
		uvm_km_free(kernel_map, (vaddr_t)old_ldt, len);
}
#endif /* USER_LDT */

/*
 * pmap_activate: activate a process' pmap (fill in %cr3 and LDT info)
 *
 * => called from cpu_switch()
 * => if proc is the curproc, then load it into the MMU
 */

void
pmap_activate(p)
	struct proc *p;
{
	struct pcb *pcb = &p->p_addr->u_pcb;
	struct pmap *pmap = p->p_vmspace->vm_map.pmap;

	pcb->pcb_pmap = pmap;
#ifndef OSKIT
	pcb->pcb_ldt_sel = pmap->pm_ldt_sel;
#endif
	pcb->pcb_cr3 = pmap->pm_pdirpa;
	if (p == curproc)
		lcr3(pcb->pcb_cr3);
#ifndef OSKIT
	if (pcb == curpcb)
		lldt(pcb->pcb_ldt_sel);
#endif
}

/*
 * pmap_deactivate: deactivate a process' pmap
 *
 * => XXX: what should this do, if anything?
 */

void
pmap_deactivate(p)
	struct proc *p;
{
}

/*
 * end of lifecycle functions
 */

/*
 * some misc. functions
 */

/*
 * pmap_extract: extract a PA for the given VA
 */

boolean_t
pmap_extract(pmap, va, pap)
	struct pmap *pmap;
	vaddr_t va;
	paddr_t *pap;
{
	pt_entry_t *ptes, pte;
	pd_entry_t pde;

	if (__predict_true((pde = pmap->pm_pdir[pdei(va)]) != 0)) {
#ifdef LARGEPAGES
		if (pde & PG_PS) {
			if (pap != NULL)
				*pap = (pde & PG_LGFRAME) | (va & ~PG_LGFRAME);
			return (TRUE);
		}
#endif
		ptes = pmap_map_ptes(pmap);
		pte = ptes[i386_btop(va)];
		pmap_unmap_ptes(pmap);

		if (__predict_true((pte & PG_V) != 0)) {
			if (pap != NULL)
				*pap = (pte & PG_FRAME) | (va & ~PG_FRAME);
			return (TRUE);
		}
	}
	return (FALSE);
}


/*
 * vtophys: virtual address to physical address.  For use by
 * machine-dependent code only.
 */

paddr_t
vtophys(va)
	vaddr_t va;
{
	paddr_t pa;

	if (pmap_extract(pmap_kernel(), va, &pa) == TRUE)
		return (pa);
	return (0);
}


/*
 * pmap_virtual_space: used during bootup [pmap_steal_memory] to
 *	determine the bounds of the kernel virtual addess space.
 */

void
pmap_virtual_space(startp, endp)
	vaddr_t *startp;
	vaddr_t *endp;
{
	*startp = virtual_avail;
	*endp = virtual_end;
}

/*
 * pmap_map: map a range of PAs into kvm
 *
 * => used during crash dump
 * => XXX: pmap_map() should be phased out?
 */

vaddr_t
pmap_map(va, spa, epa, prot)
	vaddr_t va;
	paddr_t spa, epa;
	vm_prot_t prot;
{
	while (spa < epa) {
		pmap_enter(pmap_kernel(), va, spa, prot, 0);
		va += PAGE_SIZE;
		spa += PAGE_SIZE;
	}
	return va;
}

/*
 * pmap_zero_page: zero a page
 */

void
pmap_zero_page(pa)
	paddr_t pa;
{

	simple_lock(&pmap_zero_page_lock);
	*zero_pte = (pa & PG_FRAME) | PG_V | PG_RW;	/* map in */
	pmap_update_pg((vaddr_t)zerop);			/* flush TLB */
	memset(zerop, 0, PAGE_SIZE);			/* zero */
	simple_unlock(&pmap_zero_page_lock);
}

/*
 * pmap_zero_page_uncached: the same, except uncached.  Returns
 * TRUE if the page was zero'd, FALSE if we aborted for some
 * reason.
 */

boolean_t
pmap_zero_page_uncached(pa)
	paddr_t pa;
{
	boolean_t rv = TRUE;
#ifndef OSKIT
	int i, *ptr;
#endif

	simple_lock(&pmap_zero_page_lock);

	*zero_pte = (pa & PG_FRAME) | PG_V | PG_RW |	/* map in */
	    ((cpu_class != CPUCLASS_386) ? PG_N : 0);
	pmap_update_pg((vaddr_t)zerop);			/* flush TLB */

#ifndef OSKIT
	for (i = 0, ptr = (int *) zerop; i < PAGE_SIZE / sizeof(int); i++) {
		if (sched_whichqs != 0) {
			/*
			 * A process has become ready.  Abort now,
			 * so we don't keep it waiting while we
			 * do slow memory access to finish this
			 * page.
			 */
			rv = FALSE;
			break;
		}
		*ptr++ = 0;
	}
#endif

	simple_unlock(&pmap_zero_page_lock);

	return (rv);
}

/*
 * pmap_copy_page: copy a page
 */

void
pmap_copy_page(srcpa, dstpa)
	paddr_t srcpa, dstpa;
{
	simple_lock(&pmap_copy_page_lock);
#ifdef DIAGNOSTIC
	if (*csrc_pte || *cdst_pte)
		panic("pmap_copy_page: lock botch");
#endif

	*csrc_pte = (srcpa & PG_FRAME) | PG_V | PG_RW;
	*cdst_pte = (dstpa & PG_FRAME) | PG_V | PG_RW;
	memcpy(cdstp, csrcp, PAGE_SIZE);
	*csrc_pte = *cdst_pte = 0;			/* zap! */
	pmap_update_2pg((vaddr_t)csrcp, (vaddr_t)cdstp);
	simple_unlock(&pmap_copy_page_lock);
}

/*
 * p m a p   r e m o v e   f u n c t i o n s
 *
 * functions that remove mappings
 */

/*
 * pmap_remove_ptes: remove PTEs from a PTP
 *
 * => must have proper locking on pmap_master_lock
 * => caller must hold pmap's lock
 * => PTP must be mapped into KVA
 * => PTP should be null if pmap == pmap_kernel()
 */

static void
pmap_remove_ptes(pmap, pmap_rr, ptp, ptpva, startva, endva, flags)
	struct pmap *pmap;
	struct pmap_remove_record *pmap_rr;
	struct vm_page *ptp;
	vaddr_t ptpva;
	vaddr_t startva, endva;
	int flags;
{
	struct pv_entry *pv_tofree = NULL;	/* list of pv_entrys to free */
	struct pv_entry *pve;
	pt_entry_t *pte = (pt_entry_t *) ptpva;
	pt_entry_t opte;
	int bank, off;

	/*
	 * note that ptpva points to the PTE that maps startva.   this may
	 * or may not be the first PTE in the PTP.
	 *
	 * we loop through the PTP while there are still PTEs to look at
	 * and the wire_count is greater than 1 (because we use the wire_count
	 * to keep track of the number of real PTEs in the PTP).
	 */

	for (/*null*/; startva < endva && (ptp == NULL || ptp->wire_count > 1)
			     ; pte++, startva += PAGE_SIZE) {
		if (!pmap_valid_entry(*pte))
			continue;			/* VA not mapped */
		if ((flags & PMAP_REMOVE_SKIPWIRED) && (*pte & PG_W)) {
			continue;
		}

		opte = *pte;		/* save the old PTE */
		*pte = 0;			/* zap! */
		if (opte & PG_W)
			pmap->pm_stats.wired_count--;
		pmap->pm_stats.resident_count--;

		if (pmap_rr) {		/* worried about tlb flushing? */
			if (opte & PG_G) {
				/* PG_G requires this */
				pmap_update_pg(startva);
			} else {
				if (pmap_rr->prr_npages < PMAP_RR_MAX) {
					pmap_rr->prr_vas[pmap_rr->prr_npages++]
						= startva;
				} else {
					if (pmap_rr->prr_npages == PMAP_RR_MAX)
						/* signal an overflow */
						pmap_rr->prr_npages++;
				}
			}
		}
		if (ptp)
			ptp->wire_count--;		/* dropping a PTE */

		/*
		 * if we are not on a pv_head list we are done.
		 */

		if ((opte & PG_PVLIST) == 0) {
#ifdef DIAGNOSTIC
			if (vm_physseg_find(i386_btop(opte & PG_FRAME), &off)
			    != -1)
				panic("pmap_remove_ptes: managed page without "
				      "PG_PVLIST for 0x%lx", startva);
#endif
			continue;
		}

		bank = vm_physseg_find(i386_btop(opte & PG_FRAME), &off);
#ifdef DIAGNOSTIC
		if (bank == -1)
			panic("pmap_remove_ptes: unmanaged page marked "
			      "PG_PVLIST, va = 0x%lx, pa = 0x%lx",
			      startva, (u_long)(opte & PG_FRAME));
#endif

		/* sync R/M bits */
		simple_lock(&vm_physmem[bank].pmseg.pvhead[off].pvh_lock);
		vm_physmem[bank].pmseg.attrs[off] |= (opte & (PG_U|PG_M));
		pve = pmap_remove_pv(&vm_physmem[bank].pmseg.pvhead[off], pmap,
				     startva);
		simple_unlock(&vm_physmem[bank].pmseg.pvhead[off].pvh_lock);

		if (pve) {
			pve->pv_next = pv_tofree;
			pv_tofree = pve;
		}

		/* end of "for" loop: time for next pte */
	}
	if (pv_tofree)
		pmap_free_pvs(pmap, pv_tofree);
}


/*
 * pmap_remove_pte: remove a single PTE from a PTP
 *
 * => must have proper locking on pmap_master_lock
 * => caller must hold pmap's lock
 * => PTP must be mapped into KVA
 * => PTP should be null if pmap == pmap_kernel()
 * => returns true if we removed a mapping
 */

static boolean_t
pmap_remove_pte(pmap, ptp, pte, va, flags)
	struct pmap *pmap;
	struct vm_page *ptp;
	pt_entry_t *pte;
	vaddr_t va;
	int flags;
{
	pt_entry_t opte;
	int bank, off;
	struct pv_entry *pve;

	if (!pmap_valid_entry(*pte))
		return(FALSE);		/* VA not mapped */
	if ((flags & PMAP_REMOVE_SKIPWIRED) && (*pte & PG_W)) {
		return(FALSE);
	}

	opte = *pte;			/* save the old PTE */
	*pte = 0;			/* zap! */

	if (opte & PG_W)
		pmap->pm_stats.wired_count--;
	pmap->pm_stats.resident_count--;

	if (ptp)
		ptp->wire_count--;		/* dropping a PTE */

	if (pmap_is_curpmap(pmap))
		pmap_update_pg(va);		/* flush TLB */

	/*
	 * if we are not on a pv_head list we are done.
	 */

	if ((opte & PG_PVLIST) == 0) {
#ifdef DIAGNOSTIC
		if (vm_physseg_find(i386_btop(opte & PG_FRAME), &off) != -1)
			panic("pmap_remove_pte: managed page without "
			      "PG_PVLIST for 0x%lx", va);
#endif
		return(TRUE);
	}

	bank = vm_physseg_find(i386_btop(opte & PG_FRAME), &off);
#ifdef DIAGNOSTIC
	if (bank == -1)
		panic("pmap_remove_pte: unmanaged page marked "
		    "PG_PVLIST, va = 0x%lx, pa = 0x%lx", va,
		    (u_long)(opte & PG_FRAME));
#endif

	/* sync R/M bits */
	simple_lock(&vm_physmem[bank].pmseg.pvhead[off].pvh_lock);
	vm_physmem[bank].pmseg.attrs[off] |= (opte & (PG_U|PG_M));
	pve = pmap_remove_pv(&vm_physmem[bank].pmseg.pvhead[off], pmap, va);
	simple_unlock(&vm_physmem[bank].pmseg.pvhead[off].pvh_lock);

	if (pve)
		pmap_free_pv(pmap, pve);
	return(TRUE);
}

/*
 * pmap_remove: top level mapping removal function
 *
 * => caller should not be holding any pmap locks
 */

void
pmap_remove(pmap, sva, eva)
	struct pmap *pmap;
	vaddr_t sva, eva;
{
	pmap_do_remove(pmap, sva, eva, PMAP_REMOVE_ALL);
}

/*
 * pmap_do_remove: mapping removal guts
 *
 * => caller should not be holding any pmap locks
 */

static void
pmap_do_remove(pmap, sva, eva, flags)
	struct pmap *pmap;
	vaddr_t sva, eva;
	int flags;
{
	pt_entry_t *ptes;
	boolean_t result;
	paddr_t ptppa;
	vaddr_t blkendva;
	struct vm_page *ptp;
	struct pmap_remove_record pmap_rr, *prr;

	/*
	 * we lock in the pmap => pv_head direction
	 */

	PMAP_MAP_TO_HEAD_LOCK();
	ptes = pmap_map_ptes(pmap);	/* locks pmap */

	/*
	 * removing one page?  take shortcut function.
	 */

	if (sva + PAGE_SIZE == eva) {

		if (pmap_valid_entry(pmap->pm_pdir[pdei(sva)])) {

			/* PA of the PTP */
			ptppa = pmap->pm_pdir[pdei(sva)] & PG_FRAME;

			/* get PTP if non-kernel mapping */

			if (pmap == pmap_kernel()) {
				/* we never free kernel PTPs */
				ptp = NULL;
			} else {
				if (pmap->pm_ptphint &&
				    VM_PAGE_TO_PHYS(pmap->pm_ptphint) ==
				    ptppa) {
					ptp = pmap->pm_ptphint;
				} else {
					ptp = PHYS_TO_VM_PAGE(ptppa);
#ifdef DIAGNOSTIC
					if (ptp == NULL)
						panic("pmap_remove: unmanaged "
						      "PTP detected");
#endif
				}
			}

			/* do it! */
			result = pmap_remove_pte(pmap, ptp,
			    &ptes[i386_btop(sva)], sva, flags);

			/*
			 * if mapping removed and the PTP is no longer
			 * being used, free it!
			 */

			if (result && ptp && ptp->wire_count <= 1) {
				pmap->pm_pdir[pdei(sva)] = 0;	/* zap! */
#if defined(I386_CPU)
				/* already dumped whole TLB on i386 */
				if (cpu_class != CPUCLASS_386)
#endif
				{
					pmap_update_pg(((vaddr_t) ptes) +
						       ptp->offset);
				}
				pmap->pm_stats.resident_count--;
				if (pmap->pm_ptphint == ptp)
					pmap->pm_ptphint =
						pmap->pm_obj.memq.tqh_first;
				ptp->wire_count = 0;
				uvm_pagefree(ptp);
			}