Implement pmap_copy(). (This includes the changes applied to the amd64
pmap_copy() in r349585.) Reviewed by: kib, markj Differential Revision: https://reviews.freebsd.org/D20790
This commit is contained in:
Alan Cox
parent
afa60c068e
commit
3612c1f045
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=349618
@ -3875,12 +3875,153 @@ pmap_unwire(pmap_t pmap, vm_offset_t sva, vm_offset_t eva)
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* in the destination map.
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*
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* This routine is only advisory and need not do anything.
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*
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* Because the executable mappings created by this routine are copied,
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* it should not have to flush the instruction cache.
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*/
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void
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pmap_copy(pmap_t dst_pmap, pmap_t src_pmap, vm_offset_t dst_addr, vm_size_t len,
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vm_offset_t src_addr)
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{
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struct rwlock *lock;
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struct spglist free;
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pd_entry_t *l0, *l1, *l2, srcptepaddr;
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pt_entry_t *dst_pte, ptetemp, *src_pte;
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vm_offset_t addr, end_addr, va_next;
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vm_page_t dst_l2pg, dstmpte, srcmpte;
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if (dst_addr != src_addr)
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return;
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end_addr = src_addr + len;
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lock = NULL;
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if (dst_pmap < src_pmap) {
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PMAP_LOCK(dst_pmap);
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PMAP_LOCK(src_pmap);
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} else {
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PMAP_LOCK(src_pmap);
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PMAP_LOCK(dst_pmap);
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}
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for (addr = src_addr; addr < end_addr; addr = va_next) {
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l0 = pmap_l0(src_pmap, addr);
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if (pmap_load(l0) == 0) {
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va_next = (addr + L0_SIZE) & ~L0_OFFSET;
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if (va_next < addr)
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va_next = end_addr;
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continue;
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}
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l1 = pmap_l0_to_l1(l0, addr);
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if (pmap_load(l1) == 0) {
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va_next = (addr + L1_SIZE) & ~L1_OFFSET;
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if (va_next < addr)
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va_next = end_addr;
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continue;
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}
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va_next = (addr + L2_SIZE) & ~L2_OFFSET;
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if (va_next < addr)
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va_next = end_addr;
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l2 = pmap_l1_to_l2(l1, addr);
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srcptepaddr = pmap_load(l2);
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if (srcptepaddr == 0)
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continue;
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if ((srcptepaddr & ATTR_DESCR_MASK) == L2_BLOCK) {
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if ((addr & L2_OFFSET) != 0 ||
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addr + L2_SIZE > end_addr)
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continue;
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dst_l2pg = pmap_alloc_l2(dst_pmap, addr, NULL);
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if (dst_l2pg == NULL)
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break;
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l2 = (pd_entry_t *)
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PHYS_TO_DMAP(VM_PAGE_TO_PHYS(dst_l2pg));
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l2 = &l2[pmap_l2_index(addr)];
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if (pmap_load(l2) == 0 &&
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((srcptepaddr & ATTR_SW_MANAGED) == 0 ||
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pmap_pv_insert_l2(dst_pmap, addr, srcptepaddr,
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PMAP_ENTER_NORECLAIM, &lock))) {
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(void)pmap_load_store(l2, srcptepaddr &
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~ATTR_SW_WIRED);
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pmap_resident_count_inc(dst_pmap, L2_SIZE /
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PAGE_SIZE);
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atomic_add_long(&pmap_l2_mappings, 1);
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} else
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dst_l2pg->wire_count--;
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continue;
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}
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KASSERT((srcptepaddr & ATTR_DESCR_MASK) == L2_TABLE,
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("pmap_copy: invalid L2 entry"));
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srcptepaddr &= ~ATTR_MASK;
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srcmpte = PHYS_TO_VM_PAGE(srcptepaddr);
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KASSERT(srcmpte->wire_count > 0,
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("pmap_copy: source page table page is unused"));
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if (va_next > end_addr)
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va_next = end_addr;
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src_pte = (pt_entry_t *)PHYS_TO_DMAP(srcptepaddr);
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src_pte = &src_pte[pmap_l3_index(addr)];
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dstmpte = NULL;
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for (; addr < va_next; addr += PAGE_SIZE, src_pte++) {
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ptetemp = pmap_load(src_pte);
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/*
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* We only virtual copy managed pages.
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*/
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if ((ptetemp & ATTR_SW_MANAGED) == 0)
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continue;
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if (dstmpte != NULL) {
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KASSERT(dstmpte->pindex == pmap_l2_pindex(addr),
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("dstmpte pindex/addr mismatch"));
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dstmpte->wire_count++;
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} else if ((dstmpte = pmap_alloc_l3(dst_pmap, addr,
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NULL)) == NULL)
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goto out;
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dst_pte = (pt_entry_t *)
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PHYS_TO_DMAP(VM_PAGE_TO_PHYS(dstmpte));
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dst_pte = &dst_pte[pmap_l3_index(addr)];
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if (pmap_load(dst_pte) == 0 &&
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pmap_try_insert_pv_entry(dst_pmap, addr,
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PHYS_TO_VM_PAGE(ptetemp & ~ATTR_MASK), &lock)) {
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/*
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* Clear the wired, modified, and accessed
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* (referenced) bits during the copy.
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*
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* XXX not yet
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*/
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(void)pmap_load_store(dst_pte, ptetemp &
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~ATTR_SW_WIRED);
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pmap_resident_count_inc(dst_pmap, 1);
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} else {
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SLIST_INIT(&free);
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if (pmap_unwire_l3(dst_pmap, addr, dstmpte,
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&free)) {
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/*
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* Although "addr" is not mapped,
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* paging-structure caches could
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* nonetheless have entries that refer
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* to the freed page table pages.
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* Invalidate those entries.
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*
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* XXX redundant invalidation
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*/
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pmap_invalidate_page(dst_pmap, addr);
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vm_page_free_pages_toq(&free, true);
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}
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goto out;
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}
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/* Have we copied all of the valid mappings? */
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if (dstmpte->wire_count >= srcmpte->wire_count)
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break;
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}
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}
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out:
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/*
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* XXX This barrier may not be needed because the destination pmap is
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* not active.
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*/
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dsb(ishst);
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if (lock != NULL)
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rw_wunlock(lock);
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PMAP_UNLOCK(src_pmap);
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PMAP_UNLOCK(dst_pmap);
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}
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/*
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