From: Cristiano Giuffrida <cristiano@minix3.org>
Date: Tue, 20 Jul 2010 02:08:28 +0000 (+0000)
Subject: Generalize interface of some VM functions
X-Git-Tag: v3.1.8~186
X-Git-Url: http://zhaoyanbai.com/repos/?a=commitdiff_plain;h=1b7d95df29536643a25c51cd3813fd1c88c80209;p=minix.git

Generalize interface of some VM functions
---

diff --git a/servers/vm/arch/i386/pagetable.c b/servers/vm/arch/i386/pagetable.c
index 8b8a4c426..9c836e279 100644
--- a/servers/vm/arch/i386/pagetable.c
+++ b/servers/vm/arch/i386/pagetable.c
@@ -456,6 +456,48 @@ PRIVATE int pt_ptalloc(pt_t *pt, int pde, u32_t flags)
 	return OK;
 }
 
+/*===========================================================================*
+ *			    pt_ptalloc_in_range		     		     *
+ *===========================================================================*/
+PUBLIC int pt_ptalloc_in_range(pt_t *pt, vir_bytes start, vir_bytes end,
+	u32_t flags, int verify)
+{
+/* Allocate all the page tables in the range specified. */
+	int pde, first_pde, last_pde;
+
+	first_pde = start ? I386_VM_PDE(start) : proc_pde;
+	last_pde = end ? I386_VM_PDE(end) : I386_VM_DIR_ENTRIES - 1;
+	assert(first_pde >= proc_pde && first_pde <= last_pde);
+	assert(last_pde < I386_VM_DIR_ENTRIES);
+
+	/* Scan all page-directory entries in the range. */
+	for(pde = first_pde; pde <= last_pde; pde++) {
+		assert(!(pt->pt_dir[pde] & I386_VM_BIGPAGE));
+		if(!(pt->pt_dir[pde] & I386_VM_PRESENT)) {
+			int r;
+			if(verify) {
+				printf("pt_ptalloc_in_range: no pde %d\n", pde);
+				return EFAULT;
+			}
+			assert(!pt->pt_dir[pde]);
+			if((r=pt_ptalloc(pt, pde, flags)) != OK) {
+				/* Couldn't do (complete) mapping.
+				 * Don't bother freeing any previously
+				 * allocated page tables, they're
+				 * still writable, don't point to nonsense,
+				 * and pt_ptalloc leaves the directory
+				 * and other data in a consistent state.
+				 */
+				printf("pt_ptalloc_in_range: pt_ptalloc failed\n");
+				return r;
+			}
+		}
+		assert(pt->pt_dir[pde] & I386_VM_PRESENT);
+	}
+
+	return OK;
+}
+
 PRIVATE char *ptestr(u32_t pte)
 {
 #define FLAG(constant, name) {						\
@@ -490,8 +532,7 @@ PUBLIC int pt_writemap(pt_t *pt, vir_bytes v, phys_bytes physaddr,
 {
 /* Write mapping into page table. Allocate a new page table if necessary. */
 /* Page directory and table entries for this virtual address. */
-	int p, pages, pdecheck;
-	int finalpde;
+	int p, r, pages;
 	int verify = 0;
 
 	if(writemapflags & WMF_VERIFY)
@@ -509,36 +550,13 @@ PUBLIC int pt_writemap(pt_t *pt, vir_bytes v, phys_bytes physaddr,
 	assert(physaddr == MAP_NONE || (flags & I386_VM_PRESENT));
 	assert(physaddr != MAP_NONE || !flags);
 
-	finalpde = I386_VM_PDE(v + I386_PAGE_SIZE * pages);
-
 	/* First make sure all the necessary page tables are allocated,
 	 * before we start writing in any of them, because it's a pain
-	 * to undo our work properly. Walk the range in page-directory-entry
-	 * sized leaps.
+	 * to undo our work properly.
 	 */
-	for(pdecheck = I386_VM_PDE(v); pdecheck <= finalpde; pdecheck++) {
-		assert(pdecheck >= 0 && pdecheck < I386_VM_DIR_ENTRIES);
-		assert(!(pt->pt_dir[pdecheck] & I386_VM_BIGPAGE));
-		if(!(pt->pt_dir[pdecheck] & I386_VM_PRESENT)) {
-			int r;
-			if(verify) {
-				printf("pt_writemap verify: no pde %d\n", pdecheck);
-				return EFAULT;
-			}
-			assert(!pt->pt_dir[pdecheck]);
-			if((r=pt_ptalloc(pt, pdecheck, flags)) != OK) {
-				/* Couldn't do (complete) mapping.
-				 * Don't bother freeing any previously
-				 * allocated page tables, they're
-				 * still writable, don't point to nonsense,
-				 * and pt_ptalloc leaves the directory
-				 * and other data in a consistent state.
-				 */
-				printf("pt_writemap: pt_ptalloc failed\n");
-				return r;
-			}
-		}
-		assert(pt->pt_dir[pdecheck] & I386_VM_PRESENT);
+	r = pt_ptalloc_in_range(pt, v, v + I386_PAGE_SIZE*pages, flags, verify);
+	if(r != OK) {
+		return r;
 	}
 
 	/* Now write in them. */
diff --git a/servers/vm/proto.h b/servers/vm/proto.h
index 0c52d3510..e19b202ce 100644
--- a/servers/vm/proto.h
+++ b/servers/vm/proto.h
@@ -100,6 +100,8 @@ _PROTOTYPE( void pt_init, (phys_bytes limit)				);
 _PROTOTYPE( void pt_check, (struct vmproc *vmp)				);
 _PROTOTYPE( int pt_new, (pt_t *pt)					);
 _PROTOTYPE( void pt_free, (pt_t *pt)					);
+_PROTOTYPE( int pt_ptalloc_in_range, (pt_t *pt, vir_bytes start, vir_bytes end,
+        u32_t flags, int verify));
 _PROTOTYPE( int pt_writemap, (pt_t *pt, vir_bytes v, phys_bytes physaddr, 
         size_t bytes, u32_t flags, u32_t writemapflags));
 _PROTOTYPE( int pt_checkrange, (pt_t *pt, vir_bytes v,  size_t bytes, int write));
@@ -138,6 +140,8 @@ _PROTOTYPE(int map_region_shrink,(struct vir_region *vr, vir_bytes delta));
 _PROTOTYPE(int map_unmap_region,(struct vmproc *vmp, struct vir_region *vr, vir_bytes len));
 _PROTOTYPE(int map_free_proc,(struct vmproc *vmp));
 _PROTOTYPE(int map_proc_copy,(struct vmproc *dst, struct vmproc *src));
+_PROTOTYPE(int map_proc_copy_from,(struct vmproc *dst, struct vmproc *src,
+	struct vir_region *start_src_vr));
 _PROTOTYPE(struct vir_region *map_lookup,(struct vmproc *vmp, vir_bytes addr));
 _PROTOTYPE(int map_pf,(struct vmproc *vmp,
 	struct vir_region *region, vir_bytes offset, int write));
diff --git a/servers/vm/region.c b/servers/vm/region.c
index 54d704908..2b6c67d9d 100644
--- a/servers/vm/region.c
+++ b/servers/vm/region.c
@@ -1421,19 +1421,38 @@ PUBLIC int map_writept(struct vmproc *vmp)
 }
 
 /*========================================================================*
- *				map_proc_copy			     	  *
+ *			       map_proc_copy			     	  *
  *========================================================================*/
 PUBLIC int map_proc_copy(dst, src)
 struct vmproc *dst;
 struct vmproc *src;
 {
-	struct vir_region *vr, *prevvr = NULL;
+/* Copy all the memory regions from the src process to the dst process. */
 	dst->vm_regions = NULL;
 
-	SANITYCHECK(SCL_FUNCTIONS);
+	return map_proc_copy_from(dst, src, src->vm_regions);
+}
+
+/*========================================================================*
+ *			     map_proc_copy_from			     	  *
+ *========================================================================*/
+PUBLIC int map_proc_copy_from(dst, src, start_src_vr)
+struct vmproc *dst;
+struct vmproc *src;
+struct vir_region *start_src_vr;
+{
+	struct vir_region *vr, *prevvr = NULL;
+
+	assert(start_src_vr->parent == src);
 
+	/* Copy source regions after the destination's last region (if any). */
+	for(vr = dst->vm_regions; vr; vr = vr->next) {
+		prevvr =  vr;
+	}
+
+	SANITYCHECK(SCL_FUNCTIONS);
 
-	for(vr = src->vm_regions; vr; vr = vr->next) {
+	for(vr = start_src_vr; vr; vr = vr->next) {
 		physr_iter iter_orig, iter_new;
 		struct vir_region *newvr;
 		struct phys_region *orig_ph, *new_ph;