Module Name: src
Committed By: maxv
Date: Wed Oct 18 17:12:42 UTC 2017
Modified Files:
src/sys/arch/amd64/stand/prekern: mm.c
Log Message:
If a branch is already there, use it and don't create a new one. This way
we can call mm_map_tree twice with neighboring regions.
To generate a diff of this commit:
cvs rdiff -u -r1.2 -r1.3 src/sys/arch/amd64/stand/prekern/mm.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/arch/amd64/stand/prekern/mm.c
diff -u src/sys/arch/amd64/stand/prekern/mm.c:1.2 src/sys/arch/amd64/stand/prekern/mm.c:1.3
--- src/sys/arch/amd64/stand/prekern/mm.c:1.2 Sun Oct 15 06:37:32 2017
+++ src/sys/arch/amd64/stand/prekern/mm.c Wed Oct 18 17:12:42 2017
@@ -1,4 +1,4 @@
-/* $NetBSD: mm.c,v 1.2 2017/10/15 06:37:32 maxv Exp $ */
+/* $NetBSD: mm.c,v 1.3 2017/10/18 17:12:42 maxv Exp $ */
/*
* Copyright (c) 2017 The NetBSD Foundation, Inc. All rights reserved.
@@ -82,6 +82,12 @@ mm_palloc(size_t npages)
return pa;
}
+static bool
+mm_pte_is_valid(pt_entry_t pte)
+{
+ return ((pte & PG_V) != 0);
+}
+
paddr_t
mm_vatopa(vaddr_t va)
{
@@ -111,39 +117,46 @@ mm_map_tree(vaddr_t startva, vaddr_t end
{
size_t i, size, nL4e, nL3e, nL2e;
size_t L4e_idx, L3e_idx, L2e_idx;
- paddr_t L3page_pa, L2page_pa, L1page_pa;
+ paddr_t pa;
+
+ size = endva - startva;
/*
- * Initialize constants.
+ * Build L4.
*/
- size = endva - startva;
- nL4e = roundup(size, NBPD_L4) / NBPD_L4;
- nL3e = roundup(size, NBPD_L3) / NBPD_L3;
- nL2e = roundup(size, NBPD_L2) / NBPD_L2;
L4e_idx = pl4_i(startva);
- L3e_idx = pl3_i(startva);
- L2e_idx = pl2_i(startva);
-
- ASSERT(nL4e == 1);
+ nL4e = roundup(size, NBPD_L4) / NBPD_L4;
ASSERT(L4e_idx == 511);
+ ASSERT(nL4e == 1);
+ if (!mm_pte_is_valid(L4_BASE[L4e_idx])) {
+ pa = mm_palloc(1);
+ L4_BASE[L4e_idx] = pa | PG_V | PG_RW;
+ }
/*
- * Allocate the physical pages.
+ * Build L3.
*/
- L3page_pa = mm_palloc(nL4e);
- L2page_pa = mm_palloc(nL3e);
- L1page_pa = mm_palloc(nL2e);
+ L3e_idx = pl3_i(startva);
+ nL3e = roundup(size, NBPD_L3) / NBPD_L3;
+ for (i = 0; i < nL3e; i++) {
+ if (mm_pte_is_valid(L3_BASE[L3e_idx+i])) {
+ continue;
+ }
+ pa = mm_palloc(1);
+ L3_BASE[L3e_idx+i] = pa | PG_V | PG_RW;
+ }
/*
- * Build the branch in the page tree. We link the levels together,
- * from L4 to L1.
+ * Build L2.
*/
- L4_BASE[L4e_idx] = L3page_pa | PG_V | PG_RW;
- for (i = 0; i < nL3e; i++) {
- L3_BASE[L3e_idx+i] = (L2page_pa + i * PAGE_SIZE) | PG_V | PG_RW;
- }
+ L2e_idx = pl2_i(startva);
+ nL2e = roundup(size, NBPD_L2) / NBPD_L2;
for (i = 0; i < nL2e; i++) {
- L2_BASE[L2e_idx+i] = (L1page_pa + i * PAGE_SIZE) | PG_V | PG_RW;
+ if (mm_pte_is_valid(L2_BASE[L2e_idx+i])) {
+ continue;
+ }
+ pa = mm_palloc(1);
+ L2_BASE[L2e_idx+i] = pa | PG_V | PG_RW;
}
}
