Module Name: src
Committed By: maxv
Date: Sun Oct 15 06:37:32 UTC 2017
Modified Files:
src/sys/arch/amd64/stand/prekern: mm.c
Log Message:
Descend the page tree from L4 to L1, instead of allocating a separate
branch and linking it at the end. This way we don't need to allocate VA
from the (tiny) prekern map.
To generate a diff of this commit:
cvs rdiff -u -r1.1 -r1.2 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:1.1 src/sys/arch/amd64/stand/prekern/mm.c:1.2
--- src/sys/arch/amd64/stand/prekern/mm.c:1.1 Tue Oct 10 09:29:14 2017
+++ src/sys/arch/amd64/stand/prekern/mm.c Sun Oct 15 06:37:32 2017
@@ -1,4 +1,4 @@
-/* $NetBSD: mm.c,v 1.1 2017/10/10 09:29:14 maxv Exp $ */
+/* $NetBSD: mm.c,v 1.2 2017/10/15 06:37:32 maxv Exp $ */
/*
* Copyright (c) 2017 The NetBSD Foundation, Inc. All rights reserved.
@@ -41,8 +41,7 @@ extern paddr_t kernpa_start, kernpa_end;
vaddr_t iom_base;
paddr_t pa_avail = 0;
-static vaddr_t va_avail = (PREKERNBASE + NKL2_KIMG_ENTRIES * NBPD_L2);
-static vaddr_t va_end = (PREKERNBASE + (NKL2_KIMG_ENTRIES + 1) * NBPD_L2);
+static const vaddr_t tmpva = (PREKERNBASE + NKL2_KIMG_ENTRIES * NBPD_L2);
void
mm_init(paddr_t first_pa)
@@ -50,25 +49,6 @@ mm_init(paddr_t first_pa)
pa_avail = first_pa;
}
-static paddr_t
-mm_palloc(size_t npages)
-{
- paddr_t pa = pa_avail;
- pa_avail += npages * PAGE_SIZE;
- return pa;
-}
-
-static vaddr_t
-mm_valloc(size_t npages)
-{
- vaddr_t va = va_avail;
- va_avail += npages * PAGE_SIZE;
- if (va_avail > va_end) {
- fatal("mm_valloc: no VA left");
- }
- return va;
-}
-
static void
mm_enter_pa(paddr_t pa, vaddr_t va, pte_prot_t prot)
{
@@ -81,6 +61,27 @@ mm_flush_va(vaddr_t va)
asm volatile("invlpg (%0)" ::"r" (va) : "memory");
}
+static paddr_t
+mm_palloc(size_t npages)
+{
+ paddr_t pa;
+ size_t i;
+
+ /* Allocate the physical pages */
+ pa = pa_avail;
+ pa_avail += npages * PAGE_SIZE;
+
+ /* Zero them out */
+ for (i = 0; i < npages; i++) {
+ mm_enter_pa(pa + i * PAGE_SIZE, tmpva,
+ MM_PROT_READ|MM_PROT_WRITE);
+ mm_flush_va(tmpva);
+ memset((void *)tmpva, 0, PAGE_SIZE);
+ }
+
+ return pa;
+}
+
paddr_t
mm_vatopa(vaddr_t va)
{
@@ -106,13 +107,11 @@ mm_mprotect(vaddr_t startva, size_t size
}
static void
-mm_map_va(vaddr_t startva, vaddr_t endva)
+mm_map_tree(vaddr_t startva, vaddr_t endva)
{
- size_t i, idx, size, nL4e, nL3e, nL2e;
+ size_t i, size, nL4e, nL3e, nL2e;
size_t L4e_idx, L3e_idx, L2e_idx;
- vaddr_t L3page_va, L2page_va;
paddr_t L3page_pa, L2page_pa, L1page_pa;
- pd_entry_t *pdir;
/*
* Initialize constants.
@@ -122,48 +121,30 @@ mm_map_va(vaddr_t startva, vaddr_t endva
nL3e = roundup(size, NBPD_L3) / NBPD_L3;
nL2e = roundup(size, NBPD_L2) / NBPD_L2;
L4e_idx = pl4_i(startva);
- L3e_idx = pl3_i(startva % NBPD_L4);
- L2e_idx = pl2_i(startva % NBPD_L3);
+ L3e_idx = pl3_i(startva);
+ L2e_idx = pl2_i(startva);
+
+ ASSERT(nL4e == 1);
+ ASSERT(L4e_idx == 511);
/*
- * Map the sub-tree itself.
+ * Allocate the physical pages.
*/
- L3page_va = mm_valloc(nL4e);
L3page_pa = mm_palloc(nL4e);
- L2page_va = mm_valloc(nL3e);
L2page_pa = mm_palloc(nL3e);
-
L1page_pa = mm_palloc(nL2e);
- for (i = 0; i < nL4e; i++) {
- mm_enter_pa(L3page_pa + i * PAGE_SIZE,
- L3page_va + i * PAGE_SIZE, MM_PROT_READ|MM_PROT_WRITE);
- memset((void *)(L3page_va + i * PAGE_SIZE), 0, PAGE_SIZE);
- }
-
- for (i = 0; i < nL3e; i++) {
- mm_enter_pa(L2page_pa + i * PAGE_SIZE,
- L2page_va + i * PAGE_SIZE, MM_PROT_READ|MM_PROT_WRITE);
- memset((void *)(L2page_va + i * PAGE_SIZE), 0, PAGE_SIZE);
- }
-
/*
- * Now link the levels together.
+ * Build the branch in the page tree. We link the levels together,
+ * from L4 to L1.
*/
- pdir = (pt_entry_t *)L3page_va;
- for (i = 0, idx = L3e_idx; i < nL3e; i++, idx++) {
- pdir[idx] = (L2page_pa + i * PAGE_SIZE) | PG_V | PG_RW;
+ 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;
}
-
- pdir = (pt_entry_t *)L2page_va;
- for (i = 0, idx = L2e_idx; i < nL2e; i++, idx++) {
- pdir[idx] = (L1page_pa + i * PAGE_SIZE) | PG_V | PG_RW;
+ for (i = 0; i < nL2e; i++) {
+ L2_BASE[L2e_idx+i] = (L1page_pa + i * PAGE_SIZE) | PG_V | PG_RW;
}
-
- /*
- * Finally, link the sub-tree into the tree.
- */
- L4_BASE[L4e_idx] = L3page_pa | PG_V | PG_RW;
}
/*
@@ -185,7 +166,7 @@ mm_rand_base()
randva = rounddown(KASLR_WINDOW_BASE + rnd % (KASLR_WINDOW_SIZE - size),
PAGE_SIZE);
- mm_map_va(randva, randva + size);
+ mm_map_tree(randva, randva + size);
return randva;
}
