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authorFrans Kaashoek <[email protected]>2011-08-09 21:49:13 -0400
committerFrans Kaashoek <[email protected]>2011-08-09 21:49:13 -0400
commit5460667c9cf89f1c728e9af117e9978fcec8fd8d (patch)
treed7db4bf8e70c5626e922706b900b3cb435677ff4
parent832af025a364732d2784e64fa74e516f6c2f3b0c (diff)
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-rw-r--r--vm.c8
1 files changed, 4 insertions, 4 deletions
diff --git a/vm.c b/vm.c
index 2362453..1a1bdac 100644
--- a/vm.c
+++ b/vm.c
@@ -100,8 +100,8 @@ mappages(pde_t *pgdir, void *la, uint size, uint pa, int perm, char* (*alloc)(vo
//
//
// setupkvm() and exec() set up every page table like this:
-// 0..USERTOP : user memory (text, data, stack, heap), mapped to some phys mem
-// KERNBASE+640K..KERNBASE+1M: mapped to 640K..1M
+// 0..USERTOP : user memory (text, data, stack, heap), mapped to some unused phys mem
+// KERNBASE..KERNBASE+1M: mapped to 0..1M
// KERNBASE+1M..KERNBASE+end : mapped to 1M..end
// KERNBASE+end..KERBASE+PHYSTOP : mapped to end..PHYSTOP (free memory)
// 0xfe000000..0 : mapped direct (devices such as ioapic)
@@ -117,10 +117,10 @@ static struct kmap {
uint e;
int perm;
} kmap[] = {
- { P2V(0), 0, 1024*1024, PTE_W}, // First 1Mbyte contains BIOS and IO section
+ { P2V(0), 0, 1024*1024, PTE_W}, // First 1Mbyte contains BIOS and some IO devices
{ (void *)KERNLINK, V2P(KERNLINK), V2P(data), 0}, // kernel text, rodata
{ data, V2P(data), PHYSTOP, PTE_W}, // kernel data, memory
- { (void*)DEVSPACE, DEVSPACE, 0, PTE_W}, // device mappings
+ { (void*)DEVSPACE, DEVSPACE, 0, PTE_W}, // more devices
};
// Set up kernel part of a page table.