From 4587b35847b116057e3ef1058da914b8837ff343 Mon Sep 17 00:00:00 2001
From: Robert Morris <rtm@csail.mit.edu>
Date: Sun, 19 Sep 2010 07:18:42 -0400
Subject: exec questions

---
 kalloc.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

(limited to 'kalloc.c')

diff --git a/kalloc.c b/kalloc.c
index 5f690f5..72ce58a 100644
--- a/kalloc.c
+++ b/kalloc.c
@@ -17,12 +17,12 @@ struct {
   struct run *freelist;
 } kmem;
 
+extern char end[]; // first address after kernel loaded from ELF file
+
 // Initialize free list of physical pages.
 void
 kinit(void)
 {
-  extern char end[];
-
   initlock(&kmem.lock, "kmem");
   char *p = (char*)PGROUNDUP((uint)end);
   for( ; p + PGSIZE - 1 < (char*) PHYSTOP; p += PGSIZE)
@@ -39,7 +39,7 @@ kfree(char *v)
 {
   struct run *r;
 
-  if(((uint) v) % PGSIZE || (uint)v < 1024*1024 || (uint)v >= PHYSTOP) 
+  if(((uint) v) % PGSIZE || v < end || (uint)v >= PHYSTOP) 
     panic("kfree");
 
   // Fill with junk to catch dangling refs.
-- 
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