Don't initialize the E820 map statically -- it's too big

3 files changed, 19 insertions, 7 deletions

diff --git a/memdisk/e820.h b/memdisk/e820.h
index 7f064c43..77dae74e 100644
--- a/memdisk/e820.h
+++ b/memdisk/e820.h
@@ -28,6 +28,7 @@ extern struct e820range ranges[];
 extern int nranges;
 extern uint32_t dos_mem, low_mem, high_mem;
 
+extern void e820map_init(void);
 extern void insertrange(uint64_t, uint64_t, uint32_t);
 extern void get_mem(void);
 extern void parse_mem(void);
diff --git a/memdisk/e820func.c b/memdisk/e820func.c
index 72e1bf80..d9c8465a 100644
--- a/memdisk/e820func.c
+++ b/memdisk/e820func.c
@@ -22,8 +22,17 @@
 
 #define MAXRANGES	64
 /* All of memory starts out as one range of "indeterminate" type */
-struct e820range ranges[MAXRANGES] = { { 0ULL, 0 }, { 0ULL, (uint32_t)-1 } };
-int nranges = 1;
+struct e820range ranges[MAXRANGES];
+int nranges;
+
+
+void e820map_init(void)
+{
+  nranges = 1;
+  asm volatile("cld ; rep ; stosl %0,%%es:(%1)"
+	       :: "a" (0), "S" (ranges), "c" (sizeof(ranges) >> 2));
+  ranges[1].type = -1;
+}
 
 static void insertrange_at(int where, uint64_t start, uint32_t type)
 {
diff --git a/memdisk/setup.c b/memdisk/setup.c
index 196f33bb..a2e71fba 100644
--- a/memdisk/setup.c
+++ b/memdisk/setup.c
@@ -213,13 +213,11 @@ uint32_t setup(void)
   printf("Ramdisk at 0x%08x, length 0x%08x\n",
 	 shdr->ramdisk_image, shdr->ramdisk_size);
 
-  /* Reserve the ramdisk memory */
-  insertrange(shdr->ramdisk_image, shdr->ramdisk_size, 2);
-
   geometry = get_disk_image_geometry(shdr->ramdisk_image, shdr->ramdisk_size);
 
-  get_mem();
-  parse_mem();
+  e820map_init();		/* Initialize memory data structure */
+  get_mem();			/* Query BIOS for memory map */
+  parse_mem();			/* Parse memory map */
 
   printf("dos_mem  = %#10x (%u K)\n"
 	 "low_mem  = %#10x (%u K)\n"
@@ -228,6 +226,10 @@ uint32_t setup(void)
 	 low_mem, low_mem >> 10,
 	 high_mem, high_mem >> 10);
 
+  /* Reserve the ramdisk memory */
+  insertrange(shdr->ramdisk_image, shdr->ramdisk_size, 2);
+  parse_mem();			/* Recompute variables */
+
   /* Figure out where it needs to go */
   hptr = (struct memdisk_header *) &_binary_memdisk_bin_start;
   pptr = (struct patch_area *)(_binary_memdisk_bin_start + hptr->patch_offs);