x86-32: use brk segment for allocating initial kernel pagetable

Impact: use new interface instead of previous ad hoc implementation

Rather than having special purpose init_pg_table_start/end variables
to delimit the kernel pagetable built by head_32.S, just use the brk
mechanism to extend the bss for the new pagetable.

This patch removes init_pg_table_start/end and pg0, defines __brk_base
(which is page-aligned and immediately follows _end), initializes
the brk region to start there, and uses it for the 32-bit pagetable.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

1 files changed, 0 insertions, 8 deletions

diff --git a/arch/x86/lguest/boot.c b/arch/x86/lguest/boot.c
index 9fe4dda..90e44a1 100644
--- a/arch/x86/lguest/boot.c
+++ b/arch/x86/lguest/boot.c
@@ -1058,14 +1058,6 @@ __init void lguest_init(void)
 	 * lguest_init() where the rest of the fairly chaotic boot setup
 	 * occurs. */
 
-	/* The native boot code sets up initial page tables immediately after
-	 * the kernel itself, and sets init_pg_tables_end so they're not
-	 * clobbered.  The Launcher places our initial pagetables somewhere at
-	 * the top of our physical memory, so we don't need extra space: set
-	 * init_pg_tables_end to the end of the kernel. */
-	init_pg_tables_start = __pa(pg0);
-	init_pg_tables_end = __pa(pg0);
-
 	/* As described in head_32.S, we map the first 128M of memory. */
 	max_pfn_mapped = (128*1024*1024) >> PAGE_SHIFT;