Libpayload needs to clear the bss region.

Libpayload shouldn't count on coreboot or other payloads to clear memory. This fixes problems with payloads being loaded after or on top of each other.

Change-Id: I30303d47e465e8921f47acab667c7998ba79fca7
Signed-off-by: Marc Jones <marcj303@gmail.com>
Reviewed-on: http://review.coreboot.org/66
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>

diff --git a/payloads/libpayload/arch/i386/head.S b/payloads/libpayload/arch/i386/head.S
index db18a5195fc1be97aecf135a5196a672dda99837..88db4124d5627cca620419a8da4e16df44788cde 100644 (file)
--- a/payloads/libpayload/arch/i386/head.S
+++ b/payloads/libpayload/arch/i386/head.S
@@ -70,10 +70,17 @@ _init:
        movl %esp, %esi
 
        /* Store EAX and EBX */
-
        movl %eax,loader_eax
        movl %ebx,loader_ebx
 
+       /* Clear the bss */
+       cld
+       movl $.bss, %edi
+       movl $_end, %ecx
+       subl %edi, %ecx
+       xor %ax, %ax
+       rep stosb
+
        /* Setup new stack. */
        movl $_stack, %ebx