From: Ian Campbell <ian.campbell@citrix.com>
Date: Thu, 11 Oct 2012 14:56:56 +0000 (+0100)
Subject: arm: Zero the BSS at start of day.
X-Git-Tag: archive/raspbian/4.8.0-1+rpi1~1^2~7757
X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=c113b2c4bb48f5c24397aed25d79ff975d08e87d;p=xen.git

arm: Zero the BSS at start of day.

Avoids surprises e.g. when loading via the boot-wrapper.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Tim Deegan <tim@xen.org>
Committed-by: Ian Campbell <ian.campbell@citrix.com>
---

diff --git a/xen/arch/arm/head.S b/xen/arch/arm/head.S
index cdbe011820..9fdeda7c56 100644
--- a/xen/arch/arm/head.S
+++ b/xen/arch/arm/head.S
@@ -127,8 +127,26 @@ boot_cpu:
 	add   pc, r0, r10            /* Call PA of function */
 
 hyp:
-	PRINT("- Setting up control registers -\r\n")
 
+	/* Zero BSS On the boot CPU to avoid nasty surprises */
+	teq   r12, #0
+	bne   skip_bss
+
+	PRINT("- Zero BSS -\r\n")
+	ldr   r0, =__bss_start       /* Load start & end of bss */
+	ldr   r1, =__bss_end
+	add   r0, r0, r10            /* Apply physical offset */
+	add   r1, r1, r10
+	
+	mov   r2, #0
+1:	str   r2, [r0], #4
+	cmp   r0, r1
+	blo   1b
+
+skip_bss:	
+
+	PRINT("- Setting up control registers -\r\n")
+	
 	/* Set up memory attribute type tables */
 	ldr   r0, =MAIR0VAL
 	ldr   r1, =MAIR1VAL
diff --git a/xen/arch/arm/xen.lds.S b/xen/arch/arm/xen.lds.S
index 6fb76628af..f0f4cd3d9f 100644
--- a/xen/arch/arm/xen.lds.S
+++ b/xen/arch/arm/xen.lds.S
@@ -119,6 +119,7 @@ SECTIONS
        *(.bss.percpu.read_mostly)
        . = ALIGN(SMP_CACHE_BYTES);
        __per_cpu_data_end = .;
+       __bss_end = .;
   } :text
   _end = . ;