[kvm-unit-tests PATCH 02/33] arm: Detect FDT overlap with uninitialised data

[Suzuki K Poulose]

If the FDT was placed in a region overlapping the bss/stack area, it
would have been overwritten at early boot. Assert this never happened
to detect the case.

Signed-off-by: Suzuki K Poulose <suzuki.poulose at arm.com>
---
 lib/arm/setup.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/lib/arm/setup.c b/lib/arm/setup.c
index 2f649aff..462a1d51 100644
--- a/lib/arm/setup.c
+++ b/lib/arm/setup.c
@@ -35,6 +35,7 @@
 #define NR_MEM_REGIONS		(MAX_DT_MEM_REGIONS + NR_EXTRA_MEM_REGIONS)
 
 extern unsigned long _text, _etext, _data, _edata;
+extern unsigned long stacktop;
 
 char *initrd;
 u32 initrd_size;
@@ -196,6 +197,12 @@ static void freemem_push_fdt(void **freemem, const void *fdt)
 	u32 fdt_size;
 	int ret;
 
+	/*
+	 * Ensure that the FDT was not overlapping with the uninitialised
+	 * data that was overwritten.
+	 */
+	assert((unsigned long)fdt > (unsigned long)&stacktop);
+
 	fdt_size = fdt_totalsize(fdt);
 	ret = fdt_move(fdt, *freemem, fdt_size);
 	assert(ret == 0);
-- 
2.34.1