[U-Boot] [PATCH v3] fix get_ram_size memory corruption

[Gerd Hoffmann]

base[0] is saved, but only restored in case the ram test failed.

Test case:  Start u-boot in qemu, using vexpress-a9 emulation.
qemu places the fdt at the start of ram, as a service for the
guest.  Trying to pick it up there by setting fdt_addr
accordingly fails because the fdt magic cookie is gone (zeroed
out) after calling get_ram_size.

Cc: Wolfgang Denk <wd at denx.de>
Signed-off-by: Gerd Hoffmann <kraxel at redhat.com>
---
 common/memsize.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/common/memsize.c b/common/memsize.c
index 589400d..dac1368 100644
--- a/common/memsize.c
+++ b/common/memsize.c
@@ -48,11 +48,12 @@ long get_ram_size(long *base, long maxsize)
 	*addr = 0;
 
 	sync ();
-	if ((val = *addr) != 0) {
+	val = *addr;
+	*addr = save[i];
+	if (val != 0) {
 		/* Restore the original data before leaving the function.
 		 */
 		sync ();
-		*addr = save[i];
 		for (cnt = 1; cnt < maxsize / sizeof(long); cnt <<= 1) {
 			addr  = base + cnt;
 			sync ();
-- 
1.8.3.1