[PATCH v4 7/7] [boot] Change the load address for the wrapper to fit the kernel

[Suzuki K. Poulose]

The wrapper code which uncompresses the kernel in case of a 'ppc' boot
is by default loaded at 0x00400000 and the kernel will be uncompressed
to fit the location 0-0x00400000. But with dynamic relocations, the size
of the kernel may exceed 0x00400000(4M). This would cause an overlap
of the uncompressed kernel and the boot wrapper, causing a failure in
boot.

The message looks like :


   zImage starting: loaded at 0x00400000 (sp: 0x0065ffb0)
   Allocating 0x5ce650 bytes for kernel ...
   Insufficient memory for kernel at address 0! (_start=00400000, uncompressed size=00591a20)

This patch shifts the load address of the boot wrapper code to the next higher MB,
according to the size of  the uncompressed vmlinux.

Signed-off-by: Suzuki K. Poulose <suzuki at in.ibm.com>
---

 arch/powerpc/boot/wrapper |   20 ++++++++++++++++++++
 1 files changed, 20 insertions(+), 0 deletions(-)

diff --git a/arch/powerpc/boot/wrapper b/arch/powerpc/boot/wrapper
index 14cd4bc..4d625cd 100755
--- a/arch/powerpc/boot/wrapper
+++ b/arch/powerpc/boot/wrapper
@@ -257,6 +257,8 @@ vmz="$tmpdir/`basename \"$kernel\"`.$ext"
 if [ -z "$cacheit" -o ! -f "$vmz$gzip" -o "$vmz$gzip" -ot "$kernel" ]; then
     ${CROSS}objcopy $objflags "$kernel" "$vmz.$$"
 
+    strip_size=$(stat -c %s $vmz.$$)
+
     if [ -n "$gzip" ]; then
         gzip -n -f -9 "$vmz.$$"
     fi
@@ -266,6 +268,24 @@ if [ -z "$cacheit" -o ! -f "$vmz$gzip" -o "$vmz$gzip" -ot "$kernel" ]; then
     else
 	vmz="$vmz.$$"
     fi
+else
+    # Calculate the vmlinux.strip size
+    ${CROSS}objcopy $objflags "$kernel" "$vmz.$$"
+    strip_size=$(stat -c %s $vmz.$$)
+    rm -f $vmz.$$
+fi
+
+# Round the size to next higher MB limit
+round_size=$(((strip_size + 0xfffff) & 0xfff00000))
+
+round_size=0x$(printf "%x" $round_size)
+link_addr=$(printf "%d" $link_address)
+
+if [ $link_addr -lt $strip_size ]; then
+    echo "WARN: Uncompressed kernel size(0x$(printf "%x\n" $strip_size))" \
+		" exceeds the address of the wrapper($link_address)"
+    echo "WARN: Fixing the link_address to ($round_size))"
+    link_address=$round_size
 fi
 
 vmz="$vmz$gzip"