powerpc: Change the default link address for pSeries zImage kernels

Currently we set the start of the .text section to be 4Mb for pSeries.
In situations where the zImage is > 8Mb we'll fail to boot (due to
overlapping with OF).  Move .text in a zImage from 4MB to 64MB
(well past OF).

We still will not be able to load large zImage unless we also move OF,
to that end, add a note to the zImage ELF to move OF to 32Mb.  If this
is the very first kernel booted then we'll need to move OF manually by
setting real-base.

Signed-off-by: Tony Breeds <tony@bakeyournoodle.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 13 insertions, 2 deletions

diff --git a/arch/powerpc/boot/oflib.c b/arch/powerpc/boot/oflib.c
index 95b8fd69a403..b0ec9cf3eaaf 100644
--- a/arch/powerpc/boot/oflib.c
+++ b/arch/powerpc/boot/oflib.c
@@ -168,8 +168,19 @@ void *of_claim(unsigned long virt, unsigned long size, unsigned long align)
 
 void *of_vmlinux_alloc(unsigned long size)
 {
-        void *p = malloc(size);
-
+        unsigned long start = (unsigned long)_start, end = (unsigned long)_end;
+        void *addr;
+        void *p;
+
+        /* With some older POWER4 firmware we need to claim the area the kernel
+         * will reside in.  Newer firmwares don't need this so we just ignore
+         * the return value.
+         */
+        addr = of_claim(start, end - start, 0);
+        printf("Trying to claim from 0x%lx to 0x%lx (0x%lx) got %p\r\n",
+               start, end, end - start, addr);
+
+        p = malloc(size);
         if (!p)
                 fatal("Can't allocate memory for kernel image!\n\r");