powerpc: Force memory size to be a multiple of PAGE_SIZE

Ensure that total memory size is page-aligned, because otherwise
mark_bootmem() gets upset.

This error case was triggered by using 64 KiB pages in the kernel
while arch/powerpc/boot/4xx.c arbitrarily reduced the amount of memory
by 4096 (to work around a chip bug that affects the last 256 bytes of
physical memory).

Signed-off-by: Hollis Blanchard <hollisb@us.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 15 insertions, 1 deletions

diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c
index d8266dd61dda..6f73c739f1e2 100644
--- a/arch/powerpc/kernel/prom.c
+++ b/arch/powerpc/kernel/prom.c
@@ -1160,6 +1160,8 @@ static inline void __init phyp_dump_reserve_mem(void) {}
 
 void __init early_init_devtree(void *params)
 {
+        unsigned long limit;
+
         DBG(" -> early_init_devtree(%p)\n", params);
 
         /* Setup flat device-tree pointer */
@@ -1200,7 +1202,19 @@ void __init early_init_devtree(void *params)
         early_reserve_mem();
         phyp_dump_reserve_mem();
 
-        lmb_enforce_memory_limit(memory_limit);
+        limit = memory_limit;
+        if (! limit) {
+                unsigned long memsize;
+
+                /* Ensure that total memory size is page-aligned, because
+                 * otherwise mark_bootmem() gets upset. */
+                lmb_analyze();
+                memsize = lmb_phys_mem_size();
+                if ((memsize & PAGE_MASK) != memsize)
+                        limit = memsize & PAGE_MASK;
+        }
+        lmb_enforce_memory_limit(limit);
+
         lmb_analyze();
 
         DBG("Phys. mem: %lx\n", lmb_phys_mem_size());