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 <redacted>
---
Changes from v3:
- No need to call lmb_enforce_memory_limit() with limit=lmb_phys_mem_size().

diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c
--- a/arch/powerpc/kernel/prom.c
+++ b/arch/powerpc/kernel/prom.c

@@ -1160,6 +1160,8 @@ static inline void __init phyp_dump_rese

 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 *par
       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());