powerpc: Don't use a 16G page if beyond mem= limits

commit 4792adbac9eb41cea77a45ab76258ea10d411173 upstream

If mem= is used on the boot command line to limit memory then the memory block where a 16G page resides may not be available.

Thanks to Michael Ellerman for finding the problem.

Signed-off-by: Jon Tollefson <kniht@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
index 8920eea3452844dfb906fc3f9d6b67a01d37561f..16319a523238ce5439fb55d2be86deed89b82145 100644 (file)
--- a/arch/powerpc/mm/hash_utils_64.c
+++ b/arch/powerpc/mm/hash_utils_64.c
@@ -381,8 +381,10 @@ static int __init htab_dt_scan_hugepage_blocks(unsigned long node,
        printk(KERN_INFO "Huge page(16GB) memory: "
                        "addr = 0x%lX size = 0x%lX pages = %d\n",
                        phys_addr, block_size, expected_pages);
-       lmb_reserve(phys_addr, block_size * expected_pages);
-       add_gpage(phys_addr, block_size, expected_pages);
+       if (phys_addr + (16 * GB) <= lmb_end_of_DRAM()) {
+               lmb_reserve(phys_addr, block_size * expected_pages);
+               add_gpage(phys_addr, block_size, expected_pages);
+       }
        return 0;
 }