m68k: fix ColdFire node shift size calculation

[ Upstream commit f55ab8f27548ff3431a6567d400c6757c49fd520 ]

The m68k pg_data_table is a fix size array defined in arch/m68k/mm/init.c.
Index numbers within it are defined based on memory size. But for Coldfire
these don't take into account a non-zero physical RAM base address, and this
causes us to access past the end of this array at system start time.

Change the node shift calculation so that we keep the index inside its range.

Reported-by: Angelo Dureghello <angelo@sysam.it>
Tested-by: Angelo Dureghello <angelo@sysam.it>
Signed-off-by: Greg Ungerer <gerg@linux-m68k.org>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/m68k/mm/mcfmmu.c b/arch/m68k/mm/mcfmmu.c
index 8d1408583cf42c96ce9a7f54b06f3dab862cf629..b523a604cb87b1fdaf440edf340f552aa43f1cc2 100644 (file)
--- a/arch/m68k/mm/mcfmmu.c
+++ b/arch/m68k/mm/mcfmmu.c
@@ -170,7 +170,7 @@ void __init cf_bootmem_alloc(void)
        max_pfn = max_low_pfn = PFN_DOWN(_ramend);
        high_memory = (void *)_ramend;
 
-       m68k_virt_to_node_shift = fls(_ramend - _rambase - 1) - 6;
+       m68k_virt_to_node_shift = fls(_ramend - 1) - 6;
        module_fixup(NULL, __start_fixup, __stop_fixup);
 
        /* setup bootmem data */