EDAC, amd64_edac: Shift wrapping issue in f1x_get_norm_dct_addr()

commit 6f3508f6 upstream.

dct_sel_base_off is declared as a u64 but we're only using the lower 32
bits because of a shift wrapping bug. This can possibly truncate the
upper 16 bits of DctSelBaseOffset[47:26], causing us to misdecode the CS
row.

Fixes: c8e518d5 ('amd64_edac: Sanitize f10_get_base_addr_offset')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Aravind Gopalakrishnan <Aravind.Gopalakrishnan@amd.com>
Cc: linux-edac <linux-edac@vger.kernel.org>
Link: http://lkml.kernel.org/r/20160120095451.GB19898@mwandaSigned-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>

drivers/edac/amd64_edac.c

@@ -1434,7 +1434,7 @@ static u64 f1x_get_norm_dct_addr(struct amd64_pvt *pvt, u8 range,
 	u64 chan_off;
 	u64 dram_base		= get_dram_base(pvt, range);
 	u64 hole_off		= f10_dhar_offset(pvt);
-	u64 dct_sel_base_off	= (pvt->dct_sel_hi & 0xFFFFFC00) << 16;
+	u64 dct_sel_base_off	= (u64)(pvt->dct_sel_hi & 0xFFFFFC00) << 16;
 
 	if (hi_rng) {
 		/*