x86 EDAC, sb_edac.c: Repair damage introduced when "fixing" channel address

commit ff15e95c upstream.

In commit:

  eb1af3b7 ("Fix computation of channel address")

I switched the "sck_way" variable from holding the log2 value read
from the h/w to instead be the actual number. Unfortunately it
is needed in log2 form when used to shift the address.
Tested-by: Patrick Geary <patrickg@supermicro.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Acked-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
Cc: Aristeu Rozanski <arozansk@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-edac@vger.kernel.org
Fixes: eb1af3b7 ("Fix computation of channel address")
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>

drivers/edac/sb_edac.c

@@ -1316,7 +1316,7 @@ static int get_memory_error_data(struct mem_ctl_info *mci,
 	}
 
 	ch_way = TAD_CH(reg) + 1;
-	sck_way = 1 << TAD_SOCK(reg);
+	sck_way = TAD_SOCK(reg);
 
 	if (ch_way == 3)
 		idx = addr >> 6;
@@ -1355,7 +1355,7 @@ static int get_memory_error_data(struct mem_ctl_info *mci,
 		switch(ch_way) {
 		case 2:
 		case 4:
-			sck_xch = 1 << sck_way * (ch_way >> 1);
+			sck_xch = (1 << sck_way) * (ch_way >> 1);
 			break;
 		default:
 			sprintf(msg, "Invalid mirror set. Can't decode addr");
@@ -1391,7 +1391,7 @@ static int get_memory_error_data(struct mem_ctl_info *mci,
 
 	ch_addr = addr - offset;
 	ch_addr >>= (6 + shiftup);
-	ch_addr /= ch_way * sck_way;
+	ch_addr /= sck_xch;
 	ch_addr <<= (6 + shiftup);
 	ch_addr |= addr & ((1 << (6 + shiftup)) - 1);