[patch 03/27] SPARC64: Fix memory controller register access when non-SMP.

Greg KH
2008-02-02T00:24:53Z

[-- Attachment #1: sparc64-fix-memory-controller-register-access-when-non-smp.patch --]
[-- Type: text/plain, Size: 1862 bytes --]

2.6.22-stable review patch. If anyone has any objections, please let us
know.

------------------

From: David Miller <davem@davemloft.net>

[SPARC64]: Fix memory controller register access when non-SMP.

[ Upstream commit: b332b8bc9c67165eabdfc7d10b4a2e4cc9f937d0 ]

get_cpu() always returns zero on non-SMP builds, but we
really want the physical cpu number in this code in order
to do the right thing.

Based upon a non-SMP kernel boot failure report from Bernd Zeimetz.

Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
arch/sparc64/kernel/chmc.c | 16 ++++++++++------
1 file changed, 10 insertions(+), 6 deletions(-)

--- a/arch/sparc64/kernel/chmc.c
+++ b/arch/sparc64/kernel/chmc.c
@@ -1,7 +1,6 @@
-/* $Id: chmc.c,v 1.4 2002/01/08 16:00:14 davem Exp $
- * memctrlr.c: Driver for UltraSPARC-III memory controller.
+/* memctrlr.c: Driver for UltraSPARC-III memory controller.
*
- * Copyright (C) 2001 David S. Miller (davem@redhat.com)
+ * Copyright (C) 2001, 2007 David S. Miller (davem@davemloft.net)
*/

#include <linux/module.h>
@@ -16,6 +15,7 @@
#include <linux/init.h>
#include <asm/spitfire.h>
#include <asm/chmctrl.h>
+#include <asm/cpudata.h>
#include <asm/oplib.h>
#include <asm/prom.h>
#include <asm/io.h>
@@ -242,8 +242,11 @@ int chmc_getunumber(int syndrome_code,
*/
static u64 read_mcreg(struct mctrl_info *mp, unsigned long offset)
{
- unsigned long ret;
- int this_cpu = get_cpu();
+ unsigned long ret, this_cpu;
+
+ preempt_disable();
+
+ this_cpu = real_hard_smp_processor_id();

if (mp->portid == this_cpu) {
__asm__ __volatile__("ldxa [%1] %2, %0"
@@ -255,7 +258,8 @@ static u64 read_mcreg(struct mctrl_info
: "r" (mp->regs + offset),
"i" (ASI_PHYS_BYPASS_EC_E));
}
- put_cpu();
+
+ preempt_enable();

return ret;
}

--