[PATCH -mm] IOAT: fix for UP use of cpu_physical_id()

[PATCH -mm] IOAT: fix for UP use of cpu_physical_id()

[Shannon Nelson]

Make sure we can use cpu_physical_id() even when compiled for
uni-processor.

Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Andi Kleen <ak@suse.de>
Cc: Chris Leech <chris.leech@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Shannon Nelson <shannon.nelson@intel.com>
---

 drivers/dma/ioat_dca.c |    8 ++++++++
 1 files changed, 8 insertions(+), 0 deletions(-)

diff --git a/drivers/dma/ioat_dca.c b/drivers/dma/ioat_dca.c
index c3a500b..b1af49c 100644
--- a/drivers/dma/ioat_dca.c
+++ b/drivers/dma/ioat_dca.c
@@ -25,6 +25,14 @@
 #include <linux/smp.h>
 #include <linux/interrupt.h>
 #include <linux/dca.h>
+
+// either a kernel change is needed, or we need something like this in kernel
+#ifndef CONFIG_SMP
+#include <asm/smp.h>
+#undef cpu_physical_id
+#define cpu_physical_id(cpu) (cpuid_ebx(1) >> 24)
+#endif
+
 #include "ioatdma.h"
 #include "ioatdma_registers.h"
 

Re: [PATCH -mm] IOAT: fix for UP use of cpu_physical_id()

[H. Peter Anvin]

Shannon Nelson wrote:
> Make sure we can use cpu_physical_id() even when compiled for
> uni-processor.
> 
> diff --git a/drivers/dma/ioat_dca.c b/drivers/dma/ioat_dca.c
> index c3a500b..b1af49c 100644
> --- a/drivers/dma/ioat_dca.c
> +++ b/drivers/dma/ioat_dca.c
> @@ -25,6 +25,14 @@
>  #include <linux/smp.h>
>  #include <linux/interrupt.h>
>  #include <linux/dca.h>
> +
> +// either a kernel change is needed, or we need something like this in kernel
> +#ifndef CONFIG_SMP
> +#include <asm/smp.h>
> +#undef cpu_physical_id
> +#define cpu_physical_id(cpu) (cpuid_ebx(1) >> 24)
> +#endif
> +

This value should probably be cached.  Executing cpuid to get a static
value seems like a bad idea.

	-hpa

RE: [PATCH -mm] IOAT: fix for UP use of cpu_physical_id()

[Nelson, Shannon]

>-----Original Message-----
>From: H. Peter Anvin [mailto:hpa@zytor.com] 
>Sent: Monday, August 20, 2007 3:27 PM
>To: Nelson, Shannon
>Cc: akpm@linux-foundation.org; linux-kernel@vger.kernel.org; 
>chris.leech@gmail.com; ak@suse.de; Luck, Tony
>Subject: Re: [PATCH -mm] IOAT: fix for UP use of cpu_physical_id()
>
>Shannon Nelson wrote:
>> Make sure we can use cpu_physical_id() even when compiled for
>> uni-processor.
>> 
>> diff --git a/drivers/dma/ioat_dca.c b/drivers/dma/ioat_dca.c
>> index c3a500b..b1af49c 100644
>> --- a/drivers/dma/ioat_dca.c
>> +++ b/drivers/dma/ioat_dca.c
>> @@ -25,6 +25,14 @@
>>  #include <linux/smp.h>
>>  #include <linux/interrupt.h>
>>  #include <linux/dca.h>
>> +
>> +// either a kernel change is needed, or we need something 
>like this in kernel
>> +#ifndef CONFIG_SMP
>> +#include <asm/smp.h>
>> +#undef cpu_physical_id
>> +#define cpu_physical_id(cpu) (cpuid_ebx(1) >> 24)
>> +#endif
>> +
>
>This value should probably be cached.  Executing cpuid to get a static
>value seems like a bad idea.

Yeah, this whole cpu_physical_id() gizmo needs to be fixed so it is
actually usable for non-SMP configurations.  Unfortunately, I'm not the
guy to do it.

sln
--
======================================================================
Mr. Shannon Nelson                 LAN Access Division, Intel Corp.
Shannon.Nelson@intel.com                I don't speak for Intel
(503) 712-7659                    Parents can't afford to be squeamish.