[PATCH] powerpc/oprofile: Fix error in oprofile power7_marked_instr_event() function

[PATCH] powerpc/oprofile: Fix error in oprofile power7_marked_instr_event() function

[Carl E. Love]

Ben:

Please review the following patch.  If it is acceptable, will you please
commit it to the mainline tree.  Thanks.

              Carl Love

P.S.  Looks like I sent it to the wrong mailing list the first time to
get it into the patch queue.

--------------------------------------------------------------------------
powerpc/oprofile: Fix error in oprofile power7_marked_instr_event() function

The calculation for the left shift of the mask OPROFILE_PM_PMCSEL_MSK has an
error.  The calculation is should be to shift left by (max_cntrs - cntr) times
the width of the pmsel field width.  However, the #define OPROFILE_MAX_PMC_NUM
was used instead of OPROFILE_PMSEL_FIELD_WIDTH.  This patch fixes the
calculation.

Signed-off-by: Carl Love <cel@us.ibm.com>
---
 arch/powerpc/oprofile/op_model_power4.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/powerpc/oprofile/op_model_power4.c b/arch/powerpc/oprofile/op_model_power4.c
index 315f949..f444b94 100644
--- a/arch/powerpc/oprofile/op_model_power4.c
+++ b/arch/powerpc/oprofile/op_model_power4.c
@@ -52,7 +52,7 @@ static int power7_marked_instr_event(u64 mmcr1)
 	for (pmc = 0; pmc < 4; pmc++) {
 		psel = mmcr1 & (OPROFILE_PM_PMCSEL_MSK
 				<< (OPROFILE_MAX_PMC_NUM - pmc)
-				* OPROFILE_MAX_PMC_NUM);
+				* OPROFILE_PMSEL_FIELD_WIDTH);
 		psel = (psel >> ((OPROFILE_MAX_PMC_NUM - pmc)
 				 * OPROFILE_PMSEL_FIELD_WIDTH)) & ~1ULL;
 		unit = mmcr1 & (OPROFILE_PM_UNIT_MSK
-- 
1.7.12.rc1.22.gbfbf4d4

Re: [PATCH] powerpc/oprofile: Fix error in oprofile power7_marked_instr_event() function

[Benjamin Herrenschmidt]

On Thu, 2012-11-29 at 08:42 -0800, Carl E. Love wrote:
> Ben:
> 
> Please review the following patch.  If it is acceptable, will you please
> commit it to the mainline tree.  Thanks.
> 
>               Carl Love
> 
> P.S.  Looks like I sent it to the wrong mailing list the first time to
> get it into the patch queue.

Also avoid my Notes address for patches please...

> --------------------------------------------------------------------------
> powerpc/oprofile: Fix error in oprofile power7_marked_instr_event() function
> 
> The calculation for the left shift of the mask OPROFILE_PM_PMCSEL_MSK has an
> error.  The calculation is should be to shift left by (max_cntrs - cntr) times
> the width of the pmsel field width.  However, the #define OPROFILE_MAX_PMC_NUM
> was used instead of OPROFILE_PMSEL_FIELD_WIDTH.  This patch fixes the
> calculation.

Paul, Anton, can of you ack this ?

Cheers,
Ben.

> Signed-off-by: Carl Love <cel@us.ibm.com>
> ---
>  arch/powerpc/oprofile/op_model_power4.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/powerpc/oprofile/op_model_power4.c b/arch/powerpc/oprofile/op_model_power4.c
> index 315f949..f444b94 100644
> --- a/arch/powerpc/oprofile/op_model_power4.c
> +++ b/arch/powerpc/oprofile/op_model_power4.c
> @@ -52,7 +52,7 @@ static int power7_marked_instr_event(u64 mmcr1)
>  	for (pmc = 0; pmc < 4; pmc++) {
>  		psel = mmcr1 & (OPROFILE_PM_PMCSEL_MSK
>  				<< (OPROFILE_MAX_PMC_NUM - pmc)
> -				* OPROFILE_MAX_PMC_NUM);
> +				* OPROFILE_PMSEL_FIELD_WIDTH);
>  		psel = (psel >> ((OPROFILE_MAX_PMC_NUM - pmc)
>  				 * OPROFILE_PMSEL_FIELD_WIDTH)) & ~1ULL;
>  		unit = mmcr1 & (OPROFILE_PM_UNIT_MSK

Re: [PATCH] powerpc/oprofile: Fix error in oprofile power7_marked_instr_event() function

[Paul Mackerras]

On Thu, Nov 29, 2012 at 08:42:03AM -0800, Carl E. Love wrote:
> powerpc/oprofile: Fix error in oprofile power7_marked_instr_event() function
> 
> The calculation for the left shift of the mask OPROFILE_PM_PMCSEL_MSK has an
> error.  The calculation is should be to shift left by (max_cntrs - cntr) times
> the width of the pmsel field width.  However, the #define OPROFILE_MAX_PMC_NUM
> was used instead of OPROFILE_PMSEL_FIELD_WIDTH.  This patch fixes the
> calculation.
> 
> Signed-off-by: Carl Love <cel@us.ibm.com>
> ---
>  arch/powerpc/oprofile/op_model_power4.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/powerpc/oprofile/op_model_power4.c b/arch/powerpc/oprofile/op_model_power4.c
> index 315f949..f444b94 100644
> --- a/arch/powerpc/oprofile/op_model_power4.c
> +++ b/arch/powerpc/oprofile/op_model_power4.c
> @@ -52,7 +52,7 @@ static int power7_marked_instr_event(u64 mmcr1)
>  	for (pmc = 0; pmc < 4; pmc++) {
>  		psel = mmcr1 & (OPROFILE_PM_PMCSEL_MSK
>  				<< (OPROFILE_MAX_PMC_NUM - pmc)
> -				* OPROFILE_MAX_PMC_NUM);
> +				* OPROFILE_PMSEL_FIELD_WIDTH);
>  		psel = (psel >> ((OPROFILE_MAX_PMC_NUM - pmc)
>  				 * OPROFILE_PMSEL_FIELD_WIDTH)) & ~1ULL;

Apart from the fact that those two statements would be simpler and
better as:

		psel = mmcr1 >> ((OPROFILE_MAX_PMC_NUM - pmc)
  				 * OPROFILE_PMSEL_FIELD_WIDTH);
		psel &= OPROFILE_PM_PMCSEL_MSK & ~1ULL;

the change looks correct, so:

Acked-by: Paul Mackerras <paulus@samba.org>