diff mbox series

[v2,03/10] riscv: Make legacy counter enum match the HW numbering

Message ID 20230512085321.13259-4-alexghiti@rivosinc.com
State New
Headers
Series riscv: Allow userspace to directly access perf counters |

Commit Message

Alexandre Ghiti May 12, 2023, 8:53 a.m. UTC 
  RISCV_PMU_LEGACY_INSTRET used to be set to 1 whereas the offset of this
hardware counter from CSR_CYCLE is actually 2: make this offset match the
real hw offset so that we can directly expose those values to userspace.

Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
---
 drivers/perf/riscv_pmu_legacy.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

Comments

Andrew Jones May 31, 2023, 2:01 p.m. UTC | #1 
On Fri, May 12, 2023 at 10:53:14AM +0200, Alexandre Ghiti wrote:
> RISCV_PMU_LEGACY_INSTRET used to be set to 1 whereas the offset of this
> hardware counter from CSR_CYCLE is actually 2: make this offset match the
> real hw offset so that we can directly expose those values to userspace.
> 
> Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
> ---
>  drivers/perf/riscv_pmu_legacy.c | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/perf/riscv_pmu_legacy.c b/drivers/perf/riscv_pmu_legacy.c
> index ca9e20bfc7ac..0d8c9d8849ee 100644
> --- a/drivers/perf/riscv_pmu_legacy.c
> +++ b/drivers/perf/riscv_pmu_legacy.c
> @@ -12,8 +12,11 @@
>  #include <linux/perf/riscv_pmu.h>
>  #include <linux/platform_device.h>
>  
> -#define RISCV_PMU_LEGACY_CYCLE		0
> -#define RISCV_PMU_LEGACY_INSTRET	1
> +enum {
> +	RISCV_PMU_LEGACY_CYCLE,
> +	RISCV_PMU_LEGACY_TIME,
> +	RISCV_PMU_LEGACY_INSTRET
> +};

I guess this doesn't hurt, since these are just indices internal to this
driver, but it's a bit odd to also have a RISCV_PMU_LEGACY_TIME, when
the driver is only for cycle and instret, as its Kconfig help text says.

Thanks,
drew
Alexandre Ghiti June 15, 2023, 7:16 a.m. UTC | #2 
On 31/05/2023 16:01, Andrew Jones wrote:
> On Fri, May 12, 2023 at 10:53:14AM +0200, Alexandre Ghiti wrote:
>> RISCV_PMU_LEGACY_INSTRET used to be set to 1 whereas the offset of this
>> hardware counter from CSR_CYCLE is actually 2: make this offset match the
>> real hw offset so that we can directly expose those values to userspace.
>>
>> Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
>> ---
>>   drivers/perf/riscv_pmu_legacy.c | 7 +++++--
>>   1 file changed, 5 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/perf/riscv_pmu_legacy.c b/drivers/perf/riscv_pmu_legacy.c
>> index ca9e20bfc7ac..0d8c9d8849ee 100644
>> --- a/drivers/perf/riscv_pmu_legacy.c
>> +++ b/drivers/perf/riscv_pmu_legacy.c
>> @@ -12,8 +12,11 @@
>>   #include <linux/perf/riscv_pmu.h>
>>   #include <linux/platform_device.h>
>>   
>> -#define RISCV_PMU_LEGACY_CYCLE		0
>> -#define RISCV_PMU_LEGACY_INSTRET	1
>> +enum {
>> +	RISCV_PMU_LEGACY_CYCLE,
>> +	RISCV_PMU_LEGACY_TIME,
>> +	RISCV_PMU_LEGACY_INSTRET
>> +};
> I guess this doesn't hurt, since these are just indices internal to this
> driver, but it's a bit odd to also have a RISCV_PMU_LEGACY_TIME, when
> the driver is only for cycle and instret, as its Kconfig help text says.


I understand and you're right, that's weird, so I'll change that with 
the following:

diff --git a/drivers/perf/riscv_pmu_legacy.c 
b/drivers/perf/riscv_pmu_legacy.c
index ca9e20bfc7ac..6a000abc28bb 100644
--- a/drivers/perf/riscv_pmu_legacy.c
+++ b/drivers/perf/riscv_pmu_legacy.c
@@ -13,7 +13,7 @@
  #include <linux/platform_device.h>

  #define RISCV_PMU_LEGACY_CYCLE         0
-#define RISCV_PMU_LEGACY_INSTRET       1
+#define RISCV_PMU_LEGACY_INSTRET       2

  static bool pmu_init_done;

Thanks!


> Thanks,
> drew
>
> _______________________________________________
> linux-riscv mailing list
> linux-riscv@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-riscv
diff mbox series

Patch

diff --git a/drivers/perf/riscv_pmu_legacy.c b/drivers/perf/riscv_pmu_legacy.c
index ca9e20bfc7ac..0d8c9d8849ee 100644
--- a/drivers/perf/riscv_pmu_legacy.c
+++ b/drivers/perf/riscv_pmu_legacy.c
@@ -12,8 +12,11 @@ 
 #include <linux/perf/riscv_pmu.h>
 #include <linux/platform_device.h>
 
-#define RISCV_PMU_LEGACY_CYCLE		0
-#define RISCV_PMU_LEGACY_INSTRET	1
+enum {
+	RISCV_PMU_LEGACY_CYCLE,
+	RISCV_PMU_LEGACY_TIME,
+	RISCV_PMU_LEGACY_INSTRET
+};
 
 static bool pmu_init_done;