> On 08-Jul-2020, at 5:34 PM, Michael Ellerman <m...@ellerman.id.au> wrote:
> 
> Athira Rajeev <atraj...@linux.vnet.ibm.com 
> <mailto:atraj...@linux.vnet.ibm.com>> writes:
>> From: Anju T Sudhakar <a...@linux.vnet.ibm.com>
>> 
>> Add extended regs to sample_reg_mask in the tool side to use
>> with `-I?` option. Perf tools side uses extended mask to display
>> the platform supported register names (with -I? option) to the user
>> and also send this mask to the kernel to capture the extended registers
>> in each sample. Hence decide the mask value based on the processor
>> version.
>> 
>> Signed-off-by: Anju T Sudhakar <a...@linux.vnet.ibm.com>
>> [Decide extended mask at run time based on platform]
>> Signed-off-by: Athira Rajeev <atraj...@linux.vnet.ibm.com>
>> Reviewed-by: Madhavan Srinivasan <ma...@linux.vnet.ibm.com>
> 
> Will need an ack from perf tools folks, who are not on Cc by the looks.
> 

Yes, my bad. Will make sure to add proper Cc 

>> diff --git a/tools/arch/powerpc/include/uapi/asm/perf_regs.h 
>> b/tools/arch/powerpc/include/uapi/asm/perf_regs.h
>> index f599064..485b1d5 100644
>> --- a/tools/arch/powerpc/include/uapi/asm/perf_regs.h
>> +++ b/tools/arch/powerpc/include/uapi/asm/perf_regs.h
>> @@ -48,6 +48,18 @@ enum perf_event_powerpc_regs {
>>      PERF_REG_POWERPC_DSISR,
>>      PERF_REG_POWERPC_SIER,
>>      PERF_REG_POWERPC_MMCRA,
>> -    PERF_REG_POWERPC_MAX,
>> +    /* Extended registers */
>> +    PERF_REG_POWERPC_MMCR0,
>> +    PERF_REG_POWERPC_MMCR1,
>> +    PERF_REG_POWERPC_MMCR2,
>> +    /* Max regs without the extended regs */
>> +    PERF_REG_POWERPC_MAX = PERF_REG_POWERPC_MMCRA + 1,
> 
> I don't really understand this idea of a max that's not the max.
> 
>> };
>> +
>> +#define PERF_REG_PMU_MASK   ((1ULL << PERF_REG_POWERPC_MAX) - 1)
>> +
>> +/* PERF_REG_EXTENDED_MASK value for CPU_FTR_ARCH_300 */
>> +#define PERF_REG_PMU_MASK_300   (((1ULL << (PERF_REG_POWERPC_MMCR2 + 1)) - 
>> 1) \
>> +                            - PERF_REG_PMU_MASK)
>> +
>> #endif /* _UAPI_ASM_POWERPC_PERF_REGS_H */
>> diff --git a/tools/perf/arch/powerpc/include/perf_regs.h 
>> b/tools/perf/arch/powerpc/include/perf_regs.h
>> index e18a355..46ed00d 100644
>> --- a/tools/perf/arch/powerpc/include/perf_regs.h
>> +++ b/tools/perf/arch/powerpc/include/perf_regs.h
>> @@ -64,7 +64,10 @@
>>      [PERF_REG_POWERPC_DAR] = "dar",
>>      [PERF_REG_POWERPC_DSISR] = "dsisr",
>>      [PERF_REG_POWERPC_SIER] = "sier",
>> -    [PERF_REG_POWERPC_MMCRA] = "mmcra"
>> +    [PERF_REG_POWERPC_MMCRA] = "mmcra",
>> +    [PERF_REG_POWERPC_MMCR0] = "mmcr0",
>> +    [PERF_REG_POWERPC_MMCR1] = "mmcr1",
>> +    [PERF_REG_POWERPC_MMCR2] = "mmcr2",
>> };
>> 
>> static inline const char *perf_reg_name(int id)
>> diff --git a/tools/perf/arch/powerpc/util/perf_regs.c 
>> b/tools/perf/arch/powerpc/util/perf_regs.c
>> index 0a52429..9179230 100644
>> --- a/tools/perf/arch/powerpc/util/perf_regs.c
>> +++ b/tools/perf/arch/powerpc/util/perf_regs.c
>> @@ -6,9 +6,14 @@
>> 
>> #include "../../../util/perf_regs.h"
>> #include "../../../util/debug.h"
>> +#include "../../../util/event.h"
>> +#include "../../../util/header.h"
>> +#include "../../../perf-sys.h"
>> 
>> #include <linux/kernel.h>
>> 
>> +#define PVR_POWER9          0x004E
>> +
>> const struct sample_reg sample_reg_masks[] = {
>>      SMPL_REG(r0, PERF_REG_POWERPC_R0),
>>      SMPL_REG(r1, PERF_REG_POWERPC_R1),
>> @@ -55,6 +60,9 @@
>>      SMPL_REG(dsisr, PERF_REG_POWERPC_DSISR),
>>      SMPL_REG(sier, PERF_REG_POWERPC_SIER),
>>      SMPL_REG(mmcra, PERF_REG_POWERPC_MMCRA),
>> +    SMPL_REG(mmcr0, PERF_REG_POWERPC_MMCR0),
>> +    SMPL_REG(mmcr1, PERF_REG_POWERPC_MMCR1),
>> +    SMPL_REG(mmcr2, PERF_REG_POWERPC_MMCR2),
>>      SMPL_REG_END
>> };
>> 
>> @@ -163,3 +171,50 @@ int arch_sdt_arg_parse_op(char *old_op, char **new_op)
>> 
>>      return SDT_ARG_VALID;
>> }
>> +
>> +uint64_t arch__intr_reg_mask(void)
>> +{
>> +    struct perf_event_attr attr = {
>> +            .type                   = PERF_TYPE_HARDWARE,
>> +            .config                 = PERF_COUNT_HW_CPU_CYCLES,
>> +            .sample_type            = PERF_SAMPLE_REGS_INTR,
>> +            .precise_ip             = 1,
>> +            .disabled               = 1,
>> +            .exclude_kernel         = 1,
>> +    };
>> +    int fd, ret;
>> +    char buffer[64];
>> +    u32 version;
>> +    u64 extended_mask = 0;
>> +
>> +    /* Get the PVR value to set the extended
>> +     * mask specific to platform
> 
> Comment format is wrong, and punctuation please.
> 
>> +     */
>> +    get_cpuid(buffer, sizeof(buffer));
>> +    ret = sscanf(buffer, "%u,", &version);
> 
> This is powerpc specific code, why not just use mfspr(SPRN_PVR), rather
> than redirecting via printf/sscanf.

Hi Michael

For perf tools, defines for `mfspr` , `SPRN_PVR` are in 
arch/powerpc/util/header.c 
So I have re-used existing utility. Otherwise, we will need to include these 
defines here as well
Does that sounds good ?

> 
>> +
>> +    if (ret != 1) {
>> +            pr_debug("Failed to get the processor version, unable to output 
>> extended registers\n");
>> +            return PERF_REGS_MASK;
>> +    }
>> +
>> +    if (version == PVR_POWER9)
>> +            extended_mask = PERF_REG_PMU_MASK_300;
>> +    else
>> +            return PERF_REGS_MASK;
>> +
>> +    attr.sample_regs_intr = extended_mask;
>> +    attr.sample_period = 1;
>> +    event_attr_init(&attr);
>> +
>> +    /*
>> +     * check if the pmu supports perf extended regs, before
>> +     * returning the register mask to sample.
>> +     */
>> +    fd = sys_perf_event_open(&attr, 0, -1, -1, 0);
>> +    if (fd != -1) {
>> +            close(fd);
>> +            return (extended_mask | PERF_REGS_MASK);
>> +    }
>> +    return PERF_REGS_MASK;
> 
> I think this would read a bit better like:
> 
>       mask = PERF_REGS_MASK;
> 
>       if (version == PVR_POWER9)
>               extended_mask = PERF_REG_PMU_MASK_300;
>        else
>               return mask;
> 
>        attr.sample_regs_intr = extended_mask;
>        attr.sample_period = 1;
>        event_attr_init(&attr);
> 
>        /*
>          * check if the pmu supports perf extended regs, before
>          * returning the register mask to sample.
>          */
>        fd = sys_perf_event_open(&attr, 0, -1, -1, 0);
>        if (fd != -1) {
>                close(fd);
>                mask |= extended_mask;
>        }
> 
>       return mask;

Sure, I will try with this change

Thanks
Athira
> 
> 
> cheers

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