linux-kernel - Re: [PATCH v3 18/25] perf/uapi: Extend data source fields

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Message-ID: <20251118170543.GB8204@e132581.arm.com>
Date: Tue, 18 Nov 2025 17:05:43 +0000
From: Leo Yan <leo.yan@....com>
To: Peter Zijlstra <peterz@...radead.org>, Ingo Molnar <mingo@...hat.com>,
	Arnaldo Carvalho de Melo <acme@...nel.org>,
	Namhyung Kim <namhyung@...nel.org>, Jiri Olsa <jolsa@...nel.org>,
	Ian Rogers <irogers@...gle.com>,
	Adrian Hunter <adrian.hunter@...el.com>,
	James Clark <james.clark@...aro.org>,
	Mark Rutland <mark.rutland@....com>
Cc: Arnaldo Carvalho de Melo <acme@...hat.com>,
	linux-perf-users@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 18/25] perf/uapi: Extend data source fields

On Wed, Nov 12, 2025 at 06:24:44PM +0000, Leo Yan wrote:
> Arm CPUs introduce several new types of memory operations, like MTE tag
> accessing, system register access for nested virtualization, memcpy &
> memset, and Guarded Control Stack (GCS).
> 
> For memory operation details, Arm SPE provides information like data
> (parallel) processing, floating-point, predicated, atomic, exclusive,
> acquire/release, gather/scatter, and conditional.
> 
> This commit introduces a field 'mem_op_ext' for extended operation type.
> The extended operation type can be combined with the existed operation
> type to express a memory type, for examples, a PERF_MEM_OP_GCS type can
> be set along with PERF_MEM_OP_LOAD to present a load operation for
> GCS register access.
> 
> Bit fields are also added to represent detailed operation attributes.
> 
> Signed-off-by: Leo Yan <leo.yan@....com>

Just ping perf core maintainers, is this uAPI change okay for you?

Thanks for Ian's and James' review!

Leo

> ---
>  include/uapi/linux/perf_event.h | 32 ++++++++++++++++++++++++++++++--
>  1 file changed, 30 insertions(+), 2 deletions(-)
> 
> diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h
> index 78a362b8002776e5ce83a0d7816601638c61ecc6..9b9fa59fd828756b5e8e93520da5a269f0dfff52 100644
> --- a/include/uapi/linux/perf_event.h
> +++ b/include/uapi/linux/perf_event.h
> @@ -1309,14 +1309,32 @@ union perf_mem_data_src {
>  			mem_snoopx  :  2, /* Snoop mode, ext */
>  			mem_blk     :  3, /* Access blocked */
>  			mem_hops    :  3, /* Hop level */
> -			mem_rsvd    : 18;
> +			mem_op_ext  :  4, /* Extended type of opcode */
> +			mem_dp      :  1, /* Data processing */
> +			mem_fp      :  1, /* Floating-point */
> +			mem_pred    :  1, /* Predicated */
> +			mem_atomic  :  1, /* Atomic operation */
> +			mem_excl    :  1, /* Exclusive */
> +			mem_ar      :  1, /* Acquire/release */
> +			mem_sg      :  1, /* Scatter/Gather */
> +			mem_cond    :  1, /* Conditional */
> +			mem_rsvd    :  6;
>  	};
>  };
>  #elif defined(__BIG_ENDIAN_BITFIELD)
>  union perf_mem_data_src {
>  	__u64 val;
>  	struct {
> -		__u64	mem_rsvd    : 18,
> +		__u64	mem_rsvd    :  6,
> +			mem_cond    :  1, /* Conditional */
> +			mem_sg      :  1, /* Scatter/Gather */
> +			mem_ar      :  1, /* Acquire/release */
> +			mem_excl    :  1, /* Exclusive */
> +			mem_atomic  :  1, /* Atomic operation */
> +			mem_pred    :  1, /* Predicated */
> +			mem_fp      :  1, /* Floating-point */
> +			mem_dp      :  1, /* Data processing */
> +			mem_op_ext  :  4, /* Extended type of opcode */
>  			mem_hops    :  3, /* Hop level */
>  			mem_blk     :  3, /* Access blocked */
>  			mem_snoopx  :  2, /* Snoop mode, ext */
> @@ -1426,6 +1444,16 @@ union perf_mem_data_src {
>  /* 5-7 available */
>  #define PERF_MEM_HOPS_SHIFT			43
>  
> +/* Extended type of memory opcode: */
> +#define PERF_MEM_EXT_OP_NA			0x0    /* Not available */
> +#define PERF_MEM_EXT_OP_MTE_TAG			0x1    /* MTE tag */
> +#define PERF_MEM_EXT_OP_NESTED_VIRT		0x2    /* Nested virtualization */
> +#define PERF_MEM_EXT_OP_MEMCPY			0x3    /* Memory copy */
> +#define PERF_MEM_EXT_OP_MEMSET			0x4    /* Memory set */
> +#define PERF_MEM_EXT_OP_SIMD			0x5    /* SIMD */
> +#define PERF_MEM_EXT_OP_GCS			0x6    /* Guarded Control Stack */
> +#define PERF_MEM_EXT_OP_SHIFT			46
> +
>  #define PERF_MEM_S(a, s) \
>  	(((__u64)PERF_MEM_##a##_##s) << PERF_MEM_##a##_SHIFT)
>  
> 
> -- 
> 2.34.1
>