Re: [PATCH v4 5/6] perf arm_spe: Decode Arm N1 IMPDEF events

[sashiko-bot@kernel.org]

Sashiko AI review found 1 potential issue(s):
- [Low] The relative include path `#include "../../arm64/include/asm/cputype.h"` is invalid and relies on accidental directory traversal through a compiler `-I` flag.
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commit 7fc153524fe60dc6d6f08fd73b7ea3f46e904e39
Author: James Clark <james.clark@linaro.org>

perf arm_spe: Decode Arm N1 IMPDEF events

This commit adds a framework to decode the N1 IMPDEF event for Arm SPE, 
which isn't covered by the common list. It also increases the packet 
description buffer size to accommodate more strings without falling back 
to a hex dump.

Link: https://developer.arm.com/documentation/100616/0401/Statistical-Profiling-Extension/implementation-defined-features-of-SPE

> diff --git a/tools/perf/util/arm-spe-decoder/Build b/tools/perf/util/arm-spe-decoder/Build
> index ab500e0efe244..97a298d1e2791 100644
> --- a/tools/perf/util/arm-spe-decoder/Build
> +++ b/tools/perf/util/arm-spe-decoder/Build
> @@ -1 +1,3 @@
>  perf-util-y += arm-spe-pkt-decoder.o arm-spe-decoder.o
> +
> +CFLAGS_arm-spe-pkt-decoder.o += -I$(srctree)/tools/arch/arm64/include/ -I$(OUTPUT)arch/arm64/include/generated/

[ ... ]

> diff --git a/tools/perf/util/arm-spe-decoder/arm-spe-pkt-decoder.c b/tools/perf/util/arm-spe-decoder/arm-spe-pkt-decoder.c
> index 67ca356100e53..b74f887a48f2a 100644
> --- a/tools/perf/util/arm-spe-decoder/arm-spe-pkt-decoder.c
> +++ b/tools/perf/util/arm-spe-decoder/arm-spe-pkt-decoder.c
> @@ -15,6 +15,8 @@
>  
>  #include "arm-spe-pkt-decoder.h"
>  
> +#include "../../arm64/include/asm/cputype.h"

Is this relative include path correct?

It looks like this file is located in tools/perf/util/arm-spe-decoder/, so
the relative path resolves to tools/perf/arm64/include/asm/cputype.h,
which doesn't exist.

It seems this only compiles because the newly added -I flag in the Build
file causes the preprocessor to resolve the include relative to
tools/arch/arm64/include/. The path then inadvertently evaluates back to the
correct file by traversing backwards out of the include directory and diving
back in.

Could this be made less brittle by relying directly on the include flag,
using #include <asm/cputype.h> instead?

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Sashiko AI review · https://sashiko.dev/#/patchset/20260414-james-spe-impdef-decode-v4-0-1dd30783a33b@linaro.org?part=5