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Date:   Mon, 16 Jan 2023 09:51:27 +0530
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Subject: Re: [RFC 0/4] perf tool: Fix non-".text" symbol resolution for kernel
 modules
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To:     acme@kernel.org
Cc:     jolsa@kernel.org, namhyung@kernel.org, irogers@google.com,
        kan.liang@linux.intel.com, peterz@infradead.org,
        mark.rutland@arm.com, mingo@redhat.com,
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        sandipan.das@amd.com, ananth.narayan@amd.com,
        santosh.shukla@amd.com, Ravi Bangoria <ravi.bangoria@amd.com>
References: <20230110055859.685-1-ravi.bangoria@amd.com>
From:   Ravi Bangoria <ravi.bangoria@amd.com>
In-Reply-To: <20230110055859.685-1-ravi.bangoria@amd.com>
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Hi all,

On 10-Jan-23 11:28 AM, Ravi Bangoria wrote:
> Kernel module elf contains executable code in non-".text" sections as
> well, for ex: ".noinstr.text". Plus, kernel module's memory layout
> differs from it's binary layout because .ko elf does not contain
> program header table.
> 
> Perf tries to solve it by creating special maps for allocated (SHF_ALLOC)
> elf sections, but perf uses elf addresses for map address range and thus
> these special maps remains unused because no real ip falls into their
> address range.
> 
> Solve this by preparing section specific special maps using addresses
> provided by sysfs /sys/module/.../sections/. Also save these details in
> PERF_RECORD_KMOD_SEC_MAP format in perf.data which can be consumed at
> perf-report time.

Do you guys feel this is worth to fix and I shall continue? Or --kcore /
--kallsyms workarounds are sufficient?

Thanks,
Ravi