Messages in this thread | | | Date | Thu, 26 May 2022 15:23:51 -0300 | From | Arnaldo Carvalho de Melo <> | Subject | Re: [FYI PATCH 1/1] tools arch x86: Sync the msr-index.h copy with the kernel sources |
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Em Thu, May 26, 2022 at 04:50:47PM +0000, Luck, Tony escreveu: > Sorry for being part of the problem with this getting out of sync.
There is no problem to be sorry for :-) > But, remind me again why tools has *copies* of this and other files.
We used not to have copies, using kernel headers directly. From time to time tools/perf broke due to legitimate kernel hacking. At some point Linus complained about such direct usage. Then we adopted the current model.
The way these headers are used in perf are not restricted to just including them to compile something. There are, as described in the log message for this sync, scripts that convert defines into string tables, etc, so some change may break one of these scripts, or new MSRs may use some different #define pattern, etc.
Having the tools/perf/check-headers.sh script, part of building tools, point out new changes in the original files lets people check what happened and sometimes just do as I did, update. >o Seems like pointless work to keep them in sync.
I hope to have clarified.
- Arnaldo
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