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    SubjectRe: [PATCH] x86: clean up vdso-layout.lds.S
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    > > I am wondering why we need -P -C here - but we do not need it for lds.S files?
    > > Seems like something we could let go.

    AFAIK these only affect readability of the lds.s output files.
    The difference should be entirely cosmetic.

    > > > > .altinstructions : { *(.altinstructions) }
    > > > > @@ -43,9 +42,49 @@ SECTIONS
    > > > > */
    > > > > . = ALIGN(0x100);
    > >
    > > What is 0x100?
    >
    > Um. No idea. Roland, you added this line in commit
    > f6b46ebf904f69a73907a5e6b1ed2228e3f03d9e. Can you shed some light on
    > this magic constant?

    You mean this one:

    /*
    * Align the actual code well away from the non-instruction data.
    * This is the best thing for the I-cache.
    */
    . = ALIGN(0x100);

    Reading the comment might make it obvious that it's intended for optimal
    code alignment. I suspect someone at the time told me 256 is as big as an
    I-cache line was ever likely to get. You could use L1_CACHE_BYTES instead
    I suppose.

    > What would you expect? The linker script language is quite limited in
    > its capabilities... Best I could do is split the ".broken" section into
    > several sections and move the descriptions from the individual comments
    > above here. If this muckle of empty ".broken.*" sections gets correctly
    > discarded and triggers no bug in binutils, I can probably do it.

    Adding more sections and section names unnecessarily bloats the size of the
    vDSO image. Keep the set of output sections to the necessary minimum.


    Thanks,
    Roland


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