Messages in this thread | | | From | Roland McGrath <> | Subject | Re: [PATCH] x86: clean up vdso-layout.lds.S | Date | Tue, 9 Jun 2009 00:52:47 -0700 (PDT) |
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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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