Messages in this thread | | | Date | Tue, 30 Oct 2012 15:35:38 +0000 | Subject | Re: [PATCH] scripts/recordmcount.pl: Support build with -ffunction-sections. | From | Will Newton <> |
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On Tue, Oct 30, 2012 at 3:05 PM, Steven Rostedt <rostedt@goodmis.org> wrote: > On Tue, 2012-10-30 at 14:51 +0000, Will Newton wrote: >> Scan any text section whose name begins with ".text." so >> we will find all the functions in a kernel built with >> -ffunction-sections. > > A couple of things. > > First, I'm very paranoid about a blanket "ok" on sections. We must > guarantee that all sections that starts with ".text" never is freed. And > if it is freed, that it must inform ftrace that it's about to free it > before it does. If we can not guarantee this, then we can't do it.
I share that concern, however it looks like it should be safe. The two architectures in tree that enable -ffunction-sections by default are parisc and score and they both use a .text.* wildcard in their linker script. If the support for building with --gc-sections is ever completed then that would require -ffunction-sections and a similar wildcard to be applied to section names.
> Second, most archs today do not use recordmcount.pl. They use the new > recordmcount.c file.
Ok, thanks for letting me know. Is the plan to switch over to recordmcount.c exclusively at some point?
The following architectures have some support in recordmcount.c but do not enable it:
sh, powerpc, ia64
And the following have no support in recordmcount.c as yet:
blackfin, microblaze
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