Messages in this thread | | | Date | Sat, 8 Sep 2007 00:39:50 +0200 | From | Andi Kleen <> | Subject | Re: [patch 3/8] Immediate Values - Kconfig menu in EMBEDDED |
| |
On Fri, Sep 07, 2007 at 08:46:48AM -0400, Mathieu Desnoyers wrote: > * Andi Kleen (andi@firstfloor.org) wrote: > > > +config IMMEDIATE > > > + default y if !DISABLE_IMMEDIATE > > > > It's still unclear to me why DISABLE_IMMEDIATE is needed. It would > > be better to make it just the default. > > > > It is actually the default on any non embedded configuration. Do you > think we should make it default to on on embedded configs too ?
I would prefer to not have any config options at all and let the non converted architectures always use a asm-generic fallback.
> The idea here is to give embedded system developers incentives to > create an optimized immediate value header for their architecture. I
Sounds like a quite bogus way to do this.
> fear that if it is not trivial to disable when they need to use ROM to > put the kernel code (as kprobes is, meaning, with a single config > option), they will refuse to event think about including an optimized > immediate value header for their architecture.
#ifdef CONFIG_ARCH_SPECIFIC_READONLY #include <asm-generic/generic-immediate.h> #else /* optimized implementation */ #endif
That's trivial.
> And yes, having a CONFIG_READ_ONLY_TEXT makes sense, but it implies > menu dependencies with not only immediate values but also kprobes, > paravirt, alternatives, (am I missing others ?)
paravirt and alternatives are x86 only.
I don't think CONFIG_READ_ONLY_TEXT on x86 makes sense.
On other architectures they have to deal with kprobes, but they presumably do this already. Not really your problem I suspect.
> As long as we find a way for people to disable _all_ code patching in > their kernel, I'm happy with that. But since every existing code > patching mechanism can currently be disabled one by one, it makes sense > to do the same for the immediate values. Having a global > CONFIG_READ_ONLY_TEXT should IMHO come in a separate effort.
You're clearly deep into overdesign territory here.
-Andi - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |