Messages in this thread | | | Date | Tue, 11 Oct 2005 17:14:50 -0400 | From | Brian Gerst <> | Subject | Re: using segmentation in the kernel |
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Alon Bar-Lev wrote: > Brian Gerst wrote: > >> Jonathan M. McCune wrote: >> >>> Hello, >>> >> Why send the kernel back to the 2.0 days? There is no valid reason >> for doing this with they way x86 segmentation works, which is why it >> was done away with in 2.1. >> > > But with segmentation you can set code to be read-only, disallow > execution from stack, separate modules so that they will not affect > kernel and more... > > The main problem with segmentation is that it is x86 specific...
Too much pain for for not enough gain. Segments are not fine-grained enough to work well. Look at the PaX and execshield hacks for userspace. You are far better off working at the page-table level (RO and NX pages) which has the advantage of being portable.
-- Brian Gerst - 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/
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