Messages in this thread | | | Date | Tue, 1 Dec 2015 08:24:03 +0100 | From | Ingo Molnar <> | Subject | Re: [PATCH v2 1/4] init: create cmdline param to disable readonly |
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* Russell King - ARM Linux <linux@arm.linux.org.uk> wrote:
> On Mon, Nov 30, 2015 at 01:52:10PM -0800, Kees Cook wrote: > > On Wed, Nov 25, 2015 at 11:51 PM, Ingo Molnar <mingo@kernel.org> wrote: > > > * Kees Cook <keescook@chromium.org> wrote: > > >> +#ifdef CONFIG_DEBUG_RODATA > > > > > > Btw., could you please remove the Kconfig option altogether in an additional patch > > > and make read-only sections an always-on feature? It has been default-y for years > > > and all distros have it enabled. > > > > Yeah, this is something I've wanted to do for a while, but I would > > point out that only a few architectures have actually implemented it, > > and for arm and arm64 it was very recent: > > I don't think it can entirely be a kernel command line option. On ARM, > enabling DEBUG_RODATA has a substantial effect on the size of the kernel > image - we have to pad various sections to 1MB boundaries so we can > set the appropriate permissions. > > Forcing this layout on everyone won't work.
Yeah, so I'd suggest to have it always-on on x86 (after adding the boot option), to simplify the x86 code and to make it more obvious that we rely on this.
There's a moderate amount of #ifdeffery around this:
triton:~/tip> git grep -w CONFIG_DEBUG_RODATA arch/x86/ | grep \# | wc -l 15
Thanks,
Ingo
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