Messages in this thread | | | Date | Thu, 28 Oct 2021 12:36:58 -0700 | From | Pawan Gupta <> | Subject | Re: [PATCH v2 1/2] arch/Kconfig: Make CONFIG_CPU_SPECTRE available for all architectures |
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On 28.10.2021 14:49, Mark Rutland wrote: >On Wed, Oct 27, 2021 at 06:33:22PM -0700, Pawan Gupta wrote: >> Borrow CONFIG_CPU_SPECTRE from ARM to be available for all >> architectures. This will help in configuration of features that depend >> on CPU being affected by spectre class of vulnerabilities. >> >> Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com> > >Given that spectre isn't one specific issue, biut rather a blanket term >for a bunch of things that can have variable overlap, I don't think this >makes much sense unless we're going to add finer-grained options for all >the variants, and IMO it'd make more sene for the architectures to >directly select the things that'd otherwise be dependent on this.
Isn't ARM already using CPU_SPECTRE for selecting things:
config HARDEN_BRANCH_PREDICTOR bool "Harden the branch predictor against aliasing attacks" if EXPERT depends on CPU_SPECTRE
This was the whole motivation for doing the same for x86.
Adding a condition for all architectures is also okay, but its going to a little messier:
config BPF_UNPRIV_DEFAULT_OFF default y if X86 || ARM || ...
This approach would make sense if architectures wants to explicitly select the defaults irrespective of architecture being affected by spectre.
If that's the case I will change the BPF_UNPRIV_DEFAULT_OFF default to depend on architecture. I hope BPF maintainer, Daniel is okay with it?
Pawan
Added BPF maintainers and bpf@vger to cc.
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