Messages in this thread | | | Date | Mon, 11 Jan 2021 13:40:48 +0000 | From | Marc Zyngier <> | Subject | Re: [PATCH 0/3] arm64: cpufeature: Add filter function to control |
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Hi Srinivas,
On 2021-01-09 00:29, Srinivas Ramana wrote: > This patchset adds a control function for cpufeature framework > so that the feature can be controlled at runtime. > > Defer PAC on boot core and use the filter function added to disable > PAC from command line. This will help toggling the feature on systems > that do not support PAC or where PAC needs to be disabled at runtime, > without modifying the core kernel. > > The idea of adding the filter function for cpufeature is taken from > https://lore.kernel.org/linux-arm-kernel/20200515171612.1020-25-catalin.marinas@arm.com/ > https://lore.kernel.org/linux-arm-kernel/20200515171612.1020-24-catalin.marinas@arm.com/ > > Srinivas Ramana (3): > arm64: Defer enabling pointer authentication on boot core > arm64: cpufeature: Add a filter function to cpufeature > arm64: Enable control of pointer authentication using early param > > Documentation/admin-guide/kernel-parameters.txt | 6 +++ > arch/arm64/include/asm/cpufeature.h | 8 +++- > arch/arm64/include/asm/pointer_auth.h | 10 +++++ > arch/arm64/include/asm/stackprotector.h | 1 + > arch/arm64/kernel/cpufeature.c | 53 > +++++++++++++++++++------ > arch/arm64/kernel/head.S | 4 -- > 6 files changed, 64 insertions(+), 18 deletions(-)
I've been working for some time on a similar series to allow a feature set to be disabled during the early boot phase, initially to prevent booting a kernel with VHE, but the mechanism is generic enough to deal with most architectural features.
I took the liberty to lift your first patch and to add it to my series[1], further allowing PAuth to be disabled at boot time on top of BTI and VHE.
I'd appreciate your comments on this.
Thanks,
M.
[1] https://lore.kernel.org/r/20210111132811.2455113-1-maz@kernel.org -- Jazz is not dead. It just smells funny...
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