Messages in this thread | | | Subject | Re: [PATCH 0/3] arm64: cpufeature: Add filter function to control | From | Srinivas Ramana <> | Date | Wed, 13 Jan 2021 23:15:47 -0800 |
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Hi Marc,
On 1/11/2021 5:40 AM, Marc Zyngier wrote: > 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 for sending this series. It seems to be more flexible compared you what we did. Following your discussion on allowing EXACT ftr_reg values.
Btw, do you have plan to add MTE in similar lines to control the feature? We may be needing this on some systems. > > Thanks, > > M. > > [1] https://lore.kernel.org/r/20210111132811.2455113-1-maz@kernel.org
Thanks,
-- Srinivas R
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