Messages in this thread | | | Date | Tue, 25 Oct 2022 19:26:20 +0100 | From | "Russell King (Oracle)" <> | Subject | Re: [PATCH 1/2] bitmap: add sanity check function for find_bit() |
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On Tue, Oct 25, 2022 at 10:11:51AM -0700, Yury Norov wrote: > ARMv6 may or may not support unaligned access depending on SCTLR.U > bit. This is what Russell was concerned about in the other email. > As far as I understand, linux enables that feature.
However, we still support ARMv5 and ARMv4, both of which _trap_ every unaligned access, which will make a findbit call with an unaligned pointer using word loads painfully expensive. This is the main reason we haven't used word loads in the findbit ops.
As mentioned, I have patches that do change that (and convert the thing to use assembly macros to make updates much easier.)
-- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!
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