Messages in this thread | | | Date | Tue, 27 Nov 2018 18:22:03 +0000 | From | Will Deacon <> | Subject | Re: [PATCH] arm64/bpf: use movn/movk/movk sequence to generate kernel addresses |
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Hi Ard,
On Fri, Nov 23, 2018 at 06:29:02PM +0100, Ard Biesheuvel wrote: > On arm64, all executable code is guaranteed to reside in the vmalloc > space (or the module space), and so jump targets will only use 48 > bits at most, and the remaining bits are guaranteed to be 0x1. > > This means we can generate an immediate jump address using a sequence > of one MOVN (move wide negated) and two MOVK instructions, where the > first one sets the lower 16 bits but also sets all top bits to 0x1. > > Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> > ---
Acked-by: Will Deacon <will.deacon@arm.com>
Denial, Alexei, shall I take this via arm64, or would you rather take it via davem?
Cheers,
Will
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