Messages in this thread | | | Subject | Re: [PATCH] arm64/bpf: use movn/movk/movk sequence to generate kernel addresses | From | Daniel Borkmann <> | Date | Tue, 27 Nov 2018 19:24:40 +0100 |
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On 11/27/2018 07:22 PM, Will Deacon wrote: > 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?
Yeah we can take it via bpf trees, thanks.
Cheers, Daniel
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