Messages in this thread | | | Date | Tue, 5 Sep 2023 22:32:33 +0100 | From | "Russell King (Oracle)" <> | Subject | Re: [PATCH bpf-next 4/8] arm32, bpf: add support for unconditional bswap instruction |
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On Tue, Sep 05, 2023 at 09:06:17PM +0000, Puranjay Mohan wrote: > The cpuv4 added a new unconditional bswap instruction with following > behaviour: > > BPF_ALU64 | BPF_TO_LE | BPF_END with imm = 16/32/64 means: > dst = bswap16(dst) > dst = bswap32(dst) > dst = bswap64(dst) > > As we already support converting to big-endian from little-endian we can > use the same for unconditional bswap. > Since ARM32 is always little-endian, just treat the unconditional scenario
This is not true. Arm32 BPF is disabled for BE32 but not for BE8. It's entirely possible to build a kernel using BE8 for ARMv7 and have the BPF JIT enabled:
select HAVE_EBPF_JIT if !CPU_ENDIAN_BE32
So it's not true to say "Since ARM32 is always little-endian".
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