bpf, x86: Align dispatcher branch targets to 16B

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>From Intel 64 and IA-32 Architectures Optimization Reference Manual,
3.4.1.4 Code Alignment, Assembly/Compiler Coding Rule 11: All branch
targets should be 16-byte aligned.

This commits aligns branch targets according to the Intel manual.

The nops used to align branch targets make the dispatcher larger, and
therefore the number of supported dispatch points/programs are
descreased from 64 to 48.

Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20191213175112.30208-7-bjorn.topel@gmail.com

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Björn Töpel 2019-12-13 18:51:12 +01:00 • committed by Alexei Starovoitov

parent e754f5a6e3

commit 116eb788f5

2 changed files with 30 additions and 2 deletions

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30

arch/x86/net/bpf_jit_comp.c

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2

include/linux/bpf.h

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