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| author | Björn Töpel <bjorn.topel@intel.com> | 2019-12-13 18:51:12 +0100 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2019-12-13 13:09:32 -0800 |
| commit | 116eb788f57c9c35c40b29cfaa2607020de99a84 (patch) | |
| tree | 607fdc7c30ce8dd968619afb8b90e2a980ae14ab /include/linux/bpf.h | |
| parent | e754f5a6e36b63d6732f52adcbe4c447fd66896f (diff) | |
| download | lwn-116eb788f57c9c35c40b29cfaa2607020de99a84.tar.gz lwn-116eb788f57c9c35c40b29cfaa2607020de99a84.zip | |
bpf, x86: Align dispatcher branch targets to 16B
>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
Diffstat (limited to 'include/linux/bpf.h')
| -rw-r--r-- | include/linux/bpf.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 5970989b99d1..d467983e61bb 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -471,7 +471,7 @@ struct bpf_trampoline { u64 selector; }; -#define BPF_DISPATCHER_MAX 64 /* Fits in 2048B */ +#define BPF_DISPATCHER_MAX 48 /* Fits in 2048B */ struct bpf_dispatcher_prog { struct bpf_prog *prog; |