bpf, arm64: Optimize BPF store/load using str/ldr with immediate offset #2697
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The current BPF store/load instruction is translated by the JIT into two instructions. The first instruction moves the immediate offset into a temporary register. The second instruction uses this temporary register to do the real store/load. In fact, arm64 supports addressing with immediate offsets. So This patch introduces optimization that uses arm64 str/ldr instruction with immediate offset when the offset fits. Example of generated instuction for r2 = *(u64 *)(r1 + 0): without optimization: mov x10, 0 ldr x1, [x0, x10] with optimization: ldr x1, [x0, 0] If the offset is negative, or is not aligned correctly, or exceeds max value, rollback to the use of temporary register. Result for test_bpf: # dmesg -D # insmod test_bpf.ko # dmesg | grep Summary test_bpf: Summary: 1009 PASSED, 0 FAILED, [997/997 JIT'ed] test_bpf: test_tail_calls: Summary: 8 PASSED, 0 FAILED, [8/8 JIT'ed] test_bpf: test_skb_segment: Summary: 2 PASSED, 0 FAILED Signed-off-by: Xu Kuohai <xukuohai@huawei.com>
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At least one diff in series https://patchwork.kernel.org/project/netdevbpf/list/?series=623094 expired. Closing PR. |
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Pull request for series with
subject: bpf, arm64: Optimize BPF store/load using str/ldr with immediate offset
version: 1
url: https://patchwork.kernel.org/project/netdevbpf/list/?series=622651