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[73.53.94.119]) by smtp.gmail.com with ESMTPSA id u3sm133912pfn.217.2020.05.05.17.03.31 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 05 May 2020 17:03:32 -0700 (PDT) From: Luke Nelson X-Google-Original-From: Luke Nelson To: bpf@vger.kernel.org Cc: Luke Nelson , Xi Wang , =?utf-8?b?QmrDtnJuIFTDtnBlbA==?= , Paul Walmsley , Palmer Dabbelt , Albert Ou , Alexei Starovoitov , Daniel Borkmann , Martin KaFai Lau , Song Liu , Yonghong Song , Andrii Nakryiko , John Fastabend , KP Singh , netdev@vger.kernel.org, linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH bpf-next 2/4] bpf, riscv: Optimize FROM_LE using verifier_zext on RV64 Date: Tue, 5 May 2020 17:03:18 -0700 Message-Id: <20200506000320.28965-3-luke.r.nels@gmail.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200506000320.28965-1-luke.r.nels@gmail.com> References: <20200506000320.28965-1-luke.r.nels@gmail.com> Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org This patch adds two optimizations for BPF_ALU BPF_END BPF_FROM_LE in the RV64 BPF JIT. First, it enables the verifier zero-extension optimization to avoid zero extension when imm == 32. Second, it avoids generating code for imm == 64, since it is equivalent to a no-op. Co-developed-by: Xi Wang Signed-off-by: Xi Wang Signed-off-by: Luke Nelson --- arch/riscv/net/bpf_jit_comp64.c | 20 ++++++++++++++------ 1 file changed, 14 insertions(+), 6 deletions(-) diff --git a/arch/riscv/net/bpf_jit_comp64.c b/arch/riscv/net/bpf_jit_comp64.c index e2636902a74e..c3ce9a911b66 100644 --- a/arch/riscv/net/bpf_jit_comp64.c +++ b/arch/riscv/net/bpf_jit_comp64.c @@ -542,13 +542,21 @@ int bpf_jit_emit_insn(const struct bpf_insn *insn, struct rv_jit_context *ctx, /* dst = BSWAP##imm(dst) */ case BPF_ALU | BPF_END | BPF_FROM_LE: - { - int shift = 64 - imm; - - emit(rv_slli(rd, rd, shift), ctx); - emit(rv_srli(rd, rd, shift), ctx); + switch (imm) { + case 16: + emit(rv_slli(rd, rd, 48), ctx); + emit(rv_srli(rd, rd, 48), ctx); + break; + case 32: + if (!aux->verifier_zext) + emit_zext_32(rd, ctx); + break; + case 64: + /* Do nothing */ + break; + } break; - } + case BPF_ALU | BPF_END | BPF_FROM_BE: emit(rv_addi(RV_REG_T2, RV_REG_ZERO, 0), ctx);