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[192.55.55.39]) by smtp.gmail.com with ESMTPSA id x21sm12505033pfn.164.2019.12.16.01.14.00 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 16 Dec 2019 01:14:03 -0800 (PST) From: =?utf-8?b?QmrDtnJuIFTDtnBlbA==?= To: daniel@iogearbox.net, ast@kernel.org, netdev@vger.kernel.org Cc: =?utf-8?b?QmrDtnJuIFTDtnBlbA==?= , linux-riscv@lists.infradead.org, bpf@vger.kernel.org, Luke Nelson , Xi Wang Subject: [PATCH bpf-next v2 4/9] riscv, bpf: add support for far jumps and exits Date: Mon, 16 Dec 2019 10:13:38 +0100 Message-Id: <20191216091343.23260-5-bjorn.topel@gmail.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20191216091343.23260-1-bjorn.topel@gmail.com> References: <20191216091343.23260-1-bjorn.topel@gmail.com> MIME-Version: 1.0 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org This commit add support for far (offset > 21b) jumps and exits. Reviewed-by: Luke Nelson Cc: Xi Wang Signed-off-by: Björn Töpel --- arch/riscv/net/bpf_jit_comp.c | 37 ++++++++++++++++------------------- 1 file changed, 17 insertions(+), 20 deletions(-) diff --git a/arch/riscv/net/bpf_jit_comp.c b/arch/riscv/net/bpf_jit_comp.c index c38c95df3440..2fc0f24ad30f 100644 --- a/arch/riscv/net/bpf_jit_comp.c +++ b/arch/riscv/net/bpf_jit_comp.c @@ -496,16 +496,6 @@ static int is_12b_check(int off, int insn) return 0; } -static int is_21b_check(int off, int insn) -{ - if (!is_21b_int(off)) { - pr_err("bpf-jit: insn=%d 21b < offset=%d not supported yet!\n", - insn, (int)off); - return -1; - } - return 0; -} - static void emit_imm(u8 rd, s64 val, struct rv_jit_context *ctx) { /* Note that the immediate from the add is sign-extended, @@ -820,6 +810,21 @@ static void emit_sext_32_rd(u8 *rd, struct rv_jit_context *ctx) *rd = RV_REG_T2; } +static void emit_jump_and_link(u8 rd, int rvoff, struct rv_jit_context *ctx) +{ + s64 upper, lower; + + if (is_21b_int(rvoff)) { + emit(rv_jal(rd, rvoff >> 1), ctx); + return; + } + + upper = (rvoff + (1 << 11)) >> 12; + lower = rvoff & 0xfff; + emit(rv_auipc(RV_REG_T1, upper), ctx); + emit(rv_jalr(rd, RV_REG_T1, lower), ctx); +} + static bool is_signed_bpf_cond(u8 cond) { return cond == BPF_JSGT || cond == BPF_JSLT || @@ -1101,13 +1106,7 @@ static int emit_insn(const struct bpf_insn *insn, struct rv_jit_context *ctx, /* JUMP off */ case BPF_JMP | BPF_JA: rvoff = rv_offset(i, off, ctx); - if (!is_21b_int(rvoff)) { - pr_err("bpf-jit: insn=%d offset=%d not supported yet!\n", - i, rvoff); - return -1; - } - - emit(rv_jal(RV_REG_ZERO, rvoff >> 1), ctx); + emit_jump_and_link(RV_REG_ZERO, rvoff, ctx); break; /* IF (dst COND src) JUMP off */ @@ -1245,9 +1244,7 @@ static int emit_insn(const struct bpf_insn *insn, struct rv_jit_context *ctx, break; rvoff = epilogue_offset(ctx); - if (is_21b_check(rvoff, i)) - return -1; - emit(rv_jal(RV_REG_ZERO, rvoff >> 1), ctx); + emit_jump_and_link(RV_REG_ZERO, rvoff, ctx); break; /* dst = imm64 */