From patchwork Tue Dec 6 09:14:10 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Pu Lehui X-Patchwork-Id: 13065584 X-Patchwork-Delegate: palmer@dabbelt.com Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 8BCBBC352A1 for ; Tue, 6 Dec 2022 09:13:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:Message-Id:Date:Subject:Cc :To:From:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References: List-Owner; bh=9nyHFKh6vy/78ucyvQtnqfnhRXC0S7qz70x8WMuHbrk=; b=x5oCMgJYl5foMK vNGGaWFLhS2I5tAZ/+ji02R8jZkdnfvZbmSXtCSngU9j+1/pR4/ZS5W7hEi/uGLYFq5Fb0ulHzUMb oewukxnsckKJ7sq+h+tReU4htfb5zy7tv13nklIdTMh9NLea9IVlreDTEn68CeblSvz2g8Sp1f8Nl HSL1WFtrZAQ+O8h3eGoUjWzgQQq/+LqognSvzgnBVt4q/Z/uOm0W/ndJ5qMU+KmjjW8RiBND1BhHv 7IQ/vEnBaxD1ng1H0diNH+IEg4KybQrDuPlBAf44gAGFnCNNtQsreBgJ3AHLQWcJKor/0Rl6HplGN 467We3TC87OsIydDHmwg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1p2U17-005ci5-8Q; Tue, 06 Dec 2022 09:13:33 +0000 Received: from dggsgout11.his.huawei.com ([45.249.212.51]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1p2U12-005cSc-5R for linux-riscv@lists.infradead.org; Tue, 06 Dec 2022 09:13:31 +0000 Received: from mail02.huawei.com (unknown [172.30.67.153]) by dggsgout11.his.huawei.com (SkyGuard) with ESMTP id 4NRF7x1tdJz4f3w0D for ; Tue, 6 Dec 2022 17:13:17 +0800 (CST) Received: from localhost.localdomain (unknown [10.67.175.61]) by APP4 (Coremail) with SMTP id gCh0CgCXCNavB49jTw3_Bg--.27878S2; Tue, 06 Dec 2022 17:13:20 +0800 (CST) From: Pu Lehui To: bpf@vger.kernel.org, linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org Cc: =?utf-8?b?QmrDtnJuIFTDtnBlbA==?= , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Martin KaFai Lau , Song Liu , Yonghong Song , John Fastabend , KP Singh , Stanislav Fomichev , Hao Luo , Jiri Olsa , Paul Walmsley , Palmer Dabbelt , Albert Ou , Pu Lehui , Pu Lehui Subject: [PATCH bpf v3] riscv, bpf: Emit fixed-length instructions for BPF_PSEUDO_FUNC Date: Tue, 6 Dec 2022 17:14:10 +0800 Message-Id: <20221206091410.1584784-1-pulehui@huaweicloud.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 X-CM-TRANSID: gCh0CgCXCNavB49jTw3_Bg--.27878S2 X-Coremail-Antispam: 1UD129KBjvJXoW7CFy5AFyxuryDur4UAryxZrb_yoW8uFW5pF ZxGrn3CFWvqr1fGr13tF1jqr1SkF4vqFWfKry7G3y5J3ZIqwsF93Z8Gw4jyas8Zry8Gr15 JFWjkF98ua4Dta7anT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUvF14x267AKxVW5JVWrJwAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2ocxC64kIII0Yj41l84x0c7CEw4AK67xGY2AK02 1l84ACjcxK6xIIjxv20xvE14v26w1j6s0DM28EF7xvwVC0I7IYx2IY6xkF7I0E14v26r4U JVWxJr1l84ACjcxK6I8E87Iv67AKxVW0oVCq3wA2z4x0Y4vEx4A2jsIEc7CjxVAFwI0_Gc CE3s1le2I262IYc4CY6c8Ij28IcVAaY2xG8wAqx4xG64xvF2IEw4CE5I8CrVC2j2WlYx0E 2Ix0cI8IcVAFwI0_Jr0_Jr4lYx0Ex4A2jsIE14v26r1j6r4UMcvjeVCFs4IE7xkEbVWUJV W8JwACjcxG0xvY0x0EwIxGrwACjI8F5VA0II8E6IAqYI8I648v4I1lFIxGxcIEc7CjxVA2 Y2ka0xkIwI1l42xK82IYc2Ij64vIr41l4I8I3I0E4IkC6x0Yz7v_Jr0_Gr1lx2IqxVAqx4 xG67AKxVWUJVWUGwC20s026x8GjcxK67AKxVWUGVWUWwC2zVAF1VAY17CE14v26r4a6rW5 MIIYrxkI7VAKI48JMIIF0xvE2Ix0cI8IcVAFwI0_Jr0_JF4lIxAIcVC0I7IYx2IY6xkF7I 0E14v26r4j6F4UMIIF0xvE42xK8VAvwI8IcIk0rVWrJr0_WFyUJwCI42IY6I8E87Iv67AK xVWUJVW8JwCI42IY6I8E87Iv6xkF7I0E14v26r4j6r4UJbIYCTnIWIevJa73UjIFyTuYvj fUOmhFUUUUU X-CM-SenderInfo: psxovxtxl6x35dzhxuhorxvhhfrp/ X-CFilter-Loop: Reflected X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20221206_011328_564915_7E8E45A4 X-CRM114-Status: UNSURE ( 9.93 ) X-CRM114-Notice: Please train this message. X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org From: Pu Lehui For BPF_PSEUDO_FUNC instruction, verifier will refill imm with correct addresses of bpf_calls and then run last pass of JIT. Since the emit_imm of RV64 is variable-length, which will emit appropriate length instructions accorroding to the imm, it may broke ctx->offset, and lead to unpredictable problem, such as inaccurate jump. So let's fix it with fixed-length instructions. Fixes: 69c087ba6225 ("bpf: Add bpf_for_each_map_elem() helper") Signed-off-by: Pu Lehui Suggested-by: Björn Töpel Acked-by: Björn Töpel Reviewed-by: Björn Töpel --- arch/riscv/net/bpf_jit_comp64.c | 29 ++++++++++++++++++++++++++++- 1 file changed, 28 insertions(+), 1 deletion(-) diff --git a/arch/riscv/net/bpf_jit_comp64.c b/arch/riscv/net/bpf_jit_comp64.c index 89744dbd6d86..2f6207b72e12 100644 --- a/arch/riscv/net/bpf_jit_comp64.c +++ b/arch/riscv/net/bpf_jit_comp64.c @@ -139,6 +139,25 @@ static bool in_auipc_jalr_range(s64 val) val < ((1L << 31) - (1L << 11)); } +/* Emit fixed-length instructions for address */ +static int emit_addr(u8 rd, u64 addr, bool extra_pass, struct rv_jit_context *ctx) +{ + u64 ip = (u64)(ctx->insns + ctx->ninsns); + s64 off = addr - ip; + s64 upper = (off + (1 << 11)) >> 12; + s64 lower = off & 0xfff; + + if (extra_pass && !in_auipc_jalr_range(off)) { + pr_err("bpf-jit: target offset 0x%llx is out of range\n", off); + return -ERANGE; + } + + emit(rv_auipc(rd, upper), ctx); + emit(rv_addi(rd, rd, lower), ctx); + return 0; +} + +/* Emit variable-length instructions for 32-bit and 64-bit imm */ static void emit_imm(u8 rd, s64 val, struct rv_jit_context *ctx) { /* Note that the immediate from the add is sign-extended, @@ -1053,7 +1072,15 @@ int bpf_jit_emit_insn(const struct bpf_insn *insn, struct rv_jit_context *ctx, u64 imm64; imm64 = (u64)insn1.imm << 32 | (u32)imm; - emit_imm(rd, imm64, ctx); + if (bpf_pseudo_func(insn)) { + /* fixed-length insns for extra jit pass */ + ret = emit_addr(rd, imm64, extra_pass, ctx); + if (ret) + return ret; + } else { + emit_imm(rd, imm64, ctx); + } + return 1; }