From patchwork Sun Mar 24 10:33:06 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Pu Lehui X-Patchwork-Id: 13600793 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 7A7BACD11BF for ; Sun, 24 Mar 2024 10:32:32 +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; 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Sun, 24 Mar 2024 18:31:53 +0800 (CST) Received: from ultra.huawei.com (unknown [10.90.53.71]) by APP3 (Coremail) with SMTP id _Ch0CgAXI5sXAQBmLI08Hw--.23015S2; Sun, 24 Mar 2024 18:31:53 +0800 (CST) From: Pu Lehui To: bpf@vger.kernel.org, linux-riscv@lists.infradead.org, netdev@vger.kernel.org Cc: =?utf-8?b?QmrDtnJuIFTDtnBlbA==?= , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Martin KaFai Lau , Eduard Zingerman , Song Liu , Yonghong Song , John Fastabend , KP Singh , Stanislav Fomichev , Hao Luo , Jiri Olsa , Palmer Dabbelt , Luke Nelson , Pu Lehui , Pu Lehui Subject: [PATCH bpf] riscv, bpf: Fix kfunc parameters incompatibility between bpf and riscv abi Date: Sun, 24 Mar 2024 10:33:06 +0000 Message-Id: <20240324103306.2202954-1-pulehui@huaweicloud.com> X-Mailer: git-send-email 2.34.1 MIME-Version: 1.0 X-CM-TRANSID: _Ch0CgAXI5sXAQBmLI08Hw--.23015S2 X-Coremail-Antispam: 1UD129KBjvJXoW7WrW5Xw13GF13Xr48uw4kJFb_yoW8tFy5pF 45Gr1Ykr4kXw1xZrnayF48Jr1fCr4v9a1avFyxWFy5GrZFgay5Jr4Yk3yYva45Cr15Wa4a yrWDWrn0k34kA3DanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUv014x267AKxVW5JVWrJwAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2ocxC64kIII0Yj41l84x0c7CEw4AK67xGY2AK02 1l84ACjcxK6xIIjxv20xvE14v26ryj6F1UM28EF7xvwVC0I7IYx2IY6xkF7I0E14v26F4j 6r4UJwA2z4x0Y4vEx4A2jsIE14v26rxl6s0DM28EF7xvwVC2z280aVCY1x0267AKxVW0oV Cq3wAS0I0E0xvYzxvE52x082IY62kv0487Mc02F40EFcxC0VAKzVAqx4xG6I80ewAv7VC0 I7IYx2IY67AKxVWUJVWUGwAv7VC2z280aVAFwI0_Jr0_Gr1lOx8S6xCaFVCjc4AY6r1j6r 4UM4x0Y48IcxkI7VAKI48JM4x0x7Aq67IIx4CEVc8vx2IErcIFxwACI402YVCY1x02628v n2kIc2xKxwCF04k20xvY0x0EwIxGrwCFx2IqxVCFs4IE7xkEbVWUJVW8JwC20s026c02F4 0E14v26r1j6r18MI8I3I0E7480Y4vE14v26r106r1rMI8E67AF67kF1VAFwI0_GFv_Wryl IxkGc2Ij64vIr41lIxAIcVC0I7IYx2IY67AKxVWUJVWUCwCI42IY6xIIjxv20xvEc7CjxV AFwI0_Gr0_Cr1lIxAIcVCF04k26cxKx2IYs7xG6rW3Jr0E3s1lIxAIcVC2z280aVAFwI0_ Jr0_Gr1lIxAIcVC2z280aVCY1x0267AKxVW8JVW8JrUvcSsGvfC2KfnxnUUI43ZEXa7VUb QVy7UUUUU== X-CM-SenderInfo: psxovxtxl6x35dzhxuhorxvhhfrp/ X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240324_033210_509307_1DBDEE19 X-CRM114-Status: GOOD ( 11.45 ) 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 We encountered a failing case when running selftest in no_alu32 mode: The failure case is `kfunc_call/kfunc_call_test4` and its source code is like bellow: ``` long bpf_kfunc_call_test4(signed char a, short b, int c, long d) __ksym; int kfunc_call_test4(struct __sk_buff *skb) { ... tmp = bpf_kfunc_call_test4(-3, -30, -200, -1000); ... } ``` And its corresponding asm code is: ``` 0: r1 = -3 1: r2 = -30 2: r3 = 0xffffff38 # opcode: 18 03 00 00 38 ff ff ff 00 00 00 00 00 00 00 00 4: r4 = -1000 5: call bpf_kfunc_call_test4 ``` insn 2 is parsed to ld_imm64 insn to emit 0x00000000ffffff38 imm, and converted to int type and then send to bpf_kfunc_call_test4. But since it is zero-extended in the bpf calling convention, riscv jit will directly treat it as an unsigned 32-bit int value, and then fails with the message "actual 4294966063 != expected -1234". The reason is the incompatibility between bpf and riscv abi, that is, bpf will do zero-extension on uint, but riscv64 requires sign-extension on int or uint. We can solve this problem by sign extending the 32-bit parameters in kfunc. The issue is related to [0], and thanks to Yonghong and Alexei. Link: https://github.com/llvm/llvm-project/pull/84874 [0] Fixes: d40c3847b485 ("riscv, bpf: Add kfunc support for RV64") Signed-off-by: Pu Lehui Tested-by: Puranjay Mohan Reviewed-by: Puranjay Mohan --- arch/riscv/net/bpf_jit_comp64.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/arch/riscv/net/bpf_jit_comp64.c b/arch/riscv/net/bpf_jit_comp64.c index 869e4282a2c4..e3fc39370f7d 100644 --- a/arch/riscv/net/bpf_jit_comp64.c +++ b/arch/riscv/net/bpf_jit_comp64.c @@ -1454,6 +1454,22 @@ int bpf_jit_emit_insn(const struct bpf_insn *insn, struct rv_jit_context *ctx, if (ret < 0) return ret; + if (insn->src_reg == BPF_PSEUDO_KFUNC_CALL) { + const struct btf_func_model *fm; + int idx; + + fm = bpf_jit_find_kfunc_model(ctx->prog, insn); + if (!fm) + return -EINVAL; + + for (idx = 0; idx < fm->nr_args; idx++) { + u8 reg = bpf_to_rv_reg(BPF_REG_1 + idx, ctx); + + if (fm->arg_size[idx] == sizeof(int)) + emit_sextw(reg, reg, ctx); + } + } + ret = emit_call(addr, fixed_addr, ctx); if (ret) return ret;