From patchwork Tue Jun 29 02:34:54 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: chenlifu X-Patchwork-Id: 12348869 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-17.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D716AC11F68 for ; Tue, 29 Jun 2021 02:36:13 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 9000A61D04 for ; Tue, 29 Jun 2021 02:36:13 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9000A61D04 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=huawei.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org 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:To :From:Reply-To:Cc:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References: List-Owner; bh=i0NTFi2aRUfQ7FcMYQyuMbasuoH/CCS/hUvv4a1cagQ=; b=hLA9u9Vd948BO+ TWcujrWMP5KblbF7Imt2mrMrzrUdfTPf8Atlld2tNbahY4N2R/NnS14RoonXUsYkzac9Pgz+TiXcO zCVo93cR3+CY7+GEV26b4i8hf+xspl4KCUkHhXstODjGcoWFVbSxthScot1tzIWpKvx/GEcaSYq1s 2+TcHLm9UY4J65m8DSSZsgibHwjCitIYlPsDLTf93E+Fam1pTC7HhIJSugmV0i1GBrjJ+o7nGN0P3 rb4YTiTOja78z2FR2NIOK5SnGWL8fK0WW4tsnDn8WRRMqDp5/8hZKMnGI9ThyF+uBSGIeNEkL4pOd n33Gx3Lpp2j1HIRcI9jA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1ly3bR-009d7d-Gh; Tue, 29 Jun 2021 02:35:57 +0000 Received: from szxga01-in.huawei.com ([45.249.212.187]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1ly3b2-009d5m-8B for linux-riscv@lists.infradead.org; Tue, 29 Jun 2021 02:35:34 +0000 Received: from dggemv711-chm.china.huawei.com (unknown [172.30.72.57]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4GDT2y1Qs2zXljJ; Tue, 29 Jun 2021 10:30:02 +0800 (CST) Received: from dggpemm500001.china.huawei.com (7.185.36.107) by dggemv711-chm.china.huawei.com (10.1.198.66) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2176.2; Tue, 29 Jun 2021 10:35:20 +0800 Received: from huawei.com (10.67.174.169) by dggpemm500001.china.huawei.com (7.185.36.107) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2176.2; Tue, 29 Jun 2021 10:35:19 +0800 From: Chen Lifu To: , , , , , , , , , Subject: [PATCH -next 1/2] riscv: implemented auipc simulate instruction Date: Tue, 29 Jun 2021 10:34:54 +0800 Message-ID: <20210629023455.280998-1-chenlifu@huawei.com> X-Mailer: git-send-email 2.32.0 MIME-Version: 1.0 X-Originating-IP: [10.67.174.169] X-ClientProxiedBy: dggems702-chm.china.huawei.com (10.3.19.179) To dggpemm500001.china.huawei.com (7.185.36.107) X-CFilter-Loop: Reflected X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210628_193532_687514_9E2CD8BE X-CRM114-Status: GOOD ( 13.75 ) 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 To test the kprobe-based event tracing, we prepare a kernel module 'kprobe_test.ko' to add the probes. The assembly codes (partially) of the module are as follows: ... 0000000000000000 : ... 0000000000000038 <.LVL1>: 38: 00000597 auipc a1,0x0 3c: 00058593 mv a1,a1 ... Test the kprobe-based event tracing in qemu-system-riscv64: First, install the kprobe test module: insmod /root/kprobe_test.ko Then, add a probe as a new event at an 'auipc' instruction, the following error occurs due to the instruction not allowed to probe yet: echo "p:auipc kprobe_test:kprobe_test_branch+0x38 epc=%epc opcode=+0(%epc):x32" >> /sys/kernel/debug/tracing/kprobe_events sh: write error: Invalid argument This patch implemented the 'auipc' simulate instruction and allowed to probe it. Merge this patch and perform the test again, the test results are as follows: First, add a probe at the 'auipc' instruction: echo "p:auipc kprobe_test:kprobe_test_branch+0x38 epc=%epc opcode=+0(%epc):x32" >> /sys/kernel/debug/tracing/kprobe_events echo 1 > /sys/kernel/debug/tracing/events/kprobes/auipc/enable Then, do something to run to the probe. After that, see the traced information: cat /sys/kernel/debug/tracing/trace sysctl-58 [001] d... 179.126350: auipc: (kprobe_test_branch+0x38/0x10e [kprobe_test]) epc=0xffffffff016122aa opcode=0x100073 Now we can see the traced information. The actual address of the symbol 'kprobe_test_branch' is as follows: cat /proc/kallsyms | grep kprobe_test_branch ffffffff01612272 t kprobe_test_branch [kprobe_test] Based on the traced information and the actual address of the symbol 'kprobe_test_branch', we can also see that the 'auipc' instruction has been replaced by 'ebreak(0x100073)' instruction. -------- Signed-off-by: Chen Lifu --- arch/riscv/kernel/probes/decode-insn.c | 2 +- arch/riscv/kernel/probes/simulate-insn.c | 34 ++++++++++++++++++++++++ 2 files changed, 35 insertions(+), 1 deletion(-) diff --git a/arch/riscv/kernel/probes/decode-insn.c b/arch/riscv/kernel/probes/decode-insn.c index 0ed043acc882..5eb03fb61450 100644 --- a/arch/riscv/kernel/probes/decode-insn.c +++ b/arch/riscv/kernel/probes/decode-insn.c @@ -38,11 +38,11 @@ riscv_probe_decode_insn(probe_opcode_t *addr, struct arch_probe_insn *api) RISCV_INSN_REJECTED(c_ebreak, insn); #endif - RISCV_INSN_REJECTED(auipc, insn); RISCV_INSN_REJECTED(branch, insn); RISCV_INSN_SET_SIMULATE(jal, insn); RISCV_INSN_SET_SIMULATE(jalr, insn); + RISCV_INSN_SET_SIMULATE(auipc, insn); return INSN_GOOD; } diff --git a/arch/riscv/kernel/probes/simulate-insn.c b/arch/riscv/kernel/probes/simulate-insn.c index 2519ce26377d..b81719522d5c 100644 --- a/arch/riscv/kernel/probes/simulate-insn.c +++ b/arch/riscv/kernel/probes/simulate-insn.c @@ -83,3 +83,37 @@ bool __kprobes simulate_jalr(u32 opcode, unsigned long addr, struct pt_regs *reg return ret; } + +#define auipc_rd_idx(opcode) \ + ((opcode >> 7) & 0x1f) + +#define auipc_imm(opcode) \ + ((((opcode) >> 12) & 0xfffff) << 12) + +#if __riscv_xlen == 64 +#define auipc_offset(opcode) sign_extend64(auipc_imm(opcode), 31) +#elif __riscv_xlen == 32 +#define auipc_offset(opcode) auipc_imm(opcode) +#else +#error "Unexpected __riscv_xlen" +#endif + +bool __kprobes simulate_auipc(u32 opcode, unsigned long addr, struct pt_regs *regs) +{ + /* + * auipc instruction: + * 31 12 11 7 6 0 + * | imm[31:12] | rd | opcode | + * 20 5 7 + */ + + u32 rd_idx = auipc_rd_idx(opcode); + unsigned long rd_val = addr + auipc_offset(opcode); + + if (!rv_insn_reg_set_val(regs, rd_idx, rd_val)) + return false; + + instruction_pointer_set(regs, addr + 4); + + return true; +}