From nobody Mon Sep 28 00:32:39 2026 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=pass(p=none dis=none) header.from=gmail.com ARC-Seal: i=1; a=rsa-sha256; t=1786979273; cv=none; d=zohomail.com; s=zohoarc; b=Ou0hrwJk0R7bGDdl35IvtkudCOwRcmADTwpCiBOhz1s87IeZBNzjrqoPxfKDxPctzf7Fp7mefQgu/dyWusE792REtdm5zbFkJh0BrnEmdgfXDLk6QkuOa0NZSYQs9KO3fybhU1QNR4dOrSxf9RbPCnW08IRs5M3T/MLB+EdL5Oo= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1786979273; h=Content-Type:Content-Transfer-Encoding:Cc:Cc:Date:Date:From:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:MIME-Version:Message-ID:References:Sender:Subject:Subject:To:To:Message-Id:Reply-To; bh=fCaHWbms7VaX0C/pMvmFI1FBXC/InNuvtdmBCbbe3tQ=; b=UjrHyOweV1AyGORDwxLqfv08AlCTDX4r+thntcbLdl/CcvPHSidiDy/IjisroDspdcV3e0Wg9vEEdDzHnE8WcFix6HPGKyFIBu8BMroXtXg/Bub15xepHEypSP3/wCcdSxgkxtF2M1kaakG57nLKql2psTzdWAjC441UC41UOU4= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=pass header.from= (p=none dis=none) Return-Path: Received: from lists1p.gnu.org (lists1p.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1786979273621238.06481973825385; Mon, 17 Aug 2026 08:07:53 -0700 (PDT) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists1p.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1wvyvq-00048v-Gi; Mon, 17 Aug 2026 11:07:22 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists1p.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1wvyvo-00048I-PW for qemu-devel@nongnu.org; Mon, 17 Aug 2026 11:07:20 -0400 Received: from mail-pf1-x431.google.com ([2607:f8b0:4864:20::431]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1wvyvm-0007JI-R9 for qemu-devel@nongnu.org; Mon, 17 Aug 2026 11:07:20 -0400 Received: by mail-pf1-x431.google.com with SMTP id d2e1a72fcca58-848643382fcso3637742b3a.1 for ; Mon, 17 Aug 2026 08:07:18 -0700 (PDT) Received: from X1 ([178.66.48.90]) by smtp.gmail.com with ESMTPSA id 41be03b00d2f7-cc13bf05584sm900775a12.4.2026.08.17.08.07.13 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 17 Aug 2026 08:07:16 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1786979237; x=1787584037; darn=nongnu.org; h=content-transfer-encoding:content-type:mime-version:references :in-reply-to:message-id:date:subject:cc:to:from:from:to:cc:subject :date:message-id:reply-to:content-type; bh=fCaHWbms7VaX0C/pMvmFI1FBXC/InNuvtdmBCbbe3tQ=; b=N+hjZ7hK5mKp0guDTB8wpks/yFH2rwZyEur0hw4mjTJYrUy8VVAssA++CuLyUEElNk vvV8qHhTTquvHiG9mCe/IyCQmDvcn85qQMbUBcEZVaOfoLudHCzgx135dtJPHyC7Ql7X JfF4La1QDwAmf3FnUVtrreI6VhS6JpxhGbsPybCALyTyUoUUlYdF0SObweNc4tOlVigu njVtWKBUD7eYDxCHUYL32ZZM3MVj9oQFtgfoC81oskIhINRApx/A3lWP60XIeHoCU95r sP835RqMxAvUhDRji9fY0MJ61gpwBt4sq3q9/BP+bUpERqJb6gzAkHcVx1Egs16R5HJ5 baYg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1786979237; x=1787584037; h=content-transfer-encoding:content-type:mime-version:references :in-reply-to:message-id:date:subject:cc:to:from:x-gm-gg :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to :content-type; bh=fCaHWbms7VaX0C/pMvmFI1FBXC/InNuvtdmBCbbe3tQ=; b=e6IVPcwi5YKkaP9QaGsji1kKSXeP9i24KTh+mpa5yJc5dnhjaNENQmrQ89AJC11KDy DFRbNFkSgNXOIQlCNv1u2QMWm+OSM7dkdmmYCqIxYesmU1zscSgcROw6SrO4YM5Zfcng d+41xofoMyl4RV9kS4TCvlRCy5ud0PZOYAAmoB6vVkiGIHQFwWtxToDAmZqyPbY+e2KW XE6tpSO6aetcFH11Zm197gv2YFVGhsG5hSo/svkjnoue8Gxd3BJ6p1PeeWaTlcXHMduv xfFv2qaATFQEvS5GkSviA66AeGFr2+fjFWeVTo4eXzmWhi5aEe6wvx4v+Df5uYqGtZgV LivA== X-Gm-Message-State: AOJu0Yy/RvqxLhvksVcS60lUMsvfUGNkTr7NEMEk6MXRo8mJwYz38L9O TvbwIWYejoe31VSAPRJa4Ts2pMZ9Z9r40i3/AJrXLuqsOp6WVq5tzJ+XEvC0S/WOnY3W7g== X-Gm-Gg: AR+sD13fpvwFA3ymnAG1rckAV8brcu7q+N2tUIyRpvLAcVXoCHhES8Y2W56aMZSVoZU u3ACMniCSQpsugz/qJEBEoREeHHG0WRxgXuUGKQLxZ3g8PTzBbi9RrkIIbuuGoLfdNJBXc/3jk9 ZlkcwODIZzsVRTfHGAoLg4TaKIh5CCAdG4EDbKh4A8NacFZZNuY3Bpf5hlOA71nngZJJqN1SAE8 Gz20oRDeEK7x2SM9X79cci8Y7BKnEy2MLxbjwRhQuJtpRf1y5IwMqsrhTje3y9I//228zLnAItV 0CeAjy3YMf/l2+3MgNoaGWGe/LpsUd6LunMcJlI+Aav2/yh8aBZ4+HOJ5WR7uAch+Is4mZr//J8 8pMu4vJAOEH5SWihwkKFNyEwhLhi/QwHA8TGXTtv0YQN8Pgu3ujwDZ0n22XU9OXtl2019AbaKAM 7vht1YjXzeKCzZ4KNSOcFDzq/yUlO53Lkcrah7XVmLKjA= X-Received: by 2002:a05:6a00:14cd:b0:848:5ed6:9d27 with SMTP id d2e1a72fcca58-851b892181emr1195013b3a.36.1786979236990; Mon, 17 Aug 2026 08:07:16 -0700 (PDT) From: Vladimir Isaev To: qemu-devel@nongnu.org Cc: palmer@dabbelt.com, alistair.francis@wdc.com, liwei1518@gmail.com, daniel.barboza@oss.qualcomm.com, zhiwei_liu@linux.alibaba.com, chao.liu@processmission.com, qemu-riscv@nongnu.org, joel@jms.id.au, npiggin@gmail.com, Vladimir Isaev Subject: [PATCH v2 1/2] riscv: csr: do not drop C bit on misa write Date: Mon, 17 Aug 2026 18:06:37 +0300 Message-ID: <20260817150653.40357-2-vvisaev@gmail.com> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260817150653.40357-1-vvisaev@gmail.com> References: <20260817150653.40357-1-vvisaev@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists1p.gnu.org; Received-SPF: pass client-ip=2607:f8b0:4864:20::431; envelope-from=vvisaev@gmail.com; helo=mail-pf1-x431.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, FREEMAIL_FROM=0.001, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: qemu development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer=patchew.org@nongnu.org X-ZohoMail-DKIM: pass (identity @gmail.com) X-ZM-MESSAGEID: 1786979274638158500 According to spec: > Writing misa may increase IALIGN, e.g., by disabling the "C" extension. > If an instruction that would write misa increases IALIGN, and the > subsequent instruction=E2=80=99s address is not IALIGN-bit aligned, the > write to misa is suppressed, leaving misa unchanged. So attempt to disable C extension if next instruction is not aligned should= not change the misa. Reviewed-by: Alistair Francis Signed-off-by: Vladimir Isaev Reviewed-by: Chao Liu --- target/riscv/tcg/csr.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/target/riscv/tcg/csr.c b/target/riscv/tcg/csr.c index 36f2004bc5..dbfb3381ef 100644 --- a/target/riscv/tcg/csr.c +++ b/target/riscv/tcg/csr.c @@ -2182,9 +2182,13 @@ static RISCVException write_misa(CPURISCVState *env,= int csrno, /* Mask extensions that are not supported by this hart */ val &=3D env->misa_ext_mask; =20 - /* Suppress 'C' if next instruction is not aligned. */ - if ((val & RVC) && (get_next_pc(env, ra) & 3) !=3D 0) { - val &=3D ~RVC; + /* drop write if RVC is cleared and next instruction is not aligned */ + if ((env->misa_ext & RVC) && !(val & RVC) && + (get_next_pc(env, ra) & 3) !=3D 0) { + qemu_log_mask(LOG_GUEST_ERROR, "Unable to write MISA ext value " + "0x%x, MISA.C disable failed\n", env->misa_ext); + + return RISCV_EXCP_NONE; } =20 /* Disable RVG if any of its dependencies are disabled */ --=20 2.55.0 From nobody Mon Sep 28 00:32:39 2026 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=pass(p=none dis=none) header.from=gmail.com ARC-Seal: i=1; a=rsa-sha256; t=1786979291; cv=none; d=zohomail.com; s=zohoarc; b=OhwojpO5RCFZZM/NyXPUITznyj0h0eSxkAimStaEUueDXmjWWpDFaYbxhDSdEduP2NoRZFl4BhhzPfUmkiUUG7qeZIgdZ/9SzwFHgV5rEblqiL0+ufZvBq+Uv3BlD3553OI1GgwwoNMyme28xHsbaKyoMPPSZn2L2BlRgGL7ZgY= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1786979291; h=Content-Transfer-Encoding:Cc:Cc:Date:Date:From:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:MIME-Version:Message-ID:References:Sender:Subject:Subject:To:To:Message-Id:Reply-To; bh=PD375gm/XTL7dFZJE8PXseM45sYMLiJNdxxsddeEhu0=; b=ksFuDIUQQpsn+wUCfSrXvCRysnkKjAW4D7bw8iUG3lEh8uVjSuWjYLbC7Qngfyft7t1e/ZuWPP5mXplcswP4NmMavsAzubERiuVCgpoxHUO75atcnncvwfbxhjbK9dMitUY9Ek2fHp5fKe9DNdHkIrQI/r2LlM0+H5/SCCnieOk= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=pass header.from= (p=none dis=none) Return-Path: Received: from lists1p.gnu.org (lists1p.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 17869792916481021.7095728552204; Mon, 17 Aug 2026 08:08:11 -0700 (PDT) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists1p.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1wvyvw-0004D1-6I; Mon, 17 Aug 2026 11:07:28 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists1p.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1wvyvu-0004AN-Os for qemu-devel@nongnu.org; Mon, 17 Aug 2026 11:07:26 -0400 Received: from mail-pf1-x42a.google.com ([2607:f8b0:4864:20::42a]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1wvyvs-0007PF-QZ for qemu-devel@nongnu.org; Mon, 17 Aug 2026 11:07:26 -0400 Received: by mail-pf1-x42a.google.com with SMTP id d2e1a72fcca58-84e0688b859so287135b3a.0 for ; Mon, 17 Aug 2026 08:07:24 -0700 (PDT) Received: from X1 ([178.66.48.90]) by smtp.gmail.com with ESMTPSA id 41be03b00d2f7-cc13bf05584sm900775a12.4.2026.08.17.08.07.19 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 17 Aug 2026 08:07:22 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1786979243; x=1787584043; darn=nongnu.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to:content-type; bh=PD375gm/XTL7dFZJE8PXseM45sYMLiJNdxxsddeEhu0=; b=Nq/KL1G2qqDMb23FokDPti8A+nH/JyodKmbD9aghWiFhTvdfm6C3DwWDGuKoQpJILm 0uOxm0tyL91RmPG8defOi+tzscrGTMjcXIRWRIqx+WYZoq3b3SJ0heYlMD2ax/MvISKf 5esRHsq2paJuWh3JQHt+YFSNeZ42eVoeRqs3CIqosHfRV5E7KN5Qb5wpt5dTny3F++II YB/4xXnV6ASWOJE5HFPiClMeHfaajbzfxaBnaHN/xuTIMLThDvp9xjJtkPY9WGR2qelS npuryabHOxXgBs++2O96Du3KLeeuPoM7dNfrcLcidjZSS79wlHX432WmmdPZKML2Ft28 x60Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1786979243; x=1787584043; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to:content-type; bh=PD375gm/XTL7dFZJE8PXseM45sYMLiJNdxxsddeEhu0=; b=ChXYVnoQ8lOkCx671c50AhB1we4aNfAoRJRdf/oiqgJ8XBuJO8lP41FUGjv38Jg1Ly doZC5t2dnslF4a2v4zPARR1DHSfBOMGGqxmskQkGJlIOqzInT8TFhDWLp3JeGfULbCc+ gbbzEc3toPMWuaZLh/LIYQ5VOmrttprGQoJh7167qDCf4MYH3zufIcXFV56q+FzfHaBm a2jKaZV9bM6NLiKhajlU0C7IshFYdVAMs0DUS38SWXi/p3GcpGJkMv2VJd0wPXKkhDap D1av8kAuO9TK3l8LWMlZ7dq8BlSUfWJSlBVOML8qbXY8v6Pz+ET8+zDycUqheN3FueMt iZ/A== X-Gm-Message-State: AOJu0YwZfPko+WZ7pNBNnHwjyd9bDE02cIBUEWAMnfLDdAdEDpp2zwGx P+XJnUFzEaMe8Cg5XRfZ7GE6COOmpKxYbFwAYkrYNUWWb6/SnLEbJTG7S2xcNjoU X-Gm-Gg: AR+sD13K5TruTqLF7MkE8gq0q0Ryy9IVcrhDBEi/fuj1HwSO4oy3XYZX3YZg0fOILE+ DiBwkhsVwOFpGuh2GqcYa1sQZpg8U7cobVx/2tJFis6cjA3EgtlWMgO1OaQGlvnyu0h2t+oEGf9 z6ladxFjlK3LfJQVOKSZ3VsvgOkBD6jLb35xR/AqSb6dJxMhcWs+mhj43KH2IZ2vPl8BiKJwTkW yNxGr/iqnBHZTSDBtdAsM63eYv3i4v/pKYDTyiUJVl8ATf5DvWsQYZ/Wt+8kImom5MA1yD/zt/1 Wf5GfjXzTRDiGhXCB7fB31kIEh21gRLmKp1s+X0JhKSqEh+v/h3itJjGSqjmtMb3JSb08xXnlLm cYa1BZkCPYszYlZcNp4s/DhvJdq3N8DWeq4amG2CSN4gAUJARkNdwlwf4didQE7pOKoPHQeSIEg a3771YUlq1rmv3NKjHESApaaagdl/GMNKbC6Em1dQe/Ox6 X-Received: by 2002:a05:6a00:1f03:b0:846:bc81:3e29 with SMTP id d2e1a72fcca58-84fde365255mr26772033b3a.2.1786979243206; Mon, 17 Aug 2026 08:07:23 -0700 (PDT) From: Vladimir Isaev To: qemu-devel@nongnu.org Cc: palmer@dabbelt.com, alistair.francis@wdc.com, liwei1518@gmail.com, daniel.barboza@oss.qualcomm.com, zhiwei_liu@linux.alibaba.com, chao.liu@processmission.com, qemu-riscv@nongnu.org, joel@jms.id.au, npiggin@gmail.com, Vladimir Isaev Subject: [PATCH v2 2/2] tests/tcg/riscv64: add misa write test Date: Mon, 17 Aug 2026 18:06:38 +0300 Message-ID: <20260817150653.40357-3-vvisaev@gmail.com> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260817150653.40357-1-vvisaev@gmail.com> References: <20260817150653.40357-1-vvisaev@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists1p.gnu.org; Received-SPF: pass client-ip=2607:f8b0:4864:20::42a; envelope-from=vvisaev@gmail.com; helo=mail-pf1-x42a.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, FREEMAIL_FROM=0.001, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: qemu development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer=patchew.org@nongnu.org X-ZohoMail-DKIM: pass (identity @gmail.com) X-ZM-MESSAGEID: 1786979293021158500 Content-Type: text/plain; charset="utf-8" Link: https://lore.kernel.org/r/20260321144554.606417-2-npiggin@gmail.com Suggested-by: Nicholas Piggin Signed-off-by: Vladimir Isaev Reviewed-by: Alistair Francis --- tests/tcg/riscv64/Makefile.softmmu-target | 4 ++ tests/tcg/riscv64/test-misa-w.S | 88 +++++++++++++++++++++++ 2 files changed, 92 insertions(+) create mode 100644 tests/tcg/riscv64/test-misa-w.S diff --git a/tests/tcg/riscv64/Makefile.softmmu-target b/tests/tcg/riscv64/= Makefile.softmmu-target index 82be8a2c91..2c7f00976c 100644 --- a/tests/tcg/riscv64/Makefile.softmmu-target +++ b/tests/tcg/riscv64/Makefile.softmmu-target @@ -41,5 +41,9 @@ comma:=3D , run-test-crc32: test-crc32 $(call run-test, $<, $(QEMU) -cpu rv64$(comma)xlrbr=3Dtrue $(QEMU_OPTS)$<) =20 +EXTRA_RUNS +=3D run-test-misa-w +run-test-misa-w: test-misa-w + $(call run-test, $<, $(QEMU) -cpu rv64$(comma)x-misa-w=3Dtrue$(comma)c=3D= true$(comma)v=3Dtrue $(QEMU_OPTS)$<) + # We don't currently support the multiarch system tests undefine MULTIARCH_TESTS diff --git a/tests/tcg/riscv64/test-misa-w.S b/tests/tcg/riscv64/test-misa-= w.S new file mode 100644 index 0000000000..7f1eb30023 --- /dev/null +++ b/tests/tcg/riscv64/test-misa-w.S @@ -0,0 +1,88 @@ +/* + * Test for MISA changing C and related IALIGN alignment cases + * + * This test verifies that the "C" extension can be cleared and set in MIS= A, + * that a branch to 2-byte aligned instructions can be executed when "C" is + * enabled, and that a write to MISA which would increase IALIGN and cause + * the next instruction to be unaligned is ignored. + * + * SPDX-License-Identifier: GPL-2.0-or-later + */ + +#define RVC (1 << ('C'-'A')) +#define RVV (1 << ('V'-'A')) + +.option norvc + .text + .global _start +_start: + lla t0, trap + csrw mtvec, t0 + + csrr t0, misa + li t1, RVC + not t1, t1 + and t0, t0, t1 + csrw misa, t0 + csrr t1, misa + li a0, 2 # fail code + bne t0, t1, _exit # Could not clear RVC in MISA + + li t1, RVC + or t0, t0, t1 + csrw misa, t0 + csrr t1, misa + li a0, 3 # fail code + bne t0, t1, _exit # Could not set RVC in MISA + + j unalign +. =3D . + 2 +unalign: + + li t1, RVC + not t1, t1 + and t0, t0, t1 + csrw misa, t0 + csrr t1, misa + li a0, 4 # fail code + beq t0, t1, _exit # Was able to clear RVC in MISA + + li t0, (RVC|RVV) + not t0, t0 + and t0, t0, t1 + csrw misa, t0 + csrr t0, misa + li a0, 5 # fail code + bne t0, t1, _exit # MISA write was not ignored (RVV was cleared) + + j realign +. =3D . + 2 +realign: + + # Success! + li a0, 0 + j _exit + +trap: + # Any trap is a fail code 1 + li a0, 1 + +# Exit code in a0 +_exit: + lla a1, semiargs + li t0, 0x20026 # ADP_Stopped_ApplicationExit + sd t0, 0(a1) + sd a0, 8(a1) + li a0, 0x20 # TARGET_SYS_EXIT_EXTENDED + + # Semihosting call sequence + .balign 16 + slli zero, zero, 0x1f + ebreak + srai zero, zero, 0x7 + j . + + .data + .balign 16 +semiargs: + .space 16 --=20 2.55.0