From patchwork Fri Sep 8 08:38:34 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alvin Chang X-Patchwork-Id: 13377251 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 lists.gnu.org (lists.gnu.org [209.51.188.17]) (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 491A1EE57E6 for ; Fri, 8 Sep 2023 08:39:38 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qeX0w-0008RQ-LP; Fri, 08 Sep 2023 04:38:54 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qeX0u-0008R8-IF; Fri, 08 Sep 2023 04:38:52 -0400 Received: from 60-248-80-70.hinet-ip.hinet.net ([60.248.80.70] helo=Atcsqr.andestech.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qeX0r-00032M-24; Fri, 08 Sep 2023 04:38:52 -0400 Received: from mail.andestech.com (ATCPCS16.andestech.com [10.0.1.222]) by Atcsqr.andestech.com with ESMTP id 3888cbQN000956; Fri, 8 Sep 2023 16:38:37 +0800 (+08) (envelope-from alvinga@andestech.com) Received: from atctrx.andestech.com (10.0.15.173) by ATCPCS16.andestech.com (10.0.1.222) with Microsoft SMTP Server id 14.3.498.0; Fri, 8 Sep 2023 16:38:36 +0800 From: Alvin Chang To: , CC: , Alvin Chang Subject: [PATCH v2] target/riscv: update checks on writing pmpcfg for Smepmp version 1.0 Date: Fri, 8 Sep 2023 16:38:34 +0800 Message-ID: <20230908083834.628708-1-alvinga@andestech.com> X-Mailer: git-send-email 2.34.1 MIME-Version: 1.0 X-Originating-IP: [10.0.15.173] X-DNSRBL: X-MAIL: Atcsqr.andestech.com 3888cbQN000956 Received-SPF: pass client-ip=60.248.80.70; envelope-from=alvinga@andestech.com; helo=Atcsqr.andestech.com X-Spam_score_int: -8 X-Spam_score: -0.9 X-Spam_bar: / X-Spam_report: (-0.9 / 5.0 requ) BAYES_00=-1.9, RDNS_DYNAMIC=0.982, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, TVD_RCVD_IP=0.001 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Current checks on writing pmpcfg for Smepmp follows Smepmp version 0.9.1. However, Smepmp specification has already been ratified, and there are some differences between version 0.9.1 and 1.0. In this commit we update the checks of writing pmpcfg to follow Smepmp version 1.0. When mseccfg.MML is set, the constraints to modify PMP rules are: 1. Locked rules connot be removed or modified until a PMP reset, unless mseccfg.RLB is set. 2. From Smepmp specification version 1.0, chapter 2 section 4b: Adding a rule with executable privileges that either is M-mode-only or a locked Shared-Region is not possible and such pmpcfg writes are ignored, leaving pmpcfg unchanged. The commit transfers the value of pmpcfg into the index of the Smepmp truth table, and checks the rules by aforementioned specification changes. Signed-off-by: Alvin Chang --- Changes from v1: Convert ePMP over to Smepmp. target/riscv/pmp.c | 51 ++++++++++++++++++++++++++++++++++++++-------- 1 file changed, 42 insertions(+), 9 deletions(-) diff --git a/target/riscv/pmp.c b/target/riscv/pmp.c index 9d8db493e6..d1c3fc1e4f 100644 --- a/target/riscv/pmp.c +++ b/target/riscv/pmp.c @@ -98,16 +98,49 @@ static bool pmp_write_cfg(CPURISCVState *env, uint32_t pmp_index, uint8_t val) locked = false; } - /* mseccfg.MML is set */ - if (MSECCFG_MML_ISSET(env)) { - /* not adding execute bit */ - if ((val & PMP_LOCK) != 0 && (val & PMP_EXEC) != PMP_EXEC) { - locked = false; - } - /* shared region and not adding X bit */ - if ((val & PMP_LOCK) != PMP_LOCK && - (val & 0x7) != (PMP_WRITE | PMP_EXEC)) { + /* + * mseccfg.MML is set. Locked rules cannot be removed or modified + * until a PMP reset. Besides, from Smepmp specification version 1.0 + * , chapter 2 section 4b says: + * Adding a rule with executable privileges that either is + * M-mode-only or a locked Shared-Region is not possible and such + * pmpcfg writes are ignored, leaving pmpcfg unchanged. + */ + if (MSECCFG_MML_ISSET(env) && !pmp_is_locked(env, pmp_index)) { + /* + * Convert the PMP permissions to match the truth table in the + * ePMP spec. + */ + const uint8_t epmp_operation = + ((val & PMP_LOCK) >> 4) | ((val & PMP_READ) << 2) | + (val & PMP_WRITE) | ((val & PMP_EXEC) >> 2); + + switch (epmp_operation) { + /* pmpcfg.L = 0. Neither M-mode-only nor locked Shared-Region */ + case 0: + case 1: + case 2: + case 3: + case 4: + case 5: + case 6: + case 7: + /* pmpcfg.L = 1 and pmpcfg.X = 0 (but case 10 is not allowed) */ + case 8: + case 12: + case 14: + /* pmpcfg.LRWX = 1111 */ + case 15: /* Read-only locked Shared-Region on all modes */ locked = false; + break; + /* Other rules which add new code regions are not allowed */ + case 9: + case 10: /* Execute-only locked Shared-Region on all modes */ + case 11: + case 13: + break; + default: + g_assert_not_reached(); } } } else {