From mboxrd@z Thu Jan 1 00:00:00 1970 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 92E6DC433F5 for ; Wed, 9 Feb 2022 08:54:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241963AbiBIIyk (ORCPT ); Wed, 9 Feb 2022 03:54:40 -0500 Received: from gmail-smtp-in.l.google.com ([23.128.96.19]:50328 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233052AbiBIIyh (ORCPT ); Wed, 9 Feb 2022 03:54:37 -0500 Received: from andre.telenet-ops.be (andre.telenet-ops.be [IPv6:2a02:1800:120:4::f00:15]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E239DE03018A for ; Wed, 9 Feb 2022 00:54:32 -0800 (PST) Received: from ramsan.of.borg ([IPv6:2a02:1810:ac12:ed40:54c7:c522:3859:290]) by andre.telenet-ops.be with bizsmtp id swu32600Y4VQqf501wu3YL; Wed, 09 Feb 2022 09:54:04 +0100 Received: from rox.of.borg ([192.168.97.57]) by ramsan.of.borg with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.93) (envelope-from ) id 1nHijj-000DIj-AL; Wed, 09 Feb 2022 09:54:03 +0100 Received: from geert by rox.of.borg with local (Exim 4.93) (envelope-from ) id 1nHiji-00DkM0-OH; Wed, 09 Feb 2022 09:54:02 +0100 From: Geert Uytterhoeven To: Paul Walmsley , Palmer Dabbelt , Albert Ou Cc: Atish Patra , Jessica Clarke , Anup Patel , Emil Renner Berthing , linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, Geert Uytterhoeven Subject: [PATCH v2 3/3] RISC-V: Fix IPI/RFENCE hmask on non-monotonic hartid ordering Date: Wed, 9 Feb 2022 09:54:01 +0100 Message-Id: <84ee1ae4bfc0ddbafdb38a21135f67ceb121c5e1.1644396407.git.geert@linux-m68k.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org If the boot CPU does not have the lowest hartid, "hartid - hbase" can become negative, leading to an incorrect hmask, causing userspace to crash with SEGV. This is observed on e.g. Starlight Beta, where cpuid 1 maps to hartid 0, and cpuid 0 maps to hartid 1. Fix this by detecting this case, and shifting the accumulated mask and updating hbase, if possible. Fixes: 26fb751ca37846c9 ("RISC-V: Do not use cpumask data structure for hartid bitmap") Signed-off-by: Geert Uytterhoeven Reviewed-by: Atish Patra Tested-by: Emil Renner Berthing Tested-by: Atish Patra --- v2: - Add Reviewed-by, Tested-by. --- arch/riscv/kernel/sbi.c | 57 ++++++++++++++++++++++++++++------------- 1 file changed, 39 insertions(+), 18 deletions(-) diff --git a/arch/riscv/kernel/sbi.c b/arch/riscv/kernel/sbi.c index 22444cfcd56cc646..775d3322b422fe14 100644 --- a/arch/riscv/kernel/sbi.c +++ b/arch/riscv/kernel/sbi.c @@ -250,7 +250,7 @@ static void __sbi_set_timer_v02(uint64_t stime_value) static int __sbi_send_ipi_v02(const struct cpumask *cpu_mask) { - unsigned long hartid, cpuid, hmask = 0, hbase = 0; + unsigned long hartid, cpuid, hmask = 0, hbase = 0, htop = 0; struct sbiret ret = {0}; int result; @@ -259,16 +259,27 @@ static int __sbi_send_ipi_v02(const struct cpumask *cpu_mask) for_each_cpu(cpuid, cpu_mask) { hartid = cpuid_to_hartid_map(cpuid); - if (hmask && ((hbase + BITS_PER_LONG) <= hartid)) { - ret = sbi_ecall(SBI_EXT_IPI, SBI_EXT_IPI_SEND_IPI, - hmask, hbase, 0, 0, 0, 0); - if (ret.error) - goto ecall_failed; - hmask = 0; - hbase = 0; + if (hmask) { + if (hartid + BITS_PER_LONG <= htop || + hbase + BITS_PER_LONG <= hartid) { + ret = sbi_ecall(SBI_EXT_IPI, + SBI_EXT_IPI_SEND_IPI, hmask, + hbase, 0, 0, 0, 0); + if (ret.error) + goto ecall_failed; + hmask = 0; + } else if (hartid < hbase) { + /* shift the mask to fit lower hartid */ + hmask <<= hbase - hartid; + hbase = hartid; + } } - if (!hmask) + if (!hmask) { hbase = hartid; + htop = hartid; + } else if (hartid > htop) { + htop = hartid; + } hmask |= BIT(hartid - hbase); } @@ -345,7 +356,7 @@ static int __sbi_rfence_v02(int fid, const struct cpumask *cpu_mask, unsigned long start, unsigned long size, unsigned long arg4, unsigned long arg5) { - unsigned long hartid, cpuid, hmask = 0, hbase = 0; + unsigned long hartid, cpuid, hmask = 0, hbase = 0, htop = 0; int result; if (!cpu_mask || cpumask_empty(cpu_mask)) @@ -353,16 +364,26 @@ static int __sbi_rfence_v02(int fid, const struct cpumask *cpu_mask, for_each_cpu(cpuid, cpu_mask) { hartid = cpuid_to_hartid_map(cpuid); - if (hmask && ((hbase + BITS_PER_LONG) <= hartid)) { - result = __sbi_rfence_v02_call(fid, hmask, hbase, - start, size, arg4, arg5); - if (result) - return result; - hmask = 0; - hbase = 0; + if (hmask) { + if (hartid + BITS_PER_LONG <= htop || + hbase + BITS_PER_LONG <= hartid) { + result = __sbi_rfence_v02_call(fid, hmask, + hbase, start, size, arg4, arg5); + if (result) + return result; + hmask = 0; + } else if (hartid < hbase) { + /* shift the mask to fit lower hartid */ + hmask <<= hbase - hartid; + hbase = hartid; + } } - if (!hmask) + if (!hmask) { hbase = hartid; + htop = hartid; + } else if (hartid > htop) { + htop = hartid; + } hmask |= BIT(hartid - hbase); } -- 2.25.1