From patchwork Wed Feb 9 12:37:47 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Heiko Stuebner X-Patchwork-Id: 12740237 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 7F72AC433F5 for ; Wed, 9 Feb 2022 12:38:48 +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:References:In-Reply-To: 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: List-Owner; bh=2TaV/ZsqBOuJI6Tt52DPgVES5V6duaVpgculmDmzCog=; b=YLAbaHr38FDGcL KBH4hB2F68H4QalIqzo6UQudva04jb7U7BeD+Z3kagGV2TXDvEguHAezTJumgiX+9h703lpbfJR/F /jves3vIH+isZHeYqUj4fjUcvzGOgOl/YthFyU9Nk1U/FqfHSwb9oIzcxybPn2tyxIxB0H8NvsCMd 776nVURjdK8UhLNp47tIb8CItgUvmPolcP+HU4IIEJwJy8F0j+DVkDIfJ/RNl78AsrIJofSMS0luN 4YzzFUj2CCsOzyuDb5HIXbemtpNICrwsq50Tyv0VMA73+HDRP8L3z1Vo43/xbcGiwMIncDYVldm7V O8xewhta47Ef5O79yl9Q==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nHmF7-0002G8-R6; Wed, 09 Feb 2022 12:38:41 +0000 Received: from gloria.sntech.de ([185.11.138.130]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1nHmEu-00029I-8b for linux-riscv@lists.infradead.org; Wed, 09 Feb 2022 12:38:32 +0000 Received: from ip5b412258.dynamic.kabel-deutschland.de ([91.65.34.88] helo=phil.lan) by gloria.sntech.de with esmtpsa (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1nHmEj-0001Mv-BQ; Wed, 09 Feb 2022 13:38:17 +0100 From: Heiko Stuebner To: palmer@dabbelt.com, paul.walmsley@sifive.com, aou@eecs.berkeley.edu Cc: linux-riscv@lists.infradead.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, robh+dt@kernel.org, wefu@redhat.com, liush@allwinnertech.com, guoren@kernel.org, atishp@atishpatra.org, anup@brainfault.org, drew@beagleboard.org, hch@lst.de, arnd@arndb.de, wens@csie.org, maxime@cerno.tech, gfavor@ventanamicro.com, andrea.mondelli@huawei.com, behrensj@mit.edu, xinhaoqu@huawei.com, huffman@cadence.com, mick@ics.forth.gr, allen.baum@esperantotech.com, jscheid@ventanamicro.com, rtrauben@gmail.com, samuel@sholland.org, cmuellner@linux.com, philipp.tomsich@vrull.eu, Heiko Stuebner Subject: [PATCH v6 01/14] riscv: prevent null-pointer dereference with sbi_remote_fence_i Date: Wed, 9 Feb 2022 13:37:47 +0100 Message-Id: <20220209123800.269774-2-heiko@sntech.de> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20220209123800.269774-1-heiko@sntech.de> References: <20220209123800.269774-1-heiko@sntech.de> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220209_043828_321523_C4EF2B37 X-CRM114-Status: GOOD ( 13.59 ) 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 The callback used inside sbi_remote_fence_i is set at sbi probe time to the needed variant. Before that it is a NULL pointer. Some users like the flush_icache_*() functions suggest a generic functionality, that doesn't depend on a specific boot-stage but uses sbi_remote_fence_i as one option to flush other cpu cores. So they definitly shouldn't run into null-pointer dereference issues when called "too early" during boot. So introduce an empty function to be the standard for the __sbi_rfence function pointer until sbi_init has run. Users of sbi_remote_fence_i will have separate code for the local cpu and sbi_init() is called before other cpus are brought up. So there are no other cpus present at the time when the issue might happen. Signed-off-by: Heiko Stuebner Reviewed-by: Atish Patra --- arch/riscv/kernel/sbi.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/arch/riscv/kernel/sbi.c b/arch/riscv/kernel/sbi.c index f72527fcb347..c839acd668d3 100644 --- a/arch/riscv/kernel/sbi.c +++ b/arch/riscv/kernel/sbi.c @@ -15,11 +15,19 @@ unsigned long sbi_spec_version __ro_after_init = SBI_SPEC_VERSION_DEFAULT; EXPORT_SYMBOL(sbi_spec_version); +static int __sbi_rfence_none(int fid, const struct cpumask *cpu_mask, + unsigned long start, unsigned long size, + unsigned long arg4, unsigned long arg5) +{ + return -EOPNOTSUPP; +} + static void (*__sbi_set_timer)(uint64_t stime) __ro_after_init; static int (*__sbi_send_ipi)(const struct cpumask *cpu_mask) __ro_after_init; static int (*__sbi_rfence)(int fid, const struct cpumask *cpu_mask, unsigned long start, unsigned long size, - unsigned long arg4, unsigned long arg5) __ro_after_init; + unsigned long arg4, unsigned long arg5) + __ro_after_init = __sbi_rfence_none; struct sbiret sbi_ecall(int ext, int fid, unsigned long arg0, unsigned long arg1, unsigned long arg2,