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 X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham 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 4EAE4C282DD for ; Wed, 8 Jan 2020 18:58:15 +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 20FDD20678 for ; Wed, 8 Jan 2020 18:58:15 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="YIi119Ts" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 20FDD20678 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=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.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:MIME-Version:Cc:List-Subscribe: List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id:References: In-Reply-To:Message-Id:Date:Subject:To:From:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Owner; bh=kRhPP+WJxgYLZ6O08slBChTQT2pd9DWGC5cSujMfO3I=; b=YIi119TsozpuWq0jRXHp8IknBH 0Nfe3EKUwLcp2f758e7M6X8UB7zaC43olAoKb/3oXLyNxAm+DH35D3dZzXDqt9PuFfvb8ZPJo7jEU zTiXwGAMQvBTVKrIacz2If5mhgBpGVsq47mHspHYmnMDgFz9eaqKLWH8efVE9sqLqC8vUIUFm4WGR WdfClfv3Q7XXE7YWebxyGXRUUhd6vxURrwkZshNm/lR+MHTlQMHJkMltp05Qs0yA0n2LEObN5Vame +ps6jpNSkCgV22RhZjnjaEcevk6pPwj0GiB+5iyIA++BhlG4HfKLJ55QzogkyT512BTzHOaW6vmsg zSn0MBhg==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1ipGWz-00008m-Hk; Wed, 08 Jan 2020 18:58:13 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1ipGVq-0007Td-Lx for linux-arm-kernel@lists.infradead.org; Wed, 08 Jan 2020 18:57:08 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 450861FB; Wed, 8 Jan 2020 10:57:01 -0800 (PST) Received: from lakrids.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id B55873F534; Wed, 8 Jan 2020 10:56:59 -0800 (PST) From: Mark Rutland To: linux-arm-kernel@lists.infradead.org, catalin.marinas@arm.com, will@kernel.org, james.morse@arm.com Subject: [PATCH 05/17] arm64: entry: add a call_on_stack helper Date: Wed, 8 Jan 2020 18:56:22 +0000 Message-Id: <20200108185634.1163-6-mark.rutland@arm.com> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20200108185634.1163-1-mark.rutland@arm.com> References: <20200108185634.1163-1-mark.rutland@arm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200108_105703_005708_4AD25F71 X-CRM114-Status: GOOD ( 10.66 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: mark.rutland@arm.com, keescook@chromium.org, maz@kernel.org, broonie@kernel.org, labbott@redhat.com, robin.murphy@arm.com, julien.thierry.kdev@gmail.com, alex.popov@linux.com MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org In some cases, we want to call a function from C code, using an alternative stack. Add a helper that we can use in such cases. Signed-off-by: Mark Rutland Cc: Catalin Marinas Cc: James Morse Cc: Will Deacon --- arch/arm64/include/asm/exception.h | 2 ++ arch/arm64/kernel/entry.S | 21 +++++++++++++++++++++ 2 files changed, 23 insertions(+) diff --git a/arch/arm64/include/asm/exception.h b/arch/arm64/include/asm/exception.h index b87c6e276ab1..a49038fa4faf 100644 --- a/arch/arm64/include/asm/exception.h +++ b/arch/arm64/include/asm/exception.h @@ -31,6 +31,8 @@ static inline u32 disr_to_esr(u64 disr) return esr; } +asmlinkage void call_on_stack(struct pt_regs *, void (*)(struct pt_regs *), + unsigned long); asmlinkage void enter_from_user_mode(void); void do_mem_abort(unsigned long addr, unsigned int esr, struct pt_regs *regs); void do_sp_pc_abort(unsigned long addr, unsigned int esr, struct pt_regs *regs); diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S index 53ce1877a4aa..184313c773ea 100644 --- a/arch/arm64/kernel/entry.S +++ b/arch/arm64/kernel/entry.S @@ -901,6 +901,27 @@ ENTRY(ret_from_fork) ENDPROC(ret_from_fork) NOKPROBE(ret_from_fork) +/* + * x0 = argument to function + * x1 = function to call + * x2 = new stack pointer + */ +ENTRY(call_on_stack) + /* Create a frame record to save our LR and SP (implicit in FP) */ + stp x29, x30, [sp, #-16]! + mov x29, sp + + /* Move to the new stack and call the function there */ + mov sp, x2 + blr x1 + + /* Restore SP from the FP, FP and LR from the record, and return */ + mov sp, x29 + ldp x29, x30, [sp], #16 + ret +ENDPROC(call_on_stack) +NOKPROBE(call_on_stack) + #ifdef CONFIG_ARM_SDE_INTERFACE #include -- 2.11.0 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel