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=-8.3 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_SANE_1 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 95D6BC32771 for ; Thu, 9 Jan 2020 07:59:08 +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 644FF206ED for ; Thu, 9 Jan 2020 07:59:08 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="sRhfh8o2" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 644FF206ED 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:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date: Message-ID:From:References:To:Subject:Reply-To:Content-ID:Content-Description :Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=ZKje+6jSOTWwrHSfKbiIWxghC6eS+TdLyOtf3peqJtU=; b=sRhfh8o2RqpXnL HZWNWNFEKzycvcxCyiVqAYVSvVFC0QAjmBqbSL6qyMz4R30ro7yFdUokaIZrC4wyBv1oOkwm3aHQS O2OSuKW98c4o4v2qjk9r+NDBKZceW/dBy45916vn4wNFGsVYg3f999jYXqFKVDxJ5mI1chbGYTcwi gMfNCZBQpWSMsGnoMgKEqupfnZrvJsIOOjUOT6fdG82I3a59DhfFhB7SuH6lGkdZ+nm8xKCa7kp2+ bDfsjm+c2qja1ZE6J4I8u2eY3bOYsJ+vRgLfq0Q/fufV7qh2ULvaAqrqH11KoZvuyGptTgIsxChOA 5qa+nJkmHryQ/iJKpv1A==; 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 1ipSid-0004X8-Sd; Thu, 09 Jan 2020 07:59:03 +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 1ipSiU-0004RA-Nq for linux-arm-kernel@lists.infradead.org; Thu, 09 Jan 2020 07:58:56 +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 818D31FB; Wed, 8 Jan 2020 23:58:53 -0800 (PST) Received: from [10.162.40.138] (p8cg001049571a15.blr.arm.com [10.162.40.138]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 4E4453F6C4; Thu, 9 Jan 2020 00:02:16 -0800 (PST) Subject: Re: [PATCH 05/17] arm64: entry: add a call_on_stack helper To: Mark Rutland , linux-arm-kernel@lists.infradead.org, catalin.marinas@arm.com, will@kernel.org, james.morse@arm.com References: <20200108185634.1163-1-mark.rutland@arm.com> <20200108185634.1163-6-mark.rutland@arm.com> From: Anshuman Khandual Message-ID: <98534fbd-5600-5ae2-a117-3bad76ddbe04@arm.com> Date: Thu, 9 Jan 2020 13:30:02 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <20200108185634.1163-6-mark.rutland@arm.com> Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200108_235854_862755_84DE49F7 X-CRM114-Status: GOOD ( 17.30 ) 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: 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 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 On 01/09/2020 12:26 AM, Mark Rutland wrote: > 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 A small nit. Though the definition here itself does not limit the argument type, it might worth to mention that to be struct pt_regs per the previous declaration. > + * 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 > Reviewed-by: Anshuman Khandual _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel