From patchwork Mon Feb 29 17:20:13 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: James Morse X-Patchwork-Id: 8456441 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 3E67CC0553 for ; Mon, 29 Feb 2016 17:25:15 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 5EFB02024C for ; Mon, 29 Feb 2016 17:25:14 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id E2F052022D for ; Mon, 29 Feb 2016 17:25:12 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1aaRXl-0002lD-WC; Mon, 29 Feb 2016 17:23:38 +0000 Received: from foss.arm.com ([217.140.101.70]) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1aaRWZ-00025o-Bn for linux-arm-kernel@lists.infradead.org; Mon, 29 Feb 2016 17:22:26 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 6CAF45D5; Mon, 29 Feb 2016 09:21:09 -0800 (PST) Received: from melchizedek.cambridge.arm.com (melchizedek.cambridge.arm.com [10.1.209.158]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 986953F213; Mon, 29 Feb 2016 09:22:02 -0800 (PST) From: James Morse To: linux-arm-kernel@lists.infradead.org Subject: [PATCH v6 04/14] arm64: Add new hcall HVC_CALL_FUNC Date: Mon, 29 Feb 2016 17:20:13 +0000 Message-Id: <1456766423-1554-5-git-send-email-james.morse@arm.com> X-Mailer: git-send-email 2.7.0 In-Reply-To: <1456766423-1554-1-git-send-email-james.morse@arm.com> References: <1456766423-1554-1-git-send-email-james.morse@arm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20160229_092223_565374_FC472030 X-CRM114-Status: UNSURE ( 8.99 ) X-CRM114-Notice: Please train this message. X-Spam-Score: -6.9 (------) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , Lorenzo Pieralisi , Geoff Levand , Catalin Marinas , Will Deacon , AKASHI Takahiro , James Morse , Sudeep Holla , Marc Zyngier MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-4.2 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Geoff Levand Add the new hcall HVC_CALL_FUNC that allows execution of a function at EL2. During CPU reset the CPU must be brought to the exception level it had on entry to the kernel. The HVC_CALL_FUNC hcall will provide the mechanism needed for this exception level switch. To allow the HVC_CALL_FUNC exception vector to work without a stack, which is needed to support an hcall at CPU reset, this implementation uses register x18 to store the link register across the caller provided function. This dictates that the caller provided function must preserve the contents of register x18. Signed-off-by: Geoff Levand [Renumbered labels in el1_sync()] Signed-off-by: James Morse --- arch/arm64/include/asm/virt.h | 13 +++++++++++++ arch/arm64/kernel/hyp-stub.S | 19 +++++++++++++++---- 2 files changed, 28 insertions(+), 4 deletions(-) diff --git a/arch/arm64/include/asm/virt.h b/arch/arm64/include/asm/virt.h index eb10368c329e..30700961f28c 100644 --- a/arch/arm64/include/asm/virt.h +++ b/arch/arm64/include/asm/virt.h @@ -45,6 +45,19 @@ #define HVC_SET_VECTORS 2 +/* + * HVC_CALL_FUNC - Execute a function at EL2. + * + * @x0: Physical address of the function to be executed. + * @x1: Passed as the first argument to the function. + * @x2: Passed as the second argument to the function. + * @x3: Passed as the third argument to the function. + * + * The called function must preserve the contents of register x18. + */ + +#define HVC_CALL_FUNC 3 + #define BOOT_CPU_MODE_EL1 (0xe11) #define BOOT_CPU_MODE_EL2 (0xe12) diff --git a/arch/arm64/kernel/hyp-stub.S b/arch/arm64/kernel/hyp-stub.S index 017ab519aaf1..cfacfe55e3ef 100644 --- a/arch/arm64/kernel/hyp-stub.S +++ b/arch/arm64/kernel/hyp-stub.S @@ -59,18 +59,29 @@ el1_sync: and x18, x18, #ESR_ELx_ISS_MASK cmp x17, #ESR_ELx_EC_HVC64 - b.ne 2f // Not an HVC trap + b.ne 9f // Not an HVC trap cmp x18, #HVC_GET_VECTORS b.ne 1f mrs x0, vbar_el2 - b 2f + b 9f 1: cmp x18, #HVC_SET_VECTORS b.ne 2f msr vbar_el2, x0 - -2: eret + b 9f + +2: cmp x18, #HVC_CALL_FUNC + b.ne 9f + mov x18, lr + mov lr, x0 + mov x0, x1 + mov x1, x2 + mov x2, x3 + blr lr + mov lr, x18 + +9: eret ENDPROC(el1_sync) .macro invalid_vector label