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 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 D154EC79FAE for ; Tue, 8 Sep 2026 15:22:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:Cc:List-Subscribe: List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id: Content-Transfer-Encoding:MIME-Version:References:In-Reply-To:Message-Id:Date :Subject:To:From:Reply-To:Content-Type:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=T2OcsfQB2rXyV+qEnim3LyzT5vfleOs/dQwzAKYIyC8=; b=HS+v7dav50+OYq cSrgSky8kJ8fph0r+jZHkSLlnRlqwomhr8bxUsQ+qmYM30onSefveSeMFfkEL/gI2WhU3kV52VLzI dWwrPwIIWWtPUSNgOCfpWvIPv6sxfoyzIvO9Eg3uUHLbvI6OsdmXklO19ct0l4N+NHm6fQwbxntYi hdCjbwHitcTtUlioku3S+rn6Hu2AU5OYFzx7yCdJtuGMwSYOkzl2NLXmLPiI4Or3acKhBmE8T0fIs Y5DoFlYjgfi8/D4xzGyNFjq13oA9howeCtQ9yaqGONNFLKW24y4nFJAOYDMoukx6CbDsreyELtqdn ZismkvkRPNnaqZpUxNPw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1x3xeW-00000009SlN-1pxM; Tue, 08 Sep 2026 15:22:28 +0000 Received: from desiato.infradead.org ([2001:8b0:10b:1:d65d:64ff:fe57:4e05]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1x3xeV-00000009SkV-08aN for linux-arm-kernel@bombadil.infradead.org; Tue, 08 Sep 2026 15:22:27 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=Content-Transfer-Encoding:MIME-Version :References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To: Content-Type:Content-ID:Content-Description; bh=T2OcsfQB2rXyV+qEnim3LyzT5vfleOs/dQwzAKYIyC8=; b=PX4QvquRUYiA360eBIizK3sBLJ YMboDCLZyJSE83JwYH1V6+bDaooDLKWucp9d1B27U3TYj/aqcyR/LtNGnF1ameqB6zwG9ndWAg9XU 36/5Qm5Vz6IsqJ7m6YkQVxfkEdH+gc52oItHBaYM7dtlwzC0KXsu7bWwhuUzlAkF2IjiMfzt36Xj1 V9DY/T4TOBYC2dJI2rBHz1F0qwwo/zcKfqoW8F0tNOlRV6I7Ea77CQlq0MN0FX9NITVWmeWMK1/74 fpUUNKQ+ph1pBppMerB79RABGXZ9DsI1M5ZTrrmuWvSBnFZszGn+ebtgMQRZfSimp68WQdKRmQkpT UvTUrcTg==; Received: from foss.arm.com ([217.140.110.172]) by desiato.infradead.org with esmtp (Exim 4.99.2 #2 (Red Hat Linux)) id 1x3xeS-000000000mH-0aXJ for linux-arm-kernel@lists.infradead.org; Tue, 08 Sep 2026 15:22:25 +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 682281C14; Tue, 8 Sep 2026 08:22:19 -0700 (PDT) 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 545643F7B4; Tue, 8 Sep 2026 08:22:20 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1788880943; bh=pUyEkl4bH7bjN7cz2XbK3Pl6rivIm/Z5yqVzikq2V+0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=IsfPGzHPBxawavvaQDfuX6xD0H6IW52/osuv7hqwOc67pn/cj/YkkXtt/1jrlxNzT WVk+e6qOQgpRhPfHB7PEz36ypDnGhg4WnDYxW75Np6Cl89QR7CflKXDb2cZwbRGoQb Nj5ijfMl0b/t/WjRs6Z4b7GibxibRU68+z0zUnDY= From: Mark Rutland To: linux-arm-kernel@lists.infradead.org Subject: [PATCH v4 12/21] arm64: entry: sdei: Restore all clobberable GPRs Date: Tue, 8 Sep 2026 16:17:32 +0100 Message-Id: <20260908151741.394589-13-mark.rutland@arm.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20260908151741.394589-1-mark.rutland@arm.com> References: <20260908151741.394589-1-mark.rutland@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260908_162224_381520_6D972539 X-CRM114-Status: GOOD ( 10.60 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: mark.rutland@arm.com, vladimir.murzin@arm.com, ryan.roberts@arm.com, usama.anjum@arm.com, peterz@infradead.org, catalin.marinas@arm.com, david.laight.linux@gmail.com, stable@vger.kernel.org, ruanjinjie@huawei.com, james.morse@arm.com, yang@os.amperecomputing.com, cl@gentwo.org, maz@kernel.org, david@kernel.org, ljs@kernel.org, will@kernel.org, ardb@kernel.org Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Currently __sdei_asm_handler() avoids restoring x20 to x27, as these are not be clobbered by existing code. This is correct today, but it makes it awkward to rework __sdei_asm_handler(). Given the rarity of SDEI events, restoring x20 to x27 should not have a measurable impact. Restore x20 to x27 when returning from an SDEI event handler. This will free up those GPRs for usage in __sdei_asm_handler() prior to return. Signed-off-by: Mark Rutland Tested-by: Muhammad Usama Anjum Cc: Ada Couprie Diaz Cc: Ard Biesheuvel Cc: Catalin Marinas Cc: James Morse Cc: Jinjie Ruan Cc: Marc Zyngier Cc: Peter Zijlstra Cc: Vladimir Murzin Cc: Will Deacon Cc: Yang Shi --- arch/arm64/kernel/entry.S | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S index f63049ac32dc6..a6ec5c5a2d29c 100644 --- a/arch/arm64/kernel/entry.S +++ b/arch/arm64/kernel/entry.S @@ -1044,10 +1044,14 @@ SYM_CODE_START(__sdei_asm_handler) bl __sdei_handler msr sp_el0, x28 - /* restore regs >x17 that we clobbered */ + /* restore regs >x17 that firmware won't restore */ mov x4, x19 // keep x4 for __sdei_asm_exit_trampoline - ldp x28, x29, [x4, #SDEI_EVENT_INTREGS + 16 * 14] ldp x18, x19, [x4, #SDEI_EVENT_INTREGS + 16 * 9] + ldp x20, x21, [x4, #SDEI_EVENT_INTREGS + 16 * 10] + ldp x22, x23, [x4, #SDEI_EVENT_INTREGS + 16 * 11] + ldp x24, x25, [x4, #SDEI_EVENT_INTREGS + 16 * 12] + ldp x26, x27, [x4, #SDEI_EVENT_INTREGS + 16 * 13] + ldp x28, x29, [x4, #SDEI_EVENT_INTREGS + 16 * 14] ldp lr, x1, [x4, #SDEI_EVENT_INTREGS + S_LR] mov sp, x1 -- 2.30.2