From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 81AA9353EF7 for ; Thu, 3 Sep 2026 05:56:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788414997; cv=none; b=agyMjCphYbMdgk2IAIGODO7bGMVh8oRYeMv3XxA5QUMMzyf9iqsSEyGkl+RvI20riNiqVmPGsMBzAyaY1KFKt0d3tYcg2Pmz70f+YIUh668GewuoGLssnb0w2mT90pcaLefUNMY9xVErTOTxLcpP6umwEhTExrhRYgJ3juMHAM8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788414997; c=relaxed/simple; bh=DY/csfhtR5YKRxNjL+v1oA5BkKG7eZTRM1aibwpAHZw=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=CRJopdl3JjcLMpjPsGedE7r+MCxGGuP/c93KXQ7Ds+4HB+dd4hoZU2wl2rXxhBpjJAQNr1SYdmtsZUoH2PyXT7qQZy6ylyvJBvYtmw/WYKqeQf2lUQ6Ich9XSiHJVUfw0GxuNdzjQmJtRRbO/RDG/tBk72t6f0/k1tjtt7ep9kU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b=jy33b5SC; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b="jy33b5SC" 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 8B4631596; Wed, 2 Sep 2026 22:56:29 -0700 (PDT) Received: from localhost (a079125.arm.com [10.164.21.43]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 8FDCE3F673; Wed, 2 Sep 2026 22:56:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1788414993; bh=DY/csfhtR5YKRxNjL+v1oA5BkKG7eZTRM1aibwpAHZw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=jy33b5SC5V6MzaplebERlNq+BFlc9TRUI4ImbVVvxIHngkHgnbxv0tzSSVfsfKXe3 im25pVnAOzQ05+j8tOYvftqbvXK5fe2BOtxDIf0L3t+U05xyFehzWRhUpXS4solPgf W74ItVMEC3SFf0Ed9IfLCQ/BgE1K1Fiix7t9JZPo= Date: Thu, 3 Sep 2026 11:26:29 +0530 From: Linu Cherian To: Kevin Brodsky Cc: linux-hardening@vger.kernel.org, Andrew Morton , Andy Lutomirski , Catalin Marinas , Dave Hansen , "David Hildenbrand (Arm)" , Jann Horn , Jeff Xu , Joey Gouly , Kees Cook , Linus Walleij , Marc Zyngier , Mark Brown , Matthew Wilcox , Maxwell Bland , "Mike Rapoport (IBM)" , Peter Zijlstra , Pierre Langlois , =?iso-8859-1?Q?Pierre-Cl=E9ment?= Tosi , Quentin Perret , Rick Edgecombe , Ryan Roberts , Vlastimil Babka , Will Deacon , Yang Shi , Yeoreum Yun , linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, x86@kernel.org, Ira Weiny , Lorenzo Stoakes , Thomas Gleixner Subject: Re: [PATCH RFC v9 08/25] arm64: Initialize POR_EL1 register on cpu_resume() Message-ID: References: <20260818-kpkeys-v9-0-743ad31b2c8f@arm.com> <20260818-kpkeys-v9-8-743ad31b2c8f@arm.com> Precedence: bulk X-Mailing-List: linux-hardening@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260818-kpkeys-v9-8-743ad31b2c8f@arm.com> Kevin, On Tue, Aug 18, 2026 at 03:08:50PM +0100, Kevin Brodsky wrote: > From: Yeoreum Yun > > The POR_EL1 register is reset to an unknown value after cpu_suspend(). > Since POR_EL1 always holds POR_EL1_INIT when entering cpu_suspend(), > initialize POR_EL1 with POR_EL1_INIT before cpu_do_resume(). > > Signed-off-by: Yeoreum Yun > Signed-off-by: Kevin Brodsky > --- > arch/arm64/kernel/sleep.S | 12 ++++++++++++ > 1 file changed, 12 insertions(+) > > diff --git a/arch/arm64/kernel/sleep.S b/arch/arm64/kernel/sleep.S > index f093cdf71be1..e0a6ad85cd24 100644 > --- a/arch/arm64/kernel/sleep.S > +++ b/arch/arm64/kernel/sleep.S > @@ -3,6 +3,7 @@ > #include > #include > #include > +#include > #include > > .text > @@ -134,6 +135,17 @@ SYM_FUNC_START(_cpu_resume) > /* load sp from context */ > ldr x2, [x0, #CPU_CTX_SP] > mov sp, x2 > + > +#ifdef CONFIG_ARM64_POE > +alternative_if_not ARM64_HAS_S1POE > + b .Lskip_por_set > +alternative_else_nop_endif > + mov_q x2, POR_EL1_INIT > + msr_s SYS_POR_EL1, x2 > + /* isb can be skipped since cpu_do_resume() will do it. */ > +.Lskip_por_set: > +#endif /* CONFIG_ARM64_POE */ Would it be better to move this under__cpu_setup ? -- Linu Cherian