From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794482772; b=KB5/+j6BAyJdXOoh+Ke0Xs0731Q/AGp3n418AhB7iuWCH9VlfogSkLDfPh6AJB4iq8vW d1TX3x0cayRrNm/JC86aG8ONlwS0rwXOyzQikhChwWpcW2JD9iz42Kyyb5kRGcZulPLrk f2biOkyRf0yJy8XgaZJSh90Ep3+CppfvXu4e99S57mkHYIDJiI7GgfHsoyUgLL4WUnQgd ELue5ZYGJGYSbvhjb9KD9bJPmi+TnbjjLDZN23bKamcBjYdyWZ3AKj10X6p+qX3jMB4Va aTi/UqRVfc1295YmvIyQ6YCuaYrA2RtlfTHyR0m2qfKPj/WthSkqKhjJgyGs8qGPOFw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794482772; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:MIME-Version:Content-Transfer-Encoding; bh=GZ4lZp1oW2s0U2uL8ErHvlu8up2Pjx215zhjtPcKJ2Q=; b=m23vMnoQdBlVg9pA+fp81MVkufdvXJxcQkkUP4qTYR83FhTEZPXmZjB4rFiwtYbbe9fN 2f6K3PZ+OuHLh80x55yFcZpuQ23v9ZcpJUZctlKxePRPGD4hFbbZcmDIY1pXY9Esc1PhD 8XUd7HPZ/JZb7/9OOJDmwPAHyJv39gdVdp0tw41b2n5oae+roU26meK5dzyRly2Tf9XVJ CQCY9NpW8qKO21nGaTnVrRmsA2a87TmfcRKr7KXoL6sTPe+8i1lIMTsvvyNvFHvyhCxDg 1/XfD1oyOo4flIMp9nMzV+hVkvSfCgofmKJrRQu0B/VwAzozv6QH2MQk1CNJ4tAjAaQ== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b="h/r3xrdE"; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 41947606A895 for ; Thu, 12 Nov 2026 11:26:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=h/r3xrdE Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7EC0C1F00A05; Thu, 12 Nov 2026 11:26:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794482772; bh=GZ4lZp1oW2s0U2uL8ErHvlu8up2Pjx215zhjtPcKJ2Q=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=h/r3xrdEhQleZV4yGgXPVqBfanfjsSKJ/g60PP/OJoc5XviAAJAUlX2KuMamvkihO 6S5H6k5b1RNd4xXJLVJ91kcuCCQCZTXO1k+1hQn6/O+7RvV8jNjkBRJXIlQ1V9idnR 9XiRe0gigvMNyWa7iIbigaFbf2JOHB8+iOYN0Ye9RreZ/JWwevZQj5VfLzPUXudYPN 9zN8Zh9SPvZmpMfi3VkkfJS4yMkZoVwR2dg8Pxff5QMrY76ACoV9Zd44FOHqSG8vPH /mQ1HwpQ/1l+8doGR2M/t4fFEC8tmhl4Zq43fF36z8VjNjv8+aaMf4c4pJisKk9Stz Dl7K858NfhsuA== From: Arnd Bergmann To: linux-mm@kvack.org Cc: Arnd Bergmann , Andrew Morton , Andreas Larsson , "Christophe Leroy (CS GROUP)" , Dave Hansen , "David Hildenbrand (Arm)" , Jason Gunthorpe , Linus Walleij , "Lorenzo Stoakes (ARM)" , Matthew Wilcox , Malin Jonsson , Richard Weinberger , Russell King , linux-arm-kernel@lists.infradead.org, linux-fsdevel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, x86@kernel.org Subject: [PATCH v2 6/6] ARM: add CONFIG_VMSPLIT_2G_OPT option Date: Thu, 12 Nov 2026 12:25:28 +0100 Message-ID: <20261112112528.1116405-7-arnd@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20261112112528.1116405-1-arnd@kernel.org> References: <20261112112528.1116405-1-arnd@kernel.org> X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Arnd Bergmann Unlike x86 and powerpc, there is currently no option to use exactly 2GiB of lowmem on Arm. Since 2GiB is still a relatively common configuration on embedded systems, it makes sense to allow this to be used in non-highmem builds. Add the Kconfig option and make this the default for non-LPAE builds with highmem enabled instead of CONFIG_VMSPLIT_2G. LPAE still requires the vmsplit to be on a gigabyte boundary, so this is only available for classic pagetables at the moment, same as CONFIG_VMSPLIT_3G_OPT. Tested in qemu -M virt, both with and without HIGHMEM enabled. Signed-off-by: Arnd Bergmann --- arch/arm/Kconfig | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index 797705a94b28..8992fedfdf37 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -1025,7 +1025,8 @@ config BL_SWITCHER_DUMMY_IF choice prompt "Memory split" depends on MMU - default VMSPLIT_2G if HIGHMEM || ARM_LPAE + default VMSPLIT_2G if ARM_LPAE + default VMSPLIT_2G_OPT if HIGHMEM default VMSPLIT_3G_OPT help Select the desired split between kernel and user memory. @@ -1042,6 +1043,9 @@ choice bool "3G/1G user/kernel split (for full 1G low memory)" config VMSPLIT_2G bool "2G/2G user/kernel split" + config VMSPLIT_2G_OPT + depends on !ARM_LPAE + bool "2G/2G user/kernel split (for full 2G low memory)" config VMSPLIT_1G bool "1G/3G user/kernel split" endchoice @@ -1050,6 +1054,7 @@ config PAGE_OFFSET hex default PHYS_OFFSET if !MMU default 0x40000000 if VMSPLIT_1G + default 0x70000000 if VMSPLIT_2G_OPT default 0x80000000 if VMSPLIT_2G default 0xB0000000 if VMSPLIT_3G_OPT default 0xC0000000 @@ -1058,6 +1063,7 @@ config KASAN_SHADOW_OFFSET hex depends on KASAN default 0x1f000000 if PAGE_OFFSET=0x40000000 + default 0x4f000000 if PAGE_OFFSET=0x70000000 default 0x5f000000 if PAGE_OFFSET=0x80000000 default 0x9f000000 if PAGE_OFFSET=0xC0000000 default 0x8f000000 if PAGE_OFFSET=0xB0000000 -- 2.53.0