From nobody Sat Oct 4 01:48:22 2025 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7F92E2DA767 for ; Thu, 21 Aug 2025 10:37:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755772652; cv=none; b=ZyF1bbHJ7khYvf2HXEDHCpmyDEgvayjRl12sZIEk33+nUzk0agAtw69ohDfxfd34xY5KM3CmXlsGaAGJ7CONlwvBeVF9tbx+itv3nmI7SQih0syF95/p8r5zn5wjkA8iYqslI7SC3kuJRPo3YNF6khg9nyA04gkuqvC0I82twPw= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755772652; c=relaxed/simple; bh=RVBuCyEroX7VX4W3006I0jDtc+XU/hPUdb5LYnFmQvE=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:To:Cc; b=suvksNrabmMA1+dsUb+7BqPw+3r57vNK6YVNH7aonLbrgf0tLhCA0oTnxcXGFRqjg2fW/BSTEMX6aYsmt7lG5YJt2NMYvhT+2ognLRWl8jeqkTvwHXkQQjr3Ac+aBduwNKYn+TOgmxLFwKKRILmJZHtfX3XwSpCTf4y3e+M/iwA= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=IEl1Cn87; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="IEl1Cn87" Received: by smtp.kernel.org (Postfix) with ESMTPS id 13C16C4CEED; Thu, 21 Aug 2025 10:37:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1755772651; bh=RVBuCyEroX7VX4W3006I0jDtc+XU/hPUdb5LYnFmQvE=; h=From:Date:Subject:To:Cc:Reply-To:From; b=IEl1Cn87zl7hbzEc/mR3qhN/7I7sp6TX/F7JFuJyEcbbJeLQYcNwkuwjorDWmFH3G XWkYGWkm2xzYwq6LX983MNHx1887HqzU/Eyu39DZ2Snk6OhbdVfQ+JwseqCTARDXlA pe2mmK15bYIlaXquWoo9p+/dEE/cS+mqnNrDknkOiRgwe4FSd1arpPSOdzjI+YkiaW Onk+D6bHYEP2EXCj0vdfcTmT8jqLsEzJy+AUFw9H7Zbj/+FchOx0sse/mcrCgacE0L sRPj871yOqp4vk+6bTLgcI5F6pucQCp1tdIvKxGZ1Ok3zVNXrJDnBNbcsO3VW/nofi 8pOSYMepk/evg== Received: from aws-us-west-2-korg-lkml-1.web.codeaurora.org (localhost.localdomain [127.0.0.1]) by smtp.lore.kernel.org (Postfix) with ESMTP id F20DECA0EDC; Thu, 21 Aug 2025 10:37:30 +0000 (UTC) From: Simon Schuster via B4 Relay Date: Thu, 21 Aug 2025 12:37:07 +0200 Subject: [PATCH] nios2: ensure that memblock.current_limit is set when setting pfn limits Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20250821-nios2-adjust-lowmem-bounds-v1-1-ea2dd8661ae5@siemens-energy.com> X-B4-Tracking: v=1; b=H4sIANL2pmgC/x3MwQqDMAwA0F+RnA3UglD3K8NDZ9KZMVtpVhXEf 1/x+C7vBOUsrPBoTsi8iUqKFV3bwDT7+GYUqgZrbG9c5zBKUouePkV/+E37wgu+Uomk2JOlwfl ggndQgzVzkOPOn+N1/QFbLef4bAAAAA== X-Change-ID: 20250818-nios2-adjust-lowmem-bounds-5d2d98af0fa8 To: Dinh Nguyen Cc: linux-kernel@vger.kernel.org, Simon Schuster , Andreas Oetken X-Mailer: b4 0.14.3-dev-2ce6c X-Developer-Signature: v=1; a=ed25519-sha256; t=1755772650; l=2529; i=schuster.simon@siemens-energy.com; s=20250818; h=from:subject:message-id; bh=XAavluzVGgOGPX323zI/x3pk1jtcKLayQnaSWVVemI4=; b=GcI81uCNpdeGjwM6REZsMNAj6DwIQzDGRCbchylCEARbO7bSUHPyscSO5GSDw63uq9NqcCk20 zGrVRHgILeSCebLJY4VTfGDt6FGAlApBgqOENV2dbv+4T0ZzTkxcKWz X-Developer-Key: i=schuster.simon@siemens-energy.com; a=ed25519; pk=PUhOMiSp43aSeRE1H41KApxYOluamBFFiMfKlBjocvo= X-Endpoint-Received: by B4 Relay for schuster.simon@siemens-energy.com/20250818 with auth_id=495 X-Original-From: Simon Schuster Reply-To: schuster.simon@siemens-energy.com From: Simon Schuster On nios2, with CONFIG_FLATMEM set, the kernel relies on memblock_get_current_limit() to determine the limits of mem_map, in particular for max_low_pfn. Unfortunately, memblock.current_limit is only default initialized to MEMBLOCK_ALLOC_ANYWHERE at this point of the bootup, potentially leading to situations where max_low_pfn can erroneously exceed the value of max_pfn and, thus, the valid range of available DRAM. This can in turn cause kernel-level paging failures, e.g.: [ 76.900000] Unable to handle kernel paging request at virtual address 20= 303000 [ 76.900000] ea =3D c0080890, ra =3D c000462c, cause =3D 14 [ 76.900000] Kernel panic - not syncing: Oops [ 76.900000] ---[ end Kernel panic - not syncing: Oops ]--- This patch fixes this by pre-calculating memblock.current_limit based on the upper limits of the available memory ranges via adjust_lowmem_bounds, a simplified version of the equivalent implementation within the arm architecture. Signed-off-by: Simon Schuster Signed-off-by: Andreas Oetken --- This patch was tested internally on 5.10.x stable for some time now and applies and boots cleanly on next-20250815, as well. --- arch/nios2/kernel/setup.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/arch/nios2/kernel/setup.c b/arch/nios2/kernel/setup.c index 2a40150142c3..f43f01c4ab93 100644 --- a/arch/nios2/kernel/setup.c +++ b/arch/nios2/kernel/setup.c @@ -142,6 +142,20 @@ static void __init find_limits(unsigned long *min, uns= igned long *max_low, *max_high =3D PFN_DOWN(memblock_end_of_DRAM()); } =20 +static void __init adjust_lowmem_bounds(void) +{ + phys_addr_t block_start, block_end; + u64 i; + phys_addr_t memblock_limit =3D 0; + + for_each_mem_range(i, &block_start, &block_end) { + if (block_end > memblock_limit) + memblock_limit =3D block_end; + } + + memblock_set_current_limit(memblock_limit); +} + void __init setup_arch(char **cmdline_p) { console_verbose(); @@ -157,6 +171,7 @@ void __init setup_arch(char **cmdline_p) /* Keep a copy of command line */ *cmdline_p =3D boot_command_line; =20 + adjust_lowmem_bounds(); find_limits(&min_low_pfn, &max_low_pfn, &max_pfn); =20 memblock_reserve(__pa_symbol(_stext), _end - _stext); --- base-commit: 1357b2649c026b51353c84ddd32bc963e8999603 change-id: 20250818-nios2-adjust-lowmem-bounds-5d2d98af0fa8 Best regards, --=20 Simon Schuster