From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3xtF5K39RmzDr8P for ; Thu, 14 Sep 2017 20:24:37 +1000 (AEST) Received: from pps.filterd (m0098409.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.21/8.16.0.21) with SMTP id v8EAOB4E128562 for ; Thu, 14 Sep 2017 06:24:35 -0400 Received: from e31.co.us.ibm.com (e31.co.us.ibm.com [32.97.110.149]) by mx0a-001b2d01.pphosted.com with ESMTP id 2cyqvb0gq3-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Thu, 14 Sep 2017 06:24:34 -0400 Received: from localhost by e31.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Thu, 14 Sep 2017 04:24:34 -0600 From: Stewart Smith To: obh+dt@kernel.org, frowand.list@gmail.com, devicetree@vger.kernel.org Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, Stewart Smith Subject: [PATCH] drivers: of: static DT reservations incorrectly added to dynamic list Date: Thu, 14 Sep 2017 20:24:15 +1000 Message-Id: <20170914102415.26395-1-stewart@linux.vnet.ibm.com> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , There are two types of memory reservations firmware can ask the kernel to make in the device tree: static and dynamic. See Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt If you have greater than 16 entries in /reserved-memory (as we do on POWER9 systems) you would get this scary looking error message: [ 0.000000] OF: reserved mem: not enough space all defined regions. This is harmless if all your reservations are static (which with OPAL on POWER9, they are). It is not harmless if you have any dynamic reservations after the 16th. In the first pass over the fdt to find reservations, the child nodes of /reserved-memory are added to a static array in of_reserved_mem.c so that memory can be reserved in a 2nd pass. The array has 16 entries. This is why, on my dual socket POWER9 system, I get that error 4 times with 20 static reservations. We don't have a problem on ppc though, as in arch/powerpc/kernel/prom.c we look at the new style /reserved-ranges property to do reservations, and this logic was introduced in 0962e8004e974 (well before any powernv system shipped). Google shows up no occurances of that exact error message, so we're probably safe in that no machine that people use has memory not being reserved when it should be. The fix is simple, as there's a different code path for static and dynamic allocations, we just don't add the region to the list if it's static. Since it's a static *OR* dynamic region, this is a perfectly valid thing to do (although I have not checked every real world device tree on the planet for this condition) Fixes: 3f0c8206644836e4f10a6b9fc47cda6a9a372f9b Signed-off-by: Stewart Smith --- NOTE: I've done only fairly limited testing of this on POWER, I certainly haven't tested on ARM or *anything* with dynamic allocations. So, testing and comments welcome. --- drivers/of/fdt.c | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-) diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c index ce30c9a588a4..a9a44099ed69 100644 --- a/drivers/of/fdt.c +++ b/drivers/of/fdt.c @@ -587,7 +587,7 @@ static int __init __reserved_mem_reserve_reg(unsigned long node, phys_addr_t base, size; int len; const __be32 *prop; - int nomap, first = 1; + int nomap; prop = of_get_flat_dt_prop(node, "reg", &len); if (!prop) @@ -614,10 +614,6 @@ static int __init __reserved_mem_reserve_reg(unsigned long node, uname, &base, (unsigned long)size / SZ_1M); len -= t_len; - if (first) { - fdt_reserved_mem_save_node(node, uname, base, size); - first = 0; - } } return 0; } -- 2.13.5