From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qg0-f47.google.com (mail-qg0-f47.google.com [209.85.192.47]) by kanga.kvack.org (Postfix) with ESMTP id 1D2286B0257 for ; Fri, 4 Dec 2015 19:56:20 -0500 (EST) Received: by qgeb1 with SMTP id b1so103707692qge.1 for ; Fri, 04 Dec 2015 16:56:20 -0800 (PST) Received: from mail-qk0-x22c.google.com (mail-qk0-x22c.google.com. [2607:f8b0:400d:c09::22c]) by mx.google.com with ESMTPS id v72si8883598qka.96.2015.12.04.16.56.19 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 04 Dec 2015 16:56:19 -0800 (PST) Received: by qkcb135 with SMTP id b135so2362642qkc.3 for ; Fri, 04 Dec 2015 16:56:19 -0800 (PST) MIME-Version: 1.0 In-Reply-To: <20151204151913.166e5cb795359ff1a53d26ac@linux-foundation.org> References: <201512050045.l2G9WhTi%fengguang.wu@intel.com> <20151204151424.e73641da44c61f20f10d93e9@linux-foundation.org> <20151204151913.166e5cb795359ff1a53d26ac@linux-foundation.org> Date: Fri, 4 Dec 2015 16:56:19 -0800 Message-ID: Subject: Re: [linux-next:master 4174/4356] kernel/built-in.o:undefined reference to `mmap_rnd_bits' From: Daniel Cashman Content-Type: text/plain; charset=UTF-8 Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: kbuild test robot , kbuild-all@01.org, Mark Brown , Linux Memory Management List Yes, patch-set v5 addressed the MMU case. As for HAVE_ARCH_MMAP_RND_BITS=n, I deliberately made it such that once an arch implements the feature it selects it in its Kconfig, so we shouldn't have the situation where an arch relies on an mmap_rnd_bits* in its mmap.c, but doesn't find one defined. At present, I am planning to change the arm64/Kconfing to get rid of the "if MMU" portion, per Will Deacon's request, adjust the min bit value, and add a comment. I've left the question of whether or not the value should be the number of randomized bits (current situation) or the size of the address space chunk affected up to akpm@. Please let me know what else should be done in v6 to keep these in. Thank You, Dan On Fri, Dec 4, 2015 at 3:19 PM, Andrew Morton wrote: > On Fri, 4 Dec 2015 15:14:24 -0800 Andrew Morton wrote: > >> There's also the matter of CONFIG_MMU=n. > > ah, Arnd already fixed this one. I guess I'll retain the patches > for now. > > > > From: Arnd Bergmann > Subject: ARM: avoid ARCH_MMAP_RND_BITS for NOMMU > > ARM kernels with MMU disabled fail to build because of CONFIG_ARCH_MMAP_RND_BITS: > > kernel/built-in.o:(.data+0x754): undefined reference to `mmap_rnd_bits' > kernel/built-in.o:(.data+0x76c): undefined reference to `mmap_rnd_bits_min' > kernel/built-in.o:(.data+0x770): undefined reference to `mmap_rnd_bits_max' > > This changes the newly added line to only select this allow for > MMU-enabled kernels. > > Fixes: 14570b3fd31a ("arm: mm: support ARCH_MMAP_RND_BITS") > Signed-off-by: Arnd Bergmann > Cc: Daniel Cashman > Signed-off-by: Andrew Morton > --- > > arch/arm/Kconfig | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff -puN arch/arm/Kconfig~arm-mm-support-arch_mmap_rnd_bits-fix arch/arm/Kconfig > --- a/arch/arm/Kconfig~arm-mm-support-arch_mmap_rnd_bits-fix > +++ a/arch/arm/Kconfig > @@ -35,7 +35,7 @@ config ARM > select HAVE_ARCH_BITREVERSE if (CPU_32v7M || CPU_32v7) && !CPU_32v6 > select HAVE_ARCH_JUMP_LABEL if !XIP_KERNEL && !CPU_ENDIAN_BE32 > select HAVE_ARCH_KGDB if !CPU_ENDIAN_BE32 > - select HAVE_ARCH_MMAP_RND_BITS > + select HAVE_ARCH_MMAP_RND_BITS if MMU > select HAVE_ARCH_SECCOMP_FILTER if (AEABI && !OABI_COMPAT) > select HAVE_ARCH_TRACEHOOK > select HAVE_BPF_JIT > _ > -- Dan Cashman -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org