From patchwork Tue Feb 10 06:42:17 2009 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Anton Blanchard X-Patchwork-Id: 22862 X-Patchwork-Delegate: benh@kernel.crashing.org Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from ozlabs.org (localhost [127.0.0.1]) by ozlabs.org (Postfix) with ESMTP id A621ADDED7 for ; Tue, 10 Feb 2009 17:45:47 +1100 (EST) X-Original-To: linuxppc-dev@ozlabs.org Delivered-To: linuxppc-dev@ozlabs.org Received: by ozlabs.org (Postfix, from userid 1010) id 28544DDECA; Tue, 10 Feb 2009 17:43:55 +1100 (EST) Date: Tue, 10 Feb 2009 17:42:17 +1100 From: Anton Blanchard To: linuxppc-dev@ozlabs.org Subject: [PATCH] shift 64bit unmapped_area to top of address space Message-ID: <20090210064217.GD23273@kryten> MIME-Version: 1.0 Content-Disposition: inline User-Agent: Mutt/1.5.18 (2008-05-17) X-BeenThere: linuxppc-dev@ozlabs.org X-Mailman-Version: 2.1.11 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@ozlabs.org Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@ozlabs.org We currently place mmaps just below the stack on 32bit, but leave them in the middle of the address space on 64bit: 00100000-00120000 r-xp 00100000 00:00 0 [vdso] 10000000-10010000 r-xp 00000000 08:06 179534 /tmp/sleep 10010000-10020000 rw-p 00000000 08:06 179534 /tmp/sleep 10020000-10130000 rw-p 10020000 00:00 0 [heap] 40000000000-40000030000 r-xp 00000000 08:06 440743 /lib64/ld-2.9.so 40000030000-40000040000 rw-p 00020000 08:06 440743 /lib64/ld-2.9.so 40000050000-400001f0000 r-xp 00000000 08:06 440671 /lib64/libc-2.9.so 400001f0000-40000200000 r--p 00190000 08:06 440671 /lib64/libc-2.9.so 40000200000-40000220000 rw-p 001a0000 08:06 440671 /lib64/libc-2.9.so 40000220000-40008230000 rw-p 40000220000 00:00 0 fffffbc0000-fffffd10000 rw-p fffffeb0000 00:00 0 [stack] Right now it isn't an issue, but at some stage we will run into mmap or hugetlb allocation issues. Using the same layout as 32bit gives us a some breathing room. This matches what x86-64 is doing too. 00100000-00103000 r-xp 00100000 00:00 0 [vdso] 10000000-10001000 r-xp 00000000 08:06 554894 /tmp/test 10010000-10011000 r--p 00000000 08:06 554894 /tmp/test 10011000-10012000 rw-p 00001000 08:06 554894 /tmp/test 10012000-10113000 rw-p 10012000 00:00 0 [heap] fffefdf7000-ffff7df8000 rw-p fffefdf7000 00:00 0 ffff7df8000-ffff7f97000 r-xp 00000000 08:06 130591 /lib64/libc-2.9.so ffff7f97000-ffff7fa6000 ---p 0019f000 08:06 130591 /lib64/libc-2.9.so ffff7fa6000-ffff7faa000 r--p 0019e000 08:06 130591 /lib64/libc-2.9.so ffff7faa000-ffff7fc0000 rw-p 001a2000 08:06 130591 /lib64/libc-2.9.so ffff7fc0000-ffff7fc4000 rw-p ffff7fc0000 00:00 0 ffff7fc4000-ffff7fec000 r-xp 00000000 08:06 130663 /lib64/ld-2.9.so ffff7fee000-ffff7ff0000 rw-p ffff7fee000 00:00 0 ffff7ffa000-ffff7ffb000 rw-p ffff7ffa000 00:00 0 ffff7ffb000-ffff7ffc000 r--p 00027000 08:06 130663 /lib64/ld-2.9.so ffff7ffc000-ffff7fff000 rw-p 00028000 08:06 130663 /lib64/ld-2.9.so ffff7fff000-ffff8000000 rw-p ffff7fff000 00:00 0 fffffc59000-fffffc6e000 rw-p ffffffeb000 00:00 0 [stack] Signed-off-by: Anton Blanchard diff --git a/arch/powerpc/mm/mmap.c b/arch/powerpc/mm/mmap.c index 86010fc..7db8abc 100644 --- a/arch/powerpc/mm/mmap.c +++ b/arch/powerpc/mm/mmap.c @@ -48,12 +48,6 @@ static inline unsigned long mmap_base(void) static inline int mmap_is_legacy(void) { - /* - * Force standard allocation for 64 bit programs. - */ - if (!test_thread_flag(TIF_32BIT)) - return 1; - if (current->personality & ADDR_COMPAT_LAYOUT) return 1;