From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Mon, 9 Dec 2002 17:04:59 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Mon, 9 Dec 2002 17:04:58 -0500 Received: from e4.ny.us.ibm.com ([32.97.182.104]:33156 "EHLO e4.ny.us.ibm.com") by vger.kernel.org with ESMTP id ; Mon, 9 Dec 2002 17:03:48 -0500 Message-ID: <3DF514A1.9070502@us.ibm.com> Date: Mon, 09 Dec 2002 14:09:37 -0800 From: Dave Hansen User-Agent: Mozilla/5.0 (compatible; MSIE5.5; Windows 98; X-Accept-Language: en-us, en MIME-Version: 1.0 To: benh@kernel.crashing.org CC: Arjan van de Ven , Linux Kernel Mailing List Subject: [PATCHES] (4/4) stack updates for x86 Content-Type: multipart/mixed; boundary="------------070709000206030602050305" Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org This is a multi-part message in MIME format. --------------070709000206030602050305 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit The kernel currently uses an 8k stack, per task. Here is the infrastructure needed to allow us to halve that. D-4k-stack-2.5.50+bk-5.patch make a config option to turn on 4k stacks. (there appears to be a problem with this right now). -- Dave Hansen haveblue@us.ibm.com --------------070709000206030602050305 Content-Type: text/plain; name="D-4k-stack-2.5.50+bk-5.patch" Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="D-4k-stack-2.5.50+bk-5.patch" # This is a BitKeeper generated patch for the following project: # Project Name: Linux kernel tree # This patch format is intended for GNU patch command version 2.5 or higher. # This patch includes the following deltas: # ChangeSet 1.862 -> 1.864 # include/asm-i386/thread_info.h 1.13 -> 1.15 # arch/i386/Kconfig 1.15 -> 1.16 # # The following is the BitKeeper ChangeSet Log # -------------------------------------------- # 02/12/09 haveblue@elm3b96.(none) 1.863 # Merge elm3b96.(none):/work/dave/bk/linux-2.5-stack_size-config # into elm3b96.(none):/work/dave/bk/linux-2.5-4k_stack # -------------------------------------------- # 02/12/09 haveblue@elm3b96.(none) 1.864 # thread_info.h: # do sane overflow detection with 4k stack # -------------------------------------------- # diff -Nru a/arch/i386/Kconfig b/arch/i386/Kconfig --- a/arch/i386/Kconfig Mon Dec 9 13:33:26 2002 +++ b/arch/i386/Kconfig Mon Dec 9 13:33:26 2002 @@ -720,6 +720,16 @@ low memory. Setting this option will put user-space page table entries in high memory. +config 4K_STACK + bool "Use smaller 4k per-task stacks" + help + This option will shrink the kernel's per-task stack from 8k to + 4k. This will greatly increase your chance of overflowing it. + But, if you use the per-cpu interrupt stacks as well, your chances + go way down. Also try the CONFIG_X86_STACK_CHECK overflow + detection. It is much more reliable than the currently in-kernel + version. + config MATH_EMULATION bool "Math emulation" ---help--- diff -Nru a/include/asm-i386/thread_info.h b/include/asm-i386/thread_info.h --- a/include/asm-i386/thread_info.h Mon Dec 9 13:33:26 2002 +++ b/include/asm-i386/thread_info.h Mon Dec 9 13:33:26 2002 @@ -61,10 +61,16 @@ * * preempt_count needs to be 1 initially, until the scheduler is functional. */ -#define THREAD_ORDER 1 +#ifdef CONFIG_4K_STACK +#define THREAD_ORDER 0 +#define STACK_WARN 0x200 +#define STACK_PANIC 0x100 +#else +#define THREAD_ORDER 1 +#define STACK_WARN ((THREAD_SIZE)>>1) +#define STACK_PANIC 0x100 +#endif #define INIT_THREAD_SIZE THREAD_SIZE -#define STACK_PANIC 0x200ul -#define STACK_WARN ((THREAD_SIZE)>>1) #ifndef __ASSEMBLY__ --------------070709000206030602050305--