From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1031574AbXD3Rpa (ORCPT ); Mon, 30 Apr 2007 13:45:30 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1031579AbXD3Rpa (ORCPT ); Mon, 30 Apr 2007 13:45:30 -0400 Received: from holomorphy.com ([66.93.40.71]:56443 "EHLO holomorphy.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1031574AbXD3Rp2 (ORCPT ); Mon, 30 Apr 2007 13:45:28 -0400 Date: Mon, 30 Apr 2007 10:45:10 -0700 From: William Lee Irwin III To: Andi Kleen Cc: Christoph Hellwig , Alan Cox , David Chinner , Zan Lynx , Adrian Bunk , Linux Kernel Subject: [4/6] go BUG on vmallocspace in __pa() (was: Re: [-mm patch] i386: enable 4k stacks by default) Message-ID: <20070430174510.GG19966@holomorphy.com> References: <20070428191927.GN3468@stusta.de> <1177795118.7828.6.camel@localhost> <20070430035838.GC77450368@melbourne.sgi.com> <20070430091754.24df88df@the-village.bc.nu> <20070430104806.GA14944@infradead.org> <20070430173819.GC19966@holomorphy.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20070430173819.GC19966@holomorphy.com> Organization: The Domain of Holomorphy User-Agent: Mutt/1.5.13 (2006-08-11) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Apr 30, 2007 at 10:38:19AM -0700, William Lee Irwin III wrote: > Here's what I did for i386 for someone concerned about blowing the stack. Add checks to __pa() so it goes BUG() on vmallocspace addresses. Signed-off-by: William Irwin Index: stack-paranoia/arch/i386/kernel/doublefault.c =================================================================== --- stack-paranoia.orig/arch/i386/kernel/doublefault.c 2007-04-30 10:26:15.959875324 -0700 +++ stack-paranoia/arch/i386/kernel/doublefault.c 2007-04-30 10:34:55.201465216 -0700 @@ -62,5 +62,5 @@ .ss = __KERNEL_DS, .ds = __USER_DS, - .__cr3 = __pa(swapper_pg_dir) + .__cr3 = (unsigned long)swapper_pg_dir - PAGE_OFFSET, }; Index: stack-paranoia/arch/i386/mm/pgtable.c =================================================================== --- stack-paranoia.orig/arch/i386/mm/pgtable.c 2007-04-30 10:26:16.075881935 -0700 +++ stack-paranoia/arch/i386/mm/pgtable.c 2007-04-30 10:34:55.201465216 -0700 @@ -181,6 +181,15 @@ #endif } +unsigned long __kvaddr_to_paddr(unsigned long kvaddr) +{ + if (high_memory) + BUG_ON(kvaddr >= VMALLOC_START); + else + BUG_ON(kvaddr >= (unsigned long)__va(MAXMEM)); + return kvaddr - PAGE_OFFSET; +} + pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address) { return (pte_t *)__get_free_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO); Index: stack-paranoia/include/asm-i386/page.h =================================================================== --- stack-paranoia.orig/include/asm-i386/page.h 2007-04-30 10:26:32.012790127 -0700 +++ stack-paranoia/include/asm-i386/page.h 2007-04-30 10:34:55.197464988 -0700 @@ -118,11 +118,17 @@ #define __PAGE_OFFSET ((unsigned long)CONFIG_PAGE_OFFSET) #endif - #define PAGE_OFFSET ((unsigned long)__PAGE_OFFSET) + +#ifdef __ASSEMBLY__ +#define __pa(x) ((unsigned long)(x)-PAGE_OFFSET) +#else +extern unsigned long __kvaddr_to_paddr(unsigned long); +#define __pa(x) __kvaddr_to_paddr((unsigned long)(x)) +#endif + #define VMALLOC_RESERVE ((unsigned long)__VMALLOC_RESERVE) #define MAXMEM (-__PAGE_OFFSET-__VMALLOC_RESERVE) -#define __pa(x) ((unsigned long)(x)-PAGE_OFFSET) /* __pa_symbol should be used for C visible symbols. This seems to be the official gcc blessed way to do such arithmetic. */ #define __pa_symbol(x) __pa(RELOC_HIDE((unsigned long)(x),0))