From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754626AbYJCPye (ORCPT ); Fri, 3 Oct 2008 11:54:34 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753017AbYJCPyZ (ORCPT ); Fri, 3 Oct 2008 11:54:25 -0400 Received: from nf-out-0910.google.com ([64.233.182.185]:16246 "EHLO nf-out-0910.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752801AbYJCPyZ (ORCPT ); Fri, 3 Oct 2008 11:54:25 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=date:to:cc:subject:message-id:mime-version:content-type :content-disposition:in-reply-to:user-agent:from; b=lhATI8ZXpOTuSO+A++qHscovTWfSwhbdLoiAylGdUfefO4konKayB9VL+jSE2Azfql KjUdfBSVbyEkPeDYw/8tsYh0X/kEh6ZHRYo2jVsvesXr+VPfCJLJrCnV5f+j33RNcV4O wK+nxHVflJHWNIz9b+VUG49mbn6+ewamiFS1w= Date: Fri, 3 Oct 2008 17:54:25 +0200 To: Jiri Slaby Cc: Ingo Molnar , Andi Kleen , linux-kernel@vger.kernel.org Subject: Re: [PATCH -tip] x86: fix virt_addr_valid() with CONFIG_DEBUG_VIRTUAL=y (try 2) Message-ID: <20081003155425.GA6112@localhost.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <48E62AF7.5040008@gmail.com> User-Agent: Mutt/1.5.18 (2008-05-17) From: Vegard Nossum Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Oct 3, 2008 at 4:23 PM, Jiri Slaby wrote: > Vegard Nossum napsal(a): >> How about this? It would apply to tip/x86/mm-debug. Untested. > > It is wrong in my eyes -- it's workarounding of the real problem rather than > fixing. virt_addr_valid() should be fixed/augmented to the full virtual > address domain instead or not used for the purpose you need in kmemcheck. > > As it is now, it should be used only on direct mapping addresses (more > concrete: kernel image space and physical mapping) and it returns > semi-random values on the rest -- with CONFIG_DEBUG_VIRTUAL=y it screams > instead of returning a bogus value. > Is this what you had in mind? If not, then I don't know how to do it :-) It seems that it might be structured in a better way -- but that better way eludes my imagination. Thanks for commenting! Vegard >>From 320c68f94e1a2071c64ecc9db6358801bd0c1f0b Mon Sep 17 00:00:00 2001 From: Vegard Nossum Date: Fri, 3 Oct 2008 15:58:50 +0200 Subject: [PATCH] x86: fix virt_addr_valid() virt_addr_valid() calls __pa(), which calls __phys_addr(). With CONFIG_DEBUG_VIRTUAL=y, __phys_addr() will kill the kernel if the address *isn't* valid. That's clearly wrong for virt_addr_valid(). We also incorporate the debugging checks into virt_addr_valid(). Cc: Jiri Slaby Cc: Andi Kleen Signed-off-by: Vegard Nossum --- arch/x86/kernel/doublefault_32.c | 2 +- arch/x86/mm/ioremap.c | 37 +++++++++++++++++++++++++++++++++++-- include/asm-x86/page.h | 8 +++++++- include/asm-x86/page_32.h | 4 ++-- 4 files changed, 45 insertions(+), 6 deletions(-) diff --git a/arch/x86/kernel/doublefault_32.c b/arch/x86/kernel/doublefault_32.c index 395acb1..b4f14c6 100644 --- a/arch/x86/kernel/doublefault_32.c +++ b/arch/x86/kernel/doublefault_32.c @@ -66,6 +66,6 @@ struct tss_struct doublefault_tss __cacheline_aligned = { .ds = __USER_DS, .fs = __KERNEL_PERCPU, - .__cr3 = __phys_addr_const((unsigned long)swapper_pg_dir) + .__cr3 = __pa_nodebug(swapper_pg_dir), } }; diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c index 835e062..b20389d 100644 --- a/arch/x86/mm/ioremap.c +++ b/arch/x86/mm/ioremap.c @@ -45,6 +45,28 @@ unsigned long __phys_addr(unsigned long x) } EXPORT_SYMBOL(__phys_addr); +bool __virt_addr_valid(unsigned long x) +{ + if (x >= __START_KERNEL_map) { + x -= __START_KERNEL_map; + if (x >= KERNEL_IMAGE_SIZE) + return false; + x += phys_base; + } else { + if (x < PAGE_OFFSET) + return false; + x -= PAGE_OFFSET; + if (system_state == SYSTEM_BOOTING + ? x > MAXMEM : !phys_addr_valid(x)) + { + return false; + } + } + + return pfn_valid(x >> PAGE_SHIFT); +} +EXPORT_SYMBOL(__virt_addr_valid); + #else static inline int phys_addr_valid(unsigned long addr) @@ -56,13 +78,24 @@ static inline int phys_addr_valid(unsigned long addr) unsigned long __phys_addr(unsigned long x) { /* VMALLOC_* aren't constants; not available at the boot time */ - VIRTUAL_BUG_ON(x < PAGE_OFFSET || (system_state != SYSTEM_BOOTING && - is_vmalloc_addr((void *)x))); + VIRTUAL_BUG_ON(x < PAGE_OFFSET); + VIRTUAL_BUG_ON(system_state != SYSTEM_BOOTING && + is_vmalloc_addr((void *) x)); return x - PAGE_OFFSET; } EXPORT_SYMBOL(__phys_addr); #endif +bool __virt_addr_valid(unsigned long x) +{ + if (x < PAGE_OFFSET) + return false; + if (system_state != SYSTEM_BOOTING && is_vmalloc_addr((void *) x)) + return false; + return pfn_valid((x - PAGE_OFFSET) >> PAGE_SHIFT); +} +EXPORT_SYMBOL(__virt_addr_valid); + #endif int page_is_ram(unsigned long pagenr) diff --git a/include/asm-x86/page.h b/include/asm-x86/page.h index c915747..d4f1d57 100644 --- a/include/asm-x86/page.h +++ b/include/asm-x86/page.h @@ -179,6 +179,7 @@ static inline pteval_t native_pte_flags(pte_t pte) #endif /* CONFIG_PARAVIRT */ #define __pa(x) __phys_addr((unsigned long)(x)) +#define __pa_nodebug(x) __phys_addr_nodebug((unsigned long)(x)) /* __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(__phys_reloc_hide((unsigned long)(x))) @@ -188,9 +189,14 @@ static inline pteval_t native_pte_flags(pte_t pte) #define __boot_va(x) __va(x) #define __boot_pa(x) __pa(x) +/* + * virt_to_page(kaddr) returns a valid pointer if and only if + * virt_addr_valid(kaddr) returns true. + */ #define virt_to_page(kaddr) pfn_to_page(__pa(kaddr) >> PAGE_SHIFT) #define pfn_to_kaddr(pfn) __va((pfn) << PAGE_SHIFT) -#define virt_addr_valid(kaddr) pfn_valid(__pa(kaddr) >> PAGE_SHIFT) +extern bool __virt_addr_valid(unsigned long kaddr); +#define virt_addr_valid(kaddr) __virt_addr_valid((unsigned long) (kaddr)) #endif /* __ASSEMBLY__ */ diff --git a/include/asm-x86/page_32.h b/include/asm-x86/page_32.h index 82b0109..deec501 100644 --- a/include/asm-x86/page_32.h +++ b/include/asm-x86/page_32.h @@ -71,11 +71,11 @@ typedef struct page *pgtable_t; #endif #ifndef __ASSEMBLY__ -#define __phys_addr_const(x) ((x) - PAGE_OFFSET) +#define __phys_addr_nodebug(x) ((x) - PAGE_OFFSET) #ifdef CONFIG_DEBUG_VIRTUAL extern unsigned long __phys_addr(unsigned long); #else -#define __phys_addr(x) ((x) - PAGE_OFFSET) +#define __phys_addr(x) __phys_addr_nodebug(x) #endif #define __phys_reloc_hide(x) RELOC_HIDE((x), 0) -- 1.5.5.1