From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S936189AbcKNSpk (ORCPT ); Mon, 14 Nov 2016 13:45:40 -0500 Received: from mail-qk0-f170.google.com ([209.85.220.170]:35477 "EHLO mail-qk0-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754085AbcKNSpg (ORCPT ); Mon, 14 Nov 2016 13:45:36 -0500 Subject: Re: [PATCH RFC] mm: Add debug_virt_to_phys() To: Florian Fainelli , linux-kernel@vger.kernel.org References: <20161112004449.30566-1-f.fainelli@gmail.com> Cc: Russell King , Catalin Marinas , Will Deacon , Arnd Bergmann , Nicolas Pitre , Chris Brandt , Pratyush Anand , Ard Biesheuvel , Mark Rutland , James Morse , Neeraj Upadhyay , Andrew Morton , Vlastimil Babka , Michal Hocko , "Kirill A. Shutemov" , Jerome Marchand , Konstantin Khlebnikov , Joonsoo Kim , "moderated list:ARM PORT" , "open list:GENERIC INCLUDE/ASM HEADER FILES" , "open list:MEMORY MANAGEMENT" From: Laura Abbott Message-ID: Date: Mon, 14 Nov 2016 10:45:29 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.4.0 MIME-Version: 1.0 In-Reply-To: <20161112004449.30566-1-f.fainelli@gmail.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/11/2016 04:44 PM, Florian Fainelli wrote: > When CONFIG_DEBUG_VM is turned on, virt_to_phys() maps to > debug_virt_to_phys() which helps catch vmalloc space addresses being > passed. This is helpful in debugging bogus drivers that just assume > linear mappings all over the place. > > For ARM, ARM64, Unicore32 and Microblaze, the architectures define > __virt_to_phys() as being the functional implementation of the address > translation, so we special case the debug stub to call into > __virt_to_phys directly. > > Signed-off-by: Florian Fainelli > --- > arch/arm/include/asm/memory.h | 4 ++++ > arch/arm64/include/asm/memory.h | 4 ++++ > include/asm-generic/memory_model.h | 4 ++++ > mm/debug.c | 15 +++++++++++++++ > 4 files changed, 27 insertions(+) > > diff --git a/arch/arm/include/asm/memory.h b/arch/arm/include/asm/memory.h > index 76cbd9c674df..448dec9b8b00 100644 > --- a/arch/arm/include/asm/memory.h > +++ b/arch/arm/include/asm/memory.h > @@ -260,11 +260,15 @@ static inline unsigned long __phys_to_virt(phys_addr_t x) > * translation for translating DMA addresses. Use the driver > * DMA support - see dma-mapping.h. > */ > +#ifndef CONFIG_DEBUG_VM > #define virt_to_phys virt_to_phys > static inline phys_addr_t virt_to_phys(const volatile void *x) > { > return __virt_to_phys((unsigned long)(x)); > } > +#else > +#define virt_to_phys debug_virt_to_phys > +#endif > > #define phys_to_virt phys_to_virt > static inline void *phys_to_virt(phys_addr_t x) > diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h > index b71086d25195..c9e436b28523 100644 > --- a/arch/arm64/include/asm/memory.h > +++ b/arch/arm64/include/asm/memory.h > @@ -186,11 +186,15 @@ extern u64 kimage_voffset; > * translation for translating DMA addresses. Use the driver > * DMA support - see dma-mapping.h. > */ > +#ifndef CONFIG_DEBUG_VM > #define virt_to_phys virt_to_phys > static inline phys_addr_t virt_to_phys(const volatile void *x) > { > return __virt_to_phys((unsigned long)(x)); > } > +#else > +#define virt_to_phys debug_virt_to_phys > +#endif > > #define phys_to_virt phys_to_virt > static inline void *phys_to_virt(phys_addr_t x) > diff --git a/include/asm-generic/memory_model.h b/include/asm-generic/memory_model.h > index 5148150cc80b..426085757258 100644 > --- a/include/asm-generic/memory_model.h > +++ b/include/asm-generic/memory_model.h > @@ -80,6 +80,10 @@ > #define page_to_pfn __page_to_pfn > #define pfn_to_page __pfn_to_page > > +#ifdef CONFIG_DEBUG_VM > +unsigned long debug_virt_to_phys(volatile void *address); > +#endif /* CONFIG_DEBUG_VM */ > + > #endif /* __ASSEMBLY__ */ > > #endif > diff --git a/mm/debug.c b/mm/debug.c > index 9feb699c5d25..72b2ca9b11f4 100644 > --- a/mm/debug.c > +++ b/mm/debug.c > @@ -161,4 +161,19 @@ void dump_mm(const struct mm_struct *mm) > ); > } > > +#include > +#include > + > +unsigned long debug_virt_to_phys(volatile void *address) > +{ > + BUG_ON(is_vmalloc_addr((const void *)address)); > +#if defined(CONFIG_ARM) || defined(CONFIG_ARM64) || defined(CONFIG_UNICORE32) || \ > + defined(CONFIG_MICROBLAZE) > + return __virt_to_phys(address); > +#else > + return virt_to_phys(address); > +#endif > +} > +EXPORT_SYMBOL(debug_virt_to_phys); > + > #endif /* CONFIG_DEBUG_VM */ > is_vmalloc_addr is necessary but not sufficient. This misses cases like module addresses. The x86 version (CONFIG_DEBUG_VIRTUAL) bounds checks against the known linear map to catch all cases. I'm for a generic approach to this if it can catch all cases that an architecture specific version would catch. Thanks, Laura