From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761159AbdADRUS (ORCPT ); Wed, 4 Jan 2017 12:20:18 -0500 Received: from mail-qk0-f172.google.com ([209.85.220.172]:32871 "EHLO mail-qk0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756820AbdADRUL (ORCPT ); Wed, 4 Jan 2017 12:20:11 -0500 Subject: Re: [PATCH v5 3/4] ARM: Add support for CONFIG_DEBUG_VIRTUAL To: Florian Fainelli , linux-arm-kernel@lists.infradead.org, catalin.marinas@arm.com References: <20170104011417.1496-1-f.fainelli@gmail.com> <20170104011417.1496-4-f.fainelli@gmail.com> Cc: linux@armlinux.org.uk, nicolas.pitre@linaro.org, panand@redhat.com, chris.brandt@renesas.com, arnd@arndb.de, jonathan.austin@arm.com, pawel.moll@arm.com, vladimir.murzin@arm.com, mark.rutland@arm.com, ard.biesheuvel@linaro.org, keescook@chromium.org, matt@codeblueprint.co.uk, labbott@fedoraproject.org, kirill.shutemov@linux.intel.com, ben@decadent.org.uk, js07.lee@samsung.com, stefan@agner.ch, linux-kernel@vger.kernel.org, linux-mtd@lists.infradead.org, cyrille.pitchen@atmel.com, richard@nod.at, boris.brezillon@free-electrons.com, computersforpeace@gmail.com, dwmw2@infradead.org, will.deacon@arm.com From: Laura Abbott Message-ID: <54226b74-85c2-d6c8-6e36-05b840d39734@redhat.com> Date: Wed, 4 Jan 2017 09:20:01 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.5.1 MIME-Version: 1.0 In-Reply-To: <20170104011417.1496-4-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 01/03/2017 05:14 PM, Florian Fainelli wrote: > x86 has an option: CONFIG_DEBUG_VIRTUAL to do additional checks on > virt_to_phys calls. The goal is to catch users who are calling > virt_to_phys on non-linear addresses immediately. This includes caller > using __virt_to_phys() on image addresses instead of __pa_symbol(). This > is a generally useful debug feature to spot bad code (particulary in > drivers). > > Acked-by: Russell King > Signed-off-by: Florian Fainelli This mostly looks good with a few comments below > --- > arch/arm/Kconfig | 1 + > arch/arm/include/asm/memory.h | 16 +++++++++++-- > arch/arm/mm/Makefile | 1 + > arch/arm/mm/physaddr.c | 55 +++++++++++++++++++++++++++++++++++++++++++ > 4 files changed, 71 insertions(+), 2 deletions(-) > create mode 100644 arch/arm/mm/physaddr.c > > diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig > index 5fab553fd03a..4700294f4e09 100644 > --- a/arch/arm/Kconfig > +++ b/arch/arm/Kconfig > @@ -2,6 +2,7 @@ config ARM > bool > default y > select ARCH_CLOCKSOURCE_DATA > + select ARCH_HAS_DEBUG_VIRTUAL > select ARCH_HAS_DEVMEM_IS_ALLOWED > select ARCH_HAS_ELF_RANDOMIZE > select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST > diff --git a/arch/arm/include/asm/memory.h b/arch/arm/include/asm/memory.h > index bee7511c5098..d90300193adf 100644 > --- a/arch/arm/include/asm/memory.h > +++ b/arch/arm/include/asm/memory.h > @@ -213,7 +213,7 @@ extern const void *__pv_table_begin, *__pv_table_end; > : "r" (x), "I" (__PV_BITS_31_24) \ > : "cc") > > -static inline phys_addr_t __virt_to_phys(unsigned long x) > +static inline phys_addr_t __virt_to_phys_nodebug(unsigned long x) > { > phys_addr_t t; > > @@ -245,7 +245,7 @@ static inline unsigned long __phys_to_virt(phys_addr_t x) > #define PHYS_OFFSET PLAT_PHYS_OFFSET > #define PHYS_PFN_OFFSET ((unsigned long)(PHYS_OFFSET >> PAGE_SHIFT)) > > -static inline phys_addr_t __virt_to_phys(unsigned long x) > +static inline phys_addr_t __virt_to_phys_nodebug(unsigned long x) > { > return (phys_addr_t)x - PAGE_OFFSET + PHYS_OFFSET; > } > @@ -261,6 +261,16 @@ static inline unsigned long __phys_to_virt(phys_addr_t x) > ((((unsigned long)(kaddr) - PAGE_OFFSET) >> PAGE_SHIFT) + \ > PHYS_PFN_OFFSET) > > +#define __pa_symbol_nodebug(x) __virt_to_phys_nodebug((x)) > + > +#ifdef CONFIG_DEBUG_VIRTUAL > +extern phys_addr_t __virt_to_phys(unsigned long x); > +extern phys_addr_t __phys_addr_symbol(unsigned long x); > +#else > +#define __virt_to_phys(x) __virt_to_phys_nodebug(x) > +#define __phys_addr_symbol(x) __pa_symbol_nodebug(x) > +#endif > + > /* > * These are *only* valid on the kernel direct mapped RAM memory. > * Note: Drivers should NOT use these. They are the wrong > @@ -283,9 +293,11 @@ static inline void *phys_to_virt(phys_addr_t x) > * Drivers should NOT use these either. > */ > #define __pa(x) __virt_to_phys((unsigned long)(x)) > +#define __pa_symbol(x) __phys_addr_symbol(RELOC_HIDE((unsigned long)(x), 0)) > #define __va(x) ((void *)__phys_to_virt((phys_addr_t)(x))) > #define pfn_to_kaddr(pfn) __va((phys_addr_t)(pfn) << PAGE_SHIFT) > > + Extra blank here > extern long long arch_phys_to_idmap_offset; > > /* > diff --git a/arch/arm/mm/Makefile b/arch/arm/mm/Makefile > index e8698241ece9..b3dea80715b4 100644 > --- a/arch/arm/mm/Makefile > +++ b/arch/arm/mm/Makefile > @@ -14,6 +14,7 @@ endif > > obj-$(CONFIG_ARM_PTDUMP) += dump.o > obj-$(CONFIG_MODULES) += proc-syms.o > +obj-$(CONFIG_DEBUG_VIRTUAL) += physaddr.o > > obj-$(CONFIG_ALIGNMENT_TRAP) += alignment.o > obj-$(CONFIG_HIGHMEM) += highmem.o > diff --git a/arch/arm/mm/physaddr.c b/arch/arm/mm/physaddr.c > new file mode 100644 > index 000000000000..f10bdcbcb155 > --- /dev/null > +++ b/arch/arm/mm/physaddr.c > @@ -0,0 +1,55 @@ > +#include > +#include > +#include > +#include > +#include > + > +#include > +#include > +#include > +#include > + > +#include "mm.h" > + > +static inline bool __virt_addr_valid(unsigned long x) > +{ > + /* high_memory does not get immediately defined, and there > + * are early callers of __pa() against PAGE_OFFSET > + */ Nit: All the comments in this file should have the text starting on the next line after the /* > + if (!high_memory && x >= PAGE_OFFSET) > + return true; > + > + if (high_memory && x >= PAGE_OFFSET && x < (unsigned long)high_memory) > + return true; > + > + /* ARM uses the default per-CPU allocation routing which forces us to > + * have an explicit check here to avoid a false positive > + */ This comment isn't fully descriptive, MAX_DMA_ADDRESS could be used in more places than just per-CPU allocation. Suggestion: /* * MAX_DMA_ADDRESS is a virtual address that may not correspond to an actual * physical address. Enough code relies on __pa(MAX_DMA_ADDRESS) that we just * need to work around it and always return true. */ > + if (x == MAX_DMA_ADDRESS) > + return true; > + > + return false; > +} > + > +phys_addr_t __virt_to_phys(unsigned long x) > +{ > + WARN(!__virt_addr_valid(x), > + "virt_to_phys used for non-linear address: %pK (%pS)\n", > + (void *)x, > + (void *)x); > + > + return __virt_to_phys_nodebug(x); > +} > +EXPORT_SYMBOL(__virt_to_phys); > + > +phys_addr_t __phys_addr_symbol(unsigned long x) > +{ > + /* This is bounds checking against the kernel image only. > + * __pa_symbol should only be used on kernel symbol addresses. > + */ > + VIRTUAL_BUG_ON(x < (unsigned long)KERNEL_START || > + x > (unsigned long)KERNEL_END); > + > + return __pa_symbol_nodebug(x); > +} > +EXPORT_SYMBOL(__phys_addr_symbol); > With those comments, you can add Acked-by: Laura Abbott