| Message ID | 20161112004449.30566-1-f.fainelli@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Fri, 11 Nov 2016, 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 <f.fainelli@gmail.com> > --- > 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 [...] Why don't you do something more like: static inline phys_addr_t virt_to_phys(const volatile void *x) { + debug_virt_to_phys(x); return __virt_to_phys((unsigned long)(x)); } [...] static inline void debug_virt_to_phys(const void *address) { #ifdef CONFIG_DEBUG_VM BUG_ON(is_vmalloc_addr(address)); #endif } ? Nicolas
Le 11/11/2016 à 17:49, Nicolas Pitre a écrit : > On Fri, 11 Nov 2016, 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 <f.fainelli@gmail.com> >> --- >> 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 > [...] > > Why don't you do something more like: > > static inline phys_addr_t virt_to_phys(const volatile void *x) > { > + debug_virt_to_phys(x); > return __virt_to_phys((unsigned long)(x)); > } > > [...] > > static inline void debug_virt_to_phys(const void *address) > { > #ifdef CONFIG_DEBUG_VM > BUG_ON(is_vmalloc_addr(address)); > #endif > } > > ? This is how I started doing it initially, but to get the is_vmalloc_addr() definition, we need to include linux/mm.h and then everything falls apart because of the include and dependencies chain. We could open code the is_vmalloc_addr() check because that's simple enough, but we still need VMALLOC_START and VMALLOC_END and to get there we need to include pgtable.h, and there are still some inclusion problems in doing so. The other reason was to avoid putting the same checks in architecture specific code, except for those like ARM/ARM64/Unicore32/Microblaze where I could not find a simple way to undefined virt_to_phys and redefine it to debug_virt_to_phys. Do you see an other way around this? Thanks!
On Fri, Nov 11, 2016 at 04:44:43PM -0800, 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 <f.fainelli@gmail.com> > --- > 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(+) What's the interaction between this and the DEBUG_VIRTUAL patches from Laura? http://lkml.kernel.org/r/20161102210054.16621-7-labbott@redhat.com They seem to be tackling the exact same problem afaict. Will
On Fri, 11 Nov 2016, Florian Fainelli wrote: > Le 11/11/2016 à 17:49, Nicolas Pitre a écrit : > > On Fri, 11 Nov 2016, 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 <f.fainelli@gmail.com> > >> --- > >> 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 > > [...] > > > > Why don't you do something more like: > > > > static inline phys_addr_t virt_to_phys(const volatile void *x) > > { > > + debug_virt_to_phys(x); > > return __virt_to_phys((unsigned long)(x)); > > } > > > > [...] > > > > static inline void debug_virt_to_phys(const void *address) > > { > > #ifdef CONFIG_DEBUG_VM > > BUG_ON(is_vmalloc_addr(address)); > > #endif > > } > > > > ? > > This is how I started doing it initially, but to get the > is_vmalloc_addr() definition, we need to include linux/mm.h and then > everything falls apart because of the include and dependencies chain. We > could open code the is_vmalloc_addr() check because that's simple > enough, but we still need VMALLOC_START and VMALLOC_END and to get there > we need to include pgtable.h, and there are still some inclusion > problems in doing so. > > The other reason was to avoid putting the same checks in architecture > specific code, except for those like ARM/ARM64/Unicore32/Microblaze > where I could not find a simple way to undefined virt_to_phys and > redefine it to debug_virt_to_phys. You could still move the check out of line like in your patch. But the debug function doesn't have to be the one returning the translated address. This has the advantage of cutting on the amount of ifdefery. Nicolas
Le 11/11/2016 à 21:43, Will Deacon a écrit : > On Fri, Nov 11, 2016 at 04:44:43PM -0800, 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 <f.fainelli@gmail.com> >> --- >> 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(+) > > What's the interaction between this and the DEBUG_VIRTUAL patches from Laura? > > http://lkml.kernel.org/r/20161102210054.16621-7-labbott@redhat.com > > They seem to be tackling the exact same problem afaict. Indeed thanks for pointing that out, I guess I could piggy back on this patchset and try to cover ARM. Thanks!
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 <f.fainelli@gmail.com> > --- > 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 <asm/memory.h> > +#include <linux/mm.h> > + > +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
On 11/14/2016 10:45 AM, Laura Abbott wrote: > 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 <f.fainelli@gmail.com> >> --- >> 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 <asm/memory.h> >> +#include <linux/mm.h> >> + >> +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. Indeed, thanks. > 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. For one, my patch causes an early BUG to occur on ARM64 during arch/arm64/kernel/setup.c::setup_arch when we call cpu_uninstall_idmap(). I suspect there could be a bunch of little checks like these where we'd have to have an architecture specific "is this physical/virtual address valid" that may make a generic implementation hard to come up with.
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 <asm/memory.h> +#include <linux/mm.h> + +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 */
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 <f.fainelli@gmail.com> --- 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(+)