| Message ID | 7faa60aa4a606b5c5c1ae374d82a7eee6c764b38.1592292685.git.zong.li@sifive.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Add STRICT_DEVMEM support on RISC-V | expand |
Στις 2020-06-16 10:45, Zong Li έγραψε: > Implement the 'devmem_is_allowed()' interface for RISC-V, like some of > other architectures have done. It will be called from > range_is_allowed() > when userpsace attempts to access /dev/mem. > > Access to exclusive IOMEM and kernel RAM is denied unless > CONFIG_STRICT_DEVMEM is set to 'n'. > > Test it by devmem, the result as follows: > > - CONFIG_STRICT_DEVMEM=y > $ devmem 0x10010000 > 0x00000000 > $ devmem 0x80200000 > 0x0000106F > > - CONFIG_STRICT_DEVMEM is not set > $ devmem 0x10010000 > devmem: mmap: Operation not permitted > $ devmem 0x80200000 > devmem: mmap: Operation not permitted > > Signed-off-by: Zong Li <zong.li@sifive.com> > --- > arch/riscv/Kconfig | 1 + > arch/riscv/include/asm/io.h | 2 ++ > arch/riscv/mm/init.c | 19 +++++++++++++++++++ > 3 files changed, 22 insertions(+) > > diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig > index 128192e14ff2..ffd7841ede4c 100644 > --- a/arch/riscv/Kconfig > +++ b/arch/riscv/Kconfig > @@ -16,6 +16,7 @@ config RISCV > select ARCH_HAS_BINFMT_FLAT > select ARCH_HAS_DEBUG_VIRTUAL if MMU > select ARCH_HAS_DEBUG_WX > + select ARCH_HAS_DEVMEM_IS_ALLOWED > select ARCH_HAS_GCOV_PROFILE_ALL > select ARCH_HAS_GIGANTIC_PAGE > select ARCH_HAS_MMIOWB > diff --git a/arch/riscv/include/asm/io.h b/arch/riscv/include/asm/io.h > index 3835c3295dc5..04ac65ab93ce 100644 > --- a/arch/riscv/include/asm/io.h > +++ b/arch/riscv/include/asm/io.h > @@ -147,4 +147,6 @@ __io_writes_outs(outs, u64, q, __io_pbr(), > __io_paw()) > > #include <asm-generic/io.h> > > +extern int devmem_is_allowed(unsigned long pfn); > + > #endif /* _ASM_RISCV_IO_H */ > diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c > index bbe816e03b2f..5e7e61519acc 100644 > --- a/arch/riscv/mm/init.c > +++ b/arch/riscv/mm/init.c > @@ -517,6 +517,25 @@ void mark_rodata_ro(void) > } > #endif > > +#ifdef CONFIG_STRICT_DEVMEM > +#include <linux/ioport.h> > +/* > + * devmem_is_allowed() checks to see if /dev/mem access to a certain > address > + * is valid. The argument is a physical page number. > + * > + * Disallow access to system RAM as well as device-exclusive MMIO > regions. > + * This effectively disable read()/write() on /dev/mem. > + */ > +int devmem_is_allowed(unsigned long pfn) > +{ > + if (iomem_is_exclusive(pfn << PAGE_SHIFT)) > + return 0; > + if (!page_is_ram(pfn)) > + return 1; > + return 0; > +} > +#endif > + > void __init resource_init(void) > { > struct memblock_region *region; This shouldn't be part of /mm/init.c, it has nothing to do with memory initialization, I suggest we move it to another file like mmap.c on arm/arm64. Also before using iomem_is_exclusive we should probably also mark any reserved regions with the no-map attribute as busy|exclusive, reserved-memory regions are not necessarily part of the main memory so the page_is_ram check may pass and iomem_is_exclusive won't do any good.
On Tue, Jun 16, 2020 at 8:27 PM Nick Kossifidis <mick@ics.forth.gr> wrote: > > Στις 2020-06-16 10:45, Zong Li έγραψε: > > Implement the 'devmem_is_allowed()' interface for RISC-V, like some of > > other architectures have done. It will be called from > > range_is_allowed() > > when userpsace attempts to access /dev/mem. > > > > Access to exclusive IOMEM and kernel RAM is denied unless > > CONFIG_STRICT_DEVMEM is set to 'n'. > > > > Test it by devmem, the result as follows: > > > > - CONFIG_STRICT_DEVMEM=y > > $ devmem 0x10010000 > > 0x00000000 > > $ devmem 0x80200000 > > 0x0000106F > > > > - CONFIG_STRICT_DEVMEM is not set > > $ devmem 0x10010000 > > devmem: mmap: Operation not permitted > > $ devmem 0x80200000 > > devmem: mmap: Operation not permitted > > > > Signed-off-by: Zong Li <zong.li@sifive.com> > > --- > > arch/riscv/Kconfig | 1 + > > arch/riscv/include/asm/io.h | 2 ++ > > arch/riscv/mm/init.c | 19 +++++++++++++++++++ > > 3 files changed, 22 insertions(+) > > > > diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig > > index 128192e14ff2..ffd7841ede4c 100644 > > --- a/arch/riscv/Kconfig > > +++ b/arch/riscv/Kconfig > > @@ -16,6 +16,7 @@ config RISCV > > select ARCH_HAS_BINFMT_FLAT > > select ARCH_HAS_DEBUG_VIRTUAL if MMU > > select ARCH_HAS_DEBUG_WX > > + select ARCH_HAS_DEVMEM_IS_ALLOWED > > select ARCH_HAS_GCOV_PROFILE_ALL > > select ARCH_HAS_GIGANTIC_PAGE > > select ARCH_HAS_MMIOWB > > diff --git a/arch/riscv/include/asm/io.h b/arch/riscv/include/asm/io.h > > index 3835c3295dc5..04ac65ab93ce 100644 > > --- a/arch/riscv/include/asm/io.h > > +++ b/arch/riscv/include/asm/io.h > > @@ -147,4 +147,6 @@ __io_writes_outs(outs, u64, q, __io_pbr(), > > __io_paw()) > > > > #include <asm-generic/io.h> > > > > +extern int devmem_is_allowed(unsigned long pfn); > > + > > #endif /* _ASM_RISCV_IO_H */ > > diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c > > index bbe816e03b2f..5e7e61519acc 100644 > > --- a/arch/riscv/mm/init.c > > +++ b/arch/riscv/mm/init.c > > @@ -517,6 +517,25 @@ void mark_rodata_ro(void) > > } > > #endif > > > > +#ifdef CONFIG_STRICT_DEVMEM > > +#include <linux/ioport.h> > > +/* > > + * devmem_is_allowed() checks to see if /dev/mem access to a certain > > address > > + * is valid. The argument is a physical page number. > > + * > > + * Disallow access to system RAM as well as device-exclusive MMIO > > regions. > > + * This effectively disable read()/write() on /dev/mem. > > + */ > > +int devmem_is_allowed(unsigned long pfn) > > +{ > > + if (iomem_is_exclusive(pfn << PAGE_SHIFT)) > > + return 0; > > + if (!page_is_ram(pfn)) > > + return 1; > > + return 0; > > +} > > +#endif > > + > > void __init resource_init(void) > > { > > struct memblock_region *region; > > This shouldn't be part of /mm/init.c, it has nothing to do with memory > initialization, I suggest we move it to another file like mmap.c on Let me move it, thanks. > arm/arm64. Also before using iomem_is_exclusive we should probably also > mark any reserved regions with the no-map attribute as busy|exclusive, > reserved-memory regions are not necessarily part of the main memory so > the page_is_ram check may pass and iomem_is_exclusive won't do any good. What do you think if we mark the reserved region in kdump_resource_init, and change the kdump_resource_init to a more generic name for initializing resources?
Στις 2020-06-17 04:56, Zong Li έγραψε: > On Tue, Jun 16, 2020 at 8:27 PM Nick Kossifidis <mick@ics.forth.gr> > wrote: >> >> Στις 2020-06-16 10:45, Zong Li έγραψε: >> > Implement the 'devmem_is_allowed()' interface for RISC-V, like some of >> > other architectures have done. It will be called from >> > range_is_allowed() >> > when userpsace attempts to access /dev/mem. >> > >> > Access to exclusive IOMEM and kernel RAM is denied unless >> > CONFIG_STRICT_DEVMEM is set to 'n'. >> > >> > Test it by devmem, the result as follows: >> > >> > - CONFIG_STRICT_DEVMEM=y >> > $ devmem 0x10010000 >> > 0x00000000 >> > $ devmem 0x80200000 >> > 0x0000106F >> > >> > - CONFIG_STRICT_DEVMEM is not set >> > $ devmem 0x10010000 >> > devmem: mmap: Operation not permitted >> > $ devmem 0x80200000 >> > devmem: mmap: Operation not permitted >> > >> > Signed-off-by: Zong Li <zong.li@sifive.com> >> > --- >> > arch/riscv/Kconfig | 1 + >> > arch/riscv/include/asm/io.h | 2 ++ >> > arch/riscv/mm/init.c | 19 +++++++++++++++++++ >> > 3 files changed, 22 insertions(+) >> > >> > diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig >> > index 128192e14ff2..ffd7841ede4c 100644 >> > --- a/arch/riscv/Kconfig >> > +++ b/arch/riscv/Kconfig >> > @@ -16,6 +16,7 @@ config RISCV >> > select ARCH_HAS_BINFMT_FLAT >> > select ARCH_HAS_DEBUG_VIRTUAL if MMU >> > select ARCH_HAS_DEBUG_WX >> > + select ARCH_HAS_DEVMEM_IS_ALLOWED >> > select ARCH_HAS_GCOV_PROFILE_ALL >> > select ARCH_HAS_GIGANTIC_PAGE >> > select ARCH_HAS_MMIOWB >> > diff --git a/arch/riscv/include/asm/io.h b/arch/riscv/include/asm/io.h >> > index 3835c3295dc5..04ac65ab93ce 100644 >> > --- a/arch/riscv/include/asm/io.h >> > +++ b/arch/riscv/include/asm/io.h >> > @@ -147,4 +147,6 @@ __io_writes_outs(outs, u64, q, __io_pbr(), >> > __io_paw()) >> > >> > #include <asm-generic/io.h> >> > >> > +extern int devmem_is_allowed(unsigned long pfn); >> > + >> > #endif /* _ASM_RISCV_IO_H */ >> > diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c >> > index bbe816e03b2f..5e7e61519acc 100644 >> > --- a/arch/riscv/mm/init.c >> > +++ b/arch/riscv/mm/init.c >> > @@ -517,6 +517,25 @@ void mark_rodata_ro(void) >> > } >> > #endif >> > >> > +#ifdef CONFIG_STRICT_DEVMEM >> > +#include <linux/ioport.h> >> > +/* >> > + * devmem_is_allowed() checks to see if /dev/mem access to a certain >> > address >> > + * is valid. The argument is a physical page number. >> > + * >> > + * Disallow access to system RAM as well as device-exclusive MMIO >> > regions. >> > + * This effectively disable read()/write() on /dev/mem. >> > + */ >> > +int devmem_is_allowed(unsigned long pfn) >> > +{ >> > + if (iomem_is_exclusive(pfn << PAGE_SHIFT)) >> > + return 0; >> > + if (!page_is_ram(pfn)) >> > + return 1; >> > + return 0; >> > +} >> > +#endif >> > + >> > void __init resource_init(void) >> > { >> > struct memblock_region *region; >> >> This shouldn't be part of /mm/init.c, it has nothing to do with memory >> initialization, I suggest we move it to another file like mmap.c on > > Let me move it, thanks. > >> arm/arm64. Also before using iomem_is_exclusive we should probably >> also >> mark any reserved regions with the no-map attribute as busy|exclusive, >> reserved-memory regions are not necessarily part of the main memory so >> the page_is_ram check may pass and iomem_is_exclusive won't do any >> good. > > What do you think if we mark the reserved region in > kdump_resource_init, and change the kdump_resource_init to a more > generic name for initializing resources? Sounds good to me, I'll work on this within the week. Do you agree with marking the no-map reserved-memory regions as exclusive ?
On Wed, Jun 17, 2020 at 1:28 PM Nick Kossifidis <mick@ics.forth.gr> wrote: > > Στις 2020-06-17 04:56, Zong Li έγραψε: > > On Tue, Jun 16, 2020 at 8:27 PM Nick Kossifidis <mick@ics.forth.gr> > > wrote: > >> > >> Στις 2020-06-16 10:45, Zong Li έγραψε: > >> > Implement the 'devmem_is_allowed()' interface for RISC-V, like some of > >> > other architectures have done. It will be called from > >> > range_is_allowed() > >> > when userpsace attempts to access /dev/mem. > >> > > >> > Access to exclusive IOMEM and kernel RAM is denied unless > >> > CONFIG_STRICT_DEVMEM is set to 'n'. > >> > > >> > Test it by devmem, the result as follows: > >> > > >> > - CONFIG_STRICT_DEVMEM=y > >> > $ devmem 0x10010000 > >> > 0x00000000 > >> > $ devmem 0x80200000 > >> > 0x0000106F > >> > > >> > - CONFIG_STRICT_DEVMEM is not set > >> > $ devmem 0x10010000 > >> > devmem: mmap: Operation not permitted > >> > $ devmem 0x80200000 > >> > devmem: mmap: Operation not permitted > >> > > >> > Signed-off-by: Zong Li <zong.li@sifive.com> > >> > --- > >> > arch/riscv/Kconfig | 1 + > >> > arch/riscv/include/asm/io.h | 2 ++ > >> > arch/riscv/mm/init.c | 19 +++++++++++++++++++ > >> > 3 files changed, 22 insertions(+) > >> > > >> > diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig > >> > index 128192e14ff2..ffd7841ede4c 100644 > >> > --- a/arch/riscv/Kconfig > >> > +++ b/arch/riscv/Kconfig > >> > @@ -16,6 +16,7 @@ config RISCV > >> > select ARCH_HAS_BINFMT_FLAT > >> > select ARCH_HAS_DEBUG_VIRTUAL if MMU > >> > select ARCH_HAS_DEBUG_WX > >> > + select ARCH_HAS_DEVMEM_IS_ALLOWED > >> > select ARCH_HAS_GCOV_PROFILE_ALL > >> > select ARCH_HAS_GIGANTIC_PAGE > >> > select ARCH_HAS_MMIOWB > >> > diff --git a/arch/riscv/include/asm/io.h b/arch/riscv/include/asm/io.h > >> > index 3835c3295dc5..04ac65ab93ce 100644 > >> > --- a/arch/riscv/include/asm/io.h > >> > +++ b/arch/riscv/include/asm/io.h > >> > @@ -147,4 +147,6 @@ __io_writes_outs(outs, u64, q, __io_pbr(), > >> > __io_paw()) > >> > > >> > #include <asm-generic/io.h> > >> > > >> > +extern int devmem_is_allowed(unsigned long pfn); > >> > + > >> > #endif /* _ASM_RISCV_IO_H */ > >> > diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c > >> > index bbe816e03b2f..5e7e61519acc 100644 > >> > --- a/arch/riscv/mm/init.c > >> > +++ b/arch/riscv/mm/init.c > >> > @@ -517,6 +517,25 @@ void mark_rodata_ro(void) > >> > } > >> > #endif > >> > > >> > +#ifdef CONFIG_STRICT_DEVMEM > >> > +#include <linux/ioport.h> > >> > +/* > >> > + * devmem_is_allowed() checks to see if /dev/mem access to a certain > >> > address > >> > + * is valid. The argument is a physical page number. > >> > + * > >> > + * Disallow access to system RAM as well as device-exclusive MMIO > >> > regions. > >> > + * This effectively disable read()/write() on /dev/mem. > >> > + */ > >> > +int devmem_is_allowed(unsigned long pfn) > >> > +{ > >> > + if (iomem_is_exclusive(pfn << PAGE_SHIFT)) > >> > + return 0; > >> > + if (!page_is_ram(pfn)) > >> > + return 1; > >> > + return 0; > >> > +} > >> > +#endif > >> > + > >> > void __init resource_init(void) > >> > { > >> > struct memblock_region *region; > >> > >> This shouldn't be part of /mm/init.c, it has nothing to do with memory > >> initialization, I suggest we move it to another file like mmap.c on > > > > Let me move it, thanks. > > > >> arm/arm64. Also before using iomem_is_exclusive we should probably > >> also > >> mark any reserved regions with the no-map attribute as busy|exclusive, > >> reserved-memory regions are not necessarily part of the main memory so > >> the page_is_ram check may pass and iomem_is_exclusive won't do any > >> good. > > > > What do you think if we mark the reserved region in > > kdump_resource_init, and change the kdump_resource_init to a more > > generic name for initializing resources? > > Sounds good to me, I'll work on this within the week. Do you agree with > marking the no-map reserved-memory regions as exclusive ? It's OK to me, It seems to me that exclusive is more suitable than busy when initialization.
diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig index 128192e14ff2..ffd7841ede4c 100644 --- a/arch/riscv/Kconfig +++ b/arch/riscv/Kconfig @@ -16,6 +16,7 @@ config RISCV select ARCH_HAS_BINFMT_FLAT select ARCH_HAS_DEBUG_VIRTUAL if MMU select ARCH_HAS_DEBUG_WX + select ARCH_HAS_DEVMEM_IS_ALLOWED select ARCH_HAS_GCOV_PROFILE_ALL select ARCH_HAS_GIGANTIC_PAGE select ARCH_HAS_MMIOWB diff --git a/arch/riscv/include/asm/io.h b/arch/riscv/include/asm/io.h index 3835c3295dc5..04ac65ab93ce 100644 --- a/arch/riscv/include/asm/io.h +++ b/arch/riscv/include/asm/io.h @@ -147,4 +147,6 @@ __io_writes_outs(outs, u64, q, __io_pbr(), __io_paw()) #include <asm-generic/io.h> +extern int devmem_is_allowed(unsigned long pfn); + #endif /* _ASM_RISCV_IO_H */ diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c index bbe816e03b2f..5e7e61519acc 100644 --- a/arch/riscv/mm/init.c +++ b/arch/riscv/mm/init.c @@ -517,6 +517,25 @@ void mark_rodata_ro(void) } #endif +#ifdef CONFIG_STRICT_DEVMEM +#include <linux/ioport.h> +/* + * devmem_is_allowed() checks to see if /dev/mem access to a certain address + * is valid. The argument is a physical page number. + * + * Disallow access to system RAM as well as device-exclusive MMIO regions. + * This effectively disable read()/write() on /dev/mem. + */ +int devmem_is_allowed(unsigned long pfn) +{ + if (iomem_is_exclusive(pfn << PAGE_SHIFT)) + return 0; + if (!page_is_ram(pfn)) + return 1; + return 0; +} +#endif + void __init resource_init(void) { struct memblock_region *region;
Implement the 'devmem_is_allowed()' interface for RISC-V, like some of other architectures have done. It will be called from range_is_allowed() when userpsace attempts to access /dev/mem. Access to exclusive IOMEM and kernel RAM is denied unless CONFIG_STRICT_DEVMEM is set to 'n'. Test it by devmem, the result as follows: - CONFIG_STRICT_DEVMEM=y $ devmem 0x10010000 0x00000000 $ devmem 0x80200000 0x0000106F - CONFIG_STRICT_DEVMEM is not set $ devmem 0x10010000 devmem: mmap: Operation not permitted $ devmem 0x80200000 devmem: mmap: Operation not permitted Signed-off-by: Zong Li <zong.li@sifive.com> --- arch/riscv/Kconfig | 1 + arch/riscv/include/asm/io.h | 2 ++ arch/riscv/mm/init.c | 19 +++++++++++++++++++ 3 files changed, 22 insertions(+)