From: Palmer Dabbelt <palmer@dabbelt.com> To: zong.li@sifive.com Cc: Paul Walmsley <paul.walmsley@sifive.com>, linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, zong.li@sifive.com Subject: Re: [PATCH 2/2] riscv: Support CONFIG_STRICT_DEVMEM Date: Thu, 09 Jul 2020 13:08:10 -0700 (PDT) [thread overview] Message-ID: <mhng-d4637494-2072-41f6-9a8a-1b222d89d6c4@palmerdabbelt-glaptop1> (raw) In-Reply-To: <7faa60aa4a606b5c5c1ae374d82a7eee6c764b38.1592292685.git.zong.li@sifive.com> On Tue, 16 Jun 2020 00:45:47 PDT (-0700), zong.li@sifive.com wrote: > 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. In fact, it's exactly the same (down to a few words of the comment) to the others that I checked. I'm going to put a generic version in lib/ instead, I've sent out the patches. > 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;
WARNING: multiple messages have this Message-ID (diff)
From: Palmer Dabbelt <palmer@dabbelt.com> To: zong.li@sifive.com Cc: linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, zong.li@sifive.com, Paul Walmsley <paul.walmsley@sifive.com> Subject: Re: [PATCH 2/2] riscv: Support CONFIG_STRICT_DEVMEM Date: Thu, 09 Jul 2020 13:08:10 -0700 (PDT) [thread overview] Message-ID: <mhng-d4637494-2072-41f6-9a8a-1b222d89d6c4@palmerdabbelt-glaptop1> (raw) In-Reply-To: <7faa60aa4a606b5c5c1ae374d82a7eee6c764b38.1592292685.git.zong.li@sifive.com> On Tue, 16 Jun 2020 00:45:47 PDT (-0700), zong.li@sifive.com wrote: > 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. In fact, it's exactly the same (down to a few words of the comment) to the others that I checked. I'm going to put a generic version in lib/ instead, I've sent out the patches. > 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; _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv
next prev parent reply other threads:[~2020-07-09 20:08 UTC|newest] Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-06-16 7:45 [PATCH 0/2] Add STRICT_DEVMEM support on RISC-V Zong Li 2020-06-16 7:45 ` [PATCH 1/2] riscv: Register System RAM as iomem resources Zong Li 2020-06-16 11:51 ` Nick Kossifidis 2020-06-16 11:51 ` Nick Kossifidis 2020-06-17 1:23 ` Zong Li 2020-06-17 1:23 ` Zong Li 2020-07-09 18:27 ` Palmer Dabbelt 2020-07-09 18:27 ` Palmer Dabbelt 2020-07-10 2:05 ` Nick Kossifidis 2020-07-10 2:05 ` Nick Kossifidis 2020-06-16 7:45 ` [PATCH 2/2] riscv: Support CONFIG_STRICT_DEVMEM Zong Li 2020-06-16 12:27 ` Nick Kossifidis 2020-06-16 12:27 ` Nick Kossifidis 2020-06-17 1:56 ` Zong Li 2020-06-17 1:56 ` Zong Li 2020-06-17 5:28 ` Nick Kossifidis 2020-06-17 5:28 ` Nick Kossifidis 2020-06-17 6:32 ` Zong Li 2020-06-17 6:32 ` Zong Li 2020-07-09 20:08 ` Palmer Dabbelt [this message] 2020-07-09 20:08 ` Palmer Dabbelt 2020-07-10 2:43 ` Zong Li 2020-07-10 2:43 ` Zong Li
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