From 527701eda5f196588df9b36a30651804fea7d1a7 Mon Sep 17 00:00:00 2001 From: Palmer Dabbelt Date: Thu, 9 Jul 2020 11:43:21 -0700 Subject: lib: Add a generic version of devmem_is_allowed() As part of adding support for STRICT_DEVMEM to the RISC-V port, Zong provided a devmem_is_allowed() implementation that's exactly the same as all the others I checked. Instead I'm adding a generic version, which will soon be used. Reviewed-by: Luis Chamberlain Signed-off-by: Palmer Dabbelt --- include/asm-generic/io.h | 4 ++++ lib/Kconfig | 3 +++ lib/Kconfig.debug | 2 +- lib/Makefile | 2 ++ lib/devmem_is_allowed.c | 27 +++++++++++++++++++++++++++ 5 files changed, 37 insertions(+), 1 deletion(-) create mode 100644 lib/devmem_is_allowed.c diff --git a/include/asm-generic/io.h b/include/asm-generic/io.h index dabf8cb7203b..da2e861dee1c 100644 --- a/include/asm-generic/io.h +++ b/include/asm-generic/io.h @@ -1122,6 +1122,10 @@ static inline void memcpy_toio(volatile void __iomem *addr, const void *buffer, } #endif +#ifndef CONFIG_GENERIC_DEVMEM_IS_ALLOWED +extern int devmem_is_allowed(unsigned long pfn); +#endif + #endif /* __KERNEL__ */ #endif /* __ASM_GENERIC_IO_H */ diff --git a/lib/Kconfig b/lib/Kconfig index b4b98a03ff98..b26721cf51bc 100644 --- a/lib/Kconfig +++ b/lib/Kconfig @@ -681,6 +681,9 @@ config GENERIC_LIB_CMPDI2 config GENERIC_LIB_UCMPDI2 bool +config GENERIC_LIB_DEVMEM_IS_ALLOWED + bool + config PLDMFW bool default n diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 0c781f912f9f..87410f62b501 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -1626,7 +1626,7 @@ config ARCH_HAS_DEVMEM_IS_ALLOWED config STRICT_DEVMEM bool "Filter access to /dev/mem" depends on MMU && DEVMEM - depends on ARCH_HAS_DEVMEM_IS_ALLOWED + depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED default y if PPC || X86 || ARM64 help If this option is disabled, you allow userspace (root) access to all diff --git a/lib/Makefile b/lib/Makefile index a4a4c6864f51..34011a11fbb3 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -348,3 +348,5 @@ obj-$(CONFIG_PLDMFW) += pldmfw/ obj-$(CONFIG_LIST_KUNIT_TEST) += list-test.o obj-$(CONFIG_LINEAR_RANGES_TEST) += test_linear_ranges.o obj-$(CONFIG_BITS_TEST) += test_bits.o + +obj-$(CONFIG_GENERIC_LIB_DEVMEM_IS_ALLOWED) += devmem_is_allowed.o diff --git a/lib/devmem_is_allowed.c b/lib/devmem_is_allowed.c new file mode 100644 index 000000000000..c0d67c541849 --- /dev/null +++ b/lib/devmem_is_allowed.c @@ -0,0 +1,27 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * A generic version of devmem_is_allowed. + * + * Based on arch/arm64/mm/mmap.c + * + * Copyright (C) 2020 Google, Inc. + * Copyright (C) 2012 ARM Ltd. + */ + +#include +#include + +/* + * devmem_is_allowed() checks to see if /dev/mem access to a certain address + * is valid. The argument is a physical page number. We mimic x86 here by + * disallowing 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; +} -- cgit From 78ed473c76192ab7b8e96c5948cca82db4c744fe Mon Sep 17 00:00:00 2001 From: Palmer Dabbelt Date: Thu, 9 Jul 2020 11:51:17 -0700 Subject: RISC-V: Use the new generic devmem_is_allowed() This allows us to enable STRICT_DEVMEM. Reviewed-by: Luis Chamberlain Signed-off-by: Palmer Dabbelt --- arch/riscv/Kconfig | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig index 7766e1289468..669a65d8f1d4 100644 --- a/arch/riscv/Kconfig +++ b/arch/riscv/Kconfig @@ -42,6 +42,7 @@ config RISCV select GENERIC_IOREMAP select GENERIC_IRQ_MULTI_HANDLER select GENERIC_IRQ_SHOW + select GENERIC_LIB_DEVMEM_IS_ALLOWED select GENERIC_PCI_IOMAP select GENERIC_PTDUMP if MMU select GENERIC_SCHED_CLOCK -- cgit From 914ee96654d87abc548bdd44ad9e4b3a14173cac Mon Sep 17 00:00:00 2001 From: Palmer Dabbelt Date: Thu, 9 Jul 2020 12:00:10 -0700 Subject: arm: Use the generic devmem_is_allowed() This is exactly the same as the arm64 version, which I recently copied into lib/ for use by the RISC-V port. Reviewed-by: Luis Chamberlain Signed-off-by: Palmer Dabbelt --- arch/arm/Kconfig | 2 +- arch/arm/include/asm/io.h | 1 - arch/arm/mm/mmap.c | 22 ---------------------- 3 files changed, 1 insertion(+), 24 deletions(-) diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index e00d94b16658..16095d3ab453 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -5,7 +5,6 @@ config ARM select ARCH_32BIT_OFF_T select ARCH_HAS_BINFMT_FLAT select ARCH_HAS_DEBUG_VIRTUAL if MMU - select ARCH_HAS_DEVMEM_IS_ALLOWED select ARCH_HAS_DMA_WRITE_COMBINE if !ARM_DMA_MEM_BUFFERABLE select ARCH_HAS_ELF_RANDOMIZE select ARCH_HAS_FORTIFY_SOURCE @@ -55,6 +54,7 @@ config ARM select GENERIC_IRQ_PROBE select GENERIC_IRQ_SHOW select GENERIC_IRQ_SHOW_LEVEL + select GENERIC_LIB_DEVMEM_IS_ALLOWED select GENERIC_PCI_IOMAP select GENERIC_SCHED_CLOCK select GENERIC_SMP_IDLE_THREAD diff --git a/arch/arm/include/asm/io.h b/arch/arm/include/asm/io.h index ab2b654084fa..fc748122f1e0 100644 --- a/arch/arm/include/asm/io.h +++ b/arch/arm/include/asm/io.h @@ -441,7 +441,6 @@ extern void pci_iounmap(struct pci_dev *dev, void __iomem *addr); #define ARCH_HAS_VALID_PHYS_ADDR_RANGE extern int valid_phys_addr_range(phys_addr_t addr, size_t size); extern int valid_mmap_phys_addr_range(unsigned long pfn, size_t size); -extern int devmem_is_allowed(unsigned long pfn); #endif /* diff --git a/arch/arm/mm/mmap.c b/arch/arm/mm/mmap.c index b8d912ac9e61..a0f8a0ca0788 100644 --- a/arch/arm/mm/mmap.c +++ b/arch/arm/mm/mmap.c @@ -165,25 +165,3 @@ int valid_mmap_phys_addr_range(unsigned long pfn, size_t size) { return (pfn + (size >> PAGE_SHIFT)) <= (1 + (PHYS_MASK >> PAGE_SHIFT)); } - -#ifdef CONFIG_STRICT_DEVMEM - -#include - -/* - * devmem_is_allowed() checks to see if /dev/mem access to a certain - * address is valid. The argument is a physical page number. - * We mimic x86 here by disallowing 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 -- cgit From 6585bd827407f55ee30a782492208bfaf4f52feb Mon Sep 17 00:00:00 2001 From: Palmer Dabbelt Date: Thu, 9 Jul 2020 12:05:36 -0700 Subject: arm64: Use the generic devmem_is_allowed() I recently copied this into lib/ for use by the RISC-V port. Acked-by: Catalin Marinas Reviewed-by: Luis Chamberlain Signed-off-by: Palmer Dabbelt --- arch/arm64/Kconfig | 2 +- arch/arm64/include/asm/io.h | 2 -- arch/arm64/mm/mmap.c | 21 --------------------- 3 files changed, 1 insertion(+), 24 deletions(-) diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 6d232837cbee..93d041ffe583 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -13,7 +13,6 @@ config ARM64 select ARCH_BINFMT_ELF_STATE select ARCH_HAS_DEBUG_VIRTUAL select ARCH_HAS_DEBUG_VM_PGTABLE - select ARCH_HAS_DEVMEM_IS_ALLOWED select ARCH_HAS_DMA_PREP_COHERENT select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI select ARCH_HAS_FAST_MULTIPLIER @@ -110,6 +109,7 @@ config ARM64 select GENERIC_IRQ_PROBE select GENERIC_IRQ_SHOW select GENERIC_IRQ_SHOW_LEVEL + select GENERIC_LIB_DEVMEM_IS_ALLOWED select GENERIC_PCI_IOMAP select GENERIC_PTDUMP select GENERIC_SCHED_CLOCK diff --git a/arch/arm64/include/asm/io.h b/arch/arm64/include/asm/io.h index ff50dd731852..c53eba1a7fd2 100644 --- a/arch/arm64/include/asm/io.h +++ b/arch/arm64/include/asm/io.h @@ -200,6 +200,4 @@ extern void __iomem *ioremap_cache(phys_addr_t phys_addr, size_t size); extern int valid_phys_addr_range(phys_addr_t addr, size_t size); extern int valid_mmap_phys_addr_range(unsigned long pfn, size_t size); -extern int devmem_is_allowed(unsigned long pfn); - #endif /* __ASM_IO_H */ diff --git a/arch/arm64/mm/mmap.c b/arch/arm64/mm/mmap.c index 3028bacbc4e9..07937b49cb88 100644 --- a/arch/arm64/mm/mmap.c +++ b/arch/arm64/mm/mmap.c @@ -47,24 +47,3 @@ int valid_mmap_phys_addr_range(unsigned long pfn, size_t size) { return !(((pfn << PAGE_SHIFT) + size) & ~PHYS_MASK); } - -#ifdef CONFIG_STRICT_DEVMEM - -#include - -/* - * devmem_is_allowed() checks to see if /dev/mem access to a certain address - * is valid. The argument is a physical page number. We mimic x86 here by - * disallowing 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 -- cgit