diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index fe2f17eb2b50..ae7c7364871b 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 @@ -56,6 +55,7 @@ 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 diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index f858c352f72a..dd3c81d84e28 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 @@ -112,6 +111,7 @@ 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 fd172c41df90..5ea8656a2030 100644 --- a/arch/arm64/include/asm/io.h +++ b/arch/arm64/include/asm/io.h @@ -201,6 +201,4 @@ 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 diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig index d9da5d92e40d..2b41f6d8e458 100644 --- a/arch/riscv/Kconfig +++ b/arch/riscv/Kconfig @@ -44,6 +44,7 @@ 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 diff --git a/include/asm-generic/io.h b/include/asm-generic/io.h index 9ea83d80eb6f..c6af40ce03be 100644 --- a/include/asm-generic/io.h +++ b/include/asm-generic/io.h @@ -1137,6 +1137,10 @@ 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 b46a9fd122c8..46806332a8cc 100644 --- a/lib/Kconfig +++ b/lib/Kconfig @@ -686,6 +686,9 @@ 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 d7a7bc3b6098..c63fc68f9bf2 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -1645,7 +1645,7 @@ 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 ce45af50983a..431d7d894bf7 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -352,3 +352,5 @@ obj-$(CONFIG_BITFIELD_KUNIT) += bitfield_kunit.o obj-$(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; +}