/* SPDX-License-Identifier: GPL-2.0 */ #ifndef _LINUX_EXECMEM_ALLOC_H #define _LINUX_EXECMEM_ALLOC_H #include #include #if (defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)) && \ !defined(CONFIG_KASAN_VMALLOC) #include #define MODULE_ALIGN (PAGE_SIZE << KASAN_SHADOW_SCALE_SHIFT) #else #define MODULE_ALIGN PAGE_SIZE #endif /** * enum execmem_type - types of executable memory ranges * * There are several subsystems that allocate executable memory. * Architectures define different restrictions on placement, * permissions, alignment and other parameters for memory that can be used * by these subsystems. * Types in this enum identify subsystems that allocate executable memory * and let architectures define parameters for ranges suitable for * allocations by each subsystem. * * @EXECMEM_DEFAULT: default parameters that would be used for types that * are not explicitly defined. * @EXECMEM_MODULE_TEXT: parameters for module text sections * @EXECMEM_KPROBES: parameters for kprobes * @EXECMEM_FTRACE: parameters for ftrace * @EXECMEM_BPF: parameters for BPF * @EXECMEM_MODULE_DATA: parameters for module data sections * @EXECMEM_TYPE_MAX: */ enum execmem_type { EXECMEM_DEFAULT, EXECMEM_MODULE_TEXT = EXECMEM_DEFAULT, EXECMEM_KPROBES, EXECMEM_FTRACE, EXECMEM_BPF, EXECMEM_MODULE_DATA, EXECMEM_TYPE_MAX, }; /** * enum execmem_range_flags - options for executable memory allocations * @EXECMEM_KASAN_SHADOW: allocate kasan shadow * @EXECMEM_ROX_CACHE: allocations should use ROX cache of huge pages */ enum execmem_range_flags { EXECMEM_KASAN_SHADOW = (1 << 0), EXECMEM_ROX_CACHE = (1 << 1), }; #ifdef CONFIG_ARCH_HAS_EXECMEM_ROX /** * execmem_fill_trapping_insns - set memory to contain instructions that * will trap * @ptr: pointer to memory to fill * @size: size of the range to fill * @writable: is the memory poited by @ptr is writable or ROX * * A hook for architecures to fill execmem ranges with invalid instructions. * Architectures that use EXECMEM_ROX_CACHE must implement this. */ void execmem_fill_trapping_insns(void *ptr, size_t size, bool writable); #endif /** * struct execmem_range - definition of an address space suitable for code and * related data allocations * @start: address space start * @end: address space end (inclusive) * @fallback_start: start of the secondary address space range for fallback * allocations on architectures that require it * @fallback_end: start of the secondary address space (inclusive) * @pgprot: permissions for memory in this address space * @alignment: alignment required for text allocations * @flags: options for memory allocations for this range */ struct execmem_range { unsigned long start; unsigned long end; unsigned long fallback_start; unsigned long fallback_end; pgprot_t pgprot; unsigned int alignment; enum execmem_range_flags flags; }; /** * struct execmem_info - architecture parameters for code allocations * @ranges: array of parameter sets defining architecture specific * parameters for executable memory allocations. The ranges that are not * explicitly initialized by an architecture use parameters defined for * @EXECMEM_DEFAULT. */ struct execmem_info { struct execmem_range ranges[EXECMEM_TYPE_MAX]; }; /** * execmem_arch_setup - define parameters for allocations of executable memory * * A hook for architectures to define parameters for allocations of * executable memory. These parameters should be filled into the * @execmem_info structure. * * For architectures that do not implement this method a default set of * parameters will be used * * Return: a structure defining architecture parameters and restrictions * for allocations of executable memory */ struct execmem_info *execmem_arch_setup(void); /** * execmem_alloc - allocate executable memory * @type: type of the allocation * @size: how many bytes of memory are required * * Allocates memory that will contain executable code, either generated or * loaded from kernel modules. * * Allocates memory that will contain data coupled with executable code, * like data sections in kernel modules. * * The memory will have protections defined by architecture for executable * region of the @type. * * Return: a pointer to the allocated memory or %NULL */ void *execmem_alloc(enum execmem_type type, size_t size); /** * execmem_free - free executable memory * @ptr: pointer to the memory that should be freed */ void execmem_free(void *ptr); #ifdef CONFIG_MMU /** * execmem_vmap - create virtual mapping for EXECMEM_MODULE_DATA memory * @size: size of the virtual mapping in bytes * * Maps virtually contiguous area in the range suitable for EXECMEM_MODULE_DATA. * * Return: the area descriptor on success or %NULL on failure. */ struct vm_struct *execmem_vmap(size_t size); #endif /** * execmem_update_copy - copy an update to executable memory * @dst: destination address to update * @src: source address containing the data * @size: how many bytes of memory shold be copied * * Copy @size bytes from @src to @dst using text poking if the memory at * @dst is read-only. * * Return: a pointer to @dst or NULL on error */ void *execmem_update_copy(void *dst, const void *src, size_t size); /** * execmem_is_rox - check if execmem is read-only * @type - the execmem type to check * * Return: %true if the @type is read-only, %false if it's writable */ bool execmem_is_rox(enum execmem_type type); #if defined(CONFIG_EXECMEM) && !defined(CONFIG_ARCH_WANTS_EXECMEM_LATE) void execmem_init(void); #else static inline void execmem_init(void) {} #endif #endif /* _LINUX_EXECMEM_ALLOC_H */