diff options
Diffstat (limited to 'include/linux/execmem.h')
| -rw-r--r-- | include/linux/execmem.h | 75 |
1 files changed, 75 insertions, 0 deletions
diff --git a/include/linux/execmem.h b/include/linux/execmem.h index 32cef1144117..7de229134e30 100644 --- a/include/linux/execmem.h +++ b/include/linux/execmem.h @@ -4,6 +4,7 @@ #include <linux/types.h> #include <linux/moduleloader.h> +#include <linux/cleanup.h> #if (defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)) && \ !defined(CONFIG_KASAN_VMALLOC) @@ -46,11 +47,41 @@ enum execmem_type { /** * 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 + * + * 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); + +/** + * execmem_restore_rox - restore read-only-execute permissions + * @ptr: address of the region to remap + * @size: size of the region to remap + * + * Restores read-only-execute permissions on a range [@ptr, @ptr + @size) + * after it was temporarily remapped as writable. Relies on architecture + * implementation of set_memory_rox() to restore mapping using large pages. + * + * Return: 0 on success or negative error code on failure. + */ +int execmem_restore_rox(void *ptr, size_t size); +#else +static inline int execmem_restore_rox(void *ptr, size_t size) { return 0; } +#endif + /** * struct execmem_range - definition of an address space suitable for code and * related data allocations @@ -118,11 +149,55 @@ struct execmem_info *execmem_arch_setup(void); void *execmem_alloc(enum execmem_type type, size_t size); /** + * execmem_alloc_rw - allocate writable 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. + * + * Forces writable permissions on the allocated memory and the caller is + * responsible to manage the permissions afterwards. + * + * For architectures that use ROX cache the permissions will be set to R+W. + * For architectures that don't use ROX cache the default permissions for @type + * will be used as they must be writable. + * + * Return: a pointer to the allocated memory or %NULL + */ +void *execmem_alloc_rw(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); +DEFINE_FREE(execmem, void *, if (_T) execmem_free(_T)); + +#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_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 |