1 /* SPDX-License-Identifier: MIT */ 2 /* Copyright © 2025 Intel Corporation */ 3 4 #ifndef __I915_PTR_UTIL_H__ 5 #define __I915_PTR_UTIL_H__ 6 7 #include <linux/types.h> 8 9 #define ptr_mask_bits(ptr, n) ({ \ 10 unsigned long __v = (unsigned long)(ptr); \ 11 (typeof(ptr))(__v & -BIT(n)); \ 12 }) 13 14 #define ptr_unmask_bits(ptr, n) ((unsigned long)(ptr) & (BIT(n) - 1)) 15 16 #define ptr_unpack_bits(ptr, bits, n) ({ \ 17 unsigned long __v = (unsigned long)(ptr); \ 18 *(bits) = __v & (BIT(n) - 1); \ 19 (typeof(ptr))(__v & -BIT(n)); \ 20 }) 21 22 #define ptr_pack_bits(ptr, bits, n) ({ \ 23 unsigned long __bits = (bits); \ 24 GEM_BUG_ON(__bits & -BIT(n)); \ 25 ((typeof(ptr))((unsigned long)(ptr) | __bits)); \ 26 }) 27 28 #define ptr_dec(ptr) ({ \ 29 unsigned long __v = (unsigned long)(ptr); \ 30 (typeof(ptr))(__v - 1); \ 31 }) 32 33 #define ptr_inc(ptr) ({ \ 34 unsigned long __v = (unsigned long)(ptr); \ 35 (typeof(ptr))(__v + 1); \ 36 }) 37 38 #define page_mask_bits(ptr) ptr_mask_bits(ptr, PAGE_SHIFT) 39 #define page_unmask_bits(ptr) ptr_unmask_bits(ptr, PAGE_SHIFT) 40 #define page_pack_bits(ptr, bits) ptr_pack_bits(ptr, bits, PAGE_SHIFT) 41 #define page_unpack_bits(ptr, bits) ptr_unpack_bits(ptr, bits, PAGE_SHIFT) 42 43 static __always_inline ptrdiff_t ptrdiff(const void *a, const void *b) 44 { 45 return a - b; 46 } 47 48 #define u64_to_ptr(T, x) ({ \ 49 typecheck(u64, x); \ 50 (T *)(uintptr_t)(x); \ 51 }) 52 53 /* 54 * container_of_user: Extract the superclass from a pointer to a member. 55 * 56 * Exactly like container_of() with the exception that it plays nicely 57 * with sparse for __user @ptr. 58 */ 59 #define container_of_user(ptr, type, member) ({ \ 60 void __user *__mptr = (void __user *)(ptr); \ 61 BUILD_BUG_ON_MSG(!__same_type(*(ptr), typeof_member(type, member)) && \ 62 !__same_type(*(ptr), void), \ 63 "pointer type mismatch in container_of()"); \ 64 ((type __user *)(__mptr - offsetof(type, member))); }) 65 66 #endif /* __I915_PTR_UTIL_H__ */ 67