linux/drivers/gpu/drm/i915/i915_utils.h

/*
 * Copyright © 2016 Intel Corporation
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice (including the next
 * paragraph) shall be included in all copies or substantial portions of the
 * Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 * IN THE SOFTWARE.
 *
 */

#ifndef __I915_UTILS_H
#define __I915_UTILS_H

#if GCC_VERSION >= 70000
#define add_overflows(A, B) \
	__builtin_add_overflow_p((A), (B), (typeof((A) + (B)))0)
#else
#define add_overflows(A, B) ({ \
	typeof(A) a = (A); \
	typeof(B) b = (B); \
	a + b < a; \
})
#endif

#define range_overflows(start, size, max) ({ \
	typeof(start) start__ = (start); \
	typeof(size) size__ = (size); \
	typeof(max) max__ = (max); \
	(void)(&start__ == &size__); \
	(void)(&start__ == &max__); \
	start__ > max__ || size__ > max__ - start__; \
})

#define range_overflows_t(type, start, size, max) \
	range_overflows((type)(start), (type)(size), (type)(max))

/* Note we don't consider signbits :| */
#define overflows_type(x, T) \
	(sizeof(x) > sizeof(T) && (x) >> (sizeof(T) * BITS_PER_BYTE))

#define ptr_mask_bits(ptr) ({						\
	unsigned long __v = (unsigned long)(ptr);			\
	(typeof(ptr))(__v & PAGE_MASK);					\
})

#define ptr_unpack_bits(ptr, bits) ({					\
	unsigned long __v = (unsigned long)(ptr);			\
	(bits) = __v & ~PAGE_MASK;					\
	(typeof(ptr))(__v & PAGE_MASK);					\
})

#define ptr_pack_bits(ptr, bits)					\
	((typeof(ptr))((unsigned long)(ptr) | (bits)))

#define fetch_and_zero(ptr) ({						\
	typeof(*ptr) __T = *(ptr);					\
	*(ptr) = (typeof(*ptr))0;					\
	__T;								\
})

#endif /* !__I915_UTILS_H */