forked from Minki/linux
1692cd60d9
Just do a quick check that the stolen memory address range doesn't overflow our chosen integer type. v2: Add add_overflows() to utils with the promise that gcc7 can do this better than C and then maybe it will have a proper definition in core. Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Link: http://patchwork.freedesktop.org/patch/msgid/20170130134721.5159-1-chris@chris-wilson.co.uk Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
76 lines
2.4 KiB
C
76 lines
2.4 KiB
C
/*
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* Copyright © 2016 Intel Corporation
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*
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the "Software"),
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* to deal in the Software without restriction, including without limitation
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* the rights to use, copy, modify, merge, publish, distribute, sublicense,
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* and/or sell copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice (including the next
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* paragraph) shall be included in all copies or substantial portions of the
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* Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
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* IN THE SOFTWARE.
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*
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*/
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#ifndef __I915_UTILS_H
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#define __I915_UTILS_H
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#if GCC_VERSION >= 70000
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#define add_overflows(A, B) \
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__builtin_add_overflow_p((A), (B), (typeof((A) + (B)))0)
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#else
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#define add_overflows(A, B) ({ \
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typeof(A) a = (A); \
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typeof(B) b = (B); \
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a + b < a; \
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})
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#endif
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#define range_overflows(start, size, max) ({ \
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typeof(start) start__ = (start); \
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typeof(size) size__ = (size); \
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typeof(max) max__ = (max); \
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(void)(&start__ == &size__); \
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(void)(&start__ == &max__); \
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start__ > max__ || size__ > max__ - start__; \
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})
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#define range_overflows_t(type, start, size, max) \
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range_overflows((type)(start), (type)(size), (type)(max))
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/* Note we don't consider signbits :| */
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#define overflows_type(x, T) \
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(sizeof(x) > sizeof(T) && (x) >> (sizeof(T) * BITS_PER_BYTE))
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#define ptr_mask_bits(ptr) ({ \
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unsigned long __v = (unsigned long)(ptr); \
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(typeof(ptr))(__v & PAGE_MASK); \
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})
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#define ptr_unpack_bits(ptr, bits) ({ \
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unsigned long __v = (unsigned long)(ptr); \
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(bits) = __v & ~PAGE_MASK; \
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(typeof(ptr))(__v & PAGE_MASK); \
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})
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#define ptr_pack_bits(ptr, bits) \
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((typeof(ptr))((unsigned long)(ptr) | (bits)))
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#define fetch_and_zero(ptr) ({ \
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typeof(*ptr) __T = *(ptr); \
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*(ptr) = (typeof(*ptr))0; \
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__T; \
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})
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#endif /* !__I915_UTILS_H */
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