Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
drm/i915: document range_overflows() and range_end_overflows() macros
Document the macros in preparation for making them more generally
available.
Cc: Kees Cook <kees@kernel.org>
Cc: "Gustavo A. R. Silva" <gustavoars@kernel.org>
Cc: linux-hardening@vger.kernel.org
Reviewed-by: Jouni Högander <jouni.hogander@intel.com>
Link: https://lore.kernel.org/r/20250829174601.2163064-2-jani.nikula@intel.com
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
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drivers/gpu/drm/i915/i915_utils.h
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drivers/gpu/drm/i915/i915_utils.h
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drm_err(&(i915)->drm, fmt, ##__VA_ARGS__); \
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})
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/**
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* range_overflows() - Check if a range is out of bounds
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* @start: Start of the range.
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* @size: Size of the range.
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* @max: Exclusive upper boundary.
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*
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* A strict check to determine if the range [@start, @start + @size) is
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* invalid with respect to the allowable range [0, @max). Any range
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* starting at or beyond @max is considered an overflow, even if @size is 0.
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*
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* Returns: true if the range is out of bounds.
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*/
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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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start__ >= max__ || size__ > max__ - start__; \
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})
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/**
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* range_overflows_t() - Check if a range is out of bounds
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* @type: Data type to use.
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* @start: Start of the range.
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* @size: Size of the range.
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* @max: Exclusive upper boundary.
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*
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* Same as range_overflows() but forcing the parameters to @type.
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*
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* Returns: true if the range is out of bounds.
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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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/**
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* range_end_overflows() - Check if a range's endpoint is out of bounds
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* @start: Start of the range.
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* @size: Size of the range.
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* @max: Exclusive upper boundary.
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*
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* Checks only if the endpoint of a range (@start + @size) exceeds @max.
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* Unlike range_overflows(), a zero-sized range at the boundary (@start == @max)
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* is not considered an overflow. Useful for iterator-style checks.
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*
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* Returns: true if the endpoint exceeds the boundary.
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*/
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#define range_end_overflows(start, size, max) ({ \
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typeof(start) start__ = (start); \
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typeof(size) size__ = (size); \
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start__ > max__ || size__ > max__ - start__; \
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})
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/**
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* range_end_overflows_t() - Check if a range's endpoint is out of bounds
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* @type: Data type to use.
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* @start: Start of the range.
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* @size: Size of the range.
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* @max: Exclusive upper boundary.
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*
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* Same as range_end_overflows() but forcing the parameters to @type.
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*
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* Returns: true if the endpoint exceeds the boundary.
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*/
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#define range_end_overflows_t(type, start, size, max) \
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range_end_overflows((type)(start), (type)(size), (type)(max))
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