For architectures providing their own implementation of
array_index_mask_nospec() in asm/barrier.h, attempting to use WARN_ONCE() to
complain about out-of-range parameters using WARN_ON() results in a mess
of mutually-dependent include files.
Rather than unpick the dependencies, simply have the core code in nospec.h
perform the checking for us.
Signed-off-by: Will Deacon <will.deacon@arm.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1517840166-15399-1-git-send-email-will.deacon@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
static inline unsigned long array_index_mask_nospec(unsigned long index,
unsigned long size)
{
static inline unsigned long array_index_mask_nospec(unsigned long index,
unsigned long size)
{
- /*
- * Warn developers about inappropriate array_index_nospec() usage.
- *
- * Even if the CPU speculates past the WARN_ONCE branch, the
- * sign bit of @index is taken into account when generating the
- * mask.
- *
- * This warning is compiled out when the compiler can infer that
- * @index and @size are less than LONG_MAX.
- */
- if (WARN_ONCE(index > LONG_MAX || size > LONG_MAX,
- "array_index_nospec() limited to range of [0, LONG_MAX]\n"))
- return 0;
-
/*
* Always calculate and emit the mask even if the compiler
* thinks the mask is not needed. The compiler does not take
/*
* Always calculate and emit the mask even if the compiler
* thinks the mask is not needed. The compiler does not take
+/*
+ * Warn developers about inappropriate array_index_nospec() usage.
+ *
+ * Even if the CPU speculates past the WARN_ONCE branch, the
+ * sign bit of @index is taken into account when generating the
+ * mask.
+ *
+ * This warning is compiled out when the compiler can infer that
+ * @index and @size are less than LONG_MAX.
+ */
+#define array_index_mask_nospec_check(index, size) \
+({ \
+ if (WARN_ONCE(index > LONG_MAX || size > LONG_MAX, \
+ "array_index_nospec() limited to range of [0, LONG_MAX]\n")) \
+ _mask = 0; \
+ else \
+ _mask = array_index_mask_nospec(index, size); \
+ _mask; \
+})
+
/*
* array_index_nospec - sanitize an array index after a bounds check
*
/*
* array_index_nospec - sanitize an array index after a bounds check
*
({ \
typeof(index) _i = (index); \
typeof(size) _s = (size); \
({ \
typeof(index) _i = (index); \
typeof(size) _s = (size); \
- unsigned long _mask = array_index_mask_nospec(_i, _s); \
+ unsigned long _mask = array_index_mask_nospec_check(_i, _s); \
\
BUILD_BUG_ON(sizeof(_i) > sizeof(long)); \
BUILD_BUG_ON(sizeof(_s) > sizeof(long)); \
\
BUILD_BUG_ON(sizeof(_i) > sizeof(long)); \
BUILD_BUG_ON(sizeof(_s) > sizeof(long)); \