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authorWill Deacon <will.deacon@arm.com>2018-02-05 14:16:06 +0000
committerIngo Molnar <mingo@kernel.org>2018-02-15 01:15:51 +0100
commit8fa80c503b484ddc1abbd10c7cb2ab81f3824a50 (patch)
treeb5b1d8d3cfbb754ca59916900ba1ce50d993a8a2 /include/linux/nospec.h
parentbe3233fbfcb8f5acb6e3bcd0895c3ef9e100d470 (diff)
nospec: Move array_index_nospec() parameter checking into separate macro
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>
Diffstat (limited to 'include/linux/nospec.h')
-rw-r--r--include/linux/nospec.h36
1 files changed, 21 insertions, 15 deletions
diff --git a/include/linux/nospec.h b/include/linux/nospec.h
index b99bced39ac2..fbc98e2c8228 100644
--- a/include/linux/nospec.h
+++ b/include/linux/nospec.h
@@ -20,20 +20,6 @@ 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
* into account the value of @index under speculation.
@@ -44,6 +30,26 @@ static inline unsigned long array_index_mask_nospec(unsigned long index,
#endif
/*
+ * 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
*
* For a code sequence like:
@@ -61,7 +67,7 @@ static inline unsigned long array_index_mask_nospec(unsigned long index,
({ \
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)); \