diff options
| author | Maxime COQUELIN <maxime.coquelin@st.com> | 2014-11-06 10:54:19 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-12-06 15:57:33 -0800 |
| commit | 5ee96f0b68b9522c063a7952e06333b9f27994bc (patch) | |
| tree | 59a94c065652f5fcb493dc0dbeaa3af91ec48a0f | |
| parent | 68814ef48cc23572b14b494216598d3116f71096 (diff) | |
| download | linux-stable-5ee96f0b68b9522c063a7952e06333b9f27994bc.tar.gz linux-stable-5ee96f0b68b9522c063a7952e06333b9f27994bc.tar.bz2 linux-stable-5ee96f0b68b9522c063a7952e06333b9f27994bc.zip | |
bitops: Fix shift overflow in GENMASK macros
commit 00b4d9a14125f1e51874def2b9de6092e007412d upstream.
On some 32 bits architectures, including x86, GENMASK(31, 0) returns 0
instead of the expected ~0UL.
This is the same on some 64 bits architectures with GENMASK_ULL(63, 0).
This is due to an overflow in the shift operand, 1 << 32 for GENMASK,
1 << 64 for GENMASK_ULL.
Reported-by: Eric Paire <eric.paire@st.com>
Suggested-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Maxime Coquelin <maxime.coquelin@st.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: linux@rasmusvillemoes.dk
Cc: gong.chen@linux.intel.com
Cc: John Sullivan <jsrhbz@kanargh.force9.co.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Fixes: 10ef6b0dffe4 ("bitops: Introduce a more generic BITMASK macro")
Link: http://lkml.kernel.org/r/1415267659-10563-1-git-send-email-maxime.coquelin@st.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | include/linux/bitops.h | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/include/linux/bitops.h b/include/linux/bitops.h index cbc5833fb221..38b5f5c88c18 100644 --- a/include/linux/bitops.h +++ b/include/linux/bitops.h @@ -18,8 +18,11 @@ * position @h. For example * GENMASK_ULL(39, 21) gives us the 64bit vector 0x000000ffffe00000. */ -#define GENMASK(h, l) (((U32_C(1) << ((h) - (l) + 1)) - 1) << (l)) -#define GENMASK_ULL(h, l) (((U64_C(1) << ((h) - (l) + 1)) - 1) << (l)) +#define GENMASK(h, l) \ + (((~0UL) << (l)) & (~0UL >> (BITS_PER_LONG - 1 - (h)))) + +#define GENMASK_ULL(h, l) \ + (((~0ULL) << (l)) & (~0ULL >> (BITS_PER_LONG_LONG - 1 - (h)))) extern unsigned int __sw_hweight8(unsigned int w); extern unsigned int __sw_hweight16(unsigned int w); |