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author | Jason Gunthorpe <jgg@mellanox.com> | 2018-01-29 23:26:40 +0300 |
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committer | Jason Gunthorpe <jgg@mellanox.com> | 2018-01-30 19:30:00 +0300 |
commit | e7996a9a77fc669387da43ff4823b91cc4872bd0 (patch) | |
tree | 617f0a128e222539d67e8cccc359f1bc4b984900 /arch/mips/lib/multi3.c | |
parent | b5fa635aab8f0d39a824c01991266a6d06f007fb (diff) | |
parent | d8a5b80568a9cb66810e75b182018e9edb68e8ff (diff) | |
download | linux-e7996a9a77fc669387da43ff4823b91cc4872bd0.tar.xz |
Merge tag v4.15 of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6.git
To resolve conflicts in:
drivers/infiniband/hw/mlx5/main.c
drivers/infiniband/hw/mlx5/qp.c
From patches merged into the -rc cycle. The conflict resolution matches
what linux-next has been carrying.
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Diffstat (limited to 'arch/mips/lib/multi3.c')
-rw-r--r-- | arch/mips/lib/multi3.c | 54 |
1 files changed, 54 insertions, 0 deletions
diff --git a/arch/mips/lib/multi3.c b/arch/mips/lib/multi3.c new file mode 100644 index 000000000000..111ad475aa0c --- /dev/null +++ b/arch/mips/lib/multi3.c @@ -0,0 +1,54 @@ +// SPDX-License-Identifier: GPL-2.0 +#include <linux/export.h> + +#include "libgcc.h" + +/* + * GCC 7 suboptimally generates __multi3 calls for mips64r6, so for that + * specific case only we'll implement it here. + * + * See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82981 + */ +#if defined(CONFIG_64BIT) && defined(CONFIG_CPU_MIPSR6) && (__GNUC__ == 7) + +/* multiply 64-bit values, low 64-bits returned */ +static inline long long notrace dmulu(long long a, long long b) +{ + long long res; + + asm ("dmulu %0,%1,%2" : "=r" (res) : "r" (a), "r" (b)); + return res; +} + +/* multiply 64-bit unsigned values, high 64-bits of 128-bit result returned */ +static inline long long notrace dmuhu(long long a, long long b) +{ + long long res; + + asm ("dmuhu %0,%1,%2" : "=r" (res) : "r" (a), "r" (b)); + return res; +} + +/* multiply 128-bit values, low 128-bits returned */ +ti_type notrace __multi3(ti_type a, ti_type b) +{ + TWunion res, aa, bb; + + aa.ti = a; + bb.ti = b; + + /* + * a * b = (a.lo * b.lo) + * + 2^64 * (a.hi * b.lo + a.lo * b.hi) + * [+ 2^128 * (a.hi * b.hi)] + */ + res.s.low = dmulu(aa.s.low, bb.s.low); + res.s.high = dmuhu(aa.s.low, bb.s.low); + res.s.high += dmulu(aa.s.high, bb.s.low); + res.s.high += dmulu(aa.s.low, bb.s.high); + + return res.ti; +} +EXPORT_SYMBOL(__multi3); + +#endif /* 64BIT && CPU_MIPSR6 && GCC7 */ |