From mboxrd@z Thu Jan 1 00:00:00 1970 From: Boqun Feng Subject: Re: [RFC][PATCH 18/31] locking,powerpc: Implement atomic{,64}_fetch_{add,sub,and,or,xor}{,_relaxed,_acquire,_release}() Date: Sat, 23 Apr 2016 00:41:57 +0800 Message-ID: <20160422164157.GB3369@insomnia> References: <20160422090413.393652501@infradead.org> <20160422093924.212277819@infradead.org> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="s/l3CgOIzMHHjg/5" Return-path: Received: from mail-io0-f178.google.com ([209.85.223.178]:33718 "EHLO mail-io0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754027AbcDVQis (ORCPT ); Fri, 22 Apr 2016 12:38:48 -0400 Content-Disposition: inline In-Reply-To: <20160422093924.212277819@infradead.org> Sender: linux-arch-owner@vger.kernel.org List-ID: To: Peter Zijlstra Cc: torvalds@linux-foundation.org, mingo@kernel.org, tglx@linutronix.de, will.deacon@arm.com, paulmck@linux.vnet.ibm.com, waiman.long@hpe.com, fweisbec@gmail.com, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, rth@twiddle.net, vgupta@synopsys.com, linux@arm.linux.org.uk, egtvedt@samfundet.no, realmz6@gmail.com, ysato@users.sourceforge.jp, rkuo@codeaurora.org, tony.luck@intel.com, geert@linux-m68k.org, james.hogan@imgtec.com, ralf@linux-mips.org, dhowells@redhat.com, jejb@parisc-linux.org, mpe@ellerman.id.au, schwidefsky@de.ibm.com, dalias@libc.org, davem@davemloft.net, cmetcalf@mellanox.com, jcmvbkbc@gmail.com, arnd@arndb.de, dbueso@suse.de, fengguang.wu@intel.com --s/l3CgOIzMHHjg/5 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri, Apr 22, 2016 at 11:04:31AM +0200, Peter Zijlstra wrote: > Implement FETCH-OP atomic primitives, these are very similar to the > existing OP-RETURN primitives we already have, except they return the > value of the atomic variable _before_ modification. >=20 > This is especially useful for irreversible operations -- such as > bitops (because it becomes impossible to reconstruct the state prior > to modification). >=20 >=20 > Signed-off-by: Peter Zijlstra (Intel) > --- > arch/powerpc/include/asm/atomic.h | 83 +++++++++++++++++++++++++++++++= ++----- > 1 file changed, 74 insertions(+), 9 deletions(-) >=20 > --- a/arch/powerpc/include/asm/atomic.h > +++ b/arch/powerpc/include/asm/atomic.h > @@ -78,21 +78,53 @@ static inline int atomic_##op##_return_r > return t; \ > } > =20 > +#define ATOMIC_FETCH_OP_RELAXED(op, asm_op) \ > +static inline int atomic_fetch_##op##_relaxed(int a, atomic_t *v) \ > +{ \ > + int res, t; \ > + \ > + __asm__ __volatile__( \ > +"1: lwarx %0,0,%4 # atomic_fetch_" #op "_relaxed\n" \ > + #asm_op " %1,%2,%0\n" \ Should be #asm_op " %1,%3,%0\n" right? Because %2 is v->counter and %3 is @a. Regards, Boqun > + PPC405_ERR77(0, %4) \ > +" stwcx. %1,0,%4\n" \ > +" bne- 1b\n" \ > + : "=3D&r" (res), "=3D&r" (t), "+m" (v->counter) \ > + : "r" (a), "r" (&v->counter) \ > + : "cc"); \ > + \ > + return res; \ > +} > + > #define ATOMIC_OPS(op, asm_op) \ > ATOMIC_OP(op, asm_op) \ > - ATOMIC_OP_RETURN_RELAXED(op, asm_op) > + ATOMIC_OP_RETURN_RELAXED(op, asm_op) \ > + ATOMIC_FETCH_OP_RELAXED(op, asm_op) > =20 > ATOMIC_OPS(add, add) > ATOMIC_OPS(sub, subf) > =20 > -ATOMIC_OP(and, and) > -ATOMIC_OP(or, or) > -ATOMIC_OP(xor, xor) > - > #define atomic_add_return_relaxed atomic_add_return_relaxed > #define atomic_sub_return_relaxed atomic_sub_return_relaxed > =20 > +#define atomic_fetch_add_relaxed atomic_fetch_add_relaxed > +#define atomic_fetch_sub_relaxed atomic_fetch_sub_relaxed > + > +#undef ATOMIC_OPS > +#define ATOMIC_OPS(op, asm_op) \ > + ATOMIC_OP(op, asm_op) \ > + ATOMIC_FETCH_OP_RELAXED(op, asm_op) > + > +ATOMIC_OPS(and, and) > +ATOMIC_OPS(or, or) > +ATOMIC_OPS(xor, xor) > + > +#define atomic_fetch_and_relaxed atomic_fetch_and_relaxed > +#define atomic_fetch_or_relaxed atomic_fetch_or_relaxed > +#define atomic_fetch_xor_relaxed atomic_fetch_xor_relaxed > + > #undef ATOMIC_OPS > +#undef ATOMIC_FETCH_OP_RELAXED > #undef ATOMIC_OP_RETURN_RELAXED > #undef ATOMIC_OP > =20 > @@ -329,20 +361,53 @@ atomic64_##op##_return_relaxed(long a, a > return t; \ > } > =20 > +#define ATOMIC64_FETCH_OP_RELAXED(op, asm_op) \ > +static inline long \ > +atomic64_fetch_##op##_relaxed(long a, atomic64_t *v) \ > +{ \ > + long res, t; \ > + \ > + __asm__ __volatile__( \ > +"1: ldarx %0,0,%4 # atomic64_fetch_" #op "_relaxed\n" \ > + #asm_op " %1,%3,%0\n" \ > +" stdcx. %1,0,%4\n" \ > +" bne- 1b\n" \ > + : "=3D&r" (res), "=3D&r" (t), "+m" (v->counter) \ > + : "r" (a), "r" (&v->counter) \ > + : "cc"); \ > + \ > + return t; \ > +} > + > #define ATOMIC64_OPS(op, asm_op) \ > ATOMIC64_OP(op, asm_op) \ > - ATOMIC64_OP_RETURN_RELAXED(op, asm_op) > + ATOMIC64_OP_RETURN_RELAXED(op, asm_op) \ > + ATOMIC64_FETCH_OP_RELAXED(op, asm_op) > =20 > ATOMIC64_OPS(add, add) > ATOMIC64_OPS(sub, subf) > -ATOMIC64_OP(and, and) > -ATOMIC64_OP(or, or) > -ATOMIC64_OP(xor, xor) > =20 > #define atomic64_add_return_relaxed atomic64_add_return_relaxed > #define atomic64_sub_return_relaxed atomic64_sub_return_relaxed > =20 > +#define atomic64_fetch_add_relaxed atomic64_fetch_add_relaxed > +#define atomic64_fetch_sub_relaxed atomic64_fetch_sub_relaxed > + > +#undef ATOMIC64_OPS > +#define ATOMIC64_OPS(op, asm_op) \ > + ATOMIC64_OP(op, asm_op) \ > + ATOMIC64_FETCH_OP_RELAXED(op, asm_op) > + > +ATOMIC64_OPS(and, and) > +ATOMIC64_OPS(or, or) > +ATOMIC64_OPS(xor, xor) > + > +#define atomic64_fetch_and_relaxed atomic64_fetch_and_relaxed > +#define atomic64_fetch_or_relaxed atomic64_fetch_or_relaxed > +#define atomic64_fetch_xor_relaxed atomic64_fetch_xor_relaxed > + > #undef ATOPIC64_OPS > +#undef ATOMIC64_FETCH_OP_RELAXED > #undef ATOMIC64_OP_RETURN_RELAXED > #undef ATOMIC64_OP > =20 >=20 >=20 --s/l3CgOIzMHHjg/5 Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQEcBAABCAAGBQJXGlRRAAoJEEl56MO1B/q4hyoH/0qvpP+MVq1isOPXwNbJy6MZ xBWCO3Jpw2x7FoPG0ONG1HioE2fUrze9I/4Hus7nFaySf+oegDYhsQG2DyD7k6L0 xVJi4b6OvRquoQQrvFJVmXsaJk+ihtUmMMcxyHuNa2WlePQ2wSZkMDxB5ikyIFPR kKVbc7zAk5zLLi9nNUiZJN5InTKYFoU8AnJpy/9TV7VSOcr/hrcfeeaxgXTYR0Gf iIuAiQigQ69TCiwDdVJAqy9jT1zLVtkyINZX8/wyDSahCJvv9pl/e7dTwgL3lVjp lwVDmW4E+o13fRZJWTb9K/RhcCrkRPyUBN0UVWYVOVaysS9mBH2PXcpPshpAwdY= =O5Bw -----END PGP SIGNATURE----- --s/l3CgOIzMHHjg/5--