From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by sourceware.org (Postfix) with ESMTP id 9136E3858D28 for ; Wed, 3 May 2023 18:29:40 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 9136E3858D28 Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 7251C2F4; Wed, 3 May 2023 11:30:24 -0700 (PDT) Received: from localhost (e121540-lin.manchester.arm.com [10.32.110.72]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 65E823F64C; Wed, 3 May 2023 11:29:39 -0700 (PDT) From: Richard Sandiford To: YunQiang Su Mail-Followup-To: YunQiang Su ,gcc-patches@gcc.gnu.org, macro@orcam.me.uk, jiaxun.yang@flygoat.com, syq@debian.org, richard.sandiford@arm.com Cc: gcc-patches@gcc.gnu.org, macro@orcam.me.uk, jiaxun.yang@flygoat.com, syq@debian.org Subject: Re: [PATCH v2] MIPS: add speculation_barrier support References: <20230428123327.686353-1-yunqiang.su@cipunited.com> <20230428131249.713463-1-yunqiang.su@cipunited.com> Date: Wed, 03 May 2023 19:29:38 +0100 In-Reply-To: <20230428131249.713463-1-yunqiang.su@cipunited.com> (YunQiang Su's message of "Fri, 28 Apr 2023 21:12:49 +0800") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.3 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-Spam-Status: No, score=-30.2 required=5.0 tests=BAYES_00,GIT_PATCH_0,KAM_DMARC_NONE,KAM_DMARC_STATUS,KAM_LAZY_DOMAIN_SECURITY,KAM_SHORT,SPF_HELO_NONE,SPF_NONE,TXREP,T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: YunQiang Su writes: > speculation_barrier for MIPS needs sync+jr.hb (r2+), > so we implement __speculation_barrier in libgcc, like arm32 does. Looks reasonable, but do you have a source for the fallback pre-r2 handling? (Thanks for adding that btw, since I realise it's not your focus here.) Nit: the copyright for the new files should start with this year, unless you're copying something significant from an existing file. Thanks, Richard > > gcc/ChangeLog: > * config/mips/mips-protos.h (mips_emit_speculation_barrier): New > prototype. > * config/mips/mips.cc (speculation_barrier_libfunc): New static > variable. > (mips_init_libfuncs): Initialize it. > (mips_emit_speculation_barrier): New function. > * config/mips/mips.md (speculation_barrier): Call > mips_emit_speculation_barrier. > > libgcc/ChangeLog: > * config/mips/lib1funcs.S: New file. > define __speculation_barrier and include mips16.S. > * config/mips/t-mips: define LIB1ASMSRC as mips/lib1funcs.S. > define LIB1ASMFUNCS as _speculation_barrier. > set version info for __speculation_barrier. > * config/mips/libgcc-mips.ver: New file. > * config/mips/t-mips16: don't define LIB1ASMSRC as mips16.S is > included in lib1funcs.S now. > --- > gcc/config/mips/mips-protos.h | 2 + > gcc/config/mips/mips.cc | 13 +++++++ > gcc/config/mips/mips.md | 12 ++++++ > libgcc/config/mips/lib1funcs.S | 60 ++++++++++++++++++++++++++++++ > libgcc/config/mips/libgcc-mips.ver | 21 +++++++++++ > libgcc/config/mips/t-mips | 7 ++++ > libgcc/config/mips/t-mips16 | 3 +- > 7 files changed, 116 insertions(+), 2 deletions(-) > create mode 100644 libgcc/config/mips/lib1funcs.S > create mode 100644 libgcc/config/mips/libgcc-mips.ver > > diff --git a/gcc/config/mips/mips-protos.h b/gcc/config/mips/mips-protos.h > index 20483469105..da7902c235b 100644 > --- a/gcc/config/mips/mips-protos.h > +++ b/gcc/config/mips/mips-protos.h > @@ -388,4 +388,6 @@ extern void mips_register_frame_header_opt (void); > extern void mips_expand_vec_cond_expr (machine_mode, machine_mode, rtx *); > extern void mips_expand_vec_cmp_expr (rtx *); > > +extern void mips_emit_speculation_barrier_function (void); > + > #endif /* ! GCC_MIPS_PROTOS_H */ > diff --git a/gcc/config/mips/mips.cc b/gcc/config/mips/mips.cc > index ca822758b41..139707fda34 100644 > --- a/gcc/config/mips/mips.cc > +++ b/gcc/config/mips/mips.cc > @@ -13611,6 +13611,9 @@ mips_autovectorize_vector_modes (vector_modes *modes, bool) > return 0; > } > > + > +static GTY(()) rtx speculation_barrier_libfunc; > + > /* Implement TARGET_INIT_LIBFUNCS. */ > > static void > @@ -13680,6 +13683,7 @@ mips_init_libfuncs (void) > synchronize_libfunc = init_one_libfunc ("__sync_synchronize"); > init_sync_libfuncs (UNITS_PER_WORD); > } > + speculation_barrier_libfunc = init_one_libfunc ("__speculation_barrier"); > } > > /* Build up a multi-insn sequence that loads label TARGET into $AT. */ > @@ -19092,6 +19096,15 @@ mips_avoid_hazard (rtx_insn *after, rtx_insn *insn, int *hilo_delay, > } > } > > +/* Emit a speculation barrier. > + JR.HB is needed, so we need to put > + speculation_barrier_libfunc in libgcc */ > +void > +mips_emit_speculation_barrier_function () > +{ > + emit_library_call (speculation_barrier_libfunc, LCT_NORMAL, VOIDmode); > +} > + > /* A SEQUENCE is breakable iff the branch inside it has a compact form > and the target has compact branches. */ > > diff --git a/gcc/config/mips/mips.md b/gcc/config/mips/mips.md > index ac1d77afc7d..5d04ac566dd 100644 > --- a/gcc/config/mips/mips.md > +++ b/gcc/config/mips/mips.md > @@ -160,6 +160,8 @@ > ;; The `.insn' pseudo-op. > UNSPEC_INSN_PSEUDO > UNSPEC_JRHB > + > + VUNSPEC_SPECULATION_BARRIER > ]) > > (define_constants > @@ -7455,6 +7457,16 @@ > mips_expand_conditional_move (operands); > DONE; > }) > + > +(define_expand "speculation_barrier" > + [(unspec_volatile [(const_int 0)] VUNSPEC_SPECULATION_BARRIER)] > + "" > + " > + mips_emit_speculation_barrier_function (); > + DONE; > + " > +) > + > > ;; > ;; .................... > diff --git a/libgcc/config/mips/lib1funcs.S b/libgcc/config/mips/lib1funcs.S > new file mode 100644 > index 00000000000..45d74e2e762 > --- /dev/null > +++ b/libgcc/config/mips/lib1funcs.S > @@ -0,0 +1,60 @@ > +/* Copyright (C) 1995-2023 Free Software Foundation, Inc. > + > +This file is free software; you can redistribute it and/or modify it > +under the terms of the GNU General Public License as published by the > +Free Software Foundation; either version 3, or (at your option) any > +later version. > + > +This file is distributed in the hope that it will be useful, but > +WITHOUT ANY WARRANTY; without even the implied warranty of > +MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU > +General Public License for more details. > + > +Under Section 7 of GPL version 3, you are granted additional > +permissions described in the GCC Runtime Library Exception, version > +3.1, as published by the Free Software Foundation. > + > +You should have received a copy of the GNU General Public License and > +a copy of the GCC Runtime Library Exception along with this program; > +see the files COPYING3 and COPYING.RUNTIME respectively. If not, see > +. */ > + > +#include "mips16.S" > + > +#ifdef L_speculation_barrier > + > +/* MIPS16e1 has no sync/jr.hb instructions, and MIPS16e2 lacks of jr.hb. > + So, we use normal MIPS code here, just like what we do for __sync_* */ > + .set nomips16 > + > + .set noreorder > + .globl __speculation_barrier > + .ent __speculation_barrier > + > +__speculation_barrier: > + .set push > +/* MIPS1 has no sync, and in fact it doesn't need it at all. > + We wish that all newer CPUs should run software with MIPS2+ */ > +#if __mips >= 2 > + sync /* complementation barrier for memory */ > +#endif > +#if __mips_isa_rev >= 2 > +/* MIPSr2+: sync+jr.hb is enough */ > + jr.hb $ra /* Jump with instruction hazard barrier */ > +#else > +/* Make ssnop available, ssnop only recognized by GAS since mips32, > + however it's actually available since R5500, > + and it will be decoded as nop on earlier processors */ > + .set mips32 > +/* MIPS1 to MIPSr1: R10000 have 7 stage pipeline, > + so 8 ssnop is sufficient to block all speculation on all CPUs */ > + .rept 8 > + ssnop > + .endr > + jr $ra > +#endif > + .set pop > + .end __speculation_barrier > + > + .set reorder > +#endif > diff --git a/libgcc/config/mips/libgcc-mips.ver b/libgcc/config/mips/libgcc-mips.ver > new file mode 100644 > index 00000000000..f0e9fc54965 > --- /dev/null > +++ b/libgcc/config/mips/libgcc-mips.ver > @@ -0,0 +1,21 @@ > +# Copyright (C) 2008-2023 Free Software Foundation, Inc. > +# > +# This file is part of GCC. > +# > +# GCC is free software; you can redistribute it and/or modify > +# it under the terms of the GNU General Public License as published by > +# the Free Software Foundation; either version 3, or (at your option) > +# any later version. > +# > +# GCC is distributed in the hope that it will be useful, > +# but WITHOUT ANY WARRANTY; without even the implied warranty of > +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > +# GNU General Public License for more details. > +# > +# You should have received a copy of the GNU General Public License > +# along with GCC; see the file COPYING3. If not see > +# . > + > +GCC_14.0 { > + __speculation_barrier > +} > diff --git a/libgcc/config/mips/t-mips b/libgcc/config/mips/t-mips > index 4fb8e136217..d05ef7cbf74 100644 > --- a/libgcc/config/mips/t-mips > +++ b/libgcc/config/mips/t-mips > @@ -7,3 +7,10 @@ softfp_truncations := > softfp_exclude_libgcc2 := n > > LIB2ADD_ST += $(srcdir)/config/mips/lib2funcs.c > + > + > +LIB1ASMSRC = mips/lib1funcs.S > +LIB1ASMFUNCS = _speculation_barrier > + > +# Version these symbols if building libgcc.so. > +SHLIB_MAPFILES += $(srcdir)/config/mips/libgcc-mips.ver > diff --git a/libgcc/config/mips/t-mips16 b/libgcc/config/mips/t-mips16 > index 2bad5119d51..5fd9d60d7a3 100644 > --- a/libgcc/config/mips/t-mips16 > +++ b/libgcc/config/mips/t-mips16 > @@ -16,8 +16,7 @@ > # along with GCC; see the file COPYING3. If not see > # . > > -LIB1ASMSRC = mips/mips16.S > -LIB1ASMFUNCS = _m16addsf3 _m16subsf3 _m16mulsf3 _m16divsf3 \ > +LIB1ASMFUNCS += _m16addsf3 _m16subsf3 _m16mulsf3 _m16divsf3 \ > _m16eqsf2 _m16nesf2 _m16gtsf2 _m16gesf2 _m16lesf2 _m16ltsf2 \ > _m16unordsf2 \ > _m16fltsisf _m16fix_truncsfsi _m16fltunsisf \