From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by sourceware.org (Postfix) with ESMTPS id 06FB53858D37 for ; Tue, 4 Oct 2022 16:14:05 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 06FB53858D37 Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=redhat.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1664900045; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=FP1UuZpRqMUT0Huie12PoFUBC1CjiDIIky9lvarVbaU=; b=J1/JGLX3hR/TE+1yHQFpg4x/oaE0gcyVBgtQmeJaGasDsCiveFcVXT6w5mnGBXxFhtxQkx k0RnA+S6+OjICoeARuSueXr2/mSYxhMbNtQnXzOoAYTIlEgu1Z4lRbrbiJh/0irfq1YVNc 04ZXXZ7ErJ1WJgRPpy898vkAO0TyPHE= Received: from mail-qk1-f198.google.com (mail-qk1-f198.google.com [209.85.222.198]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_128_GCM_SHA256) id us-mta-118-YP8MFZ8-MFuuP5w6wLfV3A-1; Tue, 04 Oct 2022 12:14:03 -0400 X-MC-Unique: YP8MFZ8-MFuuP5w6wLfV3A-1 Received: by mail-qk1-f198.google.com with SMTP id j13-20020a05620a288d00b006be7b2a758fso11918844qkp.1 for ; Tue, 04 Oct 2022 09:14:00 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date; bh=FP1UuZpRqMUT0Huie12PoFUBC1CjiDIIky9lvarVbaU=; b=DDWTyDTMea5zfnvk9oLK35+ximHgYKUCVPQLiWEhpDQdmsSHvsXpfEl4qOaB1OfHH8 JqARSkAjSfTRhRROkrQj9hTRdAgCTVWZd1heBV+RPkXJFm0r5ly9/A1wvYiT5lpZToyq T0aMPFcpzvzW6UHu7VB+eQOxlGZB6AGtcLJqj0H+ReOtUy4sQbzJYRWc94QWTICc/Hsq 28qeZywN2NZFJZJkQlhxjjP0kHgFHfX2UAJIHJ8E7EjLhIps9oBlKBCAKB+peK+lrusO eU2pPRuiINwcmN8hnj2EAkm9bIUTwl+baSaGVB5CTJPa6wbfYEQFpqMPMPmy45XsmxVG U1Ug== X-Gm-Message-State: ACrzQf2FQ6HWDi5q3GZYlKJ4FU3ni8sgxqELKp4VCcZ4mwchxk6PkOQl E8jvg1Ql5VWYkoQMbfYKbGMBvaIi+/iu4C2dhfCWn87ark0qVoeqAyR1Hyd6eKfyg09k2ztwAX3 FmqQ2Nda1avwLgD2CMYK9 X-Received: by 2002:a05:620a:4042:b0:6ce:3fe4:4e35 with SMTP id i2-20020a05620a404200b006ce3fe44e35mr17413686qko.276.1664900039827; Tue, 04 Oct 2022 09:13:59 -0700 (PDT) X-Google-Smtp-Source: AMsMyM62Qwin/l61C4CVWnyJKfcg+Pa4QdVhID/PHbOUIwCglDL0hCzf2pwvf6j2pGUvfeQuJHgkaA== X-Received: by 2002:a05:620a:4042:b0:6ce:3fe4:4e35 with SMTP id i2-20020a05620a404200b006ce3fe44e35mr17413661qko.276.1664900039381; Tue, 04 Oct 2022 09:13:59 -0700 (PDT) Received: from fedora ([66.187.232.65]) by smtp.gmail.com with ESMTPSA id q25-20020a37f719000000b006cf14cc6740sm9833664qkj.70.2022.10.04.09.13.58 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 04 Oct 2022 09:13:58 -0700 (PDT) Date: Tue, 4 Oct 2022 12:13:56 -0400 From: Carlos O'Donell To: Adhemerval Zanella Cc: libc-alpha@sourceware.org, "H . J . Lu" Subject: Re: [PATCH v4] elf: Remove -fno-tree-loop-distribute-patterns usage on dl-support Message-ID: References: <20220811121909.4110665-1-adhemerval.zanella@linaro.org> MIME-Version: 1.0 In-Reply-To: <20220811121909.4110665-1-adhemerval.zanella@linaro.org> X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline X-Spam-Status: No, score=-11.5 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,GIT_PATCH_0,KAM_SHORT,KAM_STOCKGEN,RCVD_IN_DNSWL_NONE,SPF_HELO_NONE,SPF_NONE,TXREP 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: On Thu, Aug 11, 2022 at 09:19:09AM -0300, Adhemerval Zanella via Libc-alpha wrote: > Besides the option being gcc specific, this approach is still fragile > and not future proof since we do not if this will be the only s/do not/do not know/g > optimization option gcc will add that transform loops to memset s/transform/transforms/g > (or any libcall). > > This patch add a new header dl-symbol-hacks.h that can be used to s/add/adds/g s/dl-symbol-hacks.h/, dl-symbol-hacks.h,/g > redirect the compiler generated libcalls to port specific string > implementatation if required (defined by dl-ifunc-generic.h). > > Checked on x86_64-linux-gnu and aarch64-linux-gnu. > --- > elf/Makefile | 5 --- > elf/dl-support.c | 1 + > elf/dl-symbol-hacks.h | 31 ++++++++++++++++ > sysdeps/aarch64/multiarch/dl-ifunc-generic.h | 24 ++++++++++++ > sysdeps/generic/dl-ifunc-generic.h | 37 +++++++++++++++++++ > .../i386/i686/multiarch/dl-ifunc-generic.h | 24 ++++++++++++ > .../powerpc64/le/multiarch/dl-ifunc-generic.h | 24 ++++++++++++ > sysdeps/s390/multiarch/dl-ifunc-generic.h | 29 +++++++++++++++ > .../sparcv9/multiarch/dl-ifunc-generic.h | 24 ++++++++++++ > .../sparc64/multiarch/dl-ifunc-generic.h | 24 ++++++++++++ > sysdeps/x86_64/multiarch/dl-ifunc-generic.h | 32 ++++++++++++++++ > 11 files changed, 250 insertions(+), 5 deletions(-) > create mode 100644 elf/dl-symbol-hacks.h > create mode 100644 sysdeps/aarch64/multiarch/dl-ifunc-generic.h > create mode 100644 sysdeps/generic/dl-ifunc-generic.h > create mode 100644 sysdeps/i386/i686/multiarch/dl-ifunc-generic.h > create mode 100644 sysdeps/powerpc/powerpc64/le/multiarch/dl-ifunc-generic.h > create mode 100644 sysdeps/s390/multiarch/dl-ifunc-generic.h > create mode 100644 sysdeps/sparc/sparc32/sparcv9/multiarch/dl-ifunc-generic.h > create mode 100644 sysdeps/sparc/sparc64/multiarch/dl-ifunc-generic.h > create mode 100644 sysdeps/x86_64/multiarch/dl-ifunc-generic.h > > diff --git a/elf/Makefile b/elf/Makefile > index 3386f0ce77..4b992bd348 100644 > --- a/elf/Makefile > +++ b/elf/Makefile > @@ -162,11 +162,6 @@ ifeq (yes,$(have-loop-to-function)) > CFLAGS-rtld.c += -fno-tree-loop-distribute-patterns > endif > > -ifeq (yes,$(have-loop-to-function)) > -# Likewise, during static library startup, memset is not yet available. > -CFLAGS-dl-support.c = -fno-tree-loop-distribute-patterns > -endif > - OK. > # Compile rtld itself without stack protection. > # Also compile all routines in the static library that are elided from > # the shared libc because they are in libc.a in the same way. > diff --git a/elf/dl-support.c b/elf/dl-support.c > index 4af0b5b2ce..6d1996ae6e 100644 > --- a/elf/dl-support.c > +++ b/elf/dl-support.c > @@ -44,6 +44,7 @@ > #include > #include > #include > +#include OK. > > extern char *__progname; > char **_dl_argv = &__progname; /* This is checked for some error messages. */ > diff --git a/elf/dl-symbol-hacks.h b/elf/dl-symbol-hacks.h > new file mode 100644 > index 0000000000..1b83b284dd > --- /dev/null > +++ b/elf/dl-symbol-hacks.h Bikeshed. Call it "dl-symbol-redir.h" since that's what it does. Can we get rid of this? Can we flatten the headers out? At the very least I think we want to remove the typo-prone macro API and always define the macros. > @@ -0,0 +1,31 @@ > +/* Symbol rediretion for loader/static initialization code. > + Copyright (C) 2022 Free Software Foundation, Inc. > + This file is part of the GNU C Library. > + > + The GNU C Library is free software; you can redistribute it and/or > + modify it under the terms of the GNU Lesser General Public > + License as published by the Free Software Foundation; either > + version 2.1 of the License, or (at your option) any later version. > + > + The GNU C Library 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 > + Lesser General Public License for more details. > + > + You should have received a copy of the GNU Lesser General Public > + License along with the GNU C Library; if not, see > + . */ > + > +#ifndef _DL_SYMBOL_HACKS_H > +#define _DL_SYMBOL_HACKS_H > + > +#include > + > +/* Some compiler optimizations may transform loops into memset/memmove > + calls and without proper redirection it might call PLT throught s/PLT throught/through the PLT via an/g > + ifunc without relocations being processed. */ > +#ifdef HAVE_MEMSET_IFUNC_GENERIC Typo unsafe macro API. Can we always define this? Use a generic definition? > +asm ("memset = " HAVE_MEMSET_IFUNC_GENERIC); > +#endif > + > +#endif > diff --git a/sysdeps/aarch64/multiarch/dl-ifunc-generic.h b/sysdeps/aarch64/multiarch/dl-ifunc-generic.h > new file mode 100644 > index 0000000000..1278a06ff0 > --- /dev/null > +++ b/sysdeps/aarch64/multiarch/dl-ifunc-generic.h Call it "dl-symbol-redir-ifunc.h"? This is not generic, it is aarch64 specific. > @@ -0,0 +1,24 @@ > +/* Symbol rediretion for loader/static initialization code. > + Copyright (C) 2022 Free Software Foundation, Inc. > + This file is part of the GNU C Library. > + > + The GNU C Library is free software; you can redistribute it and/or > + modify it under the terms of the GNU Lesser General Public > + License as published by the Free Software Foundation; either > + version 2.1 of the License, or (at your option) any later version. > + > + The GNU C Library 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 > + Lesser General Public License for more details. > + > + You should have received a copy of the GNU Lesser General Public > + License along with the GNU C Library; if not, see > + . */ > + > +#ifndef _DL_IFUNC_GENERIC_H > +#define _DL_IFUNC_GENERIC_H > + > +#define HAVE_MEMSET_IFUNC_GENERIC "__memset_generic" > + > +#endif > diff --git a/sysdeps/generic/dl-ifunc-generic.h b/sysdeps/generic/dl-ifunc-generic.h > new file mode 100644 > index 0000000000..5e1d5c1fd8 > --- /dev/null > +++ b/sysdeps/generic/dl-ifunc-generic.h Call it "dl-symbol-redir-ifunc.h"? > @@ -0,0 +1,37 @@ > +/* Symbol rediretion for loader/static initialization code. > + Copyright (C) 2022 Free Software Foundation, Inc. > + This file is part of the GNU C Library. > + > + The GNU C Library is free software; you can redistribute it and/or > + modify it under the terms of the GNU Lesser General Public > + License as published by the Free Software Foundation; either > + version 2.1 of the License, or (at your option) any later version. > + > + The GNU C Library 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 > + Lesser General Public License for more details. > + > + You should have received a copy of the GNU Lesser General Public > + License along with the GNU C Library; if not, see > + . */ > + > +#ifndef _DL_IFUNC_GENERIC_H > +#define _DL_IFUNC_GENERIC_H > + > +/* The compiler might optimize loops or other constructs to library calls even > + in freestanding mode. Although it is safe in most scenarios, on program > + loading and static startup, iFUNC resolution might require other dynamic > + relocation that are not yet done. > + > + Instead of adding per-file compiler flags to avoid the libcall generation, > + this header defines generic symbols that will be routed instead of the > + default symbols name. > + > + Each port can then define the following macro to the expected generic > + implementation if the symbol is provided as iFUNC: > + > + HAVE_MEMSET_IFUNC_GENERIC - the generic memset call. > + */ > + Define the macro by default. > +#endif > diff --git a/sysdeps/i386/i686/multiarch/dl-ifunc-generic.h b/sysdeps/i386/i686/multiarch/dl-ifunc-generic.h > new file mode 100644 > index 0000000000..a538931c03 > --- /dev/null > +++ b/sysdeps/i386/i686/multiarch/dl-ifunc-generic.h Call it "dl-symbol-redir-ifunc.h"? > @@ -0,0 +1,24 @@ > +/* Symbol rediretion for loader/static initialization code. > + Copyright (C) 2022 Free Software Foundation, Inc. > + This file is part of the GNU C Library. > + > + The GNU C Library is free software; you can redistribute it and/or > + modify it under the terms of the GNU Lesser General Public > + License as published by the Free Software Foundation; either > + version 2.1 of the License, or (at your option) any later version. > + > + The GNU C Library 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 > + Lesser General Public License for more details. > + > + You should have received a copy of the GNU Lesser General Public > + License along with the GNU C Library; if not, see > + . */ > + > +#ifndef _DL_IFUNC_GENERIC_H > +#define _DL_IFUNC_GENERIC_H > + > +#define HAVE_MEMSET_IFUNC_GENERIC "__memset_ia32" OK. > + > +#endif > diff --git a/sysdeps/powerpc/powerpc64/le/multiarch/dl-ifunc-generic.h b/sysdeps/powerpc/powerpc64/le/multiarch/dl-ifunc-generic.h > new file mode 100644 > index 0000000000..1bf516494d > --- /dev/null > +++ b/sysdeps/powerpc/powerpc64/le/multiarch/dl-ifunc-generic.h Call it "dl-symbol-redir-ifunc.h"? > @@ -0,0 +1,24 @@ > +/* Symbol rediretion for loader/static initialization code. > + Copyright (C) 2022 Free Software Foundation, Inc. > + This file is part of the GNU C Library. > + > + The GNU C Library is free software; you can redistribute it and/or > + modify it under the terms of the GNU Lesser General Public > + License as published by the Free Software Foundation; either > + version 2.1 of the License, or (at your option) any later version. > + > + The GNU C Library 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 > + Lesser General Public License for more details. > + > + You should have received a copy of the GNU Lesser General Public > + License along with the GNU C Library; if not, see > + . */ > + > +#ifndef _DL_IFUNC_GENERIC_H > +#define _DL_IFUNC_GENERIC_H > + > +#define HAVE_MEMSET_IFUNC_GENERIC "__memset_power8" OK. > + > +#endif > diff --git a/sysdeps/s390/multiarch/dl-ifunc-generic.h b/sysdeps/s390/multiarch/dl-ifunc-generic.h > new file mode 100644 > index 0000000000..b0e5ed23aa > --- /dev/null > +++ b/sysdeps/s390/multiarch/dl-ifunc-generic.h Call it "dl-symbol-redir-ifunc.h"? > @@ -0,0 +1,29 @@ > +/* Symbol rediretion for loader/static initialization code. > + Copyright (C) 2022 Free Software Foundation, Inc. > + This file is part of the GNU C Library. > + > + The GNU C Library is free software; you can redistribute it and/or > + modify it under the terms of the GNU Lesser General Public > + License as published by the Free Software Foundation; either > + version 2.1 of the License, or (at your option) any later version. > + > + The GNU C Library 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 > + Lesser General Public License for more details. > + > + You should have received a copy of the GNU Lesser General Public > + License along with the GNU C Library; if not, see > + . */ > + > +#ifndef _DL_IFUNC_GENERIC_H > +#define _DL_IFUNC_GENERIC_H > + > +#include > + > +#define IFUNC_SYMBOL_STR1(s) #s > +#define IFUNC_SYMBOL_STR(s) IFUNC_SYMBOL_STR1(s) > + > +#define HAVE_MEMSET_IFUNC_GENERIC IFUNC_SYMBOL_STR(MEMSET_DEFAULT) OK. Ugh. > + > +#endif > diff --git a/sysdeps/sparc/sparc32/sparcv9/multiarch/dl-ifunc-generic.h b/sysdeps/sparc/sparc32/sparcv9/multiarch/dl-ifunc-generic.h > new file mode 100644 > index 0000000000..417b24d2c1 > --- /dev/null > +++ b/sysdeps/sparc/sparc32/sparcv9/multiarch/dl-ifunc-generic.h Call it "dl-symbol-redir-ifunc.h"? > @@ -0,0 +1,24 @@ > +/* Symbol rediretion for loader/static initialization code. > + Copyright (C) 2022 Free Software Foundation, Inc. > + This file is part of the GNU C Library. > + > + The GNU C Library is free software; you can redistribute it and/or > + modify it under the terms of the GNU Lesser General Public > + License as published by the Free Software Foundation; either > + version 2.1 of the License, or (at your option) any later version. > + > + The GNU C Library 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 > + Lesser General Public License for more details. > + > + You should have received a copy of the GNU Lesser General Public > + License along with the GNU C Library; if not, see > + . */ > + > +#ifndef _DL_IFUNC_GENERIC_H > +#define _DL_IFUNC_GENERIC_H > + > +#define HAVE_MEMSET_IFUNC_GENERIC "__memset_ultra1" OK. > + > +#endif > diff --git a/sysdeps/sparc/sparc64/multiarch/dl-ifunc-generic.h b/sysdeps/sparc/sparc64/multiarch/dl-ifunc-generic.h > new file mode 100644 > index 0000000000..417b24d2c1 > --- /dev/null > +++ b/sysdeps/sparc/sparc64/multiarch/dl-ifunc-generic.h Call it "dl-symbol-redir-ifunc.h"? > @@ -0,0 +1,24 @@ > +/* Symbol rediretion for loader/static initialization code. > + Copyright (C) 2022 Free Software Foundation, Inc. > + This file is part of the GNU C Library. > + > + The GNU C Library is free software; you can redistribute it and/or > + modify it under the terms of the GNU Lesser General Public > + License as published by the Free Software Foundation; either > + version 2.1 of the License, or (at your option) any later version. > + > + The GNU C Library 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 > + Lesser General Public License for more details. > + > + You should have received a copy of the GNU Lesser General Public > + License along with the GNU C Library; if not, see > + . */ > + > +#ifndef _DL_IFUNC_GENERIC_H > +#define _DL_IFUNC_GENERIC_H > + > +#define HAVE_MEMSET_IFUNC_GENERIC "__memset_ultra1" OK. > + > +#endif > diff --git a/sysdeps/x86_64/multiarch/dl-ifunc-generic.h b/sysdeps/x86_64/multiarch/dl-ifunc-generic.h > new file mode 100644 > index 0000000000..7b7cf1c3d6 > --- /dev/null > +++ b/sysdeps/x86_64/multiarch/dl-ifunc-generic.h Call it "dl-symbol-redir-ifunc.h"? > @@ -0,0 +1,32 @@ > +/* Symbol rediretion for loader/static initialization code. > + Copyright (C) 2022 Free Software Foundation, Inc. > + This file is part of the GNU C Library. > + > + The GNU C Library is free software; you can redistribute it and/or > + modify it under the terms of the GNU Lesser General Public > + License as published by the Free Software Foundation; either > + version 2.1 of the License, or (at your option) any later version. > + > + The GNU C Library 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 > + Lesser General Public License for more details. > + > + You should have received a copy of the GNU Lesser General Public > + License along with the GNU C Library; if not, see > + . */ > + > +#ifndef _DL_IFUNC_GENERIC_H > +#define _DL_IFUNC_GENERIC_H > + > +#include > + > +#if MINIMUM_X86_ISA_LEVEL >= 4 > +# define HAVE_MEMSET_IFUNC_GENERIC "__memset_evex_unaligned" > +#elif MINIMUM_X86_ISA_LEVEL == 3 > +# define HAVE_MEMSET_IFUNC_GENERIC "__memset_avx2_unaligned" > +#else > +# define HAVE_MEMSET_IFUNC_GENERIC "__memset_sse2_unaligned" > +#endif OK. > + > +#endif > -- > 2.34.1 >