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Lu" X-Patchwork-Id: 945940 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=sourceware.org (client-ip=209.132.180.131; helo=sourceware.org; envelope-from=libc-alpha-return-94479-incoming=patchwork.ozlabs.org@sourceware.org; receiver=) Authentication-Results: ozlabs.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: ozlabs.org; dkim=pass (1024-bit key; secure) header.d=sourceware.org header.i=@sourceware.org header.b="YILUTPTQ"; dkim=pass (2048-bit key; unprotected) header.d=gmail.com header.i=@gmail.com header.b="dvP3ptAd"; dkim-atps=neutral Received: from sourceware.org (server1.sourceware.org [209.132.180.131]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 41WBCn4ysrz9s4w for ; Thu, 19 Jul 2018 08:10:13 +1000 (AEST) DomainKey-Signature: a=rsa-sha1; c=nofws; d=sourceware.org; h=list-id :list-unsubscribe:list-subscribe:list-archive:list-post :list-help:sender:mime-version:from:date:message-id:subject:to :cc:content-type; q=dns; s=default; b=Sbkil8YUof5w9CcwhU9XVi7jwz MQ/Hsx7LnBpusX+QW547vmOFQe0vt2p2J9n+1b2omqQn2lG2xs6RSzn5Nyl/Eul1 Msse+a+J6XmwGb32w8PDQyxpsUkSETCGEr/lTlzEZkyJACOpJNdF1jt+eDLJrvfo qZvinTMtwyU+5ShrU= DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=sourceware.org; h=list-id :list-unsubscribe:list-subscribe:list-archive:list-post :list-help:sender:mime-version:from:date:message-id:subject:to :cc:content-type; s=default; bh=/tgMBGJIyT/n6Knib0IdxFdl6ak=; b= YILUTPTQ0RO5UmWN2ZSO7dvUXdOSvI8FoM0BSO5S47KB7BM97lbMrPCKR51N5Jhb bimgpuiIzXDeS3V6Ao4lbI5boR+jGJUmhMEf+Fu5uSY03GMAZEYVh9q6V5HCrcgk QSJh2DZbCAmZnNJ9JeVrgg6v3/PWGCxaxn44HlI7SyE= Received: (qmail 36958 invoked by alias); 18 Jul 2018 22:10:07 -0000 Mailing-List: contact libc-alpha-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: libc-alpha-owner@sourceware.org Delivered-To: mailing list libc-alpha@sourceware.org Received: (qmail 36655 invoked by uid 89); 18 Jul 2018 22:10:06 -0000 Authentication-Results: sourceware.org; auth=none X-Spam-SWARE-Status: No, score=-25.3 required=5.0 tests=AWL, BAYES_00, FREEMAIL_FROM, GIT_PATCH_0, GIT_PATCH_1, GIT_PATCH_2, GIT_PATCH_3, KAM_SHORT, RCVD_IN_DNSWL_NONE, SPF_PASS, URIBL_RED autolearn=ham version=3.3.2 spammy=Never, stdinth, stdint.h, UD:stdint.h X-HELO: mail-oi0-f66.google.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:from:date:message-id:subject:to:cc; bh=sucbgoCumUbpjdKUCEoYzylzEcu1MYYzqLsPQspXAv4=; b=dvP3ptAdoaZU+ZoctiqAba8tQgne+hTNVDTDamXsObNn2bviKrAHyP9fGJMlQlV6HD Y4Sp2PfRGkrO/Guiq61uYCoH1ulotFrkCIb3t51IFJQSLNJtHyath8syE8Z3jybJBYG3 fwUF7GWL58PBgL4avJj0N3QrF2VH0YqK6RIsqGX40B2S+HzNZIrBSrVaeHX0zT6WZCHh EMTfImv9MH8svzszxfAvEEdvxkqsycL3+/8ZWXXJJy2sRu5xKBcZ+pauy01V5Qq96yCE uyQlaeKvh3NeyVvhxUPd2dxX/nHE/EOEUIzuDB0/MH76VeOt/EOjYOXtsxRND0qTVXoh TYMg== MIME-Version: 1.0 From: "H.J. Lu" Date: Wed, 18 Jul 2018 15:10:02 -0700 Message-ID: Subject: [PATCH] Add To: Joseph Myers Cc: GNU C Library On Wed, Jul 18, 2018 at 1:58 PM, Joseph Myers wrote: > On Wed, 18 Jul 2018, H.J. Lu wrote: > >> +#ifndef __INDIRECT_RETURN >> +# define __INDIRECT_RETURN >> +#endif > > This default definition is missing a comment to define the semantics of > this macro. And please avoid this #ifndef convention. Rather, the normal > glibc convention would be to have e.g. a bits/indirect-return.h installed > header, with a default version with an empty definition and a comment > documenting the semantics, and a separate x86 version. > Here is the updated patch. I am running native tests on x86 and scripts/build-many-glibcs.py now. Thanks. From 1345e8591ebc4ed6a97f228a1c0b49c9ce21339b Mon Sep 17 00:00:00 2001 From: "H.J. Lu" Date: Thu, 7 Jun 2018 20:50:11 -0700 Subject: [PATCH] Add MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Add and include it in . __INDIRECT_RETURN defined in indicates if swapcontext() requires special compiler treatment. The default __INDIRECT_RETURN is empty. On x86, when shadow stack is enabled, __INDIRECT_RETURN is defined with indirect_return attribute, which has been added to GCC 9, to indicate that swapcontext() returns via indirect branch. Otherwise __INDIRECT_RETURN is defined with returns_twice attribute. When shadow stack is enabled, remove always_inline attribute from prepare_test_buffer in string/tst-xbzero-opt.c to avoid: tst-xbzero-opt.c: In function ‘prepare_test_buffer’: tst-xbzero-opt.c:105:1: error: function ‘prepare_test_buffer’ can never be inlined because it uses setjmp prepare_test_buffer (unsigned char *buf) when indirect_return attribute isn't available. * bits/indirect-return.h: New file. * sysdeps/x86/bits/indirect-return.h: Likewise. * stdlib/Makefile (headers): Add bits/indirect-return.h. * stdlib/ucontext.h: Include . (swapcontext): Add __INDIRECT_RETURN. * string/tst-xbzero-opt.c (ALWAYS_INLINE): New. (prepare_test_buffer): Use it. --- bits/indirect-return.h | 25 +++++++++++++++++++++ stdlib/Makefile | 2 +- stdlib/ucontext.h | 6 ++++- string/tst-xbzero-opt.c | 10 ++++++++- sysdeps/x86/bits/indirect-return.h | 36 ++++++++++++++++++++++++++++++ 5 files changed, 76 insertions(+), 3 deletions(-) create mode 100644 bits/indirect-return.h create mode 100644 sysdeps/x86/bits/indirect-return.h diff --git a/bits/indirect-return.h b/bits/indirect-return.h new file mode 100644 index 0000000000..f309e160e7 --- /dev/null +++ b/bits/indirect-return.h @@ -0,0 +1,25 @@ +/* Definition of __INDIRECT_RETURN. Generic version. + Copyright (C) 2018 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 _UCONTEXT_H +# error "Never include directly; use instead." +#endif + +/* __INDIRECT_RETURN is used on swapcontext() to indicate if it + requires special compiler treatment. */ +#define __INDIRECT_RETURN diff --git a/stdlib/Makefile b/stdlib/Makefile index 808a8ceab7..b5e55b0a55 100644 --- a/stdlib/Makefile +++ b/stdlib/Makefile @@ -26,7 +26,7 @@ headers := stdlib.h bits/stdlib.h bits/stdlib-ldbl.h bits/stdlib-float.h \ monetary.h bits/monetary-ldbl.h \ inttypes.h stdint.h bits/wordsize.h \ errno.h sys/errno.h bits/errno.h bits/types/error_t.h \ - ucontext.h sys/ucontext.h \ + ucontext.h sys/ucontext.h bits/indirect-return.h \ alloca.h fmtmsg.h \ bits/stdlib-bsearch.h sys/random.h bits/stdint-intn.h \ bits/stdint-uintn.h diff --git a/stdlib/ucontext.h b/stdlib/ucontext.h index eec7611631..ec630038f6 100644 --- a/stdlib/ucontext.h +++ b/stdlib/ucontext.h @@ -22,6 +22,9 @@ #include +/* Get definition of __INDIRECT_RETURN. */ +#include + /* Get machine dependent definition of data structures. */ #include @@ -36,7 +39,8 @@ extern int setcontext (const ucontext_t *__ucp) __THROWNL; /* Save current context in context variable pointed to by OUCP and set context from variable pointed to by UCP. */ extern int swapcontext (ucontext_t *__restrict __oucp, - const ucontext_t *__restrict __ucp) __THROWNL; + const ucontext_t *__restrict __ucp) + __THROWNL __INDIRECT_RETURN; /* Manipulate user context UCP to continue with calling functions FUNC and the ARGC-1 parameters following ARGC when the context is used diff --git a/string/tst-xbzero-opt.c b/string/tst-xbzero-opt.c index cf7041f37a..d49ddef9ae 100644 --- a/string/tst-xbzero-opt.c +++ b/string/tst-xbzero-opt.c @@ -100,7 +100,15 @@ static ucontext_t uc_main, uc_co; /* Always check the test buffer immediately after filling it; this makes externally visible side effects depend on the buffer existing and having been filled in. */ -static inline __attribute__ ((always_inline)) void +#if defined __CET__ && !__GNUC_PREREQ (9, 0) +/* Note: swapcontext returns via indirect branch when SHSTK is enabled. + Without indirect_return attribute in GCC 9, swapcontext is marked + with returns_twice attribute, which prevents always_inline to work. */ +# define ALWAYS_INLINE +#else +# define ALWAYS_INLINE __attribute__ ((always_inline)) +#endif +static inline ALWAYS_INLINE void prepare_test_buffer (unsigned char *buf) { for (unsigned int i = 0; i < PATTERN_REPS; i++) diff --git a/sysdeps/x86/bits/indirect-return.h b/sysdeps/x86/bits/indirect-return.h new file mode 100644 index 0000000000..96fa0d323d --- /dev/null +++ b/sysdeps/x86/bits/indirect-return.h @@ -0,0 +1,36 @@ +/* Definition of __INDIRECT_RETURN. x86 version. + Copyright (C) 2018 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 _UCONTEXT_H +# error "Never include directly; use instead." +#endif + +/* On x86, swapcontext() returns via indirect branch when the shadow + stack is enabled. Define __INDIRECT_RETURN to indicate if + swapcontext() returns via indirect branch. */ +#if defined __CET__ && (__CET__ & 2) != 0 +/* Note: Functions returned via indirect branch returns once. Without + indirect_return attribute in GCC 9, use returns_twice attribute. */ +# if __GNUC_PREREQ (9, 0) +# define __INDIRECT_RETURN __attribute__ ((__indirect_return__)) +# else +# define __INDIRECT_RETURN __attribute__ ((__returns_twice__)) +# endif +#else +# define __INDIRECT_RETURN +#endif -- 2.17.1