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Lu" To: Jakub Jelinek Cc: soeren@soeren-tempel.net, richard.sandiford@arm.com, gcc-patches@gcc.gnu.org Subject: [PATCH] x86: Properly disable -fsplit-stack support on non-glibc targets Message-ID: References: <20220121191610.8305-1-soeren@soeren-tempel.net> <20220121201841.GK2646553@tucnak> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220121201841.GK2646553@tucnak> X-Spam-Status: No, score=-3028.8 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, FREEMAIL_FROM, GIT_PATCH_0, KAM_SHORT, RCVD_IN_BARRACUDACENTRAL, RCVD_IN_DNSWL_NONE, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on server2.sourceware.org X-BeenThere: gcc-patches@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gcc-patches mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 21 Jan 2022 21:31:36 -0000 On Fri, Jan 21, 2022 at 09:18:41PM +0100, Jakub Jelinek via Gcc-patches wrote: > On Fri, Jan 21, 2022 at 08:16:11PM +0100, soeren--- via Gcc-patches wrote: > > gcc/ChangeLog: > > > > * common/config/s390/s390-common.c (s390_supports_split_stack): > > Only support split-stack on glibc targets. > > * config/i386/gnu-user-common.h (STACK_CHECK_STATIC_BUILTIN): Ditto. > > * config/i386/gnu.h (defined): Ditto. > > Besides breaking bootstrap, this doesn't do what it talks about: > > > --- a/gcc/config/i386/gnu.h > > +++ b/gcc/config/i386/gnu.h > > @@ -35,7 +35,10 @@ along with GCC. If not, see . > > crti.o%s %{static:crtbeginT.o%s;shared|pie:crtbeginS.o%s;:crtbegin.o%s}" > > #endif > > > > -#ifdef TARGET_LIBC_PROVIDES_SSP > > +/* -fsplit-stack uses a field in the TCB at a fixed offset. This > > + field is only available for glibc. Disable -fsplit-stack for > > + other libc implementations to avoid silent TCB corruptions. */ > > +#if defined (TARGET_LIBC_PROVIDES_SSP) && OPTION_GLIBC > > > > /* i386 glibc provides __stack_chk_guard in %gs:0x14. */ > > #define TARGET_THREAD_SSP_OFFSET 0x14 > > Because this doesn't disable just -fsplit-stack support, but also > -fstack-protector*. > Does that one work on musl? > I think common/config/i386/i386-common.c (ix86_supports_split_stack) > should have been changed instead of the config/i386/gnu*.h headers. > Like this? H.J. --- Revert x86 changes in commit c163647ffbc9a20c8feb6e079dbecccfe016c82e Author: Soren Tempel Date: Fri Jan 21 19:22:46 2022 +0000 Disable -fsplit-stack support on non-glibc targets and change ix86_supports_split_stack to return true only on glibc. PR bootstrap/104170 * common/config/i386/i386-common.cc (ix86_supports_split_stack): Return true only on glibc. * config/i386/gnu-user-common.h (STACK_CHECK_STATIC_BUILTIN): Revert commit c163647ffbc. * config/i386/gnu.h (TARGET_LIBC_PROVIDES_SSP): Likewise. --- gcc/common/config/i386/i386-common.cc | 4 ++-- gcc/config/i386/gnu-user-common.h | 5 ++--- gcc/config/i386/gnu.h | 5 +---- 3 files changed, 5 insertions(+), 9 deletions(-) diff --git a/gcc/common/config/i386/i386-common.cc b/gcc/common/config/i386/i386-common.cc index cae0b880d79..78e6ff730aa 100644 --- a/gcc/common/config/i386/i386-common.cc +++ b/gcc/common/config/i386/i386-common.cc @@ -1715,9 +1715,9 @@ ix86_option_init_struct (struct gcc_options *opts) static bool ix86_supports_split_stack (bool report ATTRIBUTE_UNUSED, - struct gcc_options *opts ATTRIBUTE_UNUSED) + struct gcc_options *opts) { - bool ret = true; + bool ret = opts->x_linux_libc == LIBC_GLIBC; #ifndef TARGET_THREAD_SPLIT_STACK_OFFSET if (report) diff --git a/gcc/config/i386/gnu-user-common.h b/gcc/config/i386/gnu-user-common.h index 7525f788a9c..23b54c5be52 100644 --- a/gcc/config/i386/gnu-user-common.h +++ b/gcc/config/i386/gnu-user-common.h @@ -66,8 +66,7 @@ along with GCC; see the file COPYING3. If not see #define STACK_CHECK_STATIC_BUILTIN 1 /* We only build the -fsplit-stack support in libgcc if the - assembler has full support for the CFI directives and - targets glibc. */ -#if HAVE_GAS_CFI_PERSONALITY_DIRECTIVE && OPTION_GLIBC + assembler has full support for the CFI directives. */ +#if HAVE_GAS_CFI_PERSONALITY_DIRECTIVE #define TARGET_CAN_SPLIT_STACK #endif diff --git a/gcc/config/i386/gnu.h b/gcc/config/i386/gnu.h index daa505a5d45..401e60c9a02 100644 --- a/gcc/config/i386/gnu.h +++ b/gcc/config/i386/gnu.h @@ -35,10 +35,7 @@ along with GCC. If not, see . crti.o%s %{static:crtbeginT.o%s;shared|pie:crtbeginS.o%s;:crtbegin.o%s}" #endif -/* -fsplit-stack uses a field in the TCB at a fixed offset. This - field is only available for glibc. Disable -fsplit-stack for - other libc implementations to avoid silent TCB corruptions. */ -#if defined (TARGET_LIBC_PROVIDES_SSP) && OPTION_GLIBC +#ifdef TARGET_LIBC_PROVIDES_SSP /* i386 glibc provides __stack_chk_guard in %gs:0x14. */ #define TARGET_THREAD_SSP_OFFSET 0x14 -- 2.34.1