From patchwork Mon Feb 10 19:14:25 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Fangrui Song X-Patchwork-Id: 37867 Received: (qmail 79810 invoked by alias); 10 Feb 2020 19:14:38 -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 79802 invoked by uid 89); 10 Feb 2020 19:14:37 -0000 Authentication-Results: sourceware.org; auth=none X-Spam-SWARE-Status: No, score=-30.5 required=5.0 tests=BAYES_00, ENV_AND_HDR_SPF_MATCH, FSL_HELO_FAKE, GIT_PATCH_0, GIT_PATCH_1, GIT_PATCH_2, GIT_PATCH_3, RCVD_IN_DNSWL_NONE, SPF_PASS, USER_IN_DEF_SPF_WL autolearn=ham version=3.3.1 spammy=ba X-HELO: mail-pf1-f193.google.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:from:to:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=lk+OBlz0gJmAbwZSbHbby+q/QZe3ljeo70JbDCmbbvs=; b=TlQW1LXvzVuiA+4aGxR6jCIZcKCHj0HSn9tMIIiVFQRTIe+iDovIb8meZOMtbPEg6T SllBOHvHbELvMQBIuWK6hIe1giWgVt/SI5o8YTql8FLDZf1U795X6SKq0As8wgzIbj5d o7NUCmpLfrZ0sZ1Y5lHSrupXkCPFWWKLRcuIsi7h6M3y3dHqlQoqsc/EE9xmpiusVMZ3 rNUmuLWG6ENQciRS/uys93c6KeTJiAoeV/3aUuB3m5GwExRbRtGEf8Yr4ItNrAea2P+/ fLPG07gztR6cHJTtfubO2Mqh7O60duIjOw5nrmLMIpYSK92JKxC756WNeSL2Vle4xyYS lGsg== Return-Path: Date: Mon, 10 Feb 2020 11:14:25 -0800 From: Fangrui Song To: libc-alpha@sourceware.org Subject: [PATCH v2] Improve IFUNC check Message-ID: <20200210191425.52xvvdot7kunt2gc@google.com> References: <20200205060922.5pbgm5hfj2r6vrl2@google.com> <20200206122422.GA1533826@aurel32.net> <20200206185300.7hfx7gfrrof63mda@google.com> <20200208093746.GA98572@aurel32.net> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200208093746.GA98572@aurel32.net> On 2020-02-08, Aurelien Jarno wrote: >On 2020-02-06 10:53, Fangrui Song wrote: >> On 2020-02-06, Aurelien Jarno wrote: >> > Hi, >> > >> > On 2020-02-04 22:09, Fangrui Song wrote: >> > > GNU ld's RISCV port does not support IFUNC. ld -no-pie produces no >> > > relocation and the test passed incorrectly. Be more rigid by testing >> > > IRELATIVE explicitly. >> > >> > Thanks for your patch and sorry for the time to answer, I was testing it >> > on many architectures. First of all I confirm it fixes the issue when >> > building glibc with PIE on mips* and riscv64. I also confirm it >> > introduces no regression on aarch64, armv5, armv7, hppa, m68k, powerpc, >> > ppc64, ppc64le, s390x and x86_64. >> > >> > However it wrongly detects that IFUNC is not supported on sparc64 when >> > PIE is not in use. Here is the output of of readelf for the non-PIE >> > case: >> > >> > | Relocation section '.rela.dyn' at offset 0x110 contains 1 entry: >> > | Offset Info Type Sym. Value Sym. Name + Addend >> > | 000000200280 0000000000f8 R_SPARC_JMP_IREL 100128 >> >> sparc64 -no-pie does not produce an R_SPARC_IRELATIVE. This looks weird. >> All other archs emit an R_*_IRELATIVE. >> >> Can you dump the assembly (including .text and .[i]plt)? >> Or can someone with sparc64 experience answer why sparc64 is different >> here? > >Here is the dump of the .iplt section: >Disassembly of section .iplt: > >0000000000200200 <.iplt>: > ... > 200280: 03 00 00 80 sethi %hi(0x20000), %g1 > 200284: 30 6f ff e7 b,a %xcc, 200220 <__start+0x1000f8> > 200288: 01 00 00 00 nop > 20028c: 01 00 00 00 nop > 200290: 01 00 00 00 nop > 200294: 01 00 00 00 nop > 200298: 01 00 00 00 nop > 20029c: 01 00 00 00 nop > >There is no .text nor .plt section. > >-- >Aurelien Jarno GPG: 4096R/1DDD8C9B >aurelien@aurel32.net http://www.aurel32.net Attached PATCH v2. sparc64 has a non-conventional R_SPARC_JMP_IREL, along with conventional R_SPARC_IRELATIVE. Tested-by: Aurelien Jarno Reviewed-by: Adhemerval Zanella From 624b3a0c9e4f2f421227bb3f331723dfe807f157 Mon Sep 17 00:00:00 2001 From: Fangrui Song Date: Tue, 4 Feb 2020 21:55:44 -0800 Subject: [PATCH] Improve IFUNC check [BZ #25506] GNU ld does not support IFUNC but does not produces a relocation. The test passed incorrectly. Be more rigid by testing IRELATIVE explicitly. --- configure | 2 +- configure.ac | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/configure b/configure index b959d2d988..3b98ec312f 100755 --- a/configure +++ b/configure @@ -4035,7 +4035,7 @@ if ${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS \ -o conftest conftest.S 1>&5 2>&5; then # Do a link to see if the backend supports IFUNC relocs. $READELF -r conftest 1>&5 - LC_ALL=C $READELF -r conftest | grep 'no relocations' >/dev/null || { + LC_ALL=C $READELF -Wr conftest | grep -q 'IRELATIVE\|R_SPARC_JMP_IREL' && { libc_cv_ld_gnu_indirect_function=yes } fi diff --git a/configure.ac b/configure.ac index 49b900c1ed..e20034f301 100644 --- a/configure.ac +++ b/configure.ac @@ -649,7 +649,7 @@ if ${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS \ -o conftest conftest.S 1>&AS_MESSAGE_LOG_FD 2>&AS_MESSAGE_LOG_FD; then # Do a link to see if the backend supports IFUNC relocs. $READELF -r conftest 1>&AS_MESSAGE_LOG_FD - LC_ALL=C $READELF -r conftest | grep 'no relocations' >/dev/null || { + LC_ALL=C $READELF -Wr conftest | grep -q 'IRELATIVE\|R_SPARC_JMP_IREL' && { libc_cv_ld_gnu_indirect_function=yes } fi -- 2.25.0.341.g760bfbb309-goog