From patchwork Fri Aug 5 06:46:47 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Liebler X-Patchwork-Id: 656045 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org 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 3s5HRt4Y28z9t0J for ; Fri, 5 Aug 2016 16:47:38 +1000 (AEST) Authentication-Results: ozlabs.org; dkim=pass (1024-bit key; secure) header.d=sourceware.org header.i=@sourceware.org header.b=GLhB6HLm; dkim-atps=neutral DomainKey-Signature: a=rsa-sha1; c=nofws; d=sourceware.org; h=list-id :list-unsubscribe:list-subscribe:list-archive:list-post :list-help:sender:subject:references:to:from:date:mime-version :in-reply-to:content-type:message-id; q=dns; s=default; b=PpASF9 M8tLdgy9psQjn9yp/pf4eAoit1iEiE3Tu98KzCILBxBXHzACDcDrMfJSs010HCMK tRogodRsxj5XW61K1n+ocrq01vHJJOwvhJqgmjFKSpknorgWPwn1KmkakwTz/rrH GmQMKOEsHDusJDPZ2y242cX32sHJ2RHEWKcaE= 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:subject:references:to:from:date:mime-version :in-reply-to:content-type:message-id; s=default; bh=fIK3G7swud3A ccowXc9ntUrZ490=; b=GLhB6HLmBzo1jqYgWtWxhWICoeGsCS9Wu+Hs1GNgH4WR M1zPO4pLvORynrTcj5fUcP/WDkI/vRclg4sBSrNrtUrGWyIxOJcKG3LTb2WVGohT yG9u2hJvsHiqH7C2GmV77xuUSkjCYdzUqbkQi/NhEeR1LtDwempHrU5+BTqZl10= Received: (qmail 49093 invoked by alias); 5 Aug 2016 06:46:59 -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 48850 invoked by uid 89); 5 Aug 2016 06:46:57 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=4.1 required=5.0 tests=AWL, BAYES_00, KAM_LAZY_DOMAIN_SECURITY, MSWORD_ATTACHED, RCVD_IN_DNSWL_LOW autolearn=no version=3.3.2 spammy=plt, PLT, assemblies, redirection X-HELO: mx0a-001b2d01.pphosted.com X-IBM-Helo: d06dlp01.portsmouth.uk.ibm.com X-IBM-MailFrom: stli@linux.vnet.ibm.com X-IBM-RcptTo: libc-alpha@sourceware.org Subject: Re: [PATCH 4/8] ppc: Use libc_ifunc macro for time, gettimeofday. References: <1466682952-6301-1-git-send-email-stli@linux.vnet.ibm.com> <1466682952-6301-4-git-send-email-stli@linux.vnet.ibm.com> <579B6CDA.9020205@linux.vnet.ibm.com> <4e65f061-c5f5-d9e0-8db6-5e81d03edbc8@linux.vnet.ibm.com> To: libc-alpha@sourceware.org From: Stefan Liebler Date: Fri, 5 Aug 2016 08:46:47 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.2 MIME-Version: 1.0 In-Reply-To: <4e65f061-c5f5-d9e0-8db6-5e81d03edbc8@linux.vnet.ibm.com> X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 16080506-0020-0000-0000-000001E30B18 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 16080506-0021-0000-0000-00001D010946 Message-Id: X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:, , definitions=2016-08-05_05:, , signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=1 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1604210000 definitions=main-1608050090 On 08/02/2016 05:45 PM, Paul E. Murphy wrote: > Ok, pending approval of the first patch. > > This is an updated version due to changes in the first patch with libc_ifunc fallback if gcc does not support gcc attribute ifunc. From 223b642762d639bca416cc3e99af98d21074fcd7 Mon Sep 17 00:00:00 2001 From: Stefan Liebler Date: Thu, 4 Aug 2016 18:46:23 +0200 Subject: [PATCH 4/8] ppc: Use libc_ifunc macro for time, gettimeofday. This patch uses the libc_ifunc_hidden macro to create already existing ifunc functions time and gettimeofday on power. This way, the libc_hidden_def macro can be used instead of inline assemblies. On ppc32, the __GI_* symbols do not target the ifunc symbol and thus the redirection construct has to be applied here. ChangeLog: * sysdeps/unix/sysv/linux/powerpc/gettimeofday.c (__gettimeofday): Use libc_ifunc_hidden and libc_hidden_def macro. Redirect ifunced function in header for using it as type for ifunc function because __GI_* symbols for ppc32 do not target the ifunc symbols. * sysdeps/unix/sysv/linux/powerpc/time.c (time): Likewise. --- sysdeps/unix/sysv/linux/powerpc/gettimeofday.c | 60 ++++++++++++----------- sysdeps/unix/sysv/linux/powerpc/time.c | 67 +++++++++++++------------- 2 files changed, 65 insertions(+), 62 deletions(-) diff --git a/sysdeps/unix/sysv/linux/powerpc/gettimeofday.c b/sysdeps/unix/sysv/linux/powerpc/gettimeofday.c index 25a4e7c..16c00d7 100644 --- a/sysdeps/unix/sysv/linux/powerpc/gettimeofday.c +++ b/sysdeps/unix/sysv/linux/powerpc/gettimeofday.c @@ -15,6 +15,11 @@ License along with the GNU C Library; if not, see . */ +#if defined SHARED && !defined __powerpc64__ +# define __gettimeofday __redirect___gettimeofday +#else +# define __redirect___gettimeofday __gettimeofday +#endif #include @@ -24,30 +29,14 @@ # include # include -void *gettimeofday_ifunc (void) __asm__ ("__gettimeofday"); - -static int -__gettimeofday_syscall (struct timeval *tv, struct timezone *tz) -{ - return INLINE_SYSCALL (gettimeofday, 2, tv, tz); -} +# ifndef __powerpc64__ +# undef __gettimeofday -void * -gettimeofday_ifunc (void) +int +__gettimeofday_vsyscall (struct timeval *tv, struct timezone *tz) { - PREPARE_VERSION (linux2615, "LINUX_2.6.15", 123718565); - - /* If the vDSO is not available we fall back syscall. */ - void *vdso_gettimeofday = _dl_vdso_vsym ("__kernel_gettimeofday", &linux2615); - return (vdso_gettimeofday ? VDSO_IFUNC_RET (vdso_gettimeofday) - : (void*)__gettimeofday_syscall); + return INLINE_VSYSCALL (gettimeofday, 2, tv, tz); } -asm (".type __gettimeofday, %gnu_indirect_function"); - -/* This is doing "libc_hidden_def (__gettimeofday)" but the compiler won't - let us do it in C because it doesn't know we're defining __gettimeofday - here in this file. */ -asm (".globl __GI___gettimeofday"); /* __GI___gettimeofday is defined as hidden and for ppc32 it enables the compiler make a local call (symbol@local) for internal GLIBC usage. It @@ -55,16 +44,29 @@ asm (".globl __GI___gettimeofday"); For ppc64 a call to a function in another translation unit might use a different toc pointer thus disallowing direct branchess and making internal ifuncs calls safe. */ -#ifdef __powerpc64__ -asm ("__GI___gettimeofday = __gettimeofday"); -#else -int -__gettimeofday_vsyscall (struct timeval *tv, struct timezone *tz) +# undef libc_hidden_def +# define libc_hidden_def(name) \ + __hidden_ver1 (__gettimeofday_vsyscall, __GI___gettimeofday, \ + __gettimeofday_vsyscall); + +# endif /* !__powerpc64__ */ + +static int +__gettimeofday_syscall (struct timeval *tv, struct timezone *tz) { - return INLINE_VSYSCALL (gettimeofday, 2, tv, tz); + return INLINE_SYSCALL (gettimeofday, 2, tv, tz); } -asm ("__GI___gettimeofday = __gettimeofday_vsyscall"); -#endif + +# define INIT_ARCH() \ + PREPARE_VERSION (linux2615, "LINUX_2.6.15", 123718565); \ + void *vdso_gettimeofday = _dl_vdso_vsym ("__kernel_gettimeofday", &linux2615); + +/* If the vDSO is not available we fall back syscall. */ +libc_ifunc_hidden (__redirect___gettimeofday, __gettimeofday, + vdso_gettimeofday + ? VDSO_IFUNC_RET (vdso_gettimeofday) + : (void *) __gettimeofday_syscall); +libc_hidden_def (__gettimeofday) #else diff --git a/sysdeps/unix/sysv/linux/powerpc/time.c b/sysdeps/unix/sysv/linux/powerpc/time.c index 7973419..3da0b66 100644 --- a/sysdeps/unix/sysv/linux/powerpc/time.c +++ b/sysdeps/unix/sysv/linux/powerpc/time.c @@ -17,6 +17,11 @@ . */ #ifdef SHARED +# ifndef __powerpc64__ +# define time __redirect_time +# else +# define __redirect_time time +# endif # include # include @@ -24,7 +29,26 @@ # include # include -void *time_ifunc (void) asm ("time"); +# ifndef __powerpc64__ +# undef time + +time_t +__time_vsyscall (time_t *t) +{ + return INLINE_VSYSCALL (time, 1, t); +} + +/* __GI_time is defined as hidden and for ppc32 it enables the + compiler make a local call (symbol@local) for internal GLIBC usage. It + means the PLT won't be used and the ifunc resolver will be called directly. + For ppc64 a call to a function in another translation unit might use a + different toc pointer thus disallowing direct branchess and making internal + ifuncs calls safe. */ +# undef libc_hidden_def +# define libc_hidden_def(name) \ + __hidden_ver1 (__time_vsyscall, __GI_time, __time_vsyscall); + +# endif /* !__powerpc64__ */ static time_t time_syscall (time_t *t) @@ -42,42 +66,19 @@ time_syscall (time_t *t) return result; } -void * -time_ifunc (void) -{ - PREPARE_VERSION (linux2615, "LINUX_2.6.15", 123718565); - - /* If the vDSO is not available we fall back to the syscall. */ +# define INIT_ARCH() \ + PREPARE_VERSION (linux2615, "LINUX_2.6.15", 123718565); \ void *vdso_time = _dl_vdso_vsym ("__kernel_time", &linux2615); - return (vdso_time ? VDSO_IFUNC_RET (vdso_time) - : (void*)time_syscall); -} -asm (".type time, %gnu_indirect_function"); -/* This is doing "libc_hidden_def (time)" but the compiler won't - * let us do it in C because it doesn't know we're defining time - * here in this file. */ -asm (".globl __GI_time"); - -/* __GI_time is defined as hidden and for ppc32 it enables the - compiler make a local call (symbol@local) for internal GLIBC usage. It - means the PLT won't be used and the ifunc resolver will be called directly. - For ppc64 a call to a function in another translation unit might use a - different toc pointer thus disallowing direct branchess and making internal - ifuncs calls safe. */ -#ifdef __powerpc64__ -asm ("__GI_time = time"); -#else -time_t -__time_vsyscall (time_t *t) -{ - return INLINE_VSYSCALL (time, 1, t); -} -asm ("__GI_time = __time_vsyscall"); -#endif +/* If the vDSO is not available we fall back to the syscall. */ +libc_ifunc_hidden (__redirect_time, time, + vdso_time + ? VDSO_IFUNC_RET (vdso_time) + : (void *) time_syscall); +libc_hidden_def (time) #else #include -#endif +#endif /* !SHARED */ -- 2.3.0