From patchwork Thu Apr 23 21:27:29 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Adhemerval Zanella Netto X-Patchwork-Id: 6411 X-Patchwork-Delegate: azanella@linux.vnet.ibm.com Received: (qmail 23021 invoked by alias); 23 Apr 2015 21:27:37 -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 23012 invoked by uid 89); 23 Apr 2015 21:27:36 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-2.2 required=5.0 tests=AWL, BAYES_00, RCVD_IN_DNSWL_LOW, SPF_PASS autolearn=ham version=3.3.2 X-HELO: mail-qc0-f181.google.com X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:message-id:date:from:user-agent:mime-version:to :subject:content-type:content-transfer-encoding; bh=6XLaJuEkK9LpJ7MMQVhOBKctpWC47i20QNg61cIs6SA=; b=SCdSueYNpo++wCnHwPAEnNkDvlYHmrtEGZPezYQhKB+mzVgRP71RAkeruFmZ0xazM0 5M9kUXRc8t7UXaG3dXbSA3mSEoUbbZsSZuffMq0ufS7yDV3/K6LKmpqIpv01P+g73rPF ED+IqxC2T4f42ZNF+2Zq0Z5tMSaLo5KK4pMkPdHGjmflyIMtGaXtwku0SgDgyO/8JdIq TpI2jw8TCWl7a1lgjq97ib0KhPZq2h8i1BvsZFM+9fOlsaDyIHGbKQQSZcSqYLlb5ybE jKGFvJIsFgo5czp4ka9pPLLc6rvMfmyAq+6Vbw2Cco+M67meIIv0z0+9o/LjOREEeV1z 5s0g== X-Gm-Message-State: ALoCoQmAyNAZ8w4QWxaMH+Cb1b1nxSEl5RZn5Cdg7TeQsvwsVZR/OKe+D6DqeCEsZKNcImO6xuav X-Received: by 10.140.37.11 with SMTP id q11mr5616827qgq.86.1429824452925; Thu, 23 Apr 2015 14:27:32 -0700 (PDT) Message-ID: <553963C1.2080600@linaro.org> Date: Thu, 23 Apr 2015 18:27:29 -0300 From: Adhemerval Zanella User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.6.0 MIME-Version: 1.0 To: GNU C Library Subject: [PATCH] x86: Remove vsyscall usage This patch removes the vsyscall usage for x86_64 port. As indicated by kernel code comments [1], vsyscalls are a legacy ABI and its concept is problematic: - It interferes with ASLR. - It's awkward to write code that lives in kernel addresses but is callable by userspace at fixed addresses. - The whole concept is impossible for 32-bit compat userspace. - UML cannot easily virtualize a vsyscall. The VDSO is a better approach for such functionality. Tested on i686, x86_64, and x32. [1] arch/x86/kernel/vsyscall_64.c --- * sysdeps/unix/sysv/linux/i386/gettimeofday.c (__gettimeofday_syscall): Remove. * sysdeps/unix/sysv/linux/i386/time.c (__time_syscall): Remove. * sysdeps/unix/sysv/linux/x86/gettimeofday.c (__gettimeofday_syscall): Add function. (gettimeofday_ifunc): Use __gettimeofday_syscall as fallback mechanism if vDSO is not present. * sysdeps/unix/sysv/linux/x86/time.c (__time_syscall): Add function. (time_ifunc): Use __time_syscall as fallback mechanism if vDSO is not present. * sysdeps/unix/sysv/linux/x86_64/gettimeofday.c: Remove file. * sysdeps/unix/sysv/linux/x86_64/time.c: Likewise. --- diff --git a/sysdeps/unix/sysv/linux/i386/gettimeofday.c b/sysdeps/unix/sysv/linux/i386/gettimeofday.c index 3e00eb4..fdb0fab 100644 --- a/sysdeps/unix/sysv/linux/i386/gettimeofday.c +++ b/sysdeps/unix/sysv/linux/i386/gettimeofday.c @@ -20,16 +20,6 @@ #ifdef SHARED -# include -# include - -/* If the vDSO is not available we fall back on the syscall. */ -static int -__gettimeofday_syscall (struct timeval *tv, struct timezone *tz) -{ - return INLINE_SYSCALL (gettimeofday, 2, tv, tz); -} -# define GETTIMEOFAY_FALLBACK (void*) (&__gettimeofday_syscall) # undef libc_ifunc_hidden_def # define libc_ifunc_hidden_def(name) \ libc_ifunc_hidden_def1 (__GI_##name, __gettimeofday_syscall) diff --git a/sysdeps/unix/sysv/linux/i386/time.c b/sysdeps/unix/sysv/linux/i386/time.c index e8a4e59..66b9a6c 100644 --- a/sysdeps/unix/sysv/linux/i386/time.c +++ b/sysdeps/unix/sysv/linux/i386/time.c @@ -18,17 +18,6 @@ #ifdef SHARED -# include -# include - -/* If the vDSO is not available we fall back on the old vsyscall. */ -static time_t -__time_syscall (time_t *t) -{ - INTERNAL_SYSCALL_DECL (err); - return INTERNAL_SYSCALL (time, err, 1, t); -} -# define TIME_FALLBACK (void*) &__time_syscall # undef libc_ifunc_hidden_def # define libc_ifunc_hidden_def(name) \ libc_ifunc_hidden_def1 (__GI_##name, __time_syscall) diff --git a/sysdeps/unix/sysv/linux/x86/gettimeofday.c b/sysdeps/unix/sysv/linux/x86/gettimeofday.c index c820fd7..c9cb6ea 100644 --- a/sysdeps/unix/sysv/linux/x86/gettimeofday.c +++ b/sysdeps/unix/sysv/linux/x86/gettimeofday.c @@ -21,6 +21,14 @@ #ifdef SHARED # include +# include + +/* If the vDSO is not available we fall back on the syscall. */ +static int +__gettimeofday_syscall (struct timeval *tv, struct timezone *tz) +{ + return INLINE_SYSCALL (gettimeofday, 2, tv, tz); +} void *gettimeofday_ifunc (void) __asm__ ("__gettimeofday"); @@ -31,7 +39,7 @@ gettimeofday_ifunc (void) /* If the vDSO is not available we fall back on the old vsyscall. */ return (_dl_vdso_vsym ("__vdso_gettimeofday", &linux26) - ?: GETTIMEOFAY_FALLBACK); + ?: (void*) (&__gettimeofday_syscall)); } asm (".type __gettimeofday, %gnu_indirect_function"); diff --git a/sysdeps/unix/sysv/linux/x86/time.c b/sysdeps/unix/sysv/linux/x86/time.c index 1ab9248..3459e17 100644 --- a/sysdeps/unix/sysv/linux/x86/time.c +++ b/sysdeps/unix/sysv/linux/x86/time.c @@ -21,6 +21,15 @@ #ifdef SHARED #include +#include + +/* If the vDSO is not available we fall back on the old vsyscall. */ +static time_t +__time_syscall (time_t *t) +{ + INTERNAL_SYSCALL_DECL (err); + return INTERNAL_SYSCALL (time, err, 1, t); +} void *time_ifunc (void) __asm__ ("time"); @@ -29,7 +38,8 @@ time_ifunc (void) { PREPARE_VERSION_KNOWN (linux26, LINUX_2_6); - return _dl_vdso_vsym ("__vdso_time", &linux26) ?: TIME_FALLBACK; + return _dl_vdso_vsym ("__vdso_time", &linux26) + ?: (void*) &__time_syscall; } asm (".type time, %gnu_indirect_function"); diff --git a/sysdeps/unix/sysv/linux/x86_64/gettimeofday.c b/sysdeps/unix/sysv/linux/x86_64/gettimeofday.c deleted file mode 100644 index daa14de..0000000 --- a/sysdeps/unix/sysv/linux/x86_64/gettimeofday.c +++ /dev/null @@ -1,26 +0,0 @@ -/* Copyright (C) 2002-2015 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 - . */ - -#include - -#ifdef SHARED -/* If the vDSO is not available we fall back on the old vsyscall. */ -# define VSYSCALL_ADDR_vgettimeofday 0xffffffffff600000ul -# define GETTIMEOFAY_FALLBACK (void*)VSYSCALL_ADDR_vgettimeofday -#endif - -#include diff --git a/sysdeps/unix/sysv/linux/x86_64/time.c b/sysdeps/unix/sysv/linux/x86_64/time.c deleted file mode 100644 index 6ceb819..0000000 --- a/sysdeps/unix/sysv/linux/x86_64/time.c +++ /dev/null @@ -1,24 +0,0 @@ -/* Copyright (C) 2001-2015 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 - . */ - -#ifdef SHARED -/* If the vDSO is not available we fall back on the old vsyscall. */ -#define VSYSCALL_ADDR_vtime 0xffffffffff600400 -#define TIME_FALLBACK (void*)VSYSCALL_ADDR_vtime -#endif - -#include