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736c304a1a
This patches fixes BZ#16430 by setting a different symbol for internal GLIBC calls that points to ifunc resolvers. For PPC32, if the symbol is defined as hidden (which is the case for gettimeofday and time) the compiler will create local branches (symbol@local) and linker will not create PLT calls (required for IFUNC). This will leads to internal symbol calling the IFUNC resolver instead of the resolved symbol. For PPC64 this behavior does not occur because a call to a function in another translation unit might use a different toc pointer thus requiring a PLT call.
81 lines
2.5 KiB
C
81 lines
2.5 KiB
C
/* Copyright (C) 2005-2014 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#include <sys/time.h>
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#ifdef SHARED
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# include <dl-vdso.h>
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# include <bits/libc-vdso.h>
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# include <dl-machine.h>
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void *gettimeofday_ifunc (void) __asm__ ("__gettimeofday");
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static int
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__gettimeofday_syscall (struct timeval *tv, struct timezone *tz)
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{
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return INLINE_SYSCALL (gettimeofday, 2, tv, tz);
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}
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void *
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gettimeofday_ifunc (void)
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{
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/* If the vDSO is not available we fall back syscall. */
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return (__vdso_gettimeofday ? VDSO_IFUNC_RET (__vdso_gettimeofday)
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: __gettimeofday_syscall);
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}
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asm (".type __gettimeofday, %gnu_indirect_function");
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/* This is doing "libc_hidden_def (__gettimeofday)" but the compiler won't
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let us do it in C because it doesn't know we're defining __gettimeofday
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here in this file. */
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asm (".globl __GI___gettimeofday");
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/* __GI___gettimeofday is defined as hidden and for ppc32 it enables the
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compiler make a local call (symbol@local) for internal GLIBC usage. It
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means the PLT won't be used and the ifunc resolver will be called directly.
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For ppc64 a call to a function in another translation unit might use a
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different toc pointer thus disallowing direct branchess and making internal
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ifuncs calls safe. */
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#ifdef __powerpc64__
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asm ("__GI___gettimeofday = __gettimeofday");
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#else
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int
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__gettimeofday_vsyscall (struct timeval *tv, struct timezone *tz)
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{
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return INLINE_VSYSCALL (gettimeofday, 2, tv, tz);
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}
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asm ("__GI___gettimeofday = __gettimeofday_vsyscall");
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#endif
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#else
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# include <sysdep.h>
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# include <errno.h>
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int
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__gettimeofday (struct timeval *tv, struct timezone *tz)
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{
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return INLINE_SYSCALL (gettimeofday, 2, tv, tz);
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}
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libc_hidden_def (__gettimeofday)
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#endif
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weak_alias (__gettimeofday, gettimeofday)
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libc_hidden_weak (gettimeofday)
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