1 files changed, 74 insertions, 0 deletions
diff --git a/REORG.TODO/sysdeps/unix/sysv/linux/powerpc/libc-vdso.h b/REORG.TODO/sysdeps/unix/sysv/linux/powerpc/libc-vdso.h
new file mode 100644
index 0000000000..fb9509e2e7
--- /dev/null
+++ b/REORG.TODO/sysdeps/unix/sysv/linux/powerpc/libc-vdso.h
@@ -0,0 +1,74 @@
+/* Resolve function pointers to VDSO functions.
+   Copyright (C) 2005-2017 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
+   <http://www.gnu.org/licenses/>.  */
+
+
+#ifndef _LIBC_VDSO_H
+#define _LIBC_VDSO_H
+
+#ifdef SHARED
+
+#include <sysdep-vdso.h>
+
+extern int (*VDSO_SYMBOL(gettimeofday)) (struct timeval *, void *)
+  attribute_hidden;
+extern int (*VDSO_SYMBOL(clock_gettime)) (clockid_t, struct timespec *);
+extern int (*VDSO_SYMBOL(clock_getres)) (clockid_t, struct timespec *);
+extern unsigned long long (*VDSO_SYMBOL(get_tbfreq)) (void);
+extern int (*VDSO_SYMBOL(getcpu)) (unsigned *, unsigned *);
+extern time_t (*VDSO_SYMBOL(time)) (time_t *);
+
+#if defined(__PPC64__) || defined(__powerpc64__)
+extern void *VDSO_SYMBOL(sigtramp_rt64);
+#else
+extern void *VDSO_SYMBOL(sigtramp32);
+extern void *VDSO_SYMBOL(sigtramp_rt32);
+#endif
+
+#if (defined(__PPC64__) || defined(__powerpc64__)) && _CALL_ELF != 2
+/* The correct solution is for _dl_vdso_vsym to return the address of the OPD
+   for the kernel VDSO function.  That address would then be stored in the
+   __vdso_* variables and returned as the result of the IFUNC resolver function.
+   Yet, the kernel does not contain any OPD entries for the VDSO functions
+   (incomplete implementation).  However, PLT relocations for IFUNCs still expect
+   the address of an OPD to be returned from the IFUNC resolver function (since
+   PLT entries on PPC64 are just copies of OPDs).  The solution for now is to
+   create an artificial static OPD for each VDSO function returned by a resolver
+   function.  The TOC value is set to a non-zero value to avoid triggering lazy
+   symbol resolution via .glink0/.plt0 for a zero TOC (requires thread-safe PLT
+   sequences) when the dynamic linker isn't prepared for it e.g. RTLD_NOW.  None
+   of the kernel VDSO routines use the TOC or AUX values so any non-zero value
+   will work.  Note that function pointer comparisons will not use this artificial
+   static OPD since those are resolved via ADDR64 relocations and will point at
+   the non-IFUNC default OPD for the symbol.  Lastly, because the IFUNC relocations
+   are processed immediately at startup the resolver functions and this code need
+   not be thread-safe, but if the caller writes to a PLT slot it must do so in a
+   thread-safe manner with all the required barriers.  */
+#define VDSO_IFUNC_RET(value)                            \
+  ({                                                     \
+    static Elf64_FuncDesc vdso_opd = { .fd_toc = ~0x0 }; \
+    vdso_opd.fd_func = (Elf64_Addr)value;                \
+    &vdso_opd;                                           \
+  })
+
+#else
+#define VDSO_IFUNC_RET(value)  ((void *) (value))
+#endif
+
+#endif
+
+#endif /* _LIBC_VDSO_H */