diff options
Diffstat (limited to 'sysdeps/unix/sysv/linux/powerpc/libc-vdso.h')
| -rw-r--r-- | sysdeps/unix/sysv/linux/powerpc/libc-vdso.h | 76 |
1 files changed, 76 insertions, 0 deletions
diff --git a/sysdeps/unix/sysv/linux/powerpc/libc-vdso.h b/sysdeps/unix/sysv/linux/powerpc/libc-vdso.h new file mode 100644 index 0000000000..63a7a9bf52 --- /dev/null +++ b/sysdeps/unix/sysv/linux/powerpc/libc-vdso.h @@ -0,0 +1,76 @@ +/* Resolve function pointers to VDSO functions. + Copyright (C) 2005-2015 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 + <http://www.gnu.org/licenses/>. */ + + +#ifndef _LIBC_VDSO_H +#define _LIBC_VDSO_H + +#ifdef SHARED + +extern void *__vdso_gettimeofday attribute_hidden; + +extern void *__vdso_clock_gettime; + +extern void *__vdso_clock_getres; + +extern void *__vdso_get_tbfreq; + +extern void *__vdso_getcpu; + +extern void *__vdso_time; + +#if defined(__PPC64__) || defined(__powerpc64__) +extern void *__vdso_sigtramp_rt64; +#else +extern void *__vdso_sigtramp32; +extern void *__vdso_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 */ |