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.
The IFUNC selector for gettimeofday runs before _libc_vdso_platform_setup where
__vdso_gettimeofday is set. The selector then sets __gettimeofday (the internal
version used within GLIBC) to use the system call version instead of the vDSO one.
This patch changes the check if vDSO is available to get its value directly
instead of rely on __vdso_gettimeofday.
This patch changes it by getting the vDSO value directly.
It fixes BZ#16431.
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.
This patch fixes the vDSO symbol used directed in IFUNC resolver where
they do not have an associated ODP entry leading to undefined behavior
in some cases. It adds an artificial OPD static entry to such cases
and set its TOC to non 0 to avoid triggering lazy resolutions.
PowerPC kernel now provides a vDSO implementation for time syscall
(commit fcb41a2030abe0eb716ef0798035ef9562097f42). This patch changes
time syscall wrapper to use the vDSO when available. It also changes
the default non vDSO time on PowerPC to use sysdeps/posix/time.c
(since gettimeofday is a vDSO call).
Joseph Myers
Stefan Liebler
Adhemerval Zanella
Adhemerval Zanella
Allan McRae