S390: Fix backtrace in vdso functions.

On s390, GDB fails to show the complete backtrace from within vdso functions.
The macro INTERNAL_VSYSCALL_CALL saves the return address in r14 to r10
before branching to the vdso function. The branch-instruction updates r14
in order to let the vdso function return. Then the original address in r14 is
restored from r10. Unfortunately, there are no cfi-rules and GDB fails.

Furthermore the call of the vdso function does not comply with the s390 ABI
as no stack-frame for the vdso-function is generated.

This patch removes the s390 specific macro INTERNAL_VSYSCALL_CALL
and the common implementation in sysdeps/unix/sysv/linux/sysdep-vdso.h is used.
Then the vdso function is called via function-pointer and GCC generates a
new stack-frame and emits all needed cfi-rules.

The defines CLOBBER_[0-6] are removed as they  were only used in macro
INTERNAL_VSYSCALL_CALL.

The macro INTERNAL_VSYSCALL_NO_SYSCALL_FALLBACK is not used on s390.
The only user is power. Thus it is removed from s390 sysdep.h.

ChangeLog:

	* sysdeps/unix/sysv/linux/s390/s390-64/sysdep.h
	(INTERNAL_VSYSCALL_CALL, CLOBBER_0, CLOBBER_1, CLOBBER_2,
	 CLOBBER_3, CLOBBER_4, CLOBBER_5, CLOBBER_6,
	INTERNAL_VSYSCALL_NO_SYSCALL_FALLBACK): Remove.
	* sysdeps/unix/sysv/linux/s390/s390-32/sysdep.h: Likewise.

0 files changed, 0 insertions, 0 deletions