The time-related VDSO functionality was introduced in 2021 in
commit 87f3248cdb ("csky: Reconstruct VDSO framework") and
commit 0d3b051adb ("csky: Add VDSO with GENERIC_GETTIMEOFDAY, GENERIC_TIME_VSYSCALL, HAVE_GENERIC_VDSO").
However the corresponding aux-vector entry AT_SYSINFO_EHDR was never
wired up, making these functions impossible to test or use.
The VDSO itself is kept as it also provides rt_sigreturn which is
exposed differently to userspace.
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20241010-vdso-generic-base-v1-1-b64f0842d512@linutronix.de
It could help to reduce the latency of the time-related functions
in user space.
We have referenced arm's and riscv's implementation for the patch.
Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Cc: Vincent Chen <vincent.chen@sifive.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Reconstruct vdso framework to support future vsyscall,
vgettimeofday features. These are very important features to reduce
system calls into the kernel for performance improvement.
The patch is reference RISC-V's
Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Cc: Palmer Dabbelt <palmerdabbelt@google.com>
