Re: [PATCH v4 10/12] arm64: vdso: replace gettimeofday.S with global vgettimeofday.C

[Mark Salyzyn]

On 11/21/2017 10:03 AM, Jeffrey Bastian wrote:
> On Thu, Nov 02, 2017 at 12:22:36AM -0400, Jon Masters wrote:
> > On Nov 2, 2017, at 06:14, Mark Salyzyn <salyzyn@xxxxxxxxxxx> wrote:
> > > Holding off respin or followup patch until after we get a response
> > > from Jon Masters <jcm@xxxxxxxxxxx> on their QE tests on this patch
> > > series.
> > Copying Jeff Bastian who owns QE. Jeff, can you recall what test was
> > failing when we tried the gettimeofday C rewrite VDSO patches?
> The LTP clock_getres01 test was failing when we tried the initial
> implementation of gettimeofday-in-C.  This would be a good place to
> start when testing the new version of the patches.
>
> https://github.com/linux-test-project/ltp/blob/master/testcases/kernel/syscalls/clock_getres/clock_getres01.c
Thanks.

I ran the test (32 and 64 bit) on my latest work (but back-ported to 
4.9) and it passes. I did not change __vdso_clock_getres or the fallback 
(syscall) handler in the patch series though, so the failure has me 
wondering. Could you re-run the test with latest to be sure, and I will 
look into setting up to test with a ToT kernel (after the thanksgiving 
break).

Using bionic libc, with advance modifications to utilize 
__vdso_clock_getres; required in order to support the test.

NB: in AOSP _today_ bionic does _not_ propagate the errno correctly on 
the __vdso_clock_gettime vdso path and will understandably fail the 
similar tests. The public rubber stamp of __vdso_clock_gettime code to 
support __vdso_clock_getres will not work. errno propagation issue will 
be fixed in bionic.

-- Mark