On 04/06/2019 14:39, Christophe Leroy wrote:
Le 04/06/2019 à 15:32, Vincenzo Frascino a écrit :
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Hi Christophe,
On 04/06/2019 14:16, Christophe Leroy wrote:
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Hi Vincenzo
Le 28/05/2019 à 13:57, Vincenzo Frascino a écrit :
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Hi Michael,
thank you for your reply.
On 28/05/2019 07:19, Michael Ellerman wrote:
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Vincenzo Frascino [off-list ref] writes:
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The current version of the multiarch vDSO selftest verifies only
gettimeofday.
Extend the vDSO selftest to clock_getres, to verify that the
syscall and the vDSO library function return the same information.
The extension has been used to verify the hrtimer_resoltion fix.
This is passing for me even without patch 1 applied, shouldn't it fail
without the fix? What am I missing?
This is correct, because during the refactoring process I missed an "n" :)
if·((x.tv_sec·!=·y.tv_sec)·||·(x.tv_sec·!=·y.tv_sec))
Should be:
if·((x.tv_sec·!=·y.tv_sec)·||·(x.tv_nsec·!=·y.tv_nsec))
My mistake, I am going to fix the test and re-post v5 of this set.
Without my patch if you pass "highres=off" to the kernel (as a command line
parameter) it leads to a broken implementation of clock_getres since the value
of CLOCK_REALTIME_RES does not change at runtime.
Expected result (with highres=off):
# uname -r
5.2.0-rc2
# ./vdso_clock_getres
clock_id: CLOCK_REALTIME [FAIL]
clock_id: CLOCK_BOOTTIME [PASS]
clock_id: CLOCK_TAI [PASS]
clock_id: CLOCK_REALTIME_COARSE [PASS]
clock_id: CLOCK_MONOTONIC [FAIL]
clock_id: CLOCK_MONOTONIC_RAW [PASS]
clock_id: CLOCK_MONOTONIC_COARSE [PASS]
The reason of this behavior is that the only clocks supported by getres on
powerpc are CLOCK_REALTIME and CLOCK_MONOTONIC, the rest on the clocks use
always syscalls.
vdso64 is supposed to implement CLOCK_{REALTIME/MONOTONIC}_COARSE, so I
guess it should fail for them too ?
Or is your test done on vdso32 ?
Based on what I can see in kernel/vdso64 in 5.2-rc3:
/*
* Exact prototype of clock_getres()
*
* int __kernel_clock_getres(clockid_t clock_id, struct timespec *res);
*
*/
V_FUNCTION_BEGIN(__kernel_clock_getres)
.cfi_startproc
/* Check for supported clock IDs */
cmpwi cr0,r3,CLOCK_REALTIME
cmpwi cr1,r3,CLOCK_MONOTONIC
cror cr0*4+eq,cr0*4+eq,cr1*4+eq
bne cr0,99f
li r3,0
cmpldi cr0,r4,0
crclr cr0*4+so
beqlr
lis r5,CLOCK_REALTIME_RES@h
ori r5,r5,CLOCK_REALTIME_RES@l
std r3,TSPC64_TV_SEC(r4)
std r5,TSPC64_TV_NSEC(r4)
blr
/*
* syscall fallback
*/
99:
li r0,__NR_clock_getres
sc
blr
.cfi_endproc
V_FUNCTION_END(__kernel_clock_getres)
it does not seem so for what concerns vdso64. I did run again the test both on
ppc and ppc64 qemu instances and the result is the same to what I reported in
this thread.
Am I missing something?
I was thinking about
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=5c929885f1bb
but apparently clock_getres() was left aside. Should we do something
about it ?
Sure, but I would like this series to be merged first (since the topic is
different). I am happy, after that, to push a separate one on top that addresses
the problem.
Please let me know if it works for you and Michael.
Christophe
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Christophe
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# uname -r
5.2.0-rc2-gcc-8.2.0
# ./vdso_clock_getres
clock_id: CLOCK_REALTIME [PASS]
clock_id: CLOCK_BOOTTIME [PASS]
clock_id: CLOCK_TAI [PASS]
clock_id: CLOCK_REALTIME_COARSE [PASS]
clock_id: CLOCK_MONOTONIC [PASS]
clock_id: CLOCK_MONOTONIC_RAW [PASS]
clock_id: CLOCK_MONOTONIC_COARSE [PASS]
cheers
quoted
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
---
Note: This patch is independent from the others in this series, hence it
can be merged singularly by the kselftest maintainers.
tools/testing/selftests/vDSO/Makefile | 2 +
.../selftests/vDSO/vdso_clock_getres.c | 124 ++++++++++++++++++
2 files changed, 126 insertions(+)
create mode 100644 tools/testing/selftests/vDSO/vdso_clock_getres.c
--
Regards,
Vincenzo