Hi folks,
I was cleaning up some hotplug torture test, and happened to run that on my
HiKey960 which resulted in a failure.
Turns out just a few hotplug operations are needed to trigger this, so I
boiled it down to this small script:
for ((i = 0; i < 4; i++)); do
echo "OFF $i"
echo 0 > /sys/devices/system/cpu/cpu$i/online
echo "ON $i"
echo 1 > /sys/devices/system/cpu/cpu$i/online
echo
done
Running this results in:
----->8-----
OFF 0
[ 80.819925] CPU0: shutdown
[ 80.823851] psci: CPU0 killed.
ON 0
[ 80.841609] Detected VIPT I-cache on CPU0
[ 80.845730] CPU0: Booted secondary processor 0x0000000000 [0x410fd034]
OFF 1
[ 80.927340] CPU1: shutdown
[ 80.930204] psci: CPU1 killed.
ON 1
[ 80.948701] Detected VIPT I-cache on CPU1
[ 80.952810] CPU1: Booted secondary processor 0x0000000001 [0x410fd034]
OFF 2
[ 81.023079] CPU2: shutdown
[ 81.026465] psci: CPU2 killed.
ON 2
[ 81.036281] Detected VIPT I-cache on CPU2
[ 81.040402] CPU2: Booted secondary processor 0x0000000002 [0x410fd034]
OFF 3
[ 81.103528] CPU3: shutdown
[ 81.106382] psci: CPU3 killed.
ON 3
[ 81.121835] Detected VIPT I-cache on CPU3
[ 81.125975] CPU3: Booted secondary processor 0x0000000003 [0x410fd034]
----->8-----
Now, if I run this for CPUs [4-7], I eventually get this (takes a few tries):
----->8-----
OFF 4
[ 73.149855] CPU4: shutdown
[ 73.152628] psci: CPU4 killed.
ON 4
[ 73.157491] Detected VIPT I-cache on CPU4
[ 73.161509] CPU features: SANITY CHECK: Unexpected variation in
SYS_ID_AA64MMFR0_EL1. Boot CPU: 0x00000000001122, CPU4: 0x00000000101122
[ 73.173813] arch_timer: CPU4: Trapping CNTVCT access
[ 73.178782] CPU4: Booted secondary processor 0x0000000100 [0x410fd091]
OFF 5
[ 73.261245] CPU5: shutdown
[ 73.264043] psci: CPU5 killed.
ON 5
[ 74.272375] CPU5: failed to come online
[ 74.276264] CPU5: failed in unknown state : 0x0
./hotplug.sh: line 8: echo: write error: Input/output error
OFF 6
[ 74.311066] CPU6: shutdown
[ 74.313829] psci: CPU6 killed.
ON 6
[ 74.318544] Detected VIPT I-cache on CPU6
[ 74.322590] CPU features: SANITY CHECK: Unexpected variation in
SYS_ID_AA64MMFR0_EL1. Boot CPU: 0x00000000001122, CPU6: 0x00000000101122
[ 74.334884] arch_timer: CPU6: Trapping CNTVCT access
[ 74.339854] CPU6: Booted secondary processor 0x0000000102 [0x410fd091]
OFF 7
[ 74.394989] CPU7: shutdown
[ 74.397770] psci: CPU7 killed.
ON 7
[ 74.402295] Detected VIPT I-cache on CPU7
[ 74.406475] CPU features: SANITY CHECK: Unexpected variation in
SYS_ID_AA64MMFR0_EL1. Boot CPU: 0x00000000001122, CPU7: 0x00000000101122
[ 74.418748] arch_timer: CPU7: Trapping CNTVCT access
[ 74.423709] CPU7: Booted secondary processor 0x0000000103 [0x410fd091]
----->8-----
Trying to online CPU5 yet again yields a slightly different result:
----->8-----
[ 74.528657] psci: failed to boot CPU5 (-22)
[ 74.534577] CPU5: failed to boot: -22
[ 74.538291] CPU5: failed in unknown state : 0x0
./hotplug.sh: line 8: echo: write error: Invalid argument
----->8-----
It doesn't seem tied to any particular big CPU - I've that happen for 4 & 7.
It happens both on mainline (4.19-rc7, 3a27203102eb) and on linux-next
(774ea0551a29). I tried bisecting this but it's a bit tricky since the
mainline support for HiKey960 is relatively recent - as far as I can tell,
that issue has always been there on this board.
I wanted to have a bit of fun and investigate that myself, but psci is alien
to me and I don't really know where to look at past "psci_cpu_on()".
I'm running UEFI/ATF on that board, if that's of any help.
Cheers,
Valentin
