On 17/11/23 4:52 am, Michael Ellerman wrote: > Vishal Chourasia <vish...@linux.ibm.com> writes: >> On 15/11/23 5:46 pm, Aneesh Kumar K V wrote: >>> On 11/15/23 5:23 PM, Vishal Chourasia wrote: >>>> On 15/11/23 1:39 pm, Aneesh Kumar K.V wrote: >>>>> Vishal Chourasia <vish...@linux.ibm.com> writes: >>>>> >>>>>> This patch modifies the ARCH_HIBERNATION_POSSIBLE option to ensure that >>>>>> it >>>>>> correctly depends on these PowerPC configurations being enabled. As a >>>>>> result, >>>>>> it prevents the HOTPLUG_CPU from being selected when the required >>>>>> dependencies >>>>>> are not satisfied. >>>>>> >>>>>> This change aligns the dependency tree with the expected hardware >>>>>> support for >>>>>> CPU hot-plugging under PowerPC architectures, ensuring that the kernel >>>>>> configuration steps do not lead to inconsistent states. >>>>>> >>>>>> Signed-off-by: Vishal Chourasia <vish...@linux.ibm.com> >>>>>> --- >>>>>> During the configuration process with 'make randconfig' followed by >>>>>> 'make olddefconfig', we observed a warning indicating an unmet direct >>>>>> dependency for the HOTPLUG_CPU option. The dependency in question >>>>>> relates to >>>>>> various PowerPC configurations (PPC_PSERIES, PPC_PMAC, PPC_POWERNV, >>>>>> FSL_SOC_BOOKE) which were not enabled, yet the HOTPLUG_CPU was >>>>>> beingDuring the configuration process with 'make randconfig' followed by >>>>>> 'make olddefconfig', we observed a warning indicating an unmet direct >>>>>> dependency for the HOTPLUG_CPU option. The dependency in question >>>>>> relates to >>>>>> various PowerPC configurations (PPC_PSERIES, PPC_PMAC, PPC_POWERNV, >>>>>> FSL_SOC_BOOKE) which were not enabled, yet the HOTPLUG_CPU was being >>>>>> erroneously selected due to an implicit assumption by the PM_SLEEP_SMP >>>>>> option. >>>>>> This misalignment in dependencies could potentially lead to inconsistent >>>>>> kernel >>>>>> configuration states, especially when considering the necessary hardware >>>>>> support for CPU hot-plugging on PowerPC platforms. The patch aims to >>>>>> correct >>>>>> this by ensuring that ARCH_HIBERNATION_POSSIBLE is contingent upon the >>>>>> appropriate PowerPC configurations being active. >>>>>> >>>>>> steps to reproduce (before applying the patch): >>>>>> >>>>>> Run 'make pseries_le_defconfig' >>>>>> Run 'make menuconfig' >>>>>> Enable hibernation [ Kernel options -> Hibernation (aka 'suspend to >>>>>> disk') ] >>>>>> Disable [ Platform support -> IBM PowerNV (Non-Virtualized) platform >>>>>> support ] >>>>>> Disable [ Platform support -> IBM pSeries & new (POWER5-based) iSeries ] >>>>>> Enable SMP [ Processor support -> Symmetric multi-processing support ] >>>>>> Save the config >>>>>> Run 'make olddefconfig' >>>>>> erroneously selected due to an implicit assumption by the PM_SLEEP_SMP >>>>>> option. >>>>>> This misalignment in dependencies could potentially lead to inconsistent >>>>>> kernel >>>>>> configuration states, especially when considering the necessary hardware >>>>>> support for CPU hot-plugging on PowerPC platforms. The patch aims to >>>>>> correct >>>>>> this by ensuring that ARCH_HIBERNATION_POSSIBLE is contingent upon the >>>>>> appropriate PowerPC configurations being active. >>>>>> >>>>>> steps to reproduce (before applying the patch): >>>>>> >>>>>> Run 'make pseries_le_defconfig' >>>>>> Run 'make menuconfig' >>>>>> Enable hibernation [ Kernel options -> Hibernation (aka 'suspend to >>>>>> disk') ] >>>>>> Disable [ Platform support -> IBM PowerNV (Non-Virtualized) platform >>>>>> support ] >>>>>> Disable [ Platform support -> IBM pSeries & new (POWER5-based) iSeries ] >>>>>> Enable SMP [ Processor support -> Symmetric multi-processing support ] >>>>>> Save the config >>>>>> Run 'make olddefconfig' >>>>>> >>>>>> arch/powerpc/Kconfig | 5 +++-- >>>>>> 1 file changed, 3 insertions(+), 2 deletions(-) >>>>>> >>>>>> diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig >>>>>> index 6f105ee4f3cf..bf99ff9869f6 100644 >>>>>> --- a/arch/powerpc/Kconfig >>>>>> +++ b/arch/powerpc/Kconfig >>>>>> @@ -380,8 +380,9 @@ config DEFAULT_UIMAGE >>>>>> Used to allow a board to specify it wants a uImage built by >>>>>> default >>>>>> >>>>>> config ARCH_HIBERNATION_POSSIBLE >>>>>> - bool >>>>>> - default y >>>>>> + def_bool y >>>>>> + depends on PPC_PSERIES || \ >>>>>> + PPC_PMAC || PPC_POWERNV || FSL_SOC_BOOKE >>>>>> >>>>>> config ARCH_SUSPEND_POSSIBLE >>>>>> def_bool y >>>>>> >>>>> I am wondering whether it should be switched to using select from >>>>> config PPC? >>>>> >>>>> selecting ARCH_HIBERNATION_POSSIBLE based on value of config PPC >>>>> will not guarantee config PPC_PSERIES being set >>>>> >>>>> PPC_PSERIES can be set to N, even when config PPC is set. >> I understand what you meant before. Having ARCH_HIBERNATION_POSSIBLE under >> config PPC makes more sense. >>>>> grep -A 5 -i "config ppc_pseries" arch/powerpc/platforms/pseries/Kconfig >>>>> config PPC_PSERIES >>>>> depends on PPC64 && PPC_BOOK3S >>>>> bool "IBM pSeries & new (POWER5-based) iSeries" >>>>> select HAVE_PCSPKR_PLATFORM >>>>> select MPIC >>>>> select OF_DYNAMIC >>>>> >>> modified arch/powerpc/Kconfig >>> @@ -156,6 +156,7 @@ config PPC >>> select ARCH_HAS_UACCESS_FLUSHCACHE >>> select ARCH_HAS_UBSAN_SANITIZE_ALL >>> select ARCH_HAVE_NMI_SAFE_CMPXCHG >>> + select ARCH_HIBERNATION_POSSIBLE if (PPC_PSERIES || PPC_PMAC || >>> PPC_POWERNV || FSL_SOC_BOOKE) >>> select ARCH_KEEP_MEMBLOCK >>> select ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE if PPC_RADIX_MMU >>> select ARCH_MIGHT_HAVE_PC_PARPORT >> Though, even with these changes I was able to reproduce same warnings. >> (using steps from above) >> It's because one can enable HIBERNATION manually. > But how? You shouldn't be able to enable it manually, it depends on > ARCH_HIBERNATION_POSSIBLE which shouldn't be enabled. > > For the above to work you also need to make it default n, eg: > > diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig > index 6f105ee4f3cf..dd2a9b938188 100644 > --- a/arch/powerpc/Kconfig > +++ b/arch/powerpc/Kconfig > @@ -380,8 +380,7 @@ config DEFAULT_UIMAGE > Used to allow a board to specify it wants a uImage built by default > > config ARCH_HIBERNATION_POSSIBLE > - bool > - default y > + def_bool n > > config ARCH_SUSPEND_POSSIBLE > def_bool y
Ran make randconfig bunch of times. # make KCONFIG_SEED=0x97C94A3C randconfig make[1]: Entering directory '' GEN Makefile KCONFIG_SEED=0x97C94A3C WARNING: unmet direct dependencies detected for HOTPLUG_CPU Depends on [n]: SMP [=y] && (PPC_PSERIES [=n] || PPC_PMAC [=n] || PPC_POWERNV [=n] || FSL_SOC_BOOKE [=n]) Selected by [y]: - PM_SLEEP_SMP [=y] && SMP [=y] && (ARCH_SUSPEND_POSSIBLE [=y] || ARCH_HIBERNATION_POSSIBLE [=n]) && PM_SLEEP [=y] # # configuration written to .config # make[1]: Leaving directory '' As per my understanding, "Depends on" clause of the config HOTPLUG_CPU as CPU hotplugging is only available for SMP systems and is only available for following power platforms (PPC_PSERIES || PPC_PMAC || PPC_POWERNV || FSL_SOC_BOOKE) Also, config HOTPLUG_CPU is being selected by config PM_SLEEP_SMP config PM_SLEEP_SMP def_bool y depends on SMP depends on ARCH_SUSPEND_POSSIBLE || ARCH_HIBERNATION_POSSIBLE depends on PM_SLEEP select HOTPLUG_CPU <----- Here Power management functionality depends and vary upon arch (and in powerpc case, platforms) supporting suspend/hibernation There are some platforms which support suspend and hence ARCH_SUSPEND_POSSIBLE is set, leading to PM_SLEEP_SMP being set, and ultimately, config HOTPLUG_CPU gets set. But, CPU hotplug is not supported for such platform and hence the conflict. > > cheers
