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Wysocki" , Pavel Machek , Len Brown Cc: linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org References: <20260605-disable_boot_cpu_offline-v1-1-4c68fe1a6cf8@oss.qualcomm.com> <9b5ea951-6880-4ce8-8764-fd6bf2bd57a0@oss.qualcomm.com> Content-Language: en-US From: Sneh Mankad In-Reply-To: <9b5ea951-6880-4ce8-8764-fd6bf2bd57a0@oss.qualcomm.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Proofpoint-Spam-Info: AW1haW4tMjYwNzAzMDExMSBTYWx0ZWRfX2WMfoPq7vu8j 9XE5a8IK4nKIs7SfLX5iAGTO/U4HCqu02OhAu0nddQ5CwE8OrkkWzCyB3phIWpvhAYhkBnNh9rC tKFt4vCrYnidC6fdw1Hy0BQso7bEs8E= X-Proofpoint-ORIG-GUID: uIQHzqCaStXTMWrlyHohe1ioM-nJ9PC6 X-Authority-Analysis: v=2.4 cv=O4wJeh9W c=1 sm=1 tr=0 ts=6a479bc6 cx=c_pps a=UNFcQwm+pnOIJct1K4W+Mw==:117 a=fChuTYTh2wq5r3m49p7fHw==:17 a=IkcTkHD0fZMA:10 a=RAioF0-LDSMA:10 a=s4-Qcg_JpJYA:10 a=VkNPw1HP01LnGYTKEx00:22 a=u7WPNUs3qKkmUXheDGA7:22 a=yx91gb_oNiZeI1HMLzn7:22 a=EUspDBNiAAAA:8 a=JzDM9ypL2hb05KE4TY4A:9 a=3ZKOabzyN94A:10 a=QEXdDO2ut3YA:10 a=uKXjsCUrEbL0IQVhDsJ9:22 X-Proofpoint-GUID: uIQHzqCaStXTMWrlyHohe1ioM-nJ9PC6 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwNzAzMDExMSBTYWx0ZWRfX8B+wsnUXOCk/ qZJJsf0ITJv0wxS1dLJntBoHajOzFvmb8W5YkITYosWeIfWOKmpwzHrXQgv/aHkyvalSu/g9p2H fPZiQHkOaHOTXNyDeZtDGaFL5LFnIOuvhlRB6m4fl5S57Z/wHGCzIA/NF1YPiXqJ8FUys9T4vVy R42V0sGCTVv2q1jk1CGSvHKRMvXWuxE+dshI+M1uMwohi4Mcq02hW/U5SdLJGBPOMniCQUaXaYO jHRbEvJvkUkuidqRIh/Ra2q96kWENZ/ohfOgE3c0M9IywTzqpvYk7U/Zul6K9EwcIUuCG4rwHmz lL1T0FKYK0nvzkf8rf+ZwPYhxKogJtej3RE7JVL3s4iaPD5Vvst9HWSPKSNLgmS8+Mq+CEpAUZ2 PAnITUXXsO99bJYcP7XFtyl3JIHg7B4NycRuDfx9KevCz/C6pGqisikZcZVkfYNlSFzB0KAFdO3 MKrAOYx6o+/QmKgtKFQ== X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.125,FMLib:17.12.100.49 definitions=2026-07-03_02,2026-06-26_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 impostorscore=0 priorityscore=1501 bulkscore=0 clxscore=1015 phishscore=0 suspectscore=0 malwarescore=0 spamscore=0 adultscore=0 lowpriorityscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2607030111 On 23-Jun-26 5:10 PM, Daniel Lezcano wrote: > > Hi Sned, > > On 6/5/26 12:30, Sneh Mankad wrote: >> The Qualcomm SoCs like LeMans, Monaco support suspend to ram which leads >> the SoC to ACPI S3 similar state where SoC is turned off and DDR is >> retained. >> The hardware design on these SoCs forces a constraint to suspend and >> resume the system on boot CPU / CPU0. >> >> If CPU0 is already offline before starting suspend to ram the >> freeze_secondary_cpus() picks alternate CPU as primary / last CPU and >> proceed further to invoke PSCI SYSTEM_SUSPEND. >> This leads to a system crash. >> >> In order to prevent such an issue introduce PM_SLEEP_SMP_CPU_ZERO_STRICT >> config and when enabled prohibit the CPU0 to be offline. > > What is the status of this change ? Are you planning to send a new version with the check inside arch_cpu_is_hotpluggable() ? Yes Daniel, I am sending v2 with adding the check in arm64 specific file. Thanks, Sneh > >> Signed-off-by: Sneh Mankad >> --- >>   kernel/cpu.c         | 4 ++++ >>   kernel/power/Kconfig | 8 ++++++++ >>   2 files changed, 12 insertions(+) >> >> diff --git a/kernel/cpu.c b/kernel/cpu.c >> index bc4f7a9ba64e62d76fbb2b362f243c918defe5bc..1c878db1d9cb6df0e31cb55343851aab4e38a3a0 100644 >> --- a/kernel/cpu.c >> +++ b/kernel/cpu.c >> @@ -1478,6 +1478,10 @@ static int cpu_down_maps_locked(unsigned int cpu, enum cpuhp_state target) >>        */ >>       if (cpu_hotplug_offline_disabled) >>           return -EOPNOTSUPP; >> +#ifdef CONFIG_PM_SLEEP_SMP_CPU_ZERO_STRICT >> +    if (cpu == get_boot_cpu_id()) >> +        return -EPERM; >> +#endif >>       if (cpu_hotplug_disabled) >>           return -EBUSY; >>       return _cpu_down(cpu, 0, target); >> diff --git a/kernel/power/Kconfig b/kernel/power/Kconfig >> index 05337f437cca29da57864583166d7f9abd526507..0b342b3a4a5650a1927dc4805d1515e1d9e067c6 100644 >> --- a/kernel/power/Kconfig >> +++ b/kernel/power/Kconfig >> @@ -401,3 +401,11 @@ config ENERGY_MODEL >>         The exact usage of the energy model is subsystem-dependent. >>           If in doubt, say N. >> + >> +config PM_SLEEP_SMP_CPU_ZERO_STRICT >> +    bool "Disallow boot CPU (CPU0) offline" >> +    depends on HOTPLUG_CPU >> +    depends on SUSPEND >> +    help >> +      Disallow boot CPU (CPU0) offline when the suspend_ops->enter() >> +      has to be executed by boot CPU. >> >> --- >> base-commit: ba3e43a9e601636f5edb54e259a74f96ca3b8fd8 >> change-id: 20260603-disable_boot_cpu_offline-eb4f55ac96f2 >> >> Best regards, >