| Message ID | 20240426135126.12802-13-Jonathan.Cameron@huawei.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | ACPI/arm64: add support for virtual cpu hotplug | expand |
On 4/26/24 23:51, Jonathan Cameron wrote: > From: Jean-Philippe Brucker <jean-philippe@linaro.org> > > When a CPU is marked as disabled, but online capable in the MADT, PSCI > applies some firmware policy to control when it can be brought online. > PSCI returns DENIED to a CPU_ON request if this is not currently > permitted. The OS can learn the current policy from the _STA enabled bit. > > Handle the PSCI DENIED return code gracefully instead of printing an > error. > > Note the alternatives to the PSCI cpu_boot() callback do not > return -EPERM so the change in smp.c has no affect. > > See https://developer.arm.com/documentation/den0022/f/?lang=en page 58. > > Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org> > [ morse: Rewrote commit message ] > Signed-off-by: James Morse <james.morse@arm.com> > Tested-by: Miguel Luis <miguel.luis@oracle.com> > Tested-by: Vishnu Pajjuri <vishnu@os.amperecomputing.com> > Tested-by: Jianyong Wu <jianyong.wu@arm.com> > Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> > Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk> > Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> > --- > v8: Note in commit message that the -EPERM guard on the error print > only affects PSCI as other options never use this error code. > Should they do so in future, that may well indicate that they > now support similar refusal to boot. > --- > arch/arm64/kernel/psci.c | 2 +- > arch/arm64/kernel/smp.c | 3 ++- > 2 files changed, 3 insertions(+), 2 deletions(-) > Thanks for the check and clarification that -EPERM is only sensible to PSCI. With the clarification: Reviewed-by: Gavin Shan <gshan@redhat.com> Thanks, Gavin
diff --git a/arch/arm64/kernel/psci.c b/arch/arm64/kernel/psci.c index 29a8e444db83..fabd732d0a2d 100644 --- a/arch/arm64/kernel/psci.c +++ b/arch/arm64/kernel/psci.c @@ -40,7 +40,7 @@ static int cpu_psci_cpu_boot(unsigned int cpu) { phys_addr_t pa_secondary_entry = __pa_symbol(secondary_entry); int err = psci_ops.cpu_on(cpu_logical_map(cpu), pa_secondary_entry); - if (err) + if (err && err != -EPERM) pr_err("failed to boot CPU%d (%d)\n", cpu, err); return err; diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c index 4ced34f62dab..dc0e0b3ec2d4 100644 --- a/arch/arm64/kernel/smp.c +++ b/arch/arm64/kernel/smp.c @@ -132,7 +132,8 @@ int __cpu_up(unsigned int cpu, struct task_struct *idle) /* Now bring the CPU into our world */ ret = boot_secondary(cpu, idle); if (ret) { - pr_err("CPU%u: failed to boot: %d\n", cpu, ret); + if (ret != -EPERM) + pr_err("CPU%u: failed to boot: %d\n", cpu, ret); return ret; }