From: Jean-Philippe Brucker <jean-phili...@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. See https://developer.arm.com/documentation/den0022/f/?lang=en page 58. Signed-off-by: Jean-Philippe Brucker <jean-phili...@linaro.org> [ morse: Rewrote commit message ] Signed-off-by: James Morse <james.mo...@arm.com> Signed-off-by: Russell King (Oracle) <rmk+ker...@armlinux.org.uk> --- Changes since RFC v2 * Add specification reference * Use EPERM rather than EPROBE_DEFER --- arch/arm64/kernel/psci.c | 2 +- arch/arm64/kernel/smp.c | 3 ++- drivers/firmware/psci/psci.c | 2 ++ 3 files changed, 5 insertions(+), 2 deletions(-) diff --git a/arch/arm64/kernel/psci.c b/arch/arm64/kernel/psci.c index 29a8e444db83..4fcc0cdd757b 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 != -EPROBE_DEFER) 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 8c8f55721786..68ec7fbe166f 100644 --- a/arch/arm64/kernel/smp.c +++ b/arch/arm64/kernel/smp.c @@ -124,7 +124,8 @@ 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; } diff --git a/drivers/firmware/psci/psci.c b/drivers/firmware/psci/psci.c index d9629ff87861..ee82e7880d8c 100644 --- a/drivers/firmware/psci/psci.c +++ b/drivers/firmware/psci/psci.c @@ -218,6 +218,8 @@ static int __psci_cpu_on(u32 fn, unsigned long cpuid, unsigned long entry_point) int err; err = invoke_psci_fn(fn, cpuid, entry_point, 0); + if (err == PSCI_RET_DENIED) + return -EPERM; return psci_to_linux_errno(err); } -- 2.30.2
