Messages in this thread Patch in this message | | | Date | Tue, 17 Mar 2020 10:06:09 +0000 | From | Mark Rutland <> | Subject | Re: [PATCH] arm64/kernel: Simplify __cpu_up() by bailing out early |
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On Mon, Mar 02, 2020 at 12:21:35PM +0000, Mark Rutland wrote: > On Mon, Mar 02, 2020 at 01:03:40PM +1100, Gavin Shan wrote: > > The function __cpu_up() is invoked to bring up the target CPU through > > the backend, PSCI for example. The nested if statements won't be needed > > if we bail out early on the following two conditions where the status > > won't be checked. The code looks simplified in that case. > > > > * Error returned from the backend (e.g. PSCI) > > * The target CPU has been marked as onlined > > > > Signed-off-by: Gavin Shan <gshan@redhat.com> > > FWIW, this looks like a nice cleanup to me: > > Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Catalin, are you happy to pick this up?
Thanks, Mark.
> While this patch leaves secondary_data.{task,stack} stale on a > successful onlining, that was already the case for a timeout, and should > be fine (since the next attempt at onlining will configure those before > poking the CPU). > > Thanks, > Mark. > > > --- > > arch/arm64/kernel/smp.c | 79 +++++++++++++++++++---------------------- > > 1 file changed, 37 insertions(+), 42 deletions(-) > > > > diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c > > index d4ed9a19d8fe..2a9d8f39dc58 100644 > > --- a/arch/arm64/kernel/smp.c > > +++ b/arch/arm64/kernel/smp.c > > @@ -115,60 +115,55 @@ int __cpu_up(unsigned int cpu, struct task_struct *idle) > > update_cpu_boot_status(CPU_MMU_OFF); > > __flush_dcache_area(&secondary_data, sizeof(secondary_data)); > > > > - /* > > - * Now bring the CPU into our world. > > - */ > > + /* Now bring the CPU into our world */ > > ret = boot_secondary(cpu, idle); > > - if (ret == 0) { > > - /* > > - * CPU was successfully started, wait for it to come online or > > - * time out. > > - */ > > - wait_for_completion_timeout(&cpu_running, > > - msecs_to_jiffies(5000)); > > - > > - if (!cpu_online(cpu)) { > > - pr_crit("CPU%u: failed to come online\n", cpu); > > - ret = -EIO; > > - } > > - } else { > > + if (ret) { > > pr_err("CPU%u: failed to boot: %d\n", cpu, ret); > > return ret; > > } > > > > + /* > > + * CPU was successfully started, wait for it to come online or > > + * time out. > > + */ > > + wait_for_completion_timeout(&cpu_running, > > + msecs_to_jiffies(5000)); > > + if (cpu_online(cpu)) > > + return 0; > > + > > + pr_crit("CPU%u: failed to come online\n", cpu); > > secondary_data.task = NULL; > > secondary_data.stack = NULL; > > __flush_dcache_area(&secondary_data, sizeof(secondary_data)); > > status = READ_ONCE(secondary_data.status); > > - if (ret && status) { > > - > > - if (status == CPU_MMU_OFF) > > - status = READ_ONCE(__early_cpu_boot_status); > > + if (status == CPU_MMU_OFF) > > + status = READ_ONCE(__early_cpu_boot_status); > > > > - switch (status & CPU_BOOT_STATUS_MASK) { > > - default: > > - pr_err("CPU%u: failed in unknown state : 0x%lx\n", > > - cpu, status); > > - cpus_stuck_in_kernel++; > > - break; > > - case CPU_KILL_ME: > > - if (!op_cpu_kill(cpu)) { > > - pr_crit("CPU%u: died during early boot\n", cpu); > > - break; > > - } > > - pr_crit("CPU%u: may not have shut down cleanly\n", cpu); > > - /* Fall through */ > > - case CPU_STUCK_IN_KERNEL: > > - pr_crit("CPU%u: is stuck in kernel\n", cpu); > > - if (status & CPU_STUCK_REASON_52_BIT_VA) > > - pr_crit("CPU%u: does not support 52-bit VAs\n", cpu); > > - if (status & CPU_STUCK_REASON_NO_GRAN) > > - pr_crit("CPU%u: does not support %luK granule \n", cpu, PAGE_SIZE / SZ_1K); > > - cpus_stuck_in_kernel++; > > + switch (status & CPU_BOOT_STATUS_MASK) { > > + default: > > + pr_err("CPU%u: failed in unknown state : 0x%lx\n", > > + cpu, status); > > + cpus_stuck_in_kernel++; > > + break; > > + case CPU_KILL_ME: > > + if (!op_cpu_kill(cpu)) { > > + pr_crit("CPU%u: died during early boot\n", cpu); > > break; > > - case CPU_PANIC_KERNEL: > > - panic("CPU%u detected unsupported configuration\n", cpu); > > } > > + pr_crit("CPU%u: may not have shut down cleanly\n", cpu); > > + /* Fall through */ > > + case CPU_STUCK_IN_KERNEL: > > + pr_crit("CPU%u: is stuck in kernel\n", cpu); > > + if (status & CPU_STUCK_REASON_52_BIT_VA) > > + pr_crit("CPU%u: does not support 52-bit VAs\n", cpu); > > + if (status & CPU_STUCK_REASON_NO_GRAN) { > > + pr_crit("CPU%u: does not support %luK granule\n", > > + cpu, PAGE_SIZE / SZ_1K); > > + } > > + cpus_stuck_in_kernel++; > > + break; > > + case CPU_PANIC_KERNEL: > > + panic("CPU%u detected unsupported configuration\n", cpu); > > } > > > > return ret; > > -- > > 2.23.0 > >
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