On Thu, Dec 27, 2018 at 4:39 AM Atish Patra <atish.pa...@wdc.com> wrote: > > In SMP path, __cpu_up waits for other CPU to come online > indefinitely. This is wrong as other CPU might be disabled > in machine mode and possible CPU is set to the cpus present > in DT. > > Introduce a completion variable and waits only for a second. > > Signed-off-by: Atish Patra <atish.pa...@wdc.com> > --- > arch/riscv/kernel/smpboot.c | 14 +++++++++++--- > 1 file changed, 11 insertions(+), 3 deletions(-) > > diff --git a/arch/riscv/kernel/smpboot.c b/arch/riscv/kernel/smpboot.c > index 18cda0e8..bb8cd242 100644 > --- a/arch/riscv/kernel/smpboot.c > +++ b/arch/riscv/kernel/smpboot.c > @@ -39,6 +39,7 @@ > > void *__cpu_up_stack_pointer[NR_CPUS]; > void *__cpu_up_task_pointer[NR_CPUS]; > +static DECLARE_COMPLETION(cpu_running); > > void __init smp_prepare_boot_cpu(void) > { > @@ -77,6 +78,7 @@ void __init setup_smp(void) > > int __cpu_up(unsigned int cpu, struct task_struct *tidle) > { > + int ret = 0; > int hartid = cpuid_to_hartid_map(cpu); > tidle->thread_info.cpu = cpu; > > @@ -92,10 +94,15 @@ int __cpu_up(unsigned int cpu, struct task_struct *tidle) > task_stack_page(tidle) + THREAD_SIZE); > WRITE_ONCE(__cpu_up_task_pointer[hartid], tidle); > > - while (!cpu_online(cpu)) > - cpu_relax(); > + wait_for_completion_timeout(&cpu_running, > + msecs_to_jiffies(1000)); > > - return 0; > + if (!cpu_online(cpu)) { > + pr_crit("CPU%u: failed to come online\n", cpu); > + ret = -EIO; > + } > + > + return ret; > } > > void __init smp_cpus_done(unsigned int max_cpus) > @@ -121,6 +128,7 @@ asmlinkage void __init smp_callin(void) > * a local TLB flush right now just in case. > */ > local_flush_tlb_all(); > + complete(&cpu_running); > /* > * Disable preemption before enabling interrupts, so we don't try to > * schedule a CPU that hasn't actually started yet. > -- > 2.7.4 >
Looks good to me. Reviewed-by: Anup Patel <a...@brainfault.org>