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RISC-V: Do not wait indefinitely in __cpu_up

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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.patra@wdc.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Palmer Dabbelt <palmer@sifive.com>
This commit is contained in:
Atish Patra 2019-02-22 11:41:35 -08:00 committed by Palmer Dabbelt
parent 79a47bad61
commit e15c6e3706
No known key found for this signature in database
GPG Key ID: EF4CA1502CCBAB41
1 changed files with 12 additions and 3 deletions
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15
arch/riscv/kernel/smpboot.c
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@ -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 +94,16 @@ 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();
lockdep_assert_held(&cpu_running);
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 +129,7 @@ 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.