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authorAtish Patra <atish.patra@wdc.com>2019-02-22 11:41:35 -0800
committerPalmer Dabbelt <palmer@sifive.com>2019-03-04 10:40:36 -0800
commite15c6e37066e9ce6705f22b71e60ca2d78db8d45 (patch)
treea1fae221eda1cd98a3d61d6236980f9452640283 /arch/riscv
parentriscv: remove the HAVE_KPROBES option (diff)
downloadlinux-dev-e15c6e37066e9ce6705f22b71e60ca2d78db8d45.tar.xz
linux-dev-e15c6e37066e9ce6705f22b71e60ca2d78db8d45.zip
RISC-V: Do not wait indefinitely in __cpu_up
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>
Diffstat (limited to 'arch/riscv')
-rw-r--r--arch/riscv/kernel/smpboot.c15
1 files changed, 12 insertions, 3 deletions
diff --git a/arch/riscv/kernel/smpboot.c b/arch/riscv/kernel/smpboot.c
index 6e2813257e03..d369b669fe04 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 +94,16 @@ 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.