| Message ID | 20200907181659.92449-5-seanga2@gmail.com |
|---|---|
| State | Superseded |
| Delegated to: | Andes |
| Headers | show |
| Series | riscv: Correctly handle IPIs already pending upon boot | expand |
On Tue, Sep 8, 2020 at 2:17 AM Sean Anderson <seanga2@gmail.com> wrote: > > Even though we no longer call smp_function if an IPI was not sent by > U-Boot, we still need to clear any IPIs which were pending from the > execution environment. Otherwise, secondary harts will busy-wait in > secondary_hart_loop, instead of relaxing. > > Signed-off-by: Sean Anderson <seanga2@gmail.com> > --- > > arch/riscv/cpu/cpu.c | 18 ++++++++++++++++++ > 1 file changed, 18 insertions(+) > Reviewed-by: Bin Meng <bin.meng@windriver.com>
diff --git a/arch/riscv/cpu/cpu.c b/arch/riscv/cpu/cpu.c index bfa2d4a426..ad94744c0f 100644 --- a/arch/riscv/cpu/cpu.c +++ b/arch/riscv/cpu/cpu.c @@ -72,6 +72,15 @@ static int riscv_cpu_probe(void) return 0; } +/* + * This is called on secondary harts just after the IPI is init'd. Currently + * there's nothing to do, since we just need to clear any existing IPIs, and + * that is handled by the sending of an ipi itself. + */ +void riscv_ipi_init_secondary_hart(ulong hart, ulong arg0, ulong arg1) +{ +} + int arch_cpu_init_dm(void) { int ret; @@ -111,6 +120,15 @@ int arch_cpu_init_dm(void) ret = riscv_init_ipi(); if (ret) return ret; + + /* + * Clear all pending IPIs on secondary harts. We don't do anything on + * the boot hart, since we never send an IPI to ourselves, and no + * interrupts are enabled + */ + ret = smp_call_function((ulong)riscv_ipi_init_secondary_hart, 0, 0, 0); + if (ret) + return ret; #endif return 0;
Even though we no longer call smp_function if an IPI was not sent by U-Boot, we still need to clear any IPIs which were pending from the execution environment. Otherwise, secondary harts will busy-wait in secondary_hart_loop, instead of relaxing. Signed-off-by: Sean Anderson <seanga2@gmail.com> --- arch/riscv/cpu/cpu.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+)