On Sun, Mar 7, 2021 at 7:55 AM <guoren@xxxxxxxxxx> wrote:
>
> From: Guo Ren <guoren@xxxxxxxxxxxxxxxxx>
>
> When percpu-timers are stopped by deep power saving mode, we
> need system timer help to broadcast IPI_TIMER.
>
> This is first introduced by broken x86 hardware, where the local apic
> timer stops in C3 state. But many other architectures(powerpc, mips,
> arm, hexagon, openrisc, sh) have supported the infrastructure to
> deal with Power Management issues.
>
> Signed-off-by: Guo Ren <guoren@xxxxxxxxxxxxxxxxx>
> Cc: Arnd Bergmann <arnd@xxxxxxxx>
> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> Cc: Daniel Lezcano <daniel.lezcano@xxxxxxxxxx>
> Cc: Anup Patel <anup.patel@xxxxxxx>
> Cc: Atish Patra <atish.patra@xxxxxxx>
> Cc: Palmer Dabbelt <palmerdabbelt@xxxxxxxxxx>
> Cc: Greentime Hu <greentime.hu@xxxxxxxxxx>
Looks good to me.
Reviewed-by: Anup Patel <anup@xxxxxxxxxxxxxx>
Regards,
Anup
> ---
> arch/riscv/Kconfig | 2 ++
> arch/riscv/kernel/smp.c | 16 ++++++++++++++++
> 2 files changed, 18 insertions(+)
>
> diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
> index 85d626b8ce5e..8637e7344abe 100644
> --- a/arch/riscv/Kconfig
> +++ b/arch/riscv/Kconfig
> @@ -28,6 +28,7 @@ config RISCV
> select ARCH_HAS_SET_DIRECT_MAP
> select ARCH_HAS_SET_MEMORY
> select ARCH_HAS_STRICT_KERNEL_RWX if MMU
> + select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
> select ARCH_OPTIONAL_KERNEL_RWX if ARCH_HAS_STRICT_KERNEL_RWX
> select ARCH_OPTIONAL_KERNEL_RWX_DEFAULT
> select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT if MMU
> @@ -39,6 +40,7 @@ config RISCV
> select EDAC_SUPPORT
> select GENERIC_ARCH_TOPOLOGY if SMP
> select GENERIC_ATOMIC64 if !64BIT
> + select GENERIC_CLOCKEVENTS_BROADCAST if SMP
> select GENERIC_EARLY_IOREMAP
> select GENERIC_GETTIMEOFDAY if HAVE_GENERIC_VDSO
> select GENERIC_IOREMAP
> diff --git a/arch/riscv/kernel/smp.c b/arch/riscv/kernel/smp.c
> index ea028d9e0d24..8325d33411d8 100644
> --- a/arch/riscv/kernel/smp.c
> +++ b/arch/riscv/kernel/smp.c
> @@ -9,6 +9,7 @@
> */
>
> #include <linux/cpu.h>
> +#include <linux/clockchips.h>
> #include <linux/interrupt.h>
> #include <linux/module.h>
> #include <linux/profile.h>
> @@ -27,6 +28,7 @@ enum ipi_message_type {
> IPI_CALL_FUNC,
> IPI_CPU_STOP,
> IPI_IRQ_WORK,
> + IPI_TIMER,
> IPI_MAX
> };
>
> @@ -176,6 +178,12 @@ void handle_IPI(struct pt_regs *regs)
> irq_work_run();
> }
>
> +#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
> + if (ops & (1 << IPI_TIMER)) {
> + stats[IPI_TIMER]++;
> + tick_receive_broadcast();
> + }
> +#endif
> BUG_ON((ops >> IPI_MAX) != 0);
>
> /* Order data access and bit testing. */
> @@ -192,6 +200,7 @@ static const char * const ipi_names[] = {
> [IPI_CALL_FUNC] = "Function call interrupts",
> [IPI_CPU_STOP] = "CPU stop interrupts",
> [IPI_IRQ_WORK] = "IRQ work interrupts",
> + [IPI_TIMER] = "Timer broadcast interrupts",
> };
>
> void show_ipi_stats(struct seq_file *p, int prec)
> @@ -217,6 +226,13 @@ void arch_send_call_function_single_ipi(int cpu)
> send_ipi_single(cpu, IPI_CALL_FUNC);
> }
>
> +#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
> +void tick_broadcast(const struct cpumask *mask)
> +{
> + send_ipi_mask(mask, IPI_TIMER);
> +}
> +#endif
> +
> void smp_send_stop(void)
> {
> unsigned long timeout;
> --
> 2.25.1
>
>
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