From fb0f3d281b7f81a11e210783940f3798c4744179 Mon Sep 17 00:00:00 2001 From: Anup Patel Date: Tue, 28 Mar 2023 09:22:20 +0530 Subject: [PATCH] RISC-V: Allow marking IPIs as suitable for remote FENCEs To do remote FENCEs (i.e. remote TLB flushes) using IPI calls on the RISC-V kernel, we need hardware mechanism to directly inject IPI from the supervisor mode (i.e. RISC-V kernel) instead of using SBI calls. The upcoming AIA IMSIC devices allow direct IPI injection from the supervisor mode (i.e. RISC-V kernel). To support this, we extend the riscv_ipi_set_virq_range() function so that IPI provider (i.e. irqchip drivers can mark IPIs as suitable for remote FENCEs. Signed-off-by: Anup Patel Reviewed-by: Atish Patra Acked-by: Palmer Dabbelt Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20230328035223.1480939-5-apatel@ventanamicro.com --- arch/riscv/include/asm/smp.h | 18 ++++++++++++++++-- arch/riscv/kernel/sbi-ipi.c | 2 +- arch/riscv/kernel/smp.c | 11 ++++++++++- drivers/clocksource/timer-clint.c | 2 +- 4 files changed, 28 insertions(+), 5 deletions(-) diff --git a/arch/riscv/include/asm/smp.h b/arch/riscv/include/asm/smp.h index 4fe7a8854c2e..c4b77017ec58 100644 --- a/arch/riscv/include/asm/smp.h +++ b/arch/riscv/include/asm/smp.h @@ -16,6 +16,9 @@ struct seq_file; extern unsigned long boot_cpu_hartid; #ifdef CONFIG_SMP + +#include + /* * Mapping between linux logical cpu index and hartid. */ @@ -46,7 +49,12 @@ void riscv_ipi_disable(void); bool riscv_ipi_have_virq_range(void); /* Set the IPI interrupt numbers for arch (called by irqchip drivers) */ -void riscv_ipi_set_virq_range(int virq, int nr); +void riscv_ipi_set_virq_range(int virq, int nr, bool use_for_rfence); + +/* Check if we can use IPIs for remote FENCEs */ +DECLARE_STATIC_KEY_FALSE(riscv_ipi_for_rfence); +#define riscv_use_ipi_for_rfence() \ + static_branch_unlikely(&riscv_ipi_for_rfence) /* Check other CPUs stop or not */ bool smp_crash_stop_failed(void); @@ -96,10 +104,16 @@ static inline bool riscv_ipi_have_virq_range(void) return false; } -static inline void riscv_ipi_set_virq_range(int virq, int nr) +static inline void riscv_ipi_set_virq_range(int virq, int nr, + bool use_for_rfence) { } +static inline bool riscv_use_ipi_for_rfence(void) +{ + return false; +} + #endif /* CONFIG_SMP */ #if defined(CONFIG_HOTPLUG_CPU) && (CONFIG_SMP) diff --git a/arch/riscv/kernel/sbi-ipi.c b/arch/riscv/kernel/sbi-ipi.c index 41981ab88493..a4559695ce62 100644 --- a/arch/riscv/kernel/sbi-ipi.c +++ b/arch/riscv/kernel/sbi-ipi.c @@ -72,6 +72,6 @@ void __init sbi_ipi_init(void) "irqchip/sbi-ipi:starting", sbi_ipi_starting_cpu, NULL); - riscv_ipi_set_virq_range(virq, BITS_PER_BYTE); + riscv_ipi_set_virq_range(virq, BITS_PER_BYTE, false); pr_info("providing IPIs using SBI IPI extension\n"); } diff --git a/arch/riscv/kernel/smp.c b/arch/riscv/kernel/smp.c index 47e7ecfedb4d..5f985a197eff 100644 --- a/arch/riscv/kernel/smp.c +++ b/arch/riscv/kernel/smp.c @@ -177,7 +177,10 @@ bool riscv_ipi_have_virq_range(void) return (ipi_virq_base) ? true : false; } -void riscv_ipi_set_virq_range(int virq, int nr) +DEFINE_STATIC_KEY_FALSE(riscv_ipi_for_rfence); +EXPORT_SYMBOL_GPL(riscv_ipi_for_rfence); + +void riscv_ipi_set_virq_range(int virq, int nr, bool use_for_rfence) { int i, err; @@ -200,6 +203,12 @@ void riscv_ipi_set_virq_range(int virq, int nr) /* Enabled IPIs for boot CPU immediately */ riscv_ipi_enable(); + + /* Update RFENCE static key */ + if (use_for_rfence) + static_branch_enable(&riscv_ipi_for_rfence); + else + static_branch_disable(&riscv_ipi_for_rfence); } static const char * const ipi_names[] = { diff --git a/drivers/clocksource/timer-clint.c b/drivers/clocksource/timer-clint.c index 7ccc16dd6a76..9a55e733ae99 100644 --- a/drivers/clocksource/timer-clint.c +++ b/drivers/clocksource/timer-clint.c @@ -251,7 +251,7 @@ static int __init clint_timer_init_dt(struct device_node *np) } irq_set_chained_handler(clint_ipi_irq, clint_ipi_interrupt); - riscv_ipi_set_virq_range(rc, BITS_PER_BYTE); + riscv_ipi_set_virq_range(rc, BITS_PER_BYTE, true); clint_clear_ipi(); #endif -- 2.20.1