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([171.76.86.115]) by smtp.gmail.com with ESMTPSA id 4-20020a620504000000b00537b1aa9191sm4166738pff.178.2022.09.03.09.13.43 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 03 Sep 2022 09:13:47 -0700 (PDT) From: Anup Patel To: Palmer Dabbelt , Paul Walmsley , Thomas Gleixner , Marc Zyngier , Daniel Lezcano Cc: Atish Patra , Alistair Francis , Anup Patel , linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, Anup Patel Subject: [PATCH v9 5/7] RISC-V: Allow marking IPIs as suitable for remote FENCEs Date: Sat, 3 Sep 2022 21:43:07 +0530 Message-Id: <20220903161309.32848-6-apatel@ventanamicro.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220903161309.32848-1-apatel@ventanamicro.com> References: <20220903161309.32848-1-apatel@ventanamicro.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" 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 --- 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 79ed0b73cd4e..56976e41a21e 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; =20 #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); =20 /* 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) =20 /* Secondary hart entry */ asmlinkage void smp_callin(void); @@ -93,10 +101,16 @@ static inline bool riscv_ipi_have_virq_range(void) return false; } =20 -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) { } =20 +static inline bool riscv_use_ipi_for_rfence(void) +{ + return false; +} + #endif /* CONFIG_SMP */ =20 #if defined(CONFIG_HOTPLUG_CPU) && (CONFIG_SMP) diff --git a/arch/riscv/kernel/sbi-ipi.c b/arch/riscv/kernel/sbi-ipi.c index 0bb070a5dcb4..27fdc394d2f0 100644 --- a/arch/riscv/kernel/sbi-ipi.c +++ b/arch/riscv/kernel/sbi-ipi.c @@ -55,6 +55,6 @@ void __init sbi_ipi_init(void) return; } =20 - 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 e8a20454d65b..74b8cb1a89ab 100644 --- a/arch/riscv/kernel/smp.c +++ b/arch/riscv/kernel/smp.c @@ -145,7 +145,10 @@ bool riscv_ipi_have_virq_range(void) return (ipi_virq_base) ? true : false; } =20 -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; =20 @@ -168,6 +171,12 @@ void riscv_ipi_set_virq_range(int virq, int nr) =20 /* 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); } EXPORT_SYMBOL_GPL(riscv_ipi_set_virq_range); =20 diff --git a/drivers/clocksource/timer-clint.c b/drivers/clocksource/timer-= clint.c index ac7c2caaa65a..f418816fd706 100644 --- a/drivers/clocksource/timer-clint.c +++ b/drivers/clocksource/timer-clint.c @@ -246,7 +246,7 @@ static int __init clint_timer_init_dt(struct device_nod= e *np) goto fail_remove_cpuhp; } =20 - riscv_ipi_set_virq_range(virq, BITS_PER_BYTE); + riscv_ipi_set_virq_range(virq, BITS_PER_BYTE, true); clint_clear_ipi(clint_ipi_irq, NULL); =20 return 0; --=20 2.34.1