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Subject[PATCH v2 1/5] RISC-V: Add mechanism to provide custom IPI operations
Date
We add mechanism to set custom IPI operations so that CLINT driver
from drivers directory can provide custom IPI operations.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
---
arch/riscv/include/asm/smp.h | 11 +++++++++
arch/riscv/kernel/sbi.c | 14 ++++++++++++
arch/riscv/kernel/smp.c | 43 ++++++++++++++++++++----------------
arch/riscv/kernel/smpboot.c | 3 +--
4 files changed, 50 insertions(+), 21 deletions(-)

diff --git a/arch/riscv/include/asm/smp.h b/arch/riscv/include/asm/smp.h
index 40bb1c15a731..c6acd44767c1 100644
--- a/arch/riscv/include/asm/smp.h
+++ b/arch/riscv/include/asm/smp.h
@@ -40,6 +40,17 @@ void arch_send_call_function_single_ipi(int cpu);
int riscv_hartid_to_cpuid(int hartid);
void riscv_cpuid_to_hartid_mask(const struct cpumask *in, struct cpumask *out);

+struct riscv_ipi_ops {
+ void (*ipi_inject)(const struct cpumask *target);
+ void (*ipi_clear)(void);
+};
+
+/* Set custom IPI operations */
+void riscv_set_ipi_ops(struct riscv_ipi_ops *ops);
+
+/* Clear IPI for current CPU */
+void riscv_clear_ipi(void);
+
/*
* Obtains the hart ID of the currently executing task. This relies on
* THREAD_INFO_IN_TASK, but we define that unconditionally.
diff --git a/arch/riscv/kernel/sbi.c b/arch/riscv/kernel/sbi.c
index f383ef5672b2..226ccce0f9e0 100644
--- a/arch/riscv/kernel/sbi.c
+++ b/arch/riscv/kernel/sbi.c
@@ -547,6 +547,18 @@ static inline long sbi_get_firmware_version(void)
return __sbi_base_ecall(SBI_EXT_BASE_GET_IMP_VERSION);
}

+static void sbi_send_cpumask_ipi(const struct cpumask *target)
+{
+ struct cpumask hartid_mask;
+
+ riscv_cpuid_to_hartid_mask(target, &hartid_mask);
+
+ sbi_send_ipi(cpumask_bits(&hartid_mask));
+}
+
+static struct riscv_ipi_ops sbi_ipi_ops = {
+ .ipi_inject = sbi_send_cpumask_ipi
+};

int __init sbi_init(void)
{
@@ -587,5 +599,7 @@ int __init sbi_init(void)
__sbi_rfence = __sbi_rfence_v01;
}

+ riscv_set_ipi_ops(&sbi_ipi_ops);
+
return 0;
}
diff --git a/arch/riscv/kernel/smp.c b/arch/riscv/kernel/smp.c
index b1d4f452f843..8b85683ce203 100644
--- a/arch/riscv/kernel/smp.c
+++ b/arch/riscv/kernel/smp.c
@@ -84,9 +84,25 @@ static void ipi_stop(void)
wait_for_interrupt();
}

+static struct riscv_ipi_ops *ipi_ops;
+
+void riscv_set_ipi_ops(struct riscv_ipi_ops *ops)
+{
+ ipi_ops = ops;
+}
+EXPORT_SYMBOL_GPL(riscv_set_ipi_ops);
+
+void riscv_clear_ipi(void)
+{
+ if (ipi_ops && ipi_ops->ipi_clear)
+ ipi_ops->ipi_clear();
+
+ csr_clear(CSR_IP, IE_SIE);
+}
+EXPORT_SYMBOL_GPL(riscv_clear_ipi);
+
static void send_ipi_mask(const struct cpumask *mask, enum ipi_message_type op)
{
- struct cpumask hartid_mask;
int cpu;

smp_mb__before_atomic();
@@ -94,33 +110,22 @@ static void send_ipi_mask(const struct cpumask *mask, enum ipi_message_type op)
set_bit(op, &ipi_data[cpu].bits);
smp_mb__after_atomic();

- riscv_cpuid_to_hartid_mask(mask, &hartid_mask);
- if (IS_ENABLED(CONFIG_RISCV_SBI))
- sbi_send_ipi(cpumask_bits(&hartid_mask));
+ if (ipi_ops && ipi_ops->ipi_inject)
+ ipi_ops->ipi_inject(mask);
else
- clint_send_ipi_mask(mask);
+ pr_warn("SMP: IPI inject method not available\n");
}

static void send_ipi_single(int cpu, enum ipi_message_type op)
{
- int hartid = cpuid_to_hartid_map(cpu);
-
smp_mb__before_atomic();
set_bit(op, &ipi_data[cpu].bits);
smp_mb__after_atomic();

- if (IS_ENABLED(CONFIG_RISCV_SBI))
- sbi_send_ipi(cpumask_bits(cpumask_of(hartid)));
- else
- clint_send_ipi_single(hartid);
-}
-
-static inline void clear_ipi(void)
-{
- if (IS_ENABLED(CONFIG_RISCV_SBI))
- csr_clear(CSR_IP, IE_SIE);
+ if (ipi_ops && ipi_ops->ipi_inject)
+ ipi_ops->ipi_inject(cpumask_of(cpu));
else
- clint_clear_ipi(cpuid_to_hartid_map(smp_processor_id()));
+ pr_warn("SMP: IPI inject method not available\n");
}

void handle_IPI(struct pt_regs *regs)
@@ -131,7 +136,7 @@ void handle_IPI(struct pt_regs *regs)

irq_enter();

- clear_ipi();
+ riscv_clear_ipi();

while (true) {
unsigned long ops;
diff --git a/arch/riscv/kernel/smpboot.c b/arch/riscv/kernel/smpboot.c
index 4e9922790f6e..5fe849791bf0 100644
--- a/arch/riscv/kernel/smpboot.c
+++ b/arch/riscv/kernel/smpboot.c
@@ -147,8 +147,7 @@ asmlinkage __visible void smp_callin(void)
{
struct mm_struct *mm = &init_mm;

- if (!IS_ENABLED(CONFIG_RISCV_SBI))
- clint_clear_ipi(cpuid_to_hartid_map(smp_processor_id()));
+ riscv_clear_ipi();

/* All kernel threads share the same mm context. */
mmgrab(mm);
--
2.25.1
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