We extend struct riscv_ipi_ops so that the IPI providers (such as
SBI, CLINT driver, ACLINT SWI driver etc) can specify:
1) Name of the IPI operations
2) Whether IPIs are suitable for doing remote FENCEs
Signed-off-by: Anup Patel <[email protected]>
---
arch/riscv/include/asm/smp.h | 15 +++++++++++++++
arch/riscv/kernel/sbi.c | 2 ++
arch/riscv/kernel/smp.c | 25 ++++++++++++++++++++++++-
arch/riscv/mm/cacheflush.c | 2 +-
drivers/clocksource/timer-clint.c | 2 ++
5 files changed, 44 insertions(+), 2 deletions(-)
diff --git a/arch/riscv/include/asm/smp.h b/arch/riscv/include/asm/smp.h
index a7d2811f3536..4c4f0dde1164 100644
--- a/arch/riscv/include/asm/smp.h
+++ b/arch/riscv/include/asm/smp.h
@@ -16,11 +16,16 @@ struct seq_file;
extern unsigned long boot_cpu_hartid;
struct riscv_ipi_ops {
+ const char *name;
+ bool use_for_rfence;
void (*ipi_inject)(const struct cpumask *target);
void (*ipi_clear)(void);
};
#ifdef CONFIG_SMP
+
+#include <linux/jump_label.h>
+
/*
* Mapping between linux logical cpu index and hartid.
*/
@@ -45,6 +50,11 @@ 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);
+/* Check if we can use IPIs for remote FENCE */
+extern struct static_key_false riscv_ipi_for_rfence;
+#define riscv_use_ipi_for_rfence() \
+ static_branch_unlikely(&riscv_ipi_for_rfence)
+
/* Set custom IPI operations */
void riscv_set_ipi_ops(const struct riscv_ipi_ops *ops);
@@ -92,6 +102,11 @@ static inline void riscv_cpuid_to_hartid_mask(const struct cpumask *in,
cpumask_set_cpu(boot_cpu_hartid, out);
}
+static inline bool riscv_use_ipi_for_rfence(void)
+{
+ return false;
+}
+
static inline void riscv_set_ipi_ops(const struct riscv_ipi_ops *ops)
{
}
diff --git a/arch/riscv/kernel/sbi.c b/arch/riscv/kernel/sbi.c
index 8aeca26198f2..be2b7a89ce49 100644
--- a/arch/riscv/kernel/sbi.c
+++ b/arch/riscv/kernel/sbi.c
@@ -604,6 +604,8 @@ static void sbi_ipi_clear(void)
}
static const struct riscv_ipi_ops sbi_ipi_ops = {
+ .name = "SBI",
+ .use_for_rfence = false,
.ipi_inject = sbi_send_cpumask_ipi,
.ipi_clear = sbi_ipi_clear
};
diff --git a/arch/riscv/kernel/smp.c b/arch/riscv/kernel/smp.c
index eea0c9d11d9f..cffe3247b132 100644
--- a/arch/riscv/kernel/smp.c
+++ b/arch/riscv/kernel/smp.c
@@ -90,9 +90,32 @@ static void ipi_stop(void)
static const struct riscv_ipi_ops *ipi_ops __ro_after_init;
+DEFINE_STATIC_KEY_FALSE(riscv_ipi_for_rfence);
+EXPORT_SYMBOL_GPL(riscv_ipi_for_rfence);
+
void riscv_set_ipi_ops(const struct riscv_ipi_ops *ops)
{
- ipi_ops = ops;
+ bool updated = true;
+
+ if (!ops)
+ return;
+
+ if (!ipi_ops) {
+ ipi_ops = ops;
+ } else {
+ if (!ipi_ops->use_for_rfence && ops->use_for_rfence)
+ ipi_ops = ops;
+ else
+ updated = false;
+ }
+
+ if (updated) {
+ if (ipi_ops->use_for_rfence)
+ static_branch_enable(&riscv_ipi_for_rfence);
+ else
+ static_branch_disable(&riscv_ipi_for_rfence);
+ pr_info("switched IPI operations to %s\n", ipi_ops->name);
+ }
}
EXPORT_SYMBOL_GPL(riscv_set_ipi_ops);
diff --git a/arch/riscv/mm/cacheflush.c b/arch/riscv/mm/cacheflush.c
index 094118663285..0ffe7d560dc8 100644
--- a/arch/riscv/mm/cacheflush.c
+++ b/arch/riscv/mm/cacheflush.c
@@ -16,7 +16,7 @@ static void ipi_remote_fence_i(void *info)
void flush_icache_all(void)
{
- if (IS_ENABLED(CONFIG_RISCV_SBI))
+ if (!riscv_use_ipi_for_rfence())
sbi_remote_fence_i(NULL);
else
on_each_cpu(ipi_remote_fence_i, NULL, 1);
diff --git a/drivers/clocksource/timer-clint.c b/drivers/clocksource/timer-clint.c
index 6cfe2ab73eb0..dfdcd94c1fd5 100644
--- a/drivers/clocksource/timer-clint.c
+++ b/drivers/clocksource/timer-clint.c
@@ -55,6 +55,8 @@ static void clint_clear_ipi(void)
}
static struct riscv_ipi_ops clint_ipi_ops = {
+ .name = "CLINT",
+ .use_for_rfence = true,
.ipi_inject = clint_send_ipi,
.ipi_clear = clint_clear_ipi,
};
--
2.25.1