On Fri, 24 Jul 2020 00:18:19 PDT (-0700), Anup Patel wrote:
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@xxxxxxx>
Tested-by: Emil Renner Berhing <kernel@xxxxxxxx>
Reviewed-by: Atish Patra <atish.patra@xxxxxxx>
---
arch/riscv/include/asm/clint.h | 25 --------------------
arch/riscv/include/asm/smp.h | 19 +++++++++++++++
arch/riscv/kernel/clint.c | 23 ++++++++++++++++--
arch/riscv/kernel/sbi.c | 14 +++++++++++
arch/riscv/kernel/smp.c | 43 +++++++++++++++++++---------------
arch/riscv/kernel/smpboot.c | 3 +--
6 files changed, 79 insertions(+), 48 deletions(-)
diff --git a/arch/riscv/include/asm/clint.h b/arch/riscv/include/asm/clint.h
index a279b17a6aad..adaba98a7d6c 100644
--- a/arch/riscv/include/asm/clint.h
+++ b/arch/riscv/include/asm/clint.h
@@ -6,34 +6,9 @@
#include <linux/smp.h>
#ifdef CONFIG_RISCV_M_MODE
-extern u32 __iomem *clint_ipi_base;
-
void clint_init_boot_cpu(void);
-
-static inline void clint_send_ipi_single(unsigned long hartid)
-{
- writel(1, clint_ipi_base + hartid);
-}
-
-static inline void clint_send_ipi_mask(const struct cpumask *mask)
-{
- int cpu;
-
- for_each_cpu(cpu, mask)
- clint_send_ipi_single(cpuid_to_hartid_map(cpu));
-}
-
-static inline void clint_clear_ipi(unsigned long hartid)
-{
- writel(0, clint_ipi_base + hartid);
-}
#else /* CONFIG_RISCV_M_MODE */
#define clint_init_boot_cpu() do { } while (0)
-
-/* stubs to for code is only reachable under IS_ENABLED(CONFIG_RISCV_M_MODE): */
-void clint_send_ipi_single(unsigned long hartid);
-void clint_send_ipi_mask(const struct cpumask *hartid_mask);
-void clint_clear_ipi(unsigned long hartid);
#endif /* CONFIG_RISCV_M_MODE */
#endif /* _ASM_RISCV_CLINT_H */
So this is entirely unrelated to the actual contents of this patch, I'd just
forgotten about it before: the scheme used by clint_init_boot_cpu() only works
once per system reset (and as far as I can tell, that code only works for
two-CPU systems). Not really an issue with this patch set, but we should
probably put a sanity check in the code -- the two-CPU thing should be easy,
but the "only use the CLINT init trick once" thing need some sort of platform
interface.
diff --git a/arch/riscv/include/asm/smp.h b/arch/riscv/include/asm/smp.h
index 40bb1c15a731..68de78a8eba6 100644
--- a/arch/riscv/include/asm/smp.h
+++ b/arch/riscv/include/asm/smp.h
@@ -15,6 +15,11 @@
struct seq_file;
extern unsigned long boot_cpu_hartid;
+struct riscv_ipi_ops {
+ void (*ipi_inject)(const struct cpumask *target);
+ void (*ipi_clear)(void);
+};
+
#ifdef CONFIG_SMP
/*
* Mapping between linux logical cpu index and hartid.
@@ -40,6 +45,12 @@ 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);
+/* 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.
@@ -78,6 +89,14 @@ static inline void riscv_cpuid_to_hartid_mask(const struct cpumask *in,
cpumask_set_cpu(boot_cpu_hartid, out);
}
+static inline void riscv_set_ipi_ops(struct riscv_ipi_ops *ops)
+{
+}
It's a bit pedantic, but it seems like this should do something as of this
patch -- even though there's only a single driver, it's odd to have this both
exist and do nothing.
+
+static inline void riscv_clear_ipi(void)
+{
+}
+
#endif /* CONFIG_SMP */
#if defined(CONFIG_HOTPLUG_CPU) && (CONFIG_SMP)
diff --git a/arch/riscv/kernel/clint.c b/arch/riscv/kernel/clint.c
index 3647980d14c3..a9845ee023e2 100644
--- a/arch/riscv/kernel/clint.c
+++ b/arch/riscv/kernel/clint.c
@@ -5,11 +5,11 @@
#include <linux/io.h>
#include <linux/of_address.h>
+#include <linux/smp.h>
#include <linux/types.h>
#include <asm/clint.h>
#include <asm/csr.h>
#include <asm/timex.h>
-#include <asm/smp.h>
/*
* This is the layout used by the SiFive clint, which is also shared by the qemu
@@ -21,6 +21,24 @@
u32 __iomem *clint_ipi_base;
+static void clint_send_ipi(const struct cpumask *target)
+{
+ unsigned int cpu;
+
+ for_each_cpu(cpu, target)
+ writel(1, clint_ipi_base + cpuid_to_hartid_map(cpu));
+}
+
+static void clint_clear_ipi(void)
+{
+ writel(0, clint_ipi_base + cpuid_to_hartid_map(smp_processor_id()));
+}
+
+static struct riscv_ipi_ops clint_ipi_ops = {
+ .ipi_inject = clint_send_ipi,
+ .ipi_clear = clint_clear_ipi,
+};
+
void clint_init_boot_cpu(void)
{
struct device_node *np;
@@ -40,5 +58,6 @@ void clint_init_boot_cpu(void)
riscv_time_cmp = base + CLINT_TIME_CMP_OFF;
riscv_time_val = base + CLINT_TIME_VAL_OFF;
- clint_clear_ipi(boot_cpu_hartid);
+ clint_clear_ipi();
+ riscv_set_ipi_ops(&clint_ipi_ops);
}
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);
I don't really care that much, though, so:
Reviewed-by: Palmer Dabbelt <palmerdabbelt@xxxxxxxxxx>
