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-rw-r--r--Documentation/admin-guide/kernel-parameters.txt7
-rw-r--r--drivers/irqchip/irq-riscv-imsic-early.c20
-rw-r--r--drivers/irqchip/irq-riscv-imsic-state.c7
-rw-r--r--drivers/irqchip/irq-riscv-imsic-state.h1
4 files changed, 31 insertions, 4 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index f1f2c0874da9..7f0e12d0d260 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -2538,6 +2538,13 @@
requires the kernel to be built with
CONFIG_ARM64_PSEUDO_NMI.
+ irqchip.riscv_imsic_noipi
+ [RISC-V,EARLY]
+ Force the kernel to not use IMSIC software injected MSIs
+ as IPIs. Intended for system where IMSIC is trap-n-emulated,
+ and thus want to reduce MMIO traps when triggering IPIs
+ to multiple harts.
+
irqfixup [HW]
When an interrupt is not handled search all handlers
for it. Intended to get systems with badly broken
diff --git a/drivers/irqchip/irq-riscv-imsic-early.c b/drivers/irqchip/irq-riscv-imsic-early.c
index d9ae87808651..2709cacf4855 100644
--- a/drivers/irqchip/irq-riscv-imsic-early.c
+++ b/drivers/irqchip/irq-riscv-imsic-early.c
@@ -8,6 +8,7 @@
#include <linux/acpi.h>
#include <linux/cpu.h>
#include <linux/interrupt.h>
+#include <linux/init.h>
#include <linux/io.h>
#include <linux/irq.h>
#include <linux/irqchip.h>
@@ -21,6 +22,14 @@
#include "irq-riscv-imsic-state.h"
static int imsic_parent_irq;
+bool imsic_noipi __ro_after_init;
+
+static int __init imsic_noipi_cfg(char *buf)
+{
+ imsic_noipi = true;
+ return 0;
+}
+early_param("irqchip.riscv_imsic_noipi", imsic_noipi_cfg);
#ifdef CONFIG_SMP
static void imsic_ipi_send(unsigned int cpu)
@@ -32,12 +41,18 @@ static void imsic_ipi_send(unsigned int cpu)
static void imsic_ipi_starting_cpu(void)
{
+ if (imsic_noipi)
+ return;
+
/* Enable IPIs for current CPU. */
__imsic_id_set_enable(IMSIC_IPI_ID);
}
static void imsic_ipi_dying_cpu(void)
{
+ if (imsic_noipi)
+ return;
+
/* Disable IPIs for current CPU. */
__imsic_id_clear_enable(IMSIC_IPI_ID);
}
@@ -46,6 +61,9 @@ static int __init imsic_ipi_domain_init(void)
{
int virq;
+ if (imsic_noipi)
+ return 0;
+
/* Create IMSIC IPI multiplexing */
virq = ipi_mux_create(IMSIC_NR_IPI, imsic_ipi_send);
if (virq <= 0)
@@ -88,7 +106,7 @@ static void imsic_handle_irq(struct irq_desc *desc)
while ((local_id = csr_swap(CSR_TOPEI, 0))) {
local_id >>= TOPEI_ID_SHIFT;
- if (local_id == IMSIC_IPI_ID) {
+ if (!imsic_noipi && local_id == IMSIC_IPI_ID) {
if (IS_ENABLED(CONFIG_SMP))
ipi_mux_process();
continue;
diff --git a/drivers/irqchip/irq-riscv-imsic-state.c b/drivers/irqchip/irq-riscv-imsic-state.c
index 77670dd645ac..dc95ad856d80 100644
--- a/drivers/irqchip/irq-riscv-imsic-state.c
+++ b/drivers/irqchip/irq-riscv-imsic-state.c
@@ -134,7 +134,7 @@ static bool __imsic_local_sync(struct imsic_local_priv *lpriv)
lockdep_assert_held(&lpriv->lock);
for_each_set_bit(i, lpriv->dirty_bitmap, imsic->global.nr_ids + 1) {
- if (!i || i == IMSIC_IPI_ID)
+ if (!i || (!imsic_noipi && i == IMSIC_IPI_ID))
goto skip;
vec = &lpriv->vectors[i];
@@ -419,7 +419,7 @@ void imsic_vector_debug_show(struct seq_file *m, struct imsic_vector *vec, int i
seq_printf(m, "%*starget_cpu : %5u\n", ind, "", vec->cpu);
seq_printf(m, "%*starget_local_id : %5u\n", ind, "", vec->local_id);
seq_printf(m, "%*sis_reserved : %5u\n", ind, "",
- (vec->local_id <= IMSIC_IPI_ID) ? 1 : 0);
+ (!imsic_noipi && vec->local_id <= IMSIC_IPI_ID) ? 1 : 0);
seq_printf(m, "%*sis_enabled : %5u\n", ind, "", is_enabled ? 1 : 0);
seq_printf(m, "%*sis_move_pending : %5u\n", ind, "", mvec ? 1 : 0);
if (mvec) {
@@ -583,7 +583,8 @@ static int __init imsic_matrix_init(void)
irq_matrix_assign_system(imsic->matrix, 0, false);
/* Reserve IPI ID because it is special and used internally */
- irq_matrix_assign_system(imsic->matrix, IMSIC_IPI_ID, false);
+ if (!imsic_noipi)
+ irq_matrix_assign_system(imsic->matrix, IMSIC_IPI_ID, false);
return 0;
}
diff --git a/drivers/irqchip/irq-riscv-imsic-state.h b/drivers/irqchip/irq-riscv-imsic-state.h
index 3202ffa4e849..57f951952b0c 100644
--- a/drivers/irqchip/irq-riscv-imsic-state.h
+++ b/drivers/irqchip/irq-riscv-imsic-state.h
@@ -61,6 +61,7 @@ struct imsic_priv {
struct irq_domain *base_domain;
};
+extern bool imsic_noipi;
extern struct imsic_priv *imsic;
void __imsic_eix_update(unsigned long base_id, unsigned long num_id, bool pend, bool val);