Re: [PATCH 08/10] irqchip/gic-v3-its: Decouple its initialization from gic

From: Julien Thierry
Date: Thu Nov 08 2018 - 06:26:08 EST



On 07/11/18 22:03, Robert Richter wrote:
This patch separates its initialization from the gic. Probing and
initialization of its nodes is separate now. There is an own cpu
notifier for its now.

Signed-off-by: Robert Richter <rrichter@xxxxxxxxxx>
---
drivers/irqchip/irq-gic-v3-its.c | 58 +++++++++++++++++++++++++-------------
drivers/irqchip/irq-gic-v3.c | 14 ++++-----
include/linux/cpuhotplug.h | 1 +
include/linux/irqchip/arm-gic-v3.h | 2 +-
4 files changed, 48 insertions(+), 27 deletions(-)

diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index c28f4158ff70..fd8561fcfdf3 100644
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -167,6 +167,7 @@ static struct {
} vpe_proxy;
static LIST_HEAD(its_nodes);
+static LIST_HEAD(its_probed);
static DEFINE_RAW_SPINLOCK(its_lock);
static struct rdists *gic_rdists;
static struct irq_domain *its_parent;
@@ -3482,20 +3483,13 @@ static int __init its_compute_its_list_map(struct its_node *its)
static void its_free(struct its_node *its)
{
- raw_spin_lock(&its_lock);
- list_del(&its->entry);
- raw_spin_unlock(&its_lock);
-
kfree(its);
}
-static int __init its_init_one(struct its_node *its);
-
static int __init its_probe_one(struct resource *res,
struct fwnode_handle *handle, int numa_node)
{
struct its_node *its;
- int err;
its = kzalloc(sizeof(*its), GFP_KERNEL);
if (!its)
@@ -3510,16 +3504,12 @@ static int __init its_probe_one(struct resource *res,
its->numa_node = numa_node;
raw_spin_lock(&its_lock);
- list_add_tail(&its->entry, &its_nodes);
+ list_add_tail(&its->entry, &its_probed);
raw_spin_unlock(&its_lock);
pr_info("ITS %pR\n", res);
- err = its_init_one(its);
- if (err)
- its_free(its);
-
- return err;
+ return 0;
}
static int __init its_init_one(struct its_node *its)
@@ -3717,7 +3707,7 @@ static int redist_disable_lpis(void)
return 0;
}
-int its_cpu_init(void)
+static int its_cpu_init(unsigned int cpu)
{
if (!list_empty(&its_nodes)) {
int ret;
@@ -3913,8 +3903,6 @@ static void __init its_acpi_probe(void)
static void __init its_acpi_probe(void) { }
#endif
-static int __init its_init(void);
-
int __init its_probe(struct fwnode_handle *handle, struct rdists *rdists,
struct irq_domain *parent_domain)
{
@@ -3929,23 +3917,51 @@ int __init its_probe(struct fwnode_handle *handle, struct rdists *rdists,
gic_rdists = rdists;
- return its_init();
+ return 0;
}
-static int __init its_init(void)
+int __init its_init(void)
{
struct its_node *its;
bool has_v4 = false;
int err;
+ if (list_empty(&its_probed))
+ return 0;
+
+ raw_spin_lock(&its_lock);
+redo:
+ list_for_each_entry(its, &its_probed, entry) {
+ list_del_init(&its->entry);
+
+ raw_spin_unlock(&its_lock);
+
+ /* Needs to be called in non-atomic context */
+ err = its_init_one(its);
+ if (err)
+ its_free(its);
+
+ raw_spin_lock(&its_lock);
+
+ if (!err)
+ list_add_tail(&its->entry, &its_nodes);
+
+ goto redo;

Again, you're starting a loop only to work on the first element and then restarting the loop.

Just do a while (!list_empty()), and without gotos...

+ }
+
+ raw_spin_unlock(&its_lock);
+
if (list_empty(&its_nodes)) {
pr_warn("ITS: No ITS available, not enabling LPIs\n");
return -ENXIO;
}
err = allocate_lpi_tables();
- if (err)
+ if (err) {
+ pr_warn("ITS: Failed to initialize (%d), not enabling LPIs\n",
+ err);
return err;
+ }
list_for_each_entry(its, &its_nodes, entry)
has_v4 |= its->is_v4;
@@ -3960,5 +3976,9 @@ static int __init its_init(void)
register_syscore_ops(&its_syscore_ops);
+ cpuhp_setup_state(CPUHP_AP_IRQ_GIC_ITS_STARTING,
+ "irqchip/arm/gicv3-its:starting",
+ its_cpu_init, NULL);
+
return 0;
}
diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c
index e04108b7c6b7..d2942efdb6d5 100644
--- a/drivers/irqchip/irq-gic-v3.c
+++ b/drivers/irqchip/irq-gic-v3.c
@@ -685,9 +685,6 @@ static int gic_starting_cpu(unsigned int cpu)
{
gic_cpu_init();
- if (gic_dist_supports_lpis())
- its_cpu_init();
-
return 0;
}
@@ -815,7 +812,7 @@ static int gic_set_affinity(struct irq_data *d, const struct cpumask *mask_val,
#else
#define gic_set_affinity NULL
#define gic_smp_init() do { } while(0)
-#endif
+#endif /* CONFIG_SMP */
#ifdef CONFIG_CPU_PM
/* Check whether it's single security state view */
@@ -1131,10 +1128,8 @@ static int __init gic_init_bases(void __iomem *dist_base,
gic_cpu_init();
gic_cpu_pm_init();
- if (gic_dist_supports_lpis()) {
+ if (gic_dist_supports_lpis())
its_probe(handle, &gic_data.rdists, gic_data.domain);
- its_cpu_init();
- }
return 0;
@@ -1327,6 +1322,9 @@ static int __init gic_of_init(struct device_node *node, struct device_node *pare
if (static_branch_likely(&supports_deactivate_key))
gic_of_setup_kvm_info(node);
+
+ its_init();
+
return 0;
out_unmap_rdist:
@@ -1630,6 +1628,8 @@ gic_acpi_init(struct acpi_subtable_header *header, const unsigned long end)
if (static_branch_likely(&supports_deactivate_key))
gic_acpi_setup_kvm_info();
+ its_init();
+
return 0;
out_fwhandle_free:
diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
index e0cd2baa8380..584f73585142 100644
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -96,6 +96,7 @@ enum cpuhp_state {
CPUHP_AP_SCHED_STARTING,
CPUHP_AP_RCUTREE_DYING,
CPUHP_AP_IRQ_GIC_STARTING,
+ CPUHP_AP_IRQ_GIC_ITS_STARTING,
CPUHP_AP_IRQ_HIP04_STARTING,
CPUHP_AP_IRQ_ARMADA_XP_STARTING,
CPUHP_AP_IRQ_BCM2836_STARTING,
diff --git a/include/linux/irqchip/arm-gic-v3.h b/include/linux/irqchip/arm-gic-v3.h
index a6fdb2910f73..f4348fa4260a 100644
--- a/include/linux/irqchip/arm-gic-v3.h
+++ b/include/linux/irqchip/arm-gic-v3.h
@@ -602,9 +602,9 @@ struct rdists {
struct irq_domain;
struct fwnode_handle;
-int its_cpu_init(void);
int its_probe(struct fwnode_handle *handle, struct rdists *rdists,
struct irq_domain *domain);
+int its_init(void);
int mbi_init(struct fwnode_handle *fwnode, struct irq_domain *parent);
static inline bool gic_enable_sre(void)


--
Julien Thierry