irqchip/gic-v5: Move LPI allocation into the LPI domain

commit dec85d2fbd20de3711a71e65397dfdb40c3fa953 upstream.

The IPI and ITS MSI domains currently allocate and release LPIs
directly, then pass the selected LPI ID to the parent LPI domain. This
leaks the LPI domain's allocation policy into its child domains and
forces each child to duplicate part of the parent domain's teardown.

Make the LPI domain allocate LPIs in its .alloc() callback and release
them in a matching .free() callback. Child domains can then request a
parent interrupt without passing an implementation-specific LPI ID,
and the LPI lifetime is tied to the domain that owns the LPI
namespace.

Remove the gicv5_alloc_lpi() and gicv5_free_lpi() wrappers now that no
external caller needs to manage LPIs directly.

This is a preparatory change for an actual leakage problem in the
allocation code and therefore tagged with the same Fixes tag.

Fixes: 0f0101325876 ("irqchip/gic-v5: Add GICv5 LPI/IPI support")
Signed-off-by: Sascha Bischoff <sascha.bischoff@arm.com>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260506093634.382062-2-sascha.bischoff@arm.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/irqchip/irq-gic-v5-its.c b/drivers/irqchip/irq-gic-v5-its.c
index 8e22134b9f48676573f6ab61b55fbc2cd6242157..e21235b5079be00b86c226a32cfdcb890eb9a939 100644 (file)
--- a/drivers/irqchip/irq-gic-v5-its.c
+++ b/drivers/irqchip/irq-gic-v5-its.c
@@ -927,8 +927,8 @@ static void gicv5_its_free_eventid(struct gicv5_its_dev *its_dev, u32 event_id_b
 static int gicv5_its_irq_domain_alloc(struct irq_domain *domain, unsigned int virq,
                                      unsigned int nr_irqs, void *arg)
 {
-       u32 device_id, event_id_base, lpi;
        struct gicv5_its_dev *its_dev;
+       u32 device_id, event_id_base;
        msi_alloc_info_t *info = arg;
        irq_hw_number_t hwirq;
        struct irq_data *irqd;
@@ -947,16 +947,8 @@ static int gicv5_its_irq_domain_alloc(struct irq_domain *domain, unsigned int vi
        device_id = its_dev->device_id;
 
        for (i = 0; i < nr_irqs; i++) {
-               ret = gicv5_alloc_lpi();
-               if (ret < 0) {
-                       pr_debug("Failed to find free LPI!\n");
-                       goto out_free_irqs;
-               }
-               lpi = ret;
-
-               ret = irq_domain_alloc_irqs_parent(domain, virq + i, 1, &lpi);
+               ret = irq_domain_alloc_irqs_parent(domain, virq + i, 1, NULL);
                if (ret) {
-                       gicv5_free_lpi(lpi);
                        goto out_free_irqs;
                }
 
@@ -981,7 +973,6 @@ static int gicv5_its_irq_domain_alloc(struct irq_domain *domain, unsigned int vi
 out_free_irqs:
        while (--i >= 0) {
                irqd = irq_domain_get_irq_data(domain, virq + i);
-               gicv5_free_lpi(irqd->parent_data->hwirq);
                irq_domain_reset_irq_data(irqd);
                irq_domain_free_irqs_parent(domain, virq + i, 1);
        }
@@ -1011,7 +1002,6 @@ static void gicv5_its_irq_domain_free(struct irq_domain *domain, unsigned int vi
        for (i = 0; i < nr_irqs; i++) {
                d = irq_domain_get_irq_data(domain, virq + i);
 
-               gicv5_free_lpi(d->parent_data->hwirq);
                irq_domain_reset_irq_data(d);
                irq_domain_free_irqs_parent(domain, virq + i, 1);
        }

diff --git a/drivers/irqchip/irq-gic-v5.c b/drivers/irqchip/irq-gic-v5.c
index 41ef286c4d78122b7a2130d7f00f6c2c782216cc..3e7c329b68fe391ec2d39e7a76c17371c3670f08 100644 (file)
--- a/drivers/irqchip/irq-gic-v5.c
+++ b/drivers/irqchip/irq-gic-v5.c
@@ -58,16 +58,6 @@ static void release_lpi(u32 lpi)
        ida_free(&lpi_ida, lpi);
 }
 
-int gicv5_alloc_lpi(void)
-{
-       return alloc_lpi();
-}
-
-void gicv5_free_lpi(u32 lpi)
-{
-       release_lpi(lpi);
-}
-
 static void gicv5_ppi_priority_init(void)
 {
        write_sysreg_s(REPEAT_BYTE(GICV5_IRQ_PRI_MI), SYS_ICC_PPI_PRIORITYR0_EL1);
@@ -751,18 +741,36 @@ static void gicv5_lpi_config_reset(struct irq_data *d)
        gicv5_lpi_irq_write_pending_state(d, false);
 }
 
+static void gicv5_irq_lpi_domain_free(struct irq_domain *domain, unsigned int virq,
+                                     unsigned int nr_irqs)
+{
+       struct irq_data *d;
+
+       if (WARN_ON_ONCE(nr_irqs != 1))
+               return;
+
+       d = irq_domain_get_irq_data(domain, virq);
+
+       release_lpi(d->hwirq);
+
+       irq_set_handler(virq, NULL);
+       irq_domain_reset_irq_data(d);
+}
+
 static int gicv5_irq_lpi_domain_alloc(struct irq_domain *domain, unsigned int virq,
                                      unsigned int nr_irqs, void *arg)
 {
        irq_hw_number_t hwirq;
        struct irq_data *irqd;
-       u32 *lpi = arg;
        int ret;
 
        if (WARN_ON_ONCE(nr_irqs != 1))
                return -EINVAL;
 
-       hwirq = *lpi;
+       ret = alloc_lpi();
+       if (ret < 0)
+               return ret;
+       hwirq = ret;
 
        irqd = irq_domain_get_irq_data(domain, virq);
 
@@ -771,8 +779,10 @@ static int gicv5_irq_lpi_domain_alloc(struct irq_domain *domain, unsigned int vi
        irqd_set_single_target(irqd);
 
        ret = gicv5_irs_iste_alloc(hwirq);
-       if (ret < 0)
+       if (ret < 0) {
+               release_lpi(hwirq);
                return ret;
+       }
 
        gicv5_hwirq_init(hwirq, GICV5_IRQ_PRI_MI, GICV5_HWIRQ_TYPE_LPI);
        gicv5_lpi_config_reset(irqd);
@@ -782,7 +792,7 @@ static int gicv5_irq_lpi_domain_alloc(struct irq_domain *domain, unsigned int vi
 
 static const struct irq_domain_ops gicv5_irq_lpi_domain_ops = {
        .alloc  = gicv5_irq_lpi_domain_alloc,
-       .free   = gicv5_irq_domain_free,
+       .free   = gicv5_irq_lpi_domain_free,
 };
 
 void __init gicv5_init_lpi_domain(void)
@@ -804,21 +814,12 @@ static int gicv5_irq_ipi_domain_alloc(struct irq_domain *domain, unsigned int vi
 {
        struct irq_data *irqd;
        int ret, i;
-       u32 lpi;
 
        for (i = 0; i < nr_irqs; i++) {
-               ret = gicv5_alloc_lpi();
-               if (ret < 0)
+               ret = irq_domain_alloc_irqs_parent(domain, virq + i, 1, NULL);
+               if (ret)
                        return ret;
 
-               lpi = ret;
-
-               ret = irq_domain_alloc_irqs_parent(domain, virq + i, 1, &lpi);
-               if (ret) {
-                       gicv5_free_lpi(lpi);
-                       return ret;
-               }
-
                irqd = irq_domain_get_irq_data(domain, virq + i);
 
                irq_domain_set_hwirq_and_chip(domain, virq + i, i,
@@ -844,8 +845,6 @@ static void gicv5_irq_ipi_domain_free(struct irq_domain *domain, unsigned int vi
                if (!d)
                        return;
 
-               gicv5_free_lpi(d->parent_data->hwirq);
-
                irq_set_handler(virq + i, NULL);
                irq_domain_reset_irq_data(d);
                irq_domain_free_irqs_parent(domain, virq + i, 1);

diff --git a/include/linux/irqchip/arm-gic-v5.h b/include/linux/irqchip/arm-gic-v5.h
index 68ddcdb1cec5a55dc8d2a7edc3ffe90b74bcf05c..49994060f152907b8c63e9767f9112db534b7ef3 100644 (file)
--- a/include/linux/irqchip/arm-gic-v5.h
+++ b/include/linux/irqchip/arm-gic-v5.h
@@ -387,8 +387,5 @@ struct gicv5_its_itt_cfg {
 void gicv5_init_lpis(u32 max);
 void gicv5_deinit_lpis(void);
 
-int gicv5_alloc_lpi(void);
-void gicv5_free_lpi(u32 lpi);
-
 void __init gicv5_its_of_probe(struct device_node *parent);
 #endif