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-rw-r--r--arch/x86/include/asm/hardirq.h1
-rw-r--r--arch/x86/include/asm/idtentry.h1
-rw-r--r--arch/x86/include/asm/irq_vectors.h3
-rw-r--r--arch/x86/include/asm/uintr.h22
-rw-r--r--arch/x86/kernel/idt.c1
-rw-r--r--arch/x86/kernel/irq.c18
-rw-r--r--arch/x86/kernel/uintr_core.c94
-rw-r--r--arch/x86/kernel/uintr_fd.c15
8 files changed, 136 insertions, 19 deletions
diff --git a/arch/x86/include/asm/hardirq.h b/arch/x86/include/asm/hardirq.h
index 279afc01f1ac..a4623fdb65a1 100644
--- a/arch/x86/include/asm/hardirq.h
+++ b/arch/x86/include/asm/hardirq.h
@@ -22,6 +22,7 @@ typedef struct {
#endif
#ifdef CONFIG_X86_USER_INTERRUPTS
unsigned int uintr_spurious_count;
+ unsigned int uintr_kernel_notifications;
#endif
unsigned int x86_platform_ipis; /* arch dependent */
unsigned int apic_perf_irqs;
diff --git a/arch/x86/include/asm/idtentry.h b/arch/x86/include/asm/idtentry.h
index 5929a6f9eeee..0ac7ef592283 100644
--- a/arch/x86/include/asm/idtentry.h
+++ b/arch/x86/include/asm/idtentry.h
@@ -673,6 +673,7 @@ DECLARE_IDTENTRY_SYSVEC(POSTED_INTR_NESTED_VECTOR, sysvec_kvm_posted_intr_nested
#ifdef CONFIG_X86_USER_INTERRUPTS
DECLARE_IDTENTRY_SYSVEC(UINTR_NOTIFICATION_VECTOR, sysvec_uintr_spurious_interrupt);
+DECLARE_IDTENTRY_SYSVEC(UINTR_KERNEL_VECTOR, sysvec_uintr_kernel_notification);
#endif
#if IS_ENABLED(CONFIG_HYPERV)
diff --git a/arch/x86/include/asm/irq_vectors.h b/arch/x86/include/asm/irq_vectors.h
index d26faa504931..1d289b3ee0da 100644
--- a/arch/x86/include/asm/irq_vectors.h
+++ b/arch/x86/include/asm/irq_vectors.h
@@ -106,8 +106,9 @@
/* Vector for User interrupt notifications */
#define UINTR_NOTIFICATION_VECTOR 0xec
+#define UINTR_KERNEL_VECTOR 0xeb
-#define LOCAL_TIMER_VECTOR 0xeb
+#define LOCAL_TIMER_VECTOR 0xea
#define NR_VECTORS 256
diff --git a/arch/x86/include/asm/uintr.h b/arch/x86/include/asm/uintr.h
index ef3521dd7fb9..64113ef523ca 100644
--- a/arch/x86/include/asm/uintr.h
+++ b/arch/x86/include/asm/uintr.h
@@ -4,11 +4,29 @@
#ifdef CONFIG_X86_USER_INTERRUPTS
+/* User Posted Interrupt Descriptor (UPID) */
+struct uintr_upid {
+ struct {
+ u8 status; /* bit 0: ON, bit 1: SN, bit 2-7: reserved */
+ u8 reserved1; /* Reserved */
+ u8 nv; /* Notification vector */
+ u8 reserved2; /* Reserved */
+ u32 ndst; /* Notification destination */
+ } nc __packed; /* Notification control */
+ u64 puir; /* Posted user interrupt requests */
+} __aligned(64);
+
+/* UPID Notification control status */
+#define UPID_ON 0x0 /* Outstanding notification */
+#define UPID_SN 0x1 /* Suppressed notification */
+
struct uintr_upid_ctx {
+ struct list_head node;
struct task_struct *task; /* Receiver task */
struct uintr_upid *upid;
refcount_t refs;
bool receiver_active; /* Flag for UPID being mapped to a receiver */
+ bool waiting;
};
struct uintr_receiver_info {
@@ -43,11 +61,15 @@ void uintr_free(struct task_struct *task);
void switch_uintr_prepare(struct task_struct *prev);
void switch_uintr_return(void);
+int uintr_receiver_wait(void);
+void uintr_wake_up_process(void);
+
#else /* !CONFIG_X86_USER_INTERRUPTS */
static inline void uintr_free(struct task_struct *task) {}
static inline void switch_uintr_prepare(struct task_struct *prev) {}
static inline void switch_uintr_return(void) {}
+static inline void uintr_wake_up_process(void) {}
#endif /* CONFIG_X86_USER_INTERRUPTS */
diff --git a/arch/x86/kernel/idt.c b/arch/x86/kernel/idt.c
index d8c45e0728f0..8d4fd7509523 100644
--- a/arch/x86/kernel/idt.c
+++ b/arch/x86/kernel/idt.c
@@ -149,6 +149,7 @@ static const __initconst struct idt_data apic_idts[] = {
# endif
#ifdef CONFIG_X86_USER_INTERRUPTS
INTG(UINTR_NOTIFICATION_VECTOR, asm_sysvec_uintr_spurious_interrupt),
+ INTG(UINTR_KERNEL_VECTOR, asm_sysvec_uintr_kernel_notification),
#endif
# ifdef CONFIG_IRQ_WORK
INTG(IRQ_WORK_VECTOR, asm_sysvec_irq_work),
diff --git a/arch/x86/kernel/irq.c b/arch/x86/kernel/irq.c
index e3c35668c7c5..22349f5c301b 100644
--- a/arch/x86/kernel/irq.c
+++ b/arch/x86/kernel/irq.c
@@ -22,6 +22,7 @@
#include <asm/desc.h>
#include <asm/traps.h>
#include <asm/thermal.h>
+#include <asm/uintr.h>
#define CREATE_TRACE_POINTS
#include <asm/trace/irq_vectors.h>
@@ -187,6 +188,11 @@ int arch_show_interrupts(struct seq_file *p, int prec)
for_each_online_cpu(j)
seq_printf(p, "%10u ", irq_stats(j)->uintr_spurious_count);
seq_puts(p, " User-interrupt spurious event\n");
+
+ seq_printf(p, "%*s: ", prec, "UKN");
+ for_each_online_cpu(j)
+ seq_printf(p, "%10u ", irq_stats(j)->uintr_kernel_notifications);
+ seq_puts(p, " User-interrupt kernel notification event\n");
#endif
return 0;
}
@@ -356,6 +362,18 @@ DEFINE_IDTENTRY_SYSVEC_SIMPLE(sysvec_uintr_spurious_interrupt)
ack_APIC_irq();
inc_irq_stat(uintr_spurious_count);
}
+
+/*
+ * Handler for UINTR_KERNEL_VECTOR.
+ */
+DEFINE_IDTENTRY_SYSVEC(sysvec_uintr_kernel_notification)
+{
+ /* TODO: Add entry-exit tracepoints */
+ ack_APIC_irq();
+ inc_irq_stat(uintr_kernel_notifications);
+
+ uintr_wake_up_process();
+}
#endif
diff --git a/arch/x86/kernel/uintr_core.c b/arch/x86/kernel/uintr_core.c
index 8f331c5fe0cf..4e5545e6d903 100644
--- a/arch/x86/kernel/uintr_core.c
+++ b/arch/x86/kernel/uintr_core.c
@@ -28,22 +28,6 @@
#define UINTR_MAX_UITT_NR 256
#define UINTR_MAX_UVEC_NR 64
-/* User Posted Interrupt Descriptor (UPID) */
-struct uintr_upid {
- struct {
- u8 status; /* bit 0: ON, bit 1: SN, bit 2-7: reserved */
- u8 reserved1; /* Reserved */
- u8 nv; /* Notification vector */
- u8 reserved2; /* Reserved */
- u32 ndst; /* Notification destination */
- } nc __packed; /* Notification control */
- u64 puir; /* Posted user interrupt requests */
-} __aligned(64);
-
-/* UPID Notification control status */
-#define UPID_ON 0x0 /* Outstanding notification */
-#define UPID_SN 0x1 /* Suppressed notification */
-
struct uintr_receiver {
struct uintr_upid_ctx *upid_ctx;
u64 uvec_mask; /* track active vector per bit */
@@ -70,6 +54,10 @@ struct uintr_sender {
u64 uitt_mask[BITS_TO_U64(UINTR_MAX_UITT_NR)];
};
+/* TODO: To remove the global lock, move to a per-cpu wait list. */
+static DEFINE_SPINLOCK(uintr_wait_lock);
+static struct list_head uintr_wait_list = LIST_HEAD_INIT(uintr_wait_list);
+
inline bool uintr_arch_enabled(void)
{
return static_cpu_has(X86_FEATURE_UINTR);
@@ -80,6 +68,12 @@ static inline bool is_uintr_receiver(struct task_struct *t)
return !!t->thread.ui_recv;
}
+/* Always make sure task is_uintr_receiver() before calling */
+static inline bool is_uintr_waiting(struct task_struct *t)
+{
+ return t->thread.ui_recv->upid_ctx->waiting;
+}
+
static inline bool is_uintr_sender(struct task_struct *t)
{
return !!t->thread.ui_send;
@@ -151,6 +145,7 @@ static struct uintr_upid_ctx *alloc_upid(void)
refcount_set(&upid_ctx->refs, 1);
upid_ctx->task = get_task_struct(current);
upid_ctx->receiver_active = true;
+ upid_ctx->waiting = false;
return upid_ctx;
}
@@ -494,6 +489,68 @@ int do_uintr_register_sender(struct uintr_receiver_info *r_info,
return 0;
}
+int uintr_receiver_wait(void)
+{
+ struct uintr_upid_ctx *upid_ctx;
+ unsigned long flags;
+
+ if (!is_uintr_receiver(current))
+ return -EOPNOTSUPP;
+
+ upid_ctx = current->thread.ui_recv->upid_ctx;
+ upid_ctx->upid->nc.nv = UINTR_KERNEL_VECTOR;
+ upid_ctx->waiting = true;
+ spin_lock_irqsave(&uintr_wait_lock, flags);
+ list_add(&upid_ctx->node, &uintr_wait_list);
+ spin_unlock_irqrestore(&uintr_wait_lock, flags);
+
+ set_current_state(TASK_INTERRUPTIBLE);
+ schedule();
+
+ return -EINTR;
+}
+
+/*
+ * Runs in interrupt context.
+ * Scan through all UPIDs to check if any interrupt is on going.
+ */
+void uintr_wake_up_process(void)
+{
+ struct uintr_upid_ctx *upid_ctx, *tmp;
+ unsigned long flags;
+
+ spin_lock_irqsave(&uintr_wait_lock, flags);
+ list_for_each_entry_safe(upid_ctx, tmp, &uintr_wait_list, node) {
+ if (test_bit(UPID_ON, (unsigned long *)&upid_ctx->upid->nc.status)) {
+ set_bit(UPID_SN, (unsigned long *)&upid_ctx->upid->nc.status);
+ upid_ctx->upid->nc.nv = UINTR_NOTIFICATION_VECTOR;
+ upid_ctx->waiting = false;
+ wake_up_process(upid_ctx->task);
+ list_del(&upid_ctx->node);
+ }
+ }
+ spin_unlock_irqrestore(&uintr_wait_lock, flags);
+}
+
+/* Called when task is unregistering/exiting */
+static void uintr_remove_task_wait(struct task_struct *task)
+{
+ struct uintr_upid_ctx *upid_ctx, *tmp;
+ unsigned long flags;
+
+ spin_lock_irqsave(&uintr_wait_lock, flags);
+ list_for_each_entry_safe(upid_ctx, tmp, &uintr_wait_list, node) {
+ if (upid_ctx->task == task) {
+ pr_debug("wait: Removing task %d from wait\n",
+ upid_ctx->task->pid);
+ upid_ctx->upid->nc.nv = UINTR_NOTIFICATION_VECTOR;
+ upid_ctx->waiting = false;
+ list_del(&upid_ctx->node);
+ }
+ }
+ spin_unlock_irqrestore(&uintr_wait_lock, flags);
+}
+
int do_uintr_unregister_handler(void)
{
struct task_struct *t = current;
@@ -548,7 +605,7 @@ int do_uintr_unregister_handler(void)
* based on this UPID.
*/
set_bit(UPID_SN, (unsigned long *)&ui_recv->upid_ctx->upid->nc.status);
-
+ uintr_remove_task_wait(t);
put_upid_ref(ui_recv->upid_ctx);
kfree(ui_recv);
t->thread.ui_recv = NULL;
@@ -684,7 +741,7 @@ void switch_uintr_prepare(struct task_struct *prev)
{
struct uintr_upid *upid;
- if (is_uintr_receiver(prev)) {
+ if (is_uintr_receiver(prev) && !is_uintr_waiting(prev)) {
upid = prev->thread.ui_recv->upid_ctx->upid;
set_bit(UPID_SN, (unsigned long *)&upid->nc.status);
}
@@ -806,6 +863,7 @@ void uintr_free(struct task_struct *t)
* generated based on this UPID.
*/
set_bit(UPID_SN, (unsigned long *)&ui_recv->upid_ctx->upid->nc.status);
+ uintr_remove_task_wait(t);
ui_recv->upid_ctx->receiver_active = false;
put_upid_ref(ui_recv->upid_ctx);
kfree(ui_recv);
diff --git a/arch/x86/kernel/uintr_fd.c b/arch/x86/kernel/uintr_fd.c
index 3c82c032c0b9..a7e55d98c0c7 100644
--- a/arch/x86/kernel/uintr_fd.c
+++ b/arch/x86/kernel/uintr_fd.c
@@ -283,3 +283,18 @@ out_fdput:
fdput(f);
return ret;
}
+
+/*
+ * sys_uintr_wait - Wait for a user interrupt
+ */
+SYSCALL_DEFINE1(uintr_wait, unsigned int, flags)
+{
+ if (!uintr_arch_enabled())
+ return -EOPNOTSUPP;
+
+ if (flags)
+ return -EINVAL;
+
+ /* TODO: Add a timeout option */
+ return uintr_receiver_wait();
+}
generated by cgit v1.2.3 (git 2.39.1) at 2025-12-30 18:21:33 +0000