/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ASM_X86_UINTR_H
#define _ASM_X86_UINTR_H

#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 {
	struct uintr_upid_ctx *upid_ctx;	/* UPID context */
	struct callback_head twork;		/* Task work head */
	u64 uvec;				/* Vector number */
};

struct uintr_sender_info {
	struct list_head node;
	struct uintr_uitt_ctx *uitt_ctx;
	struct task_struct *task;
	struct uintr_upid_ctx *r_upid_ctx;	/* Receiver's UPID context */
	struct callback_head twork;		/* Task work head */
	unsigned int uitt_index;
};

bool uintr_arch_enabled(void);
int do_uintr_register_handler(u64 handler);
int do_uintr_unregister_handler(void);
int do_uintr_register_vector(struct uintr_receiver_info *r_info);
void do_uintr_unregister_vector(struct uintr_receiver_info *r_info);

int do_uintr_register_sender(struct uintr_receiver_info *r_info,
			     struct uintr_sender_info *s_info);
void do_uintr_unregister_sender(struct uintr_receiver_info *r_info,
				struct uintr_sender_info *s_info);

void uintr_free(struct task_struct *task);

/* TODO: Inline the context switch related functions */
void switch_uintr_prepare(struct task_struct *prev);
void switch_uintr_return(void);

int uintr_receiver_wait(ktime_t *expires);
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 */

#endif /* _ASM_X86_UINTR_H */