arch: arm64: hh: Add Haven arm64 hypercall interface

/* SPDX-License-Identifier: GPL-2.0-only */

/*

 * Copyright (c) 2020, The Linux Foundation. All rights reserved.

 */

#ifndef __ASM_HH_HCALL_H

#define __ASM_HH_HCALL_H

#include <linux/types.h>

#include <linux/haven/hcall_common.h>

/**

 * _hh_hcall: Performs an AArch64-specific call into hypervisor using Haven ABI

 * @hcall_num: Hypercall function ID to invoke

 * @args: Hypercall argument registers

 * @resp: Pointer to location to store response

 */

static inline int _hh_hcall(const hh_hcall_fnid_t hcall_num,

	const struct hh_hcall_args args,

	struct hh_hcall_resp *resp)

{

	uint64_t _x18;

	register uint64_t _x0 asm("x0") = args.arg0;

	register uint64_t _x1 asm("x1") = args.arg1;

	register uint64_t _x2 asm("x2") = args.arg2;

	register uint64_t _x3 asm("x3") = args.arg3;

	register uint64_t _x4 asm("x4") = args.arg4;

	register uint64_t _x5 asm("x5") = args.arg5;

	register uint64_t _x6 asm("x6") = args.arg6;

	register uint64_t _x7 asm("x7") = args.arg7;

	asm volatile (

		"str	x18, [%[_x18]]\n"

		"hvc	%[num]\n"

		"ldr	x18, [%[_x18]]\n"

		"str	xzr, [%[_x18]]\n"

		: "+r"(_x0), "+r"(_x1), "+r"(_x2), "+r"(_x3), "+r"(_x4),

		  "+r"(_x5), "+r"(_x6), "+r"(_x7)

		: [num] "i" (hcall_num), [_x18] "r"(&_x18)

		: "x9", "x10", "x11", "x12", "x13", "x14", "x15", "x16", "x17",

		  "memory"

		);

	resp->resp0 = _x0;

	resp->resp1 = _x1;

	resp->resp2 = _x2;

	resp->resp3 = _x3;

	resp->resp4 = _x4;

	resp->resp5 = _x5;

	resp->resp6 = _x6;

	resp->resp7 = _x7;

	return _x0;

}

#endif