// Copyright 2019 The gVisor Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

// +build arm64

package ring0

// Useful bits.
const (
	_PGD_PGT_BASE = 0x1000
	_PGD_PGT_SIZE = 0x1000
	_PUD_PGT_BASE = 0x2000
	_PUD_PGT_SIZE = 0x1000
	_PMD_PGT_BASE = 0x3000
	_PMD_PGT_SIZE = 0x4000
	_PTE_PGT_BASE = 0x7000
	_PTE_PGT_SIZE = 0x1000
)

const (
	// DAIF bits:debug, sError, IRQ, FIQ.
	_PSR_D_BIT      = 0x00000200
	_PSR_A_BIT      = 0x00000100
	_PSR_I_BIT      = 0x00000080
	_PSR_F_BIT      = 0x00000040
	_PSR_DAIF_SHIFT = 6
	_PSR_DAIF_MASK  = 0xf << _PSR_DAIF_SHIFT

	// PSR bits.
	_PSR_MODE_EL0t = 0x00000000
	_PSR_MODE_EL1t = 0x00000004
	_PSR_MODE_EL1h = 0x00000005
	_PSR_MODE_MASK = 0x0000000f

	PsrFlagsClear = _PSR_MODE_MASK | _PSR_DAIF_MASK
	PsrModeMask   = _PSR_MODE_MASK

	// KernelFlagsSet should always be set in the kernel.
	KernelFlagsSet = _PSR_MODE_EL1h | _PSR_D_BIT | _PSR_A_BIT | _PSR_I_BIT | _PSR_F_BIT

	// UserFlagsSet are always set in userspace.
	UserFlagsSet = _PSR_MODE_EL0t
)

// Vector is an exception vector.
type Vector uintptr

// Exception vectors.
const (
	El1SyncInvalid = iota
	El1IrqInvalid
	El1FiqInvalid
	El1ErrorInvalid
	El1Sync
	El1Irq
	El1Fiq
	El1Error
	El0Sync
	El0Irq
	El0Fiq
	El0Error
	El0Sync_invalid
	El0Irq_invalid
	El0Fiq_invalid
	El0Error_invalid
	El1Sync_da
	El1Sync_ia
	El1Sync_sp_pc
	El1Sync_undef
	El1Sync_dbg
	El1Sync_inv
	El0Sync_svc
	El0Sync_da
	El0Sync_ia
	El0Sync_fpsimd_acc
	El0Sync_sve_acc
	El0Sync_sys
	El0Sync_sp_pc
	El0Sync_undef
	El0Sync_dbg
	El0Sync_inv
	_NR_INTERRUPTS
)

// System call vectors.
const (
	Syscall                 Vector = El0Sync_svc
	PageFault               Vector = El0Sync_da
	VirtualizationException Vector = El0Error
)

// VirtualAddressBits returns the number bits available for virtual addresses.
func VirtualAddressBits() uint32 {
	return 48
}

// PhysicalAddressBits returns the number of bits available for physical addresses.
func PhysicalAddressBits() uint32 {
	return 40
}