1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * (not much of an) Emulation layer for 32bit guests.
  4 *
  5 * Copyright (C) 2012,2013 - ARM Ltd
  6 * Author: Marc Zyngier <marc.zyngier@arm.com>
  7 *
  8 * based on arch/arm/kvm/emulate.c
  9 * Copyright (C) 2012 - Virtual Open Systems and Columbia University
 10 * Author: Christoffer Dall <c.dall@virtualopensystems.com>
 11 */
 12
 13#include <linux/kvm_host.h>
 14#include <asm/kvm_emulate.h>
 15#include <asm/kvm_hyp.h>
 16
 17/*
 18 * Table taken from ARMv8 ARM DDI0487B-B, table G1-10.
 19 */
 20static const u8 return_offsets[8][2] = {
 21	[0] = { 0, 0 },		/* Reset, unused */
 22	[1] = { 4, 2 },		/* Undefined */
 23	[2] = { 0, 0 },		/* SVC, unused */
 24	[3] = { 4, 4 },		/* Prefetch abort */
 25	[4] = { 8, 8 },		/* Data abort */
 26	[5] = { 0, 0 },		/* HVC, unused */
 27	[6] = { 4, 4 },		/* IRQ, unused */
 28	[7] = { 4, 4 },		/* FIQ, unused */
 29};
 30
 31static void prepare_fault32(struct kvm_vcpu *vcpu, u32 mode, u32 vect_offset)
 32{
 33	unsigned long cpsr;
 34	unsigned long new_spsr_value = *vcpu_cpsr(vcpu);
 35	bool is_thumb = (new_spsr_value & PSR_AA32_T_BIT);
 36	u32 return_offset = return_offsets[vect_offset >> 2][is_thumb];
 37	u32 sctlr = vcpu_cp15(vcpu, c1_SCTLR);
 38
 39	cpsr = mode | PSR_AA32_I_BIT;
 40
 41	if (sctlr & (1 << 30))
 42		cpsr |= PSR_AA32_T_BIT;
 43	if (sctlr & (1 << 25))
 44		cpsr |= PSR_AA32_E_BIT;
 45
 46	*vcpu_cpsr(vcpu) = cpsr;
 47
 48	/* Note: These now point to the banked copies */
 49	vcpu_write_spsr(vcpu, new_spsr_value);
 50	*vcpu_reg32(vcpu, 14) = *vcpu_pc(vcpu) + return_offset;
 51
 52	/* Branch to exception vector */
 53	if (sctlr & (1 << 13))
 54		vect_offset += 0xffff0000;
 55	else /* always have security exceptions */
 56		vect_offset += vcpu_cp15(vcpu, c12_VBAR);
 57
 58	*vcpu_pc(vcpu) = vect_offset;
 59}
 60
 61void kvm_inject_undef32(struct kvm_vcpu *vcpu)
 62{
 63	prepare_fault32(vcpu, PSR_AA32_MODE_UND, 4);
 64}
 65
 66/*
 67 * Modelled after TakeDataAbortException() and TakePrefetchAbortException
 68 * pseudocode.
 69 */
 70static void inject_abt32(struct kvm_vcpu *vcpu, bool is_pabt,
 71			 unsigned long addr)
 72{
 73	u32 vect_offset;
 74	u32 *far, *fsr;
 75	bool is_lpae;
 76
 77	if (is_pabt) {
 78		vect_offset = 12;
 79		far = &vcpu_cp15(vcpu, c6_IFAR);
 80		fsr = &vcpu_cp15(vcpu, c5_IFSR);
 81	} else { /* !iabt */
 82		vect_offset = 16;
 83		far = &vcpu_cp15(vcpu, c6_DFAR);
 84		fsr = &vcpu_cp15(vcpu, c5_DFSR);
 85	}
 86
 87	prepare_fault32(vcpu, PSR_AA32_MODE_ABT | PSR_AA32_A_BIT, vect_offset);
 88
 89	*far = addr;
 90
 91	/* Give the guest an IMPLEMENTATION DEFINED exception */
 92	is_lpae = (vcpu_cp15(vcpu, c2_TTBCR) >> 31);
 93	if (is_lpae)
 94		*fsr = 1 << 9 | 0x34;
 95	else
 96		*fsr = 0x14;
 97}
 98
 99void kvm_inject_dabt32(struct kvm_vcpu *vcpu, unsigned long addr)
100{
101	inject_abt32(vcpu, false, addr);
102}
103
104void kvm_inject_pabt32(struct kvm_vcpu *vcpu, unsigned long addr)
105{
106	inject_abt32(vcpu, true, addr);
107}