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 */
20 static 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
prepare_fault32(struct kvm_vcpu * vcpu,u32 mode,u32 vect_offset)31 static 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
kvm_inject_undef32(struct kvm_vcpu * vcpu)61 void 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 */
inject_abt32(struct kvm_vcpu * vcpu,bool is_pabt,unsigned long addr)70 static 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
kvm_inject_dabt32(struct kvm_vcpu * vcpu,unsigned long addr)99 void kvm_inject_dabt32(struct kvm_vcpu *vcpu, unsigned long addr)
100 {
101 inject_abt32(vcpu, false, addr);
102 }
103
kvm_inject_pabt32(struct kvm_vcpu * vcpu,unsigned long addr)104 void kvm_inject_pabt32(struct kvm_vcpu *vcpu, unsigned long addr)
105 {
106 inject_abt32(vcpu, true, addr);
107 }
108
