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1/* SPDX-License-Identifier: GPL-2.0 */
2/* arch/arm64/include/asm/kvm_ptrauth.h: Guest/host ptrauth save/restore
3 * Copyright 2019 Arm Limited
4 * Authors: Mark Rutland <mark.rutland@arm.com>
5 * Amit Daniel Kachhap <amit.kachhap@arm.com>
6 */
7
8#ifndef __ASM_KVM_PTRAUTH_H
9#define __ASM_KVM_PTRAUTH_H
10
11#ifdef __ASSEMBLY__
12
13#include <asm/sysreg.h>
14
15#ifdef CONFIG_ARM64_PTR_AUTH
16
17#define PTRAUTH_REG_OFFSET(x) (x - CPU_APIAKEYLO_EL1)
18
19/*
20 * CPU_AP*_EL1 values exceed immediate offset range (512) for stp
21 * instruction so below macros takes CPU_APIAKEYLO_EL1 as base and
22 * calculates the offset of the keys from this base to avoid an extra add
23 * instruction. These macros assumes the keys offsets follow the order of
24 * the sysreg enum in kvm_host.h.
25 */
26.macro ptrauth_save_state base, reg1, reg2
27 mrs_s \reg1, SYS_APIAKEYLO_EL1
28 mrs_s \reg2, SYS_APIAKEYHI_EL1
29 stp \reg1, \reg2, [\base, #PTRAUTH_REG_OFFSET(CPU_APIAKEYLO_EL1)]
30 mrs_s \reg1, SYS_APIBKEYLO_EL1
31 mrs_s \reg2, SYS_APIBKEYHI_EL1
32 stp \reg1, \reg2, [\base, #PTRAUTH_REG_OFFSET(CPU_APIBKEYLO_EL1)]
33 mrs_s \reg1, SYS_APDAKEYLO_EL1
34 mrs_s \reg2, SYS_APDAKEYHI_EL1
35 stp \reg1, \reg2, [\base, #PTRAUTH_REG_OFFSET(CPU_APDAKEYLO_EL1)]
36 mrs_s \reg1, SYS_APDBKEYLO_EL1
37 mrs_s \reg2, SYS_APDBKEYHI_EL1
38 stp \reg1, \reg2, [\base, #PTRAUTH_REG_OFFSET(CPU_APDBKEYLO_EL1)]
39 mrs_s \reg1, SYS_APGAKEYLO_EL1
40 mrs_s \reg2, SYS_APGAKEYHI_EL1
41 stp \reg1, \reg2, [\base, #PTRAUTH_REG_OFFSET(CPU_APGAKEYLO_EL1)]
42.endm
43
44.macro ptrauth_restore_state base, reg1, reg2
45 ldp \reg1, \reg2, [\base, #PTRAUTH_REG_OFFSET(CPU_APIAKEYLO_EL1)]
46 msr_s SYS_APIAKEYLO_EL1, \reg1
47 msr_s SYS_APIAKEYHI_EL1, \reg2
48 ldp \reg1, \reg2, [\base, #PTRAUTH_REG_OFFSET(CPU_APIBKEYLO_EL1)]
49 msr_s SYS_APIBKEYLO_EL1, \reg1
50 msr_s SYS_APIBKEYHI_EL1, \reg2
51 ldp \reg1, \reg2, [\base, #PTRAUTH_REG_OFFSET(CPU_APDAKEYLO_EL1)]
52 msr_s SYS_APDAKEYLO_EL1, \reg1
53 msr_s SYS_APDAKEYHI_EL1, \reg2
54 ldp \reg1, \reg2, [\base, #PTRAUTH_REG_OFFSET(CPU_APDBKEYLO_EL1)]
55 msr_s SYS_APDBKEYLO_EL1, \reg1
56 msr_s SYS_APDBKEYHI_EL1, \reg2
57 ldp \reg1, \reg2, [\base, #PTRAUTH_REG_OFFSET(CPU_APGAKEYLO_EL1)]
58 msr_s SYS_APGAKEYLO_EL1, \reg1
59 msr_s SYS_APGAKEYHI_EL1, \reg2
60.endm
61
62/*
63 * Both ptrauth_switch_to_guest and ptrauth_switch_to_host macros will
64 * check for the presence of one of the cpufeature flag
65 * ARM64_HAS_ADDRESS_AUTH_ARCH or ARM64_HAS_ADDRESS_AUTH_IMP_DEF and
66 * then proceed ahead with the save/restore of Pointer Authentication
67 * key registers.
68 */
69.macro ptrauth_switch_to_guest g_ctxt, reg1, reg2, reg3
70alternative_if ARM64_HAS_ADDRESS_AUTH_ARCH
71 b 1000f
72alternative_else_nop_endif
73alternative_if_not ARM64_HAS_ADDRESS_AUTH_IMP_DEF
74 b 1001f
75alternative_else_nop_endif
761000:
77 ldr \reg1, [\g_ctxt, #(VCPU_HCR_EL2 - VCPU_CONTEXT)]
78 and \reg1, \reg1, #(HCR_API | HCR_APK)
79 cbz \reg1, 1001f
80 add \reg1, \g_ctxt, #CPU_APIAKEYLO_EL1
81 ptrauth_restore_state \reg1, \reg2, \reg3
821001:
83.endm
84
85.macro ptrauth_switch_to_host g_ctxt, h_ctxt, reg1, reg2, reg3
86alternative_if ARM64_HAS_ADDRESS_AUTH_ARCH
87 b 2000f
88alternative_else_nop_endif
89alternative_if_not ARM64_HAS_ADDRESS_AUTH_IMP_DEF
90 b 2001f
91alternative_else_nop_endif
922000:
93 ldr \reg1, [\g_ctxt, #(VCPU_HCR_EL2 - VCPU_CONTEXT)]
94 and \reg1, \reg1, #(HCR_API | HCR_APK)
95 cbz \reg1, 2001f
96 add \reg1, \g_ctxt, #CPU_APIAKEYLO_EL1
97 ptrauth_save_state \reg1, \reg2, \reg3
98 add \reg1, \h_ctxt, #CPU_APIAKEYLO_EL1
99 ptrauth_restore_state \reg1, \reg2, \reg3
100 isb
1012001:
102.endm
103
104#else /* !CONFIG_ARM64_PTR_AUTH */
105.macro ptrauth_switch_to_guest g_ctxt, reg1, reg2, reg3
106.endm
107.macro ptrauth_switch_to_host g_ctxt, h_ctxt, reg1, reg2, reg3
108.endm
109#endif /* CONFIG_ARM64_PTR_AUTH */
110#endif /* __ASSEMBLY__ */
111#endif /* __ASM_KVM_PTRAUTH_H */