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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_hyp macros will
64 * check for the presence ARM64_HAS_ADDRESS_AUTH, which is defined as
65 * (ARM64_HAS_ADDRESS_AUTH_ARCH || ARM64_HAS_ADDRESS_AUTH_IMP_DEF) and
66 * then proceed ahead with the save/restore of Pointer Authentication
67 * key registers if enabled for the guest.
68 */
69.macro ptrauth_switch_to_guest g_ctxt, reg1, reg2, reg3
70alternative_if_not ARM64_HAS_ADDRESS_AUTH
71 b .L__skip_switch\@
72alternative_else_nop_endif
73 mrs \reg1, hcr_el2
74 and \reg1, \reg1, #(HCR_API | HCR_APK)
75 cbz \reg1, .L__skip_switch\@
76 add \reg1, \g_ctxt, #CPU_APIAKEYLO_EL1
77 ptrauth_restore_state \reg1, \reg2, \reg3
78.L__skip_switch\@:
79.endm
80
81.macro ptrauth_switch_to_hyp g_ctxt, h_ctxt, reg1, reg2, reg3
82alternative_if_not ARM64_HAS_ADDRESS_AUTH
83 b .L__skip_switch\@
84alternative_else_nop_endif
85 mrs \reg1, hcr_el2
86 and \reg1, \reg1, #(HCR_API | HCR_APK)
87 cbz \reg1, .L__skip_switch\@
88 add \reg1, \g_ctxt, #CPU_APIAKEYLO_EL1
89 ptrauth_save_state \reg1, \reg2, \reg3
90 add \reg1, \h_ctxt, #CPU_APIAKEYLO_EL1
91 ptrauth_restore_state \reg1, \reg2, \reg3
92 isb
93.L__skip_switch\@:
94.endm
95
96#else /* !CONFIG_ARM64_PTR_AUTH */
97.macro ptrauth_switch_to_guest g_ctxt, reg1, reg2, reg3
98.endm
99.macro ptrauth_switch_to_hyp g_ctxt, h_ctxt, reg1, reg2, reg3
100.endm
101#endif /* CONFIG_ARM64_PTR_AUTH */
102
103#else /* !__ASSEMBLY */
104
105#define __ptrauth_save_key(ctxt, key) \
106 do { \
107 u64 __val; \
108 __val = read_sysreg_s(SYS_ ## key ## KEYLO_EL1); \
109 ctxt_sys_reg(ctxt, key ## KEYLO_EL1) = __val; \
110 __val = read_sysreg_s(SYS_ ## key ## KEYHI_EL1); \
111 ctxt_sys_reg(ctxt, key ## KEYHI_EL1) = __val; \
112 } while(0)
113
114#define ptrauth_save_keys(ctxt) \
115 do { \
116 __ptrauth_save_key(ctxt, APIA); \
117 __ptrauth_save_key(ctxt, APIB); \
118 __ptrauth_save_key(ctxt, APDA); \
119 __ptrauth_save_key(ctxt, APDB); \
120 __ptrauth_save_key(ctxt, APGA); \
121 } while(0)
122
123#endif /* __ASSEMBLY__ */
124#endif /* __ASM_KVM_PTRAUTH_H */