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 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
70 alternative_if_not ARM64_HAS_ADDRESS_AUTH
71 	b	.L__skip_switch\@
72 alternative_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_host g_ctxt, h_ctxt, reg1, reg2, reg3
82 alternative_if_not ARM64_HAS_ADDRESS_AUTH
83 	b	.L__skip_switch\@
84 alternative_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_host g_ctxt, h_ctxt, reg1, reg2, reg3
100 .endm
101 #endif /* CONFIG_ARM64_PTR_AUTH */
102 #endif /* __ASSEMBLY__ */
103 #endif /* __ASM_KVM_PTRAUTH_H */
104