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#endif /* __ASSEMBLY__ */
103#endif /* __ASM_KVM_PTRAUTH_H */
104