kvm_ptrauth.h

  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 __ASSEMBLER__
 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  /* !__ASSEMBLER__ */
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 /* __ASSEMBLER__ */
124#endif /* __ASM_KVM_PTRAUTH_H */