/* SPDX-License-Identifier: GPL-2.0 */
/* arch/arm64/include/asm/kvm_ptrauth.h: Guest/host ptrauth save/restore
 * Copyright 2019 Arm Limited
 * Authors: Mark Rutland <mark.rutland@arm.com>
 *         Amit Daniel Kachhap <amit.kachhap@arm.com>
 */

#ifndef __ASM_KVM_PTRAUTH_H
#define __ASM_KVM_PTRAUTH_H

#ifdef __ASSEMBLER__

#include <asm/sysreg.h>

#ifdef  CONFIG_ARM64_PTR_AUTH

#define PTRAUTH_REG_OFFSET(x)   (x - CPU_APIAKEYLO_EL1)

/*
 * CPU_AP*_EL1 values exceed immediate offset range (512) for stp
 * instruction so below macros takes CPU_APIAKEYLO_EL1 as base and
 * calculates the offset of the keys from this base to avoid an extra add
 * instruction. These macros assumes the keys offsets follow the order of
 * the sysreg enum in kvm_host.h.
 */
.macro  ptrauth_save_state base, reg1, reg2
        mrs_s   \reg1, SYS_APIAKEYLO_EL1
        mrs_s   \reg2, SYS_APIAKEYHI_EL1
        stp     \reg1, \reg2, [\base, #PTRAUTH_REG_OFFSET(CPU_APIAKEYLO_EL1)]
        mrs_s   \reg1, SYS_APIBKEYLO_EL1
        mrs_s   \reg2, SYS_APIBKEYHI_EL1
        stp     \reg1, \reg2, [\base, #PTRAUTH_REG_OFFSET(CPU_APIBKEYLO_EL1)]
        mrs_s   \reg1, SYS_APDAKEYLO_EL1
        mrs_s   \reg2, SYS_APDAKEYHI_EL1
        stp     \reg1, \reg2, [\base, #PTRAUTH_REG_OFFSET(CPU_APDAKEYLO_EL1)]
        mrs_s   \reg1, SYS_APDBKEYLO_EL1
        mrs_s   \reg2, SYS_APDBKEYHI_EL1
        stp     \reg1, \reg2, [\base, #PTRAUTH_REG_OFFSET(CPU_APDBKEYLO_EL1)]
        mrs_s   \reg1, SYS_APGAKEYLO_EL1
        mrs_s   \reg2, SYS_APGAKEYHI_EL1
        stp     \reg1, \reg2, [\base, #PTRAUTH_REG_OFFSET(CPU_APGAKEYLO_EL1)]
.endm

.macro  ptrauth_restore_state base, reg1, reg2
        ldp     \reg1, \reg2, [\base, #PTRAUTH_REG_OFFSET(CPU_APIAKEYLO_EL1)]
        msr_s   SYS_APIAKEYLO_EL1, \reg1
        msr_s   SYS_APIAKEYHI_EL1, \reg2
        ldp     \reg1, \reg2, [\base, #PTRAUTH_REG_OFFSET(CPU_APIBKEYLO_EL1)]
        msr_s   SYS_APIBKEYLO_EL1, \reg1
        msr_s   SYS_APIBKEYHI_EL1, \reg2
        ldp     \reg1, \reg2, [\base, #PTRAUTH_REG_OFFSET(CPU_APDAKEYLO_EL1)]
        msr_s   SYS_APDAKEYLO_EL1, \reg1
        msr_s   SYS_APDAKEYHI_EL1, \reg2
        ldp     \reg1, \reg2, [\base, #PTRAUTH_REG_OFFSET(CPU_APDBKEYLO_EL1)]
        msr_s   SYS_APDBKEYLO_EL1, \reg1
        msr_s   SYS_APDBKEYHI_EL1, \reg2
        ldp     \reg1, \reg2, [\base, #PTRAUTH_REG_OFFSET(CPU_APGAKEYLO_EL1)]
        msr_s   SYS_APGAKEYLO_EL1, \reg1
        msr_s   SYS_APGAKEYHI_EL1, \reg2
.endm

/*
 * Both ptrauth_switch_to_guest and ptrauth_switch_to_hyp macros will
 * check for the presence ARM64_HAS_ADDRESS_AUTH, which is defined as
 * (ARM64_HAS_ADDRESS_AUTH_ARCH || ARM64_HAS_ADDRESS_AUTH_IMP_DEF) and
 * then proceed ahead with the save/restore of Pointer Authentication
 * key registers if enabled for the guest.
 */
.macro ptrauth_switch_to_guest g_ctxt, reg1, reg2, reg3
alternative_if_not ARM64_HAS_ADDRESS_AUTH
        b       .L__skip_switch\@
alternative_else_nop_endif
        mrs     \reg1, hcr_el2
        and     \reg1, \reg1, #(HCR_API | HCR_APK)
        cbz     \reg1, .L__skip_switch\@
        add     \reg1, \g_ctxt, #CPU_APIAKEYLO_EL1
        ptrauth_restore_state   \reg1, \reg2, \reg3
.L__skip_switch\@:
.endm

.macro ptrauth_switch_to_hyp g_ctxt, h_ctxt, reg1, reg2, reg3
alternative_if_not ARM64_HAS_ADDRESS_AUTH
        b       .L__skip_switch\@
alternative_else_nop_endif
        mrs     \reg1, hcr_el2
        and     \reg1, \reg1, #(HCR_API | HCR_APK)
        cbz     \reg1, .L__skip_switch\@
        add     \reg1, \g_ctxt, #CPU_APIAKEYLO_EL1
        ptrauth_save_state      \reg1, \reg2, \reg3
        add     \reg1, \h_ctxt, #CPU_APIAKEYLO_EL1
        ptrauth_restore_state   \reg1, \reg2, \reg3
        isb
.L__skip_switch\@:
.endm

#else /* !CONFIG_ARM64_PTR_AUTH */
.macro ptrauth_switch_to_guest g_ctxt, reg1, reg2, reg3
.endm
.macro ptrauth_switch_to_hyp g_ctxt, h_ctxt, reg1, reg2, reg3
.endm
#endif /* CONFIG_ARM64_PTR_AUTH */

#else  /* !__ASSEMBLER__ */

#define __ptrauth_save_key(ctxt, key)                                   \
        do {                                                            \
                u64 __val;                                              \
                __val = read_sysreg_s(SYS_ ## key ## KEYLO_EL1);        \
                ctxt_sys_reg(ctxt, key ## KEYLO_EL1) = __val;           \
                __val = read_sysreg_s(SYS_ ## key ## KEYHI_EL1);        \
                ctxt_sys_reg(ctxt, key ## KEYHI_EL1) = __val;           \
        } while(0)

#define ptrauth_save_keys(ctxt)                                         \
        do {                                                            \
                __ptrauth_save_key(ctxt, APIA);                         \
                __ptrauth_save_key(ctxt, APIB);                         \
                __ptrauth_save_key(ctxt, APDA);                         \
                __ptrauth_save_key(ctxt, APDB);                         \
                __ptrauth_save_key(ctxt, APGA);                         \
        } while(0)

#endif /* __ASSEMBLER__ */
#endif /* __ASM_KVM_PTRAUTH_H */