LXR linux/arch/arm64/include/asm/kvm

   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 of one of the cpufeature flag
  65 * ARM64_HAS_ADDRESS_AUTH_ARCH or ARM64_HAS_ADDRESS_AUTH_IMP_DEF and
  66 * then proceed ahead with the save/restore of Pointer Authentication
  67 * key registers.
  68 */
  69.macro ptrauth_switch_to_guest g_ctxt, reg1, reg2, reg3
  70alternative_if ARM64_HAS_ADDRESS_AUTH_ARCH
  71        b       1000f
  72alternative_else_nop_endif
  73alternative_if_not ARM64_HAS_ADDRESS_AUTH_IMP_DEF
  74        b       1001f
  75alternative_else_nop_endif
  761000:
  77        ldr     \reg1, [\g_ctxt, #(VCPU_HCR_EL2 - VCPU_CONTEXT)]
  78        and     \reg1, \reg1, #(HCR_API | HCR_APK)
  79        cbz     \reg1, 1001f
  80        add     \reg1, \g_ctxt, #CPU_APIAKEYLO_EL1
  81        ptrauth_restore_state   \reg1, \reg2, \reg3
  821001:
  83.endm
  84
  85.macro ptrauth_switch_to_host g_ctxt, h_ctxt, reg1, reg2, reg3
  86alternative_if ARM64_HAS_ADDRESS_AUTH_ARCH
  87        b       2000f
  88alternative_else_nop_endif
  89alternative_if_not ARM64_HAS_ADDRESS_AUTH_IMP_DEF
  90        b       2001f
  91alternative_else_nop_endif
  922000:
  93        ldr     \reg1, [\g_ctxt, #(VCPU_HCR_EL2 - VCPU_CONTEXT)]
  94        and     \reg1, \reg1, #(HCR_API | HCR_APK)
  95        cbz     \reg1, 2001f
  96        add     \reg1, \g_ctxt, #CPU_APIAKEYLO_EL1
  97        ptrauth_save_state      \reg1, \reg2, \reg3
  98        add     \reg1, \h_ctxt, #CPU_APIAKEYLO_EL1
  99        ptrauth_restore_state   \reg1, \reg2, \reg3
 100        isb
 1012001:
 102.endm
 103
 104#else /* !CONFIG_ARM64_PTR_AUTH */
 105.macro ptrauth_switch_to_guest g_ctxt, reg1, reg2, reg3
 106.endm
 107.macro ptrauth_switch_to_host g_ctxt, h_ctxt, reg1, reg2, reg3
 108.endm
 109#endif /* CONFIG_ARM64_PTR_AUTH */
 110#endif /* __ASSEMBLY__ */
 111#endif /* __ASM_KVM_PTRAUTH_H */
 112