arch/arm64/include/asm/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 __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
  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_hyp 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_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 */