KVM: arm/arm64: Context-switch ptrauth registers

[sfrench/cifs-2.6.git] / arch / arm64 / include / asm / kvm_ptrauth.h

diff --git a/arch/arm64/include/asm/kvm_ptrauth.h b/arch/arm64/include/asm/kvm_ptrauth.h
new file mode 100644 (file)
index 0000000..6301813
--- /dev/null
+++ b/arch/arm64/include/asm/kvm_ptrauth.h
@@ -0,0 +1,111 @@
+/* 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 __ASSEMBLY__
+
+#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_host macros will
+ * check for the presence of one of the cpufeature flag
+ * ARM64_HAS_ADDRESS_AUTH_ARCH or ARM64_HAS_ADDRESS_AUTH_IMP_DEF and
+ * then proceed ahead with the save/restore of Pointer Authentication
+ * key registers.
+ */
+.macro ptrauth_switch_to_guest g_ctxt, reg1, reg2, reg3
+alternative_if ARM64_HAS_ADDRESS_AUTH_ARCH
+       b       1000f
+alternative_else_nop_endif
+alternative_if_not ARM64_HAS_ADDRESS_AUTH_IMP_DEF
+       b       1001f
+alternative_else_nop_endif
+1000:
+       ldr     \reg1, [\g_ctxt, #(VCPU_HCR_EL2 - VCPU_CONTEXT)]
+       and     \reg1, \reg1, #(HCR_API | HCR_APK)
+       cbz     \reg1, 1001f
+       add     \reg1, \g_ctxt, #CPU_APIAKEYLO_EL1
+       ptrauth_restore_state   \reg1, \reg2, \reg3
+1001:
+.endm
+
+.macro ptrauth_switch_to_host g_ctxt, h_ctxt, reg1, reg2, reg3
+alternative_if ARM64_HAS_ADDRESS_AUTH_ARCH
+       b       2000f
+alternative_else_nop_endif
+alternative_if_not ARM64_HAS_ADDRESS_AUTH_IMP_DEF
+       b       2001f
+alternative_else_nop_endif
+2000:
+       ldr     \reg1, [\g_ctxt, #(VCPU_HCR_EL2 - VCPU_CONTEXT)]
+       and     \reg1, \reg1, #(HCR_API | HCR_APK)
+       cbz     \reg1, 2001f
+       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
+2001:
+.endm
+
+#else /* !CONFIG_ARM64_PTR_AUTH */
+.macro ptrauth_switch_to_guest g_ctxt, reg1, reg2, reg3
+.endm
+.macro ptrauth_switch_to_host g_ctxt, h_ctxt, reg1, reg2, reg3
+.endm
+#endif /* CONFIG_ARM64_PTR_AUTH */
+#endif /* __ASSEMBLY__ */
+#endif /* __ASM_KVM_PTRAUTH_H */