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Linux kernel mirror (for testing)
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1/* SPDX-License-Identifier: GPL-2.0-only */
2/*
3 * Copyright (C) 2012 ARM Ltd.
4 * Author: Marc Zyngier <marc.zyngier@arm.com>
5 */
6
7#ifndef __ASM__VIRT_H
8#define __ASM__VIRT_H
9
10/*
11 * The arm64 hcall implementation uses x0 to specify the hcall
12 * number. A value less than HVC_STUB_HCALL_NR indicates a special
13 * hcall, such as set vector. Any other value is handled in a
14 * hypervisor specific way.
15 *
16 * The hypercall is allowed to clobber any of the caller-saved
17 * registers (x0-x18), so it is advisable to use it through the
18 * indirection of a function call (as implemented in hyp-stub.S).
19 */
20
21/*
22 * HVC_SET_VECTORS - Set the value of the vbar_el2 register.
23 *
24 * @x1: Physical address of the new vector table.
25 */
26#define HVC_SET_VECTORS 0
27
28/*
29 * HVC_SOFT_RESTART - CPU soft reset, used by the cpu_soft_restart routine.
30 */
31#define HVC_SOFT_RESTART 1
32
33/*
34 * HVC_RESET_VECTORS - Restore the vectors to the original HYP stubs
35 */
36#define HVC_RESET_VECTORS 2
37
38/*
39 * HVC_VHE_RESTART - Upgrade the CPU from EL1 to EL2, if possible
40 */
41#define HVC_VHE_RESTART 3
42
43/* Max number of HYP stub hypercalls */
44#define HVC_STUB_HCALL_NR 4
45
46/* Error returned when an invalid stub number is passed into x0 */
47#define HVC_STUB_ERR 0xbadca11
48
49#define BOOT_CPU_MODE_EL1 (0xe11)
50#define BOOT_CPU_MODE_EL2 (0xe12)
51
52#ifndef __ASSEMBLY__
53
54#include <asm/ptrace.h>
55#include <asm/sections.h>
56#include <asm/sysreg.h>
57#include <asm/cpufeature.h>
58
59/*
60 * __boot_cpu_mode records what mode CPUs were booted in.
61 * A correctly-implemented bootloader must start all CPUs in the same mode:
62 * In this case, both 32bit halves of __boot_cpu_mode will contain the
63 * same value (either 0 if booted in EL1, BOOT_CPU_MODE_EL2 if booted in EL2).
64 *
65 * Should the bootloader fail to do this, the two values will be different.
66 * This allows the kernel to flag an error when the secondaries have come up.
67 */
68extern u32 __boot_cpu_mode[2];
69
70#define ARM64_VECTOR_TABLE_LEN SZ_2K
71
72void __hyp_set_vectors(phys_addr_t phys_vector_base);
73void __hyp_reset_vectors(void);
74
75DECLARE_STATIC_KEY_FALSE(kvm_protected_mode_initialized);
76
77/* Reports the availability of HYP mode */
78static inline bool is_hyp_mode_available(void)
79{
80 /*
81 * If KVM protected mode is initialized, all CPUs must have been booted
82 * in EL2. Avoid checking __boot_cpu_mode as CPUs now come up in EL1.
83 */
84 if (IS_ENABLED(CONFIG_KVM) &&
85 static_branch_likely(&kvm_protected_mode_initialized))
86 return true;
87
88 return (__boot_cpu_mode[0] == BOOT_CPU_MODE_EL2 &&
89 __boot_cpu_mode[1] == BOOT_CPU_MODE_EL2);
90}
91
92/* Check if the bootloader has booted CPUs in different modes */
93static inline bool is_hyp_mode_mismatched(void)
94{
95 /*
96 * If KVM protected mode is initialized, all CPUs must have been booted
97 * in EL2. Avoid checking __boot_cpu_mode as CPUs now come up in EL1.
98 */
99 if (IS_ENABLED(CONFIG_KVM) &&
100 static_branch_likely(&kvm_protected_mode_initialized))
101 return false;
102
103 return __boot_cpu_mode[0] != __boot_cpu_mode[1];
104}
105
106static inline bool is_kernel_in_hyp_mode(void)
107{
108 return read_sysreg(CurrentEL) == CurrentEL_EL2;
109}
110
111static __always_inline bool has_vhe(void)
112{
113 /*
114 * Code only run in VHE/NVHE hyp context can assume VHE is present or
115 * absent. Otherwise fall back to caps.
116 */
117 if (is_vhe_hyp_code())
118 return true;
119 else if (is_nvhe_hyp_code())
120 return false;
121 else
122 return cpus_have_final_cap(ARM64_HAS_VIRT_HOST_EXTN);
123}
124
125static __always_inline bool is_protected_kvm_enabled(void)
126{
127 if (is_vhe_hyp_code())
128 return false;
129 else
130 return cpus_have_final_cap(ARM64_KVM_PROTECTED_MODE);
131}
132
133static inline bool is_hyp_nvhe(void)
134{
135 return is_hyp_mode_available() && !is_kernel_in_hyp_mode();
136}
137
138#endif /* __ASSEMBLY__ */
139
140#endif /* ! __ASM__VIRT_H */