1/* SPDX-License-Identifier: GPL-2.0-only */
2/*
3 * Hypervisor stub
4 *
5 * Copyright (C) 2012 ARM Ltd.
6 * Author: Marc Zyngier <marc.zyngier@arm.com>
7 */
8
9#include <linux/init.h>
10#include <linux/linkage.h>
11
12#include <asm/assembler.h>
13#include <asm/el2_setup.h>
14#include <asm/kvm_arm.h>
15#include <asm/kvm_asm.h>
16#include <asm/ptrace.h>
17#include <asm/virt.h>
18
19 .text
20 .pushsection .hyp.text, "ax"
21
22 .align 11
23
24SYM_CODE_START(__hyp_stub_vectors)
25 ventry el2_sync_invalid // Synchronous EL2t
26 ventry el2_irq_invalid // IRQ EL2t
27 ventry el2_fiq_invalid // FIQ EL2t
28 ventry el2_error_invalid // Error EL2t
29
30 ventry elx_sync // Synchronous EL2h
31 ventry el2_irq_invalid // IRQ EL2h
32 ventry el2_fiq_invalid // FIQ EL2h
33 ventry el2_error_invalid // Error EL2h
34
35 ventry elx_sync // Synchronous 64-bit EL1
36 ventry el1_irq_invalid // IRQ 64-bit EL1
37 ventry el1_fiq_invalid // FIQ 64-bit EL1
38 ventry el1_error_invalid // Error 64-bit EL1
39
40 ventry el1_sync_invalid // Synchronous 32-bit EL1
41 ventry el1_irq_invalid // IRQ 32-bit EL1
42 ventry el1_fiq_invalid // FIQ 32-bit EL1
43 ventry el1_error_invalid // Error 32-bit EL1
44SYM_CODE_END(__hyp_stub_vectors)
45
46 .align 11
47
48SYM_CODE_START_LOCAL(elx_sync)
49 cmp x0, #HVC_SET_VECTORS
50 b.ne 1f
51 msr vbar_el2, x1
52 b 9f
53
541: cmp x0, #HVC_FINALISE_EL2
55 b.eq __finalise_el2
56
572: cmp x0, #HVC_SOFT_RESTART
58 b.ne 3f
59 mov x0, x2
60 mov x2, x4
61 mov x4, x1
62 mov x1, x3
63 br x4 // no return
64
653: cmp x0, #HVC_RESET_VECTORS
66 beq 9f // Nothing to reset!
67
68 /* Someone called kvm_call_hyp() against the hyp-stub... */
69 mov_q x0, HVC_STUB_ERR
70 eret
71
729: mov x0, xzr
73 eret
74SYM_CODE_END(elx_sync)
75
76SYM_CODE_START_LOCAL(__finalise_el2)
77 finalise_el2_state
78
79 // nVHE? No way! Give me the real thing!
80 // Sanity check: MMU *must* be off
81 mrs x1, sctlr_el2
82 tbnz x1, #0, 1f
83
84 // Needs to be VHE capable, obviously
85 check_override id_aa64mmfr1 ID_AA64MMFR1_EL1_VH_SHIFT 0f 1f x1 x2
86
870: // Check whether we only want the hypervisor to run VHE, not the kernel
88 adr_l x1, arm64_sw_feature_override
89 ldr x2, [x1, FTR_OVR_VAL_OFFSET]
90 ldr x1, [x1, FTR_OVR_MASK_OFFSET]
91 and x2, x2, x1
92 ubfx x2, x2, #ARM64_SW_FEATURE_OVERRIDE_HVHE, #4
93 cbz x2, 2f
94
951: mov_q x0, HVC_STUB_ERR
96 eret
972:
98 // Engage the VHE magic!
99 mov_q x0, HCR_HOST_VHE_FLAGS
100 msr hcr_el2, x0
101 isb
102
103 // Use the EL1 allocated stack, per-cpu offset
104 mrs x0, sp_el1
105 mov sp, x0
106 mrs x0, tpidr_el1
107 msr tpidr_el2, x0
108
109 // FP configuration, vectors
110 mrs_s x0, SYS_CPACR_EL12
111 msr cpacr_el1, x0
112 mrs_s x0, SYS_VBAR_EL12
113 msr vbar_el1, x0
114
115 // Use EL2 translations for SPE & TRBE and disable access from EL1
116 mrs x0, mdcr_el2
117 bic x0, x0, #(MDCR_EL2_E2PB_MASK << MDCR_EL2_E2PB_SHIFT)
118 bic x0, x0, #(MDCR_EL2_E2TB_MASK << MDCR_EL2_E2TB_SHIFT)
119 msr mdcr_el2, x0
120
121 // Transfer the MM state from EL1 to EL2
122 mrs_s x0, SYS_TCR_EL12
123 msr tcr_el1, x0
124 mrs_s x0, SYS_TTBR0_EL12
125 msr ttbr0_el1, x0
126 mrs_s x0, SYS_TTBR1_EL12
127 msr ttbr1_el1, x0
128 mrs_s x0, SYS_MAIR_EL12
129 msr mair_el1, x0
130 mrs x1, REG_ID_AA64MMFR3_EL1
131 ubfx x1, x1, #ID_AA64MMFR3_EL1_TCRX_SHIFT, #4
132 cbz x1, .Lskip_tcr2
133 mrs x0, REG_TCR2_EL12
134 msr REG_TCR2_EL1, x0
135
136 // Transfer permission indirection state
137 mrs x1, REG_ID_AA64MMFR3_EL1
138 ubfx x1, x1, #ID_AA64MMFR3_EL1_S1PIE_SHIFT, #4
139 cbz x1, .Lskip_indirection
140 mrs x0, REG_PIRE0_EL12
141 msr REG_PIRE0_EL1, x0
142 mrs x0, REG_PIR_EL12
143 msr REG_PIR_EL1, x0
144
145.Lskip_indirection:
146.Lskip_tcr2:
147
148 isb
149
150 // Hack the exception return to stay at EL2
151 mrs x0, spsr_el1
152 and x0, x0, #~PSR_MODE_MASK
153 mov x1, #PSR_MODE_EL2h
154 orr x0, x0, x1
155 msr spsr_el1, x0
156
157 b enter_vhe
158SYM_CODE_END(__finalise_el2)
159
160 // At the point where we reach enter_vhe(), we run with
161 // the MMU off (which is enforced by __finalise_el2()).
162 // We thus need to be in the idmap, or everything will
163 // explode when enabling the MMU.
164
165 .pushsection .idmap.text, "ax"
166
167SYM_CODE_START_LOCAL(enter_vhe)
168 // Invalidate TLBs before enabling the MMU
169 tlbi vmalle1
170 dsb nsh
171 isb
172
173 // Enable the EL2 S1 MMU, as set up from EL1
174 mrs_s x0, SYS_SCTLR_EL12
175 set_sctlr_el1 x0
176
177 // Disable the EL1 S1 MMU for a good measure
178 mov_q x0, INIT_SCTLR_EL1_MMU_OFF
179 msr_s SYS_SCTLR_EL12, x0
180
181 mov x0, xzr
182
183 eret
184SYM_CODE_END(enter_vhe)
185
186 .popsection
187
188.macro invalid_vector label
189SYM_CODE_START_LOCAL(\label)
190 b \label
191SYM_CODE_END(\label)
192.endm
193
194 invalid_vector el2_sync_invalid
195 invalid_vector el2_irq_invalid
196 invalid_vector el2_fiq_invalid
197 invalid_vector el2_error_invalid
198 invalid_vector el1_sync_invalid
199 invalid_vector el1_irq_invalid
200 invalid_vector el1_fiq_invalid
201 invalid_vector el1_error_invalid
202
203 .popsection
204
205/*
206 * __hyp_set_vectors: Call this after boot to set the initial hypervisor
207 * vectors as part of hypervisor installation. On an SMP system, this should
208 * be called on each CPU.
209 *
210 * x0 must be the physical address of the new vector table, and must be
211 * 2KB aligned.
212 *
213 * Before calling this, you must check that the stub hypervisor is installed
214 * everywhere, by waiting for any secondary CPUs to be brought up and then
215 * checking that is_hyp_mode_available() is true.
216 *
217 * If not, there is a pre-existing hypervisor, some CPUs failed to boot, or
218 * something else went wrong... in such cases, trying to install a new
219 * hypervisor is unlikely to work as desired.
220 *
221 * When you call into your shiny new hypervisor, sp_el2 will contain junk,
222 * so you will need to set that to something sensible at the new hypervisor's
223 * initialisation entry point.
224 */
225
226SYM_FUNC_START(__hyp_set_vectors)
227 mov x1, x0
228 mov x0, #HVC_SET_VECTORS
229 hvc #0
230 ret
231SYM_FUNC_END(__hyp_set_vectors)
232
233SYM_FUNC_START(__hyp_reset_vectors)
234 mov x0, #HVC_RESET_VECTORS
235 hvc #0
236 ret
237SYM_FUNC_END(__hyp_reset_vectors)
238
239/*
240 * Entry point to finalise EL2 and switch to VHE if deemed capable
241 *
242 * w0: boot mode, as returned by init_kernel_el()
243 */
244SYM_FUNC_START(finalise_el2)
245 // Need to have booted at EL2
246 cmp w0, #BOOT_CPU_MODE_EL2
247 b.ne 1f
248
249 // and still be at EL1
250 mrs x0, CurrentEL
251 cmp x0, #CurrentEL_EL1
252 b.ne 1f
253
254 mov x0, #HVC_FINALISE_EL2
255 hvc #0
2561:
257 ret
258SYM_FUNC_END(finalise_el2)
259

source code of linux/arch/arm64/kernel/hyp-stub.S