xref: /openbmc/linux/arch/arm64/kernel/hyp-stub.S (revision 0edbfea5)
1/*
2 * Hypervisor stub
3 *
4 * Copyright (C) 2012 ARM Ltd.
5 * Author:	Marc Zyngier <marc.zyngier@arm.com>
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
18 */
19
20#include <linux/init.h>
21#include <linux/linkage.h>
22#include <linux/irqchip/arm-gic-v3.h>
23
24#include <asm/assembler.h>
25#include <asm/kvm_arm.h>
26#include <asm/kvm_asm.h>
27#include <asm/ptrace.h>
28#include <asm/virt.h>
29
30	.text
31	.align 11
32
33ENTRY(__hyp_stub_vectors)
34	ventry	el2_sync_invalid		// Synchronous EL2t
35	ventry	el2_irq_invalid			// IRQ EL2t
36	ventry	el2_fiq_invalid			// FIQ EL2t
37	ventry	el2_error_invalid		// Error EL2t
38
39	ventry	el2_sync_invalid		// Synchronous EL2h
40	ventry	el2_irq_invalid			// IRQ EL2h
41	ventry	el2_fiq_invalid			// FIQ EL2h
42	ventry	el2_error_invalid		// Error EL2h
43
44	ventry	el1_sync			// Synchronous 64-bit EL1
45	ventry	el1_irq_invalid			// IRQ 64-bit EL1
46	ventry	el1_fiq_invalid			// FIQ 64-bit EL1
47	ventry	el1_error_invalid		// Error 64-bit EL1
48
49	ventry	el1_sync_invalid		// Synchronous 32-bit EL1
50	ventry	el1_irq_invalid			// IRQ 32-bit EL1
51	ventry	el1_fiq_invalid			// FIQ 32-bit EL1
52	ventry	el1_error_invalid		// Error 32-bit EL1
53ENDPROC(__hyp_stub_vectors)
54
55	.align 11
56
57el1_sync:
58	mrs	x30, esr_el2
59	lsr	x30, x30, #ESR_ELx_EC_SHIFT
60
61	cmp	x30, #ESR_ELx_EC_HVC64
62	b.ne	9f				// Not an HVC trap
63
64	cmp	x0, #HVC_GET_VECTORS
65	b.ne	1f
66	mrs	x0, vbar_el2
67	b	9f
68
691:	cmp	x0, #HVC_SET_VECTORS
70	b.ne	2f
71	msr	vbar_el2, x1
72	b	9f
73
74	/* Someone called kvm_call_hyp() against the hyp-stub... */
752:	mov     x0, #ARM_EXCEPTION_HYP_GONE
76
779:	eret
78ENDPROC(el1_sync)
79
80.macro invalid_vector	label
81\label:
82	b \label
83ENDPROC(\label)
84.endm
85
86	invalid_vector	el2_sync_invalid
87	invalid_vector	el2_irq_invalid
88	invalid_vector	el2_fiq_invalid
89	invalid_vector	el2_error_invalid
90	invalid_vector	el1_sync_invalid
91	invalid_vector	el1_irq_invalid
92	invalid_vector	el1_fiq_invalid
93	invalid_vector	el1_error_invalid
94
95/*
96 * __hyp_set_vectors: Call this after boot to set the initial hypervisor
97 * vectors as part of hypervisor installation.  On an SMP system, this should
98 * be called on each CPU.
99 *
100 * x0 must be the physical address of the new vector table, and must be
101 * 2KB aligned.
102 *
103 * Before calling this, you must check that the stub hypervisor is installed
104 * everywhere, by waiting for any secondary CPUs to be brought up and then
105 * checking that is_hyp_mode_available() is true.
106 *
107 * If not, there is a pre-existing hypervisor, some CPUs failed to boot, or
108 * something else went wrong... in such cases, trying to install a new
109 * hypervisor is unlikely to work as desired.
110 *
111 * When you call into your shiny new hypervisor, sp_el2 will contain junk,
112 * so you will need to set that to something sensible at the new hypervisor's
113 * initialisation entry point.
114 */
115
116ENTRY(__hyp_get_vectors)
117	str	lr, [sp, #-16]!
118	mov	x0, #HVC_GET_VECTORS
119	hvc	#0
120	ldr	lr, [sp], #16
121	ret
122ENDPROC(__hyp_get_vectors)
123
124ENTRY(__hyp_set_vectors)
125	str	lr, [sp, #-16]!
126	mov	x1, x0
127	mov	x0, #HVC_SET_VECTORS
128	hvc	#0
129	ldr	lr, [sp], #16
130	ret
131ENDPROC(__hyp_set_vectors)
132