1/*
2 * Copyright (C) 2012,2013 - ARM Ltd
3 * Author: Marc Zyngier <marc.zyngier@arm.com>
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License, version 2, as
7 * published by the Free Software Foundation.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
16 */
17
18#include <linux/linkage.h>
19
20#include <asm/assembler.h>
21#include <asm/kvm_arm.h>
22#include <asm/kvm_mmu.h>
23#include <asm/pgtable-hwdef.h>
24#include <asm/sysreg.h>
25#include <asm/virt.h>
26
27	.text
28	.pushsection	.hyp.idmap.text, "ax"
29
30	.align	11
31
32ENTRY(__kvm_hyp_init)
33	ventry	__invalid		// Synchronous EL2t
34	ventry	__invalid		// IRQ EL2t
35	ventry	__invalid		// FIQ EL2t
36	ventry	__invalid		// Error EL2t
37
38	ventry	__invalid		// Synchronous EL2h
39	ventry	__invalid		// IRQ EL2h
40	ventry	__invalid		// FIQ EL2h
41	ventry	__invalid		// Error EL2h
42
43	ventry	__do_hyp_init		// Synchronous 64-bit EL1
44	ventry	__invalid		// IRQ 64-bit EL1
45	ventry	__invalid		// FIQ 64-bit EL1
46	ventry	__invalid		// Error 64-bit EL1
47
48	ventry	__invalid		// Synchronous 32-bit EL1
49	ventry	__invalid		// IRQ 32-bit EL1
50	ventry	__invalid		// FIQ 32-bit EL1
51	ventry	__invalid		// Error 32-bit EL1
52
53__invalid:
54	b	.
55
56	/*
57	 * x0: HYP pgd
58	 * x1: HYP stack
59	 * x2: HYP vectors
60	 * x3: per-CPU offset
61	 */
62__do_hyp_init:
63	/* Check for a stub HVC call */
64	cmp	x0, #HVC_STUB_HCALL_NR
65	b.lo	__kvm_handle_stub_hvc
66
67	phys_to_ttbr x4, x0
68	msr	ttbr0_el2, x4
69
70	mrs	x4, tcr_el1
71	ldr	x5, =TCR_EL2_MASK
72	and	x4, x4, x5
73	mov	x5, #TCR_EL2_RES1
74	orr	x4, x4, x5
75
76	/*
77	 * The ID map may be configured to use an extended virtual address
78	 * range. This is only the case if system RAM is out of range for the
79	 * currently configured page size and VA_BITS, in which case we will
80	 * also need the extended virtual range for the HYP ID map, or we won't
81	 * be able to enable the EL2 MMU.
82	 *
83	 * However, at EL2, there is only one TTBR register, and we can't switch
84	 * between translation tables *and* update TCR_EL2.T0SZ at the same
85	 * time. Bottom line: we need to use the extended range with *both* our
86	 * translation tables.
87	 *
88	 * So use the same T0SZ value we use for the ID map.
89	 */
90	ldr_l	x5, idmap_t0sz
91	bfi	x4, x5, TCR_T0SZ_OFFSET, TCR_TxSZ_WIDTH
92
93	/*
94	 * Set the PS bits in TCR_EL2.
95	 */
96	tcr_compute_pa_size x4, #TCR_EL2_PS_SHIFT, x5, x6
97
98	msr	tcr_el2, x4
99
100	mrs	x4, mair_el1
101	msr	mair_el2, x4
102	isb
103
104	/* Invalidate the stale TLBs from Bootloader */
105	tlbi	alle2
106	dsb	sy
107
108	/*
109	 * Preserve all the RES1 bits while setting the default flags,
110	 * as well as the EE bit on BE. Drop the A flag since the compiler
111	 * is allowed to generate unaligned accesses.
112	 */
113	ldr	x4, =(SCTLR_EL2_RES1 | (SCTLR_ELx_FLAGS & ~SCTLR_ELx_A))
114CPU_BE(	orr	x4, x4, #SCTLR_ELx_EE)
115	msr	sctlr_el2, x4
116	isb
117
118	/* Set the stack and new vectors */
119	kern_hyp_va	x1
120	mov	sp, x1
121	msr	vbar_el2, x2
122
123	/* Set tpidr_el2 for use by HYP */
124	msr	tpidr_el2, x3
125
126	/* Hello, World! */
127	eret
128ENDPROC(__kvm_hyp_init)
129
130ENTRY(__kvm_handle_stub_hvc)
131	cmp	x0, #HVC_SOFT_RESTART
132	b.ne	1f
133
134	/* This is where we're about to jump, staying at EL2 */
135	msr	elr_el2, x1
136	mov	x0, #(PSR_F_BIT | PSR_I_BIT | PSR_A_BIT | PSR_D_BIT | PSR_MODE_EL2h)
137	msr	spsr_el2, x0
138
139	/* Shuffle the arguments, and don't come back */
140	mov	x0, x2
141	mov	x1, x3
142	mov	x2, x4
143	b	reset
144
1451:	cmp	x0, #HVC_RESET_VECTORS
146	b.ne	1f
147reset:
148	/*
149	 * Reset kvm back to the hyp stub. Do not clobber x0-x4 in
150	 * case we coming via HVC_SOFT_RESTART.
151	 */
152	mrs	x5, sctlr_el2
153	ldr	x6, =SCTLR_ELx_FLAGS
154	bic	x5, x5, x6		// Clear SCTL_M and etc
155	pre_disable_mmu_workaround
156	msr	sctlr_el2, x5
157	isb
158
159	/* Install stub vectors */
160	adr_l	x5, __hyp_stub_vectors
161	msr	vbar_el2, x5
162	mov	x0, xzr
163	eret
164
1651:	/* Bad stub call */
166	ldr	x0, =HVC_STUB_ERR
167	eret
168
169ENDPROC(__kvm_handle_stub_hvc)
170
171	.ltorg
172
173	.popsection
174