1/*
2 * Copyright (C) 2012 - Virtual Open Systems and Columbia University
3 * Author: Christoffer Dall <c.dall@virtualopensystems.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, write to the Free Software
16 * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
17 */
18
19#include <linux/linkage.h>
20#include <asm/assembler.h>
21#include <asm/unified.h>
22#include <asm/asm-offsets.h>
23#include <asm/kvm_asm.h>
24#include <asm/kvm_arm.h>
25#include <asm/kvm_mmu.h>
26#include <asm/virt.h>
27
28/********************************************************************
29 * Hypervisor initialization
30 *   - should be called with:
31 *       r0 = top of Hyp stack (kernel VA)
32 *       r1 = pointer to hyp vectors
33 *       r2,r3 = Hypervisor pgd pointer
34 *
35 * The init scenario is:
36 * - We jump in HYP with 3 parameters: runtime HYP pgd, runtime stack,
37 *   runtime vectors
38 * - Invalidate TLBs
39 * - Set stack and vectors
40 * - Setup the page tables
41 * - Enable the MMU
42 * - Profit! (or eret, if you only care about the code).
43 *
44 * Another possibility is to get a HYP stub hypercall.
45 * We discriminate between the two by checking if r0 contains a value
46 * that is less than HVC_STUB_HCALL_NR.
47 */
48
49	.text
50	.pushsection    .hyp.idmap.text,"ax"
51	.align 5
52__kvm_hyp_init:
53	.globl __kvm_hyp_init
54
55	@ Hyp-mode exception vector
56	W(b)	.
57	W(b)	.
58	W(b)	.
59	W(b)	.
60	W(b)	.
61	W(b)	__do_hyp_init
62	W(b)	.
63	W(b)	.
64
65__do_hyp_init:
66	@ Check for a stub hypercall
67	cmp	r0, #HVC_STUB_HCALL_NR
68	blo	__kvm_handle_stub_hvc
69
70	@ Set stack pointer
71	mov	sp, r0
72
73	@ Set HVBAR to point to the HYP vectors
74	mcr	p15, 4, r1, c12, c0, 0	@ HVBAR
75
76	@ Set the HTTBR to point to the hypervisor PGD pointer passed
77	mcrr	p15, 4, rr_lo_hi(r2, r3), c2
78
79	@ Set the HTCR and VTCR to the same shareability and cacheability
80	@ settings as the non-secure TTBCR and with T0SZ == 0.
81	mrc	p15, 4, r0, c2, c0, 2	@ HTCR
82	ldr	r2, =HTCR_MASK
83	bic	r0, r0, r2
84	mrc	p15, 0, r1, c2, c0, 2	@ TTBCR
85	and	r1, r1, #(HTCR_MASK & ~TTBCR_T0SZ)
86	orr	r0, r0, r1
87	mcr	p15, 4, r0, c2, c0, 2	@ HTCR
88
89	@ Use the same memory attributes for hyp. accesses as the kernel
90	@ (copy MAIRx ro HMAIRx).
91	mrc	p15, 0, r0, c10, c2, 0
92	mcr	p15, 4, r0, c10, c2, 0
93	mrc	p15, 0, r0, c10, c2, 1
94	mcr	p15, 4, r0, c10, c2, 1
95
96	@ Invalidate the stale TLBs from Bootloader
97	mcr	p15, 4, r0, c8, c7, 0	@ TLBIALLH
98	dsb	ish
99
100	@ Set the HSCTLR to:
101	@  - ARM/THUMB exceptions: Kernel config (Thumb-2 kernel)
102	@  - Endianness: Kernel config
103	@  - Fast Interrupt Features: Kernel config
104	@  - Write permission implies XN: disabled
105	@  - Instruction cache: enabled
106	@  - Data/Unified cache: enabled
107	@  - MMU: enabled (this code must be run from an identity mapping)
108	mrc	p15, 4, r0, c1, c0, 0	@ HSCR
109	ldr	r2, =HSCTLR_MASK
110	bic	r0, r0, r2
111	mrc	p15, 0, r1, c1, c0, 0	@ SCTLR
112	ldr	r2, =(HSCTLR_EE | HSCTLR_FI | HSCTLR_I | HSCTLR_C)
113	and	r1, r1, r2
114 ARM(	ldr	r2, =(HSCTLR_M)					)
115 THUMB(	ldr	r2, =(HSCTLR_M | HSCTLR_TE)			)
116	orr	r1, r1, r2
117	orr	r0, r0, r1
118	mcr	p15, 4, r0, c1, c0, 0	@ HSCR
119	isb
120
121	eret
122
123ENTRY(__kvm_handle_stub_hvc)
124	cmp	r0, #HVC_SOFT_RESTART
125	bne	1f
126
127	/* The target is expected in r1 */
128	msr	ELR_hyp, r1
129	mrs	r0, cpsr
130	bic	r0, r0, #MODE_MASK
131	orr	r0, r0, #HYP_MODE
132THUMB(	orr	r0, r0, #PSR_T_BIT	)
133	msr	spsr_cxsf, r0
134	b	reset
135
1361:	cmp	r0, #HVC_RESET_VECTORS
137	bne	1f
138
139reset:
140	/* We're now in idmap, disable MMU */
141	mrc	p15, 4, r1, c1, c0, 0	@ HSCTLR
142	ldr	r0, =(HSCTLR_M | HSCTLR_A | HSCTLR_C | HSCTLR_I)
143	bic	r1, r1, r0
144	mcr	p15, 4, r1, c1, c0, 0	@ HSCTLR
145
146	/*
147	 * Install stub vectors, using ardb's VA->PA trick.
148	 */
1490:	adr	r0, 0b					@ PA(0)
150	movw	r1, #:lower16:__hyp_stub_vectors - 0b   @ VA(stub) - VA(0)
151	movt	r1, #:upper16:__hyp_stub_vectors - 0b
152	add	r1, r1, r0				@ PA(stub)
153	mcr	p15, 4, r1, c12, c0, 0	@ HVBAR
154	b	exit
155
1561:	ldr	r0, =HVC_STUB_ERR
157	eret
158
159exit:
160	mov	r0, #0
161	eret
162ENDPROC(__kvm_handle_stub_hvc)
163
164	.ltorg
165
166	.globl __kvm_hyp_init_end
167__kvm_hyp_init_end:
168
169	.popsection
170