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