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	 */
 61__do_hyp_init:
 62	/* Check for a stub HVC call */
 63	cmp	x0, #HVC_STUB_HCALL_NR
 64	b.lo	__kvm_handle_stub_hvc
 65
 66	phys_to_ttbr x4, x0
 67	msr	ttbr0_el2, x4
 68
 69	mrs	x4, tcr_el1
 70	ldr	x5, =TCR_EL2_MASK
 71	and	x4, x4, x5
 72	mov	x5, #TCR_EL2_RES1
 73	orr	x4, x4, x5
 74
 75	/*
 76	 * The ID map may be configured to use an extended virtual address
 77	 * range. This is only the case if system RAM is out of range for the
 78	 * currently configured page size and VA_BITS, in which case we will
 79	 * also need the extended virtual range for the HYP ID map, or we won't
 80	 * be able to enable the EL2 MMU.
 81	 *
 82	 * However, at EL2, there is only one TTBR register, and we can't switch
 83	 * between translation tables *and* update TCR_EL2.T0SZ at the same
 84	 * time. Bottom line: we need to use the extended range with *both* our
 85	 * translation tables.
 86	 *
 87	 * So use the same T0SZ value we use for the ID map.
 88	 */
 89	ldr_l	x5, idmap_t0sz
 90	bfi	x4, x5, TCR_T0SZ_OFFSET, TCR_TxSZ_WIDTH
 91
 92	/*
 93	 * Set the PS bits in TCR_EL2.
 94	 */
 95	tcr_compute_pa_size x4, #TCR_EL2_PS_SHIFT, x5, x6
 96
 97	msr	tcr_el2, x4
 98
 99	mrs	x4, mair_el1
100	msr	mair_el2, x4
101	isb
102
103	/* Invalidate the stale TLBs from Bootloader */
104	tlbi	alle2
105	dsb	sy
106
107	/*
108	 * Preserve all the RES1 bits while setting the default flags,
109	 * as well as the EE bit on BE. Drop the A flag since the compiler
110	 * is allowed to generate unaligned accesses.
111	 */
112	ldr	x4, =(SCTLR_EL2_RES1 | (SCTLR_ELx_FLAGS & ~SCTLR_ELx_A))
113CPU_BE(	orr	x4, x4, #SCTLR_ELx_EE)
114	msr	sctlr_el2, x4
115	isb
116
117	/* Set the stack and new vectors */
118	kern_hyp_va	x1
119	mov	sp, x1
120	msr	vbar_el2, x2
121
122	/* copy tpidr_el1 into tpidr_el2 for use by HYP */
123	mrs	x1, tpidr_el1
124	msr	tpidr_el2, x1
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