1/* SPDX-License-Identifier: GPL-2.0-only */
  2/*
  3 * Copyright (C) 2012 - Virtual Open Systems and Columbia University
  4 * Author: Christoffer Dall <c.dall@virtualopensystems.com>
  5 */
  6
  7#include <linux/linkage.h>
  8#include <asm/assembler.h>
  9#include <asm/unified.h>
 10#include <asm/asm-offsets.h>
 11#include <asm/kvm_asm.h>
 12#include <asm/kvm_arm.h>
 13#include <asm/kvm_mmu.h>
 14#include <asm/virt.h>
 15
 16/********************************************************************
 17 * Hypervisor initialization
 18 *   - should be called with:
 19 *       r0 = top of Hyp stack (kernel VA)
 20 *       r1 = pointer to hyp vectors
 21 *       r2,r3 = Hypervisor pgd pointer
 22 *
 23 * The init scenario is:
 24 * - We jump in HYP with 3 parameters: runtime HYP pgd, runtime stack,
 25 *   runtime vectors
 26 * - Invalidate TLBs
 27 * - Set stack and vectors
 28 * - Setup the page tables
 29 * - Enable the MMU
 30 * - Profit! (or eret, if you only care about the code).
 31 *
 32 * Another possibility is to get a HYP stub hypercall.
 33 * We discriminate between the two by checking if r0 contains a value
 34 * that is less than HVC_STUB_HCALL_NR.
 35 */
 36
 37	.text
 38	.pushsection    .hyp.idmap.text,"ax"
 39	.align 5
 40__kvm_hyp_init:
 41	.globl __kvm_hyp_init
 42
 43	@ Hyp-mode exception vector
 44	W(b)	.
 45	W(b)	.
 46	W(b)	.
 47	W(b)	.
 48	W(b)	.
 49	W(b)	__do_hyp_init
 50	W(b)	.
 51	W(b)	.
 52
 53__do_hyp_init:
 54	@ Check for a stub hypercall
 55	cmp	r0, #HVC_STUB_HCALL_NR
 56	blo	__kvm_handle_stub_hvc
 57
 58	@ Set stack pointer
 59	mov	sp, r0
 60
 61	@ Set HVBAR to point to the HYP vectors
 62	mcr	p15, 4, r1, c12, c0, 0	@ HVBAR
 63
 64	@ Set the HTTBR to point to the hypervisor PGD pointer passed
 65	mcrr	p15, 4, rr_lo_hi(r2, r3), c2
 66
 67	@ Set the HTCR and VTCR to the same shareability and cacheability
 68	@ settings as the non-secure TTBCR and with T0SZ == 0.
 69	mrc	p15, 4, r0, c2, c0, 2	@ HTCR
 70	ldr	r2, =HTCR_MASK
 71	bic	r0, r0, r2
 72	mrc	p15, 0, r1, c2, c0, 2	@ TTBCR
 73	and	r1, r1, #(HTCR_MASK & ~TTBCR_T0SZ)
 74	orr	r0, r0, r1
 75	mcr	p15, 4, r0, c2, c0, 2	@ HTCR
 76
 77	@ Use the same memory attributes for hyp. accesses as the kernel
 78	@ (copy MAIRx ro HMAIRx).
 79	mrc	p15, 0, r0, c10, c2, 0
 80	mcr	p15, 4, r0, c10, c2, 0
 81	mrc	p15, 0, r0, c10, c2, 1
 82	mcr	p15, 4, r0, c10, c2, 1
 83
 84	@ Invalidate the stale TLBs from Bootloader
 85	mcr	p15, 4, r0, c8, c7, 0	@ TLBIALLH
 86	dsb	ish
 87
 88	@ Set the HSCTLR to:
 89	@  - ARM/THUMB exceptions: Kernel config (Thumb-2 kernel)
 90	@  - Endianness: Kernel config
 91	@  - Fast Interrupt Features: Kernel config
 92	@  - Write permission implies XN: disabled
 93	@  - Instruction cache: enabled
 94	@  - Data/Unified cache: enabled
 95	@  - MMU: enabled (this code must be run from an identity mapping)
 96	mrc	p15, 4, r0, c1, c0, 0	@ HSCR
 97	ldr	r2, =HSCTLR_MASK
 98	bic	r0, r0, r2
 99	mrc	p15, 0, r1, c1, c0, 0	@ SCTLR
100	ldr	r2, =(HSCTLR_EE | HSCTLR_FI | HSCTLR_I | HSCTLR_C)
101	and	r1, r1, r2
102 ARM(	ldr	r2, =(HSCTLR_M)					)
103 THUMB(	ldr	r2, =(HSCTLR_M | HSCTLR_TE)			)
104	orr	r1, r1, r2
105	orr	r0, r0, r1
106	mcr	p15, 4, r0, c1, c0, 0	@ HSCR
107	isb
108
109	eret
110
111ENTRY(__kvm_handle_stub_hvc)
112	cmp	r0, #HVC_SOFT_RESTART
113	bne	1f
114
115	/* The target is expected in r1 */
116	msr	ELR_hyp, r1
117	mrs	r0, cpsr
118	bic	r0, r0, #MODE_MASK
119	orr	r0, r0, #HYP_MODE
120THUMB(	orr	r0, r0, #PSR_T_BIT	)
121	msr	spsr_cxsf, r0
122	b	reset
123
1241:	cmp	r0, #HVC_RESET_VECTORS
125	bne	1f
126
127reset:
128	/* We're now in idmap, disable MMU */
129	mrc	p15, 4, r1, c1, c0, 0	@ HSCTLR
130	ldr	r0, =(HSCTLR_M | HSCTLR_A | HSCTLR_C | HSCTLR_I)
131	bic	r1, r1, r0
132	mcr	p15, 4, r1, c1, c0, 0	@ HSCTLR
133
134	/*
135	 * Install stub vectors, using ardb's VA->PA trick.
136	 */
1370:	adr	r0, 0b					@ PA(0)
138	movw	r1, #:lower16:__hyp_stub_vectors - 0b   @ VA(stub) - VA(0)
139	movt	r1, #:upper16:__hyp_stub_vectors - 0b
140	add	r1, r1, r0				@ PA(stub)
141	mcr	p15, 4, r1, c12, c0, 0	@ HVBAR
142	b	exit
143
1441:	ldr	r0, =HVC_STUB_ERR
145	eret
146
147exit:
148	mov	r0, #0
149	eret
150ENDPROC(__kvm_handle_stub_hvc)
151
152	.ltorg
153
154	.globl __kvm_hyp_init_end
155__kvm_hyp_init_end:
156
157	.popsection