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 msr ttbr0_el2, x0 67 68 mrs x4, tcr_el1 69 ldr x5, =TCR_EL2_MASK 70 and x4, x4, x5 71 mov x5, #TCR_EL2_RES1 72 orr x4, x4, x5 73 74#ifndef CONFIG_ARM64_VA_BITS_48 75 /* 76 * If we are running with VA_BITS < 48, we may be running with an extra 77 * level of translation in the ID map. This is only the case if system 78 * RAM is out of range for the currently configured page size and number 79 * of translation levels, in which case we will also need the extra 80 * level for the HYP ID map, or we won't 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 the extra level in *both* our translation 85 * 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#endif 92 /* 93 * Read the PARange bits from ID_AA64MMFR0_EL1 and set the PS bits in 94 * TCR_EL2. 95 */ 96 mrs x5, ID_AA64MMFR0_EL1 97 bfi x4, x5, #16, #3 98 99 msr tcr_el2, x4 100 101 mrs x4, mair_el1 102 msr mair_el2, x4 103 isb 104 105 /* Invalidate the stale TLBs from Bootloader */ 106 tlbi alle2 107 dsb sy 108 109 /* 110 * Preserve all the RES1 bits while setting the default flags, 111 * as well as the EE bit on BE. Drop the A flag since the compiler 112 * is allowed to generate unaligned accesses. 113 */ 114 ldr x4, =(SCTLR_EL2_RES1 | (SCTLR_ELx_FLAGS & ~SCTLR_ELx_A)) 115CPU_BE( orr x4, x4, #SCTLR_ELx_EE) 116 msr sctlr_el2, x4 117 isb 118 119 /* Set the stack and new vectors */ 120 kern_hyp_va x1 121 mov sp, x1 122 kern_hyp_va x2 123 msr vbar_el2, x2 124 125 /* Hello, World! */ 126 eret 127ENDPROC(__kvm_hyp_init) 128 129ENTRY(__kvm_handle_stub_hvc) 130 cmp x0, #HVC_SOFT_RESTART 131 b.ne 1f 132 133 /* This is where we're about to jump, staying at EL2 */ 134 msr elr_el2, x1 135 mov x0, #(PSR_F_BIT | PSR_I_BIT | PSR_A_BIT | PSR_D_BIT | PSR_MODE_EL2h) 136 msr spsr_el2, x0 137 138 /* Shuffle the arguments, and don't come back */ 139 mov x0, x2 140 mov x1, x3 141 mov x2, x4 142 b reset 143 1441: cmp x0, #HVC_RESET_VECTORS 145 b.ne 1f 146reset: 147 /* 148 * Reset kvm back to the hyp stub. Do not clobber x0-x4 in 149 * case we coming via HVC_SOFT_RESTART. 150 */ 151 mrs x5, sctlr_el2 152 ldr x6, =SCTLR_ELx_FLAGS 153 bic x5, x5, x6 // Clear SCTL_M and etc 154 msr sctlr_el2, x5 155 isb 156 157 /* Install stub vectors */ 158 adr_l x5, __hyp_stub_vectors 159 msr vbar_el2, x5 160 mov x0, xzr 161 eret 162 1631: /* Bad stub call */ 164 ldr x0, =HVC_STUB_ERR 165 eret 166 167ENDPROC(__kvm_handle_stub_hvc) 168 169 .ltorg 170 171 .popsection 172