1 /* SPDX-License-Identifier: GPL-2.0-only */ 2 /* 3 * Hypervisor stub 4 * 5 * Copyright (C) 2012 ARM Ltd. 6 * Author: Marc Zyngier <marc.zyngier@arm.com> 7 */ 8 9 #include <linux/init.h> 10 #include <linux/linkage.h> 11 12 #include <asm/assembler.h> 13 #include <asm/el2_setup.h> 14 #include <asm/kvm_arm.h> 15 #include <asm/kvm_asm.h> 16 #include <asm/ptrace.h> 17 #include <asm/virt.h> 18 19 .text 20 .pushsection .hyp.text, "ax" 21 22 .align 11 23 24 SYM_CODE_START(__hyp_stub_vectors) 25 ventry el2_sync_invalid // Synchronous EL2t 26 ventry el2_irq_invalid // IRQ EL2t 27 ventry el2_fiq_invalid // FIQ EL2t 28 ventry el2_error_invalid // Error EL2t 29 30 ventry elx_sync // Synchronous EL2h 31 ventry el2_irq_invalid // IRQ EL2h 32 ventry el2_fiq_invalid // FIQ EL2h 33 ventry el2_error_invalid // Error EL2h 34 35 ventry elx_sync // Synchronous 64-bit EL1 36 ventry el1_irq_invalid // IRQ 64-bit EL1 37 ventry el1_fiq_invalid // FIQ 64-bit EL1 38 ventry el1_error_invalid // Error 64-bit EL1 39 40 ventry el1_sync_invalid // Synchronous 32-bit EL1 41 ventry el1_irq_invalid // IRQ 32-bit EL1 42 ventry el1_fiq_invalid // FIQ 32-bit EL1 43 ventry el1_error_invalid // Error 32-bit EL1 44 SYM_CODE_END(__hyp_stub_vectors) 45 46 .align 11 47 48 SYM_CODE_START_LOCAL(elx_sync) 49 cmp x0, #HVC_SET_VECTORS 50 b.ne 1f 51 msr vbar_el2, x1 52 b 9f 53 54 1: cmp x0, #HVC_FINALISE_EL2 55 b.eq __finalise_el2 56 57 2: cmp x0, #HVC_SOFT_RESTART 58 b.ne 3f 59 mov x0, x2 60 mov x2, x4 61 mov x4, x1 62 mov x1, x3 63 br x4 // no return 64 65 3: cmp x0, #HVC_RESET_VECTORS 66 beq 9f // Nothing to reset! 67 68 /* Someone called kvm_call_hyp() against the hyp-stub... */ 69 mov_q x0, HVC_STUB_ERR 70 eret 71 72 9: mov x0, xzr 73 eret 74 SYM_CODE_END(elx_sync) 75 76 SYM_CODE_START_LOCAL(__finalise_el2) 77 finalise_el2_state 78 79 // nVHE? No way! Give me the real thing! 80 // Sanity check: MMU *must* be off 81 mrs x1, sctlr_el2 82 tbnz x1, #0, 1f 83 84 // Needs to be VHE capable, obviously 85 check_override id_aa64mmfr1 ID_AA64MMFR1_EL1_VH_SHIFT 0f 1f x1 x2 86 87 0: // Check whether we only want the hypervisor to run VHE, not the kernel 88 adr_l x1, arm64_sw_feature_override 89 ldr x2, [x1, FTR_OVR_VAL_OFFSET] 90 ldr x1, [x1, FTR_OVR_MASK_OFFSET] 91 and x2, x2, x1 92 ubfx x2, x2, #ARM64_SW_FEATURE_OVERRIDE_HVHE, #4 93 cbz x2, 2f 94 95 1: mov_q x0, HVC_STUB_ERR 96 eret 97 2: 98 // Engage the VHE magic! 99 mov_q x0, HCR_HOST_VHE_FLAGS 100 msr hcr_el2, x0 101 isb 102 103 // Use the EL1 allocated stack, per-cpu offset 104 mrs x0, sp_el1 105 mov sp, x0 106 mrs x0, tpidr_el1 107 msr tpidr_el2, x0 108 109 // FP configuration, vectors 110 mrs_s x0, SYS_CPACR_EL12 111 msr cpacr_el1, x0 112 mrs_s x0, SYS_VBAR_EL12 113 msr vbar_el1, x0 114 115 // Use EL2 translations for SPE & TRBE and disable access from EL1 116 mrs x0, mdcr_el2 117 bic x0, x0, #(MDCR_EL2_E2PB_MASK << MDCR_EL2_E2PB_SHIFT) 118 bic x0, x0, #(MDCR_EL2_E2TB_MASK << MDCR_EL2_E2TB_SHIFT) 119 msr mdcr_el2, x0 120 121 // Transfer the MM state from EL1 to EL2 122 mrs_s x0, SYS_TCR_EL12 123 msr tcr_el1, x0 124 mrs_s x0, SYS_TTBR0_EL12 125 msr ttbr0_el1, x0 126 mrs_s x0, SYS_TTBR1_EL12 127 msr ttbr1_el1, x0 128 mrs_s x0, SYS_MAIR_EL12 129 msr mair_el1, x0 130 mrs x1, REG_ID_AA64MMFR3_EL1 131 ubfx x1, x1, #ID_AA64MMFR3_EL1_TCRX_SHIFT, #4 132 cbz x1, .Lskip_tcr2 133 mrs x0, REG_TCR2_EL12 134 msr REG_TCR2_EL1, x0 135 136 // Transfer permission indirection state 137 mrs x1, REG_ID_AA64MMFR3_EL1 138 ubfx x1, x1, #ID_AA64MMFR3_EL1_S1PIE_SHIFT, #4 139 cbz x1, .Lskip_indirection 140 mrs x0, REG_PIRE0_EL12 141 msr REG_PIRE0_EL1, x0 142 mrs x0, REG_PIR_EL12 143 msr REG_PIR_EL1, x0 144 145 .Lskip_indirection: 146 .Lskip_tcr2: 147 148 isb 149 150 // Hack the exception return to stay at EL2 151 mrs x0, spsr_el1 152 and x0, x0, #~PSR_MODE_MASK 153 mov x1, #PSR_MODE_EL2h 154 orr x0, x0, x1 155 msr spsr_el1, x0 156 157 b enter_vhe 158 SYM_CODE_END(__finalise_el2) 159 160 // At the point where we reach enter_vhe(), we run with 161 // the MMU off (which is enforced by __finalise_el2()). 162 // We thus need to be in the idmap, or everything will 163 // explode when enabling the MMU. 164 165 .pushsection .idmap.text, "ax" 166 167 SYM_CODE_START_LOCAL(enter_vhe) 168 // Invalidate TLBs before enabling the MMU 169 tlbi vmalle1 170 dsb nsh 171 isb 172 173 // Enable the EL2 S1 MMU, as set up from EL1 174 mrs_s x0, SYS_SCTLR_EL12 175 set_sctlr_el1 x0 176 177 // Disable the EL1 S1 MMU for a good measure 178 mov_q x0, INIT_SCTLR_EL1_MMU_OFF 179 msr_s SYS_SCTLR_EL12, x0 180 181 mov x0, xzr 182 183 eret 184 SYM_CODE_END(enter_vhe) 185 186 .popsection 187 188 .macro invalid_vector label 189 SYM_CODE_START_LOCAL(\label) 190 b \label 191 SYM_CODE_END(\label) 192 .endm 193 194 invalid_vector el2_sync_invalid 195 invalid_vector el2_irq_invalid 196 invalid_vector el2_fiq_invalid 197 invalid_vector el2_error_invalid 198 invalid_vector el1_sync_invalid 199 invalid_vector el1_irq_invalid 200 invalid_vector el1_fiq_invalid 201 invalid_vector el1_error_invalid 202 203 .popsection 204 205 /* 206 * __hyp_set_vectors: Call this after boot to set the initial hypervisor 207 * vectors as part of hypervisor installation. On an SMP system, this should 208 * be called on each CPU. 209 * 210 * x0 must be the physical address of the new vector table, and must be 211 * 2KB aligned. 212 * 213 * Before calling this, you must check that the stub hypervisor is installed 214 * everywhere, by waiting for any secondary CPUs to be brought up and then 215 * checking that is_hyp_mode_available() is true. 216 * 217 * If not, there is a pre-existing hypervisor, some CPUs failed to boot, or 218 * something else went wrong... in such cases, trying to install a new 219 * hypervisor is unlikely to work as desired. 220 * 221 * When you call into your shiny new hypervisor, sp_el2 will contain junk, 222 * so you will need to set that to something sensible at the new hypervisor's 223 * initialisation entry point. 224 */ 225 226 SYM_FUNC_START(__hyp_set_vectors) 227 mov x1, x0 228 mov x0, #HVC_SET_VECTORS 229 hvc #0 230 ret 231 SYM_FUNC_END(__hyp_set_vectors) 232 233 SYM_FUNC_START(__hyp_reset_vectors) 234 mov x0, #HVC_RESET_VECTORS 235 hvc #0 236 ret 237 SYM_FUNC_END(__hyp_reset_vectors) 238 239 /* 240 * Entry point to finalise EL2 and switch to VHE if deemed capable 241 * 242 * w0: boot mode, as returned by init_kernel_el() 243 */ 244 SYM_FUNC_START(finalise_el2) 245 // Need to have booted at EL2 246 cmp w0, #BOOT_CPU_MODE_EL2 247 b.ne 1f 248 249 // and still be at EL1 250 mrs x0, CurrentEL 251 cmp x0, #CurrentEL_EL1 252 b.ne 1f 253 254 mov x0, #HVC_FINALISE_EL2 255 hvc #0 256 1: 257 ret 258 SYM_FUNC_END(finalise_el2)
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