1/* 2 * Copyright (C) 2015 - 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/asm-offsets.h> 21#include <asm/assembler.h> 22#include <asm/fpsimdmacros.h> 23#include <asm/kvm.h> 24#include <asm/kvm_arm.h> 25#include <asm/kvm_asm.h> 26#include <asm/kvm_mmu.h> 27#include <asm/kvm_ptrauth.h> 28 29#define CPU_GP_REG_OFFSET(x) (CPU_GP_REGS + x) 30#define CPU_XREG_OFFSET(x) CPU_GP_REG_OFFSET(CPU_USER_PT_REGS + 8*x) 31 32 .text 33 .pushsection .hyp.text, "ax" 34 35.macro save_callee_saved_regs ctxt 36 stp x19, x20, [\ctxt, #CPU_XREG_OFFSET(19)] 37 stp x21, x22, [\ctxt, #CPU_XREG_OFFSET(21)] 38 stp x23, x24, [\ctxt, #CPU_XREG_OFFSET(23)] 39 stp x25, x26, [\ctxt, #CPU_XREG_OFFSET(25)] 40 stp x27, x28, [\ctxt, #CPU_XREG_OFFSET(27)] 41 stp x29, lr, [\ctxt, #CPU_XREG_OFFSET(29)] 42.endm 43 44.macro restore_callee_saved_regs ctxt 45 ldp x19, x20, [\ctxt, #CPU_XREG_OFFSET(19)] 46 ldp x21, x22, [\ctxt, #CPU_XREG_OFFSET(21)] 47 ldp x23, x24, [\ctxt, #CPU_XREG_OFFSET(23)] 48 ldp x25, x26, [\ctxt, #CPU_XREG_OFFSET(25)] 49 ldp x27, x28, [\ctxt, #CPU_XREG_OFFSET(27)] 50 ldp x29, lr, [\ctxt, #CPU_XREG_OFFSET(29)] 51.endm 52 53/* 54 * u64 __guest_enter(struct kvm_vcpu *vcpu, 55 * struct kvm_cpu_context *host_ctxt); 56 */ 57ENTRY(__guest_enter) 58 // x0: vcpu 59 // x1: host context 60 // x2-x17: clobbered by macros 61 // x18: guest context 62 63 // Store the host regs 64 save_callee_saved_regs x1 65 66 add x18, x0, #VCPU_CONTEXT 67 68 // Macro ptrauth_switch_to_guest format: 69 // ptrauth_switch_to_guest(guest cxt, tmp1, tmp2, tmp3) 70 // The below macro to restore guest keys is not implemented in C code 71 // as it may cause Pointer Authentication key signing mismatch errors 72 // when this feature is enabled for kernel code. 73 ptrauth_switch_to_guest x18, x0, x1, x2 74 75 // Restore guest regs x0-x17 76 ldp x0, x1, [x18, #CPU_XREG_OFFSET(0)] 77 ldp x2, x3, [x18, #CPU_XREG_OFFSET(2)] 78 ldp x4, x5, [x18, #CPU_XREG_OFFSET(4)] 79 ldp x6, x7, [x18, #CPU_XREG_OFFSET(6)] 80 ldp x8, x9, [x18, #CPU_XREG_OFFSET(8)] 81 ldp x10, x11, [x18, #CPU_XREG_OFFSET(10)] 82 ldp x12, x13, [x18, #CPU_XREG_OFFSET(12)] 83 ldp x14, x15, [x18, #CPU_XREG_OFFSET(14)] 84 ldp x16, x17, [x18, #CPU_XREG_OFFSET(16)] 85 86 // Restore guest regs x19-x29, lr 87 restore_callee_saved_regs x18 88 89 // Restore guest reg x18 90 ldr x18, [x18, #CPU_XREG_OFFSET(18)] 91 92 // Do not touch any register after this! 93 eret 94 sb 95ENDPROC(__guest_enter) 96 97ENTRY(__guest_exit) 98 // x0: return code 99 // x1: vcpu 100 // x2-x29,lr: vcpu regs 101 // vcpu x0-x1 on the stack 102 103 add x1, x1, #VCPU_CONTEXT 104 105 ALTERNATIVE(nop, SET_PSTATE_PAN(1), ARM64_HAS_PAN, CONFIG_ARM64_PAN) 106 107 // Store the guest regs x2 and x3 108 stp x2, x3, [x1, #CPU_XREG_OFFSET(2)] 109 110 // Retrieve the guest regs x0-x1 from the stack 111 ldp x2, x3, [sp], #16 // x0, x1 112 113 // Store the guest regs x0-x1 and x4-x18 114 stp x2, x3, [x1, #CPU_XREG_OFFSET(0)] 115 stp x4, x5, [x1, #CPU_XREG_OFFSET(4)] 116 stp x6, x7, [x1, #CPU_XREG_OFFSET(6)] 117 stp x8, x9, [x1, #CPU_XREG_OFFSET(8)] 118 stp x10, x11, [x1, #CPU_XREG_OFFSET(10)] 119 stp x12, x13, [x1, #CPU_XREG_OFFSET(12)] 120 stp x14, x15, [x1, #CPU_XREG_OFFSET(14)] 121 stp x16, x17, [x1, #CPU_XREG_OFFSET(16)] 122 str x18, [x1, #CPU_XREG_OFFSET(18)] 123 124 // Store the guest regs x19-x29, lr 125 save_callee_saved_regs x1 126 127 get_host_ctxt x2, x3 128 129 // Macro ptrauth_switch_to_guest format: 130 // ptrauth_switch_to_host(guest cxt, host cxt, tmp1, tmp2, tmp3) 131 // The below macro to save/restore keys is not implemented in C code 132 // as it may cause Pointer Authentication key signing mismatch errors 133 // when this feature is enabled for kernel code. 134 ptrauth_switch_to_host x1, x2, x3, x4, x5 135 136 // Now restore the host regs 137 restore_callee_saved_regs x2 138 139alternative_if ARM64_HAS_RAS_EXTN 140 // If we have the RAS extensions we can consume a pending error 141 // without an unmask-SError and isb. 142 esb 143 mrs_s x2, SYS_DISR_EL1 144 str x2, [x1, #(VCPU_FAULT_DISR - VCPU_CONTEXT)] 145 cbz x2, 1f 146 msr_s SYS_DISR_EL1, xzr 147 orr x0, x0, #(1<<ARM_EXIT_WITH_SERROR_BIT) 1481: ret 149alternative_else 150 // If we have a pending asynchronous abort, now is the 151 // time to find out. From your VAXorcist book, page 666: 152 // "Threaten me not, oh Evil one! For I speak with 153 // the power of DEC, and I command thee to show thyself!" 154 mrs x2, elr_el2 155 mrs x3, esr_el2 156 mrs x4, spsr_el2 157 mov x5, x0 158 159 dsb sy // Synchronize against in-flight ld/st 160 nop 161 msr daifclr, #4 // Unmask aborts 162alternative_endif 163 164 // This is our single instruction exception window. A pending 165 // SError is guaranteed to occur at the earliest when we unmask 166 // it, and at the latest just after the ISB. 167 .global abort_guest_exit_start 168abort_guest_exit_start: 169 170 isb 171 172 .global abort_guest_exit_end 173abort_guest_exit_end: 174 175 // If the exception took place, restore the EL1 exception 176 // context so that we can report some information. 177 // Merge the exception code with the SError pending bit. 178 tbz x0, #ARM_EXIT_WITH_SERROR_BIT, 1f 179 msr elr_el2, x2 180 msr esr_el2, x3 181 msr spsr_el2, x4 182 orr x0, x0, x5 1831: ret 184ENDPROC(__guest_exit) 185