arch/arm64/kvm/hyp/hyp-entry.S

   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/alternative.h>
  21 #include <asm/assembler.h>
  22 #include <asm/cpufeature.h>
  23 #include <asm/kvm_arm.h>
  24 #include <asm/kvm_asm.h>
  25 #include <asm/kvm_mmu.h>
  26
  27         .text
  28         .pushsection    .hyp.text, "ax"
  29
  30 .macro  save_x0_to_x3
  31         stp     x0, x1, [sp, #-16]!
  32         stp     x2, x3, [sp, #-16]!
  33 .endm
  34
  35 .macro  restore_x0_to_x3
  36         ldp     x2, x3, [sp], #16
  37         ldp     x0, x1, [sp], #16
  38 .endm
  39
  40 .macro do_el2_call
  41         /*
  42          * Shuffle the parameters before calling the function
  43          * pointed to in x0. Assumes parameters in x[1,2,3].
  44          */
  45         sub     sp, sp, #16
  46         str     lr, [sp]
  47         mov     lr, x0
  48         mov     x0, x1
  49         mov     x1, x2
  50         mov     x2, x3
  51         blr     lr
  52         ldr     lr, [sp]
  53         add     sp, sp, #16
  54 .endm
  55
  56 ENTRY(__vhe_hyp_call)
  57         do_el2_call
  58         /*
  59          * We used to rely on having an exception return to get
  60          * an implicit isb. In the E2H case, we don't have it anymore.
  61          * rather than changing all the leaf functions, just do it here
  62          * before returning to the rest of the kernel.
  63          */
  64         isb
  65         ret
  66 ENDPROC(__vhe_hyp_call)
  67
  68 el1_sync:                               // Guest trapped into EL2
  69         save_x0_to_x3
  70
  71 alternative_if_not ARM64_HAS_VIRT_HOST_EXTN
  72         mrs     x1, esr_el2
  73 alternative_else
  74         mrs     x1, esr_el1
  75 alternative_endif
  76         lsr     x2, x1, #ESR_ELx_EC_SHIFT
  77
  78         cmp     x2, #ESR_ELx_EC_HVC64
  79         b.ne    el1_trap
  80
  81         mrs     x3, vttbr_el2           // If vttbr is valid, the 64bit guest
  82         cbnz    x3, el1_trap            // called HVC
  83
  84         /* Here, we're pretty sure the host called HVC. */
  85         restore_x0_to_x3
  86
  87         /* Check for __hyp_get_vectors */
  88         cbnz    x0, 1f
  89         mrs     x0, vbar_el2
  90         b       2f
  91
  92 1:
  93         /*
  94          * Perform the EL2 call
  95          */
  96         kern_hyp_va     x0
  97         do_el2_call
  98
  99 2:      eret
 100
 101 el1_trap:
 102         /*
 103          * x1: ESR
 104          * x2: ESR_EC
 105          */
 106
 107         /* Guest accessed VFP/SIMD registers, save host, restore Guest */
 108         cmp     x2, #ESR_ELx_EC_FP_ASIMD
 109         b.eq    __fpsimd_guest_restore
 110
 111         mrs     x0, tpidr_el2
 112         mov     x1, #ARM_EXCEPTION_TRAP
 113         b       __guest_exit
 114
 115 el1_irq:
 116         save_x0_to_x3
 117         mrs     x0, tpidr_el2
 118         mov     x1, #ARM_EXCEPTION_IRQ
 119         b       __guest_exit
 120
 121 ENTRY(__hyp_do_panic)
 122         mov     lr, #(PSR_F_BIT | PSR_I_BIT | PSR_A_BIT | PSR_D_BIT |\
 123                       PSR_MODE_EL1h)
 124         msr     spsr_el2, lr
 125         ldr     lr, =panic
 126         msr     elr_el2, lr
 127         eret
 128 ENDPROC(__hyp_do_panic)
 129
 130 .macro invalid_vector   label, target = __hyp_panic
 131         .align  2
 132 \label:
 133         b \target
 134 ENDPROC(\label)
 135 .endm
 136
 137         /* None of these should ever happen */
 138         invalid_vector  el2t_sync_invalid
 139         invalid_vector  el2t_irq_invalid
 140         invalid_vector  el2t_fiq_invalid
 141         invalid_vector  el2t_error_invalid
 142         invalid_vector  el2h_sync_invalid
 143         invalid_vector  el2h_irq_invalid
 144         invalid_vector  el2h_fiq_invalid
 145         invalid_vector  el2h_error_invalid
 146         invalid_vector  el1_sync_invalid
 147         invalid_vector  el1_irq_invalid
 148         invalid_vector  el1_fiq_invalid
 149         invalid_vector  el1_error_invalid
 150
 151         .ltorg
 152
 153         .align 11
 154
 155 ENTRY(__kvm_hyp_vector)
 156         ventry  el2t_sync_invalid               // Synchronous EL2t
 157         ventry  el2t_irq_invalid                // IRQ EL2t
 158         ventry  el2t_fiq_invalid                // FIQ EL2t
 159         ventry  el2t_error_invalid              // Error EL2t
 160
 161         ventry  el2h_sync_invalid               // Synchronous EL2h
 162         ventry  el2h_irq_invalid                // IRQ EL2h
 163         ventry  el2h_fiq_invalid                // FIQ EL2h
 164         ventry  el2h_error_invalid              // Error EL2h
 165
 166         ventry  el1_sync                        // Synchronous 64-bit EL1
 167         ventry  el1_irq                         // IRQ 64-bit EL1
 168         ventry  el1_fiq_invalid                 // FIQ 64-bit EL1
 169         ventry  el1_error_invalid               // Error 64-bit EL1
 170
 171         ventry  el1_sync                        // Synchronous 32-bit EL1
 172         ventry  el1_irq                         // IRQ 32-bit EL1
 173         ventry  el1_fiq_invalid                 // FIQ 32-bit EL1
 174         ventry  el1_error_invalid               // Error 32-bit EL1
 175 ENDPROC(__kvm_hyp_vector)