arch/arm64/kernel/hyp-stub.S

   1 /*
   2  * Hypervisor stub
   3  *
   4  * Copyright (C) 2012 ARM Ltd.
   5  * Author:      Marc Zyngier <marc.zyngier@arm.com>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #include <linux/init.h>
  21 #include <linux/linkage.h>
  22
  23 #include <asm/assembler.h>
  24 #include <asm/ptrace.h>
  25 #include <asm/virt.h>
  26
  27         .text
  28         .align 11
  29
  30 ENTRY(__hyp_stub_vectors)
  31         ventry  el2_sync_invalid                // Synchronous EL2t
  32         ventry  el2_irq_invalid                 // IRQ EL2t
  33         ventry  el2_fiq_invalid                 // FIQ EL2t
  34         ventry  el2_error_invalid               // Error EL2t
  35
  36         ventry  el2_sync_invalid                // Synchronous EL2h
  37         ventry  el2_irq_invalid                 // IRQ EL2h
  38         ventry  el2_fiq_invalid                 // FIQ EL2h
  39         ventry  el2_error_invalid               // Error EL2h
  40
  41         ventry  el1_sync                        // Synchronous 64-bit EL1
  42         ventry  el1_irq_invalid                 // IRQ 64-bit EL1
  43         ventry  el1_fiq_invalid                 // FIQ 64-bit EL1
  44         ventry  el1_error_invalid               // Error 64-bit EL1
  45
  46         ventry  el1_sync_invalid                // Synchronous 32-bit EL1
  47         ventry  el1_irq_invalid                 // IRQ 32-bit EL1
  48         ventry  el1_fiq_invalid                 // FIQ 32-bit EL1
  49         ventry  el1_error_invalid               // Error 32-bit EL1
  50 ENDPROC(__hyp_stub_vectors)
  51
  52         .align 11
  53
  54 el1_sync:
  55         mrs     x1, esr_el2
  56         lsr     x1, x1, #26
  57         cmp     x1, #0x16
  58         b.ne    2f                              // Not an HVC trap
  59         cbz     x0, 1f
  60         msr     vbar_el2, x0                    // Set vbar_el2
  61         b       2f
  62 1:      mrs     x0, vbar_el2                    // Return vbar_el2
  63 2:      eret
  64 ENDPROC(el1_sync)
  65
  66 .macro invalid_vector   label
  67 \label:
  68         b \label
  69 ENDPROC(\label)
  70 .endm
  71
  72         invalid_vector  el2_sync_invalid
  73         invalid_vector  el2_irq_invalid
  74         invalid_vector  el2_fiq_invalid
  75         invalid_vector  el2_error_invalid
  76         invalid_vector  el1_sync_invalid
  77         invalid_vector  el1_irq_invalid
  78         invalid_vector  el1_fiq_invalid
  79         invalid_vector  el1_error_invalid
  80
  81 /*
  82  * __hyp_set_vectors: Call this after boot to set the initial hypervisor
  83  * vectors as part of hypervisor installation.  On an SMP system, this should
  84  * be called on each CPU.
  85  *
  86  * x0 must be the physical address of the new vector table, and must be
  87  * 2KB aligned.
  88  *
  89  * Before calling this, you must check that the stub hypervisor is installed
  90  * everywhere, by waiting for any secondary CPUs to be brought up and then
  91  * checking that is_hyp_mode_available() is true.
  92  *
  93  * If not, there is a pre-existing hypervisor, some CPUs failed to boot, or
  94  * something else went wrong... in such cases, trying to install a new
  95  * hypervisor is unlikely to work as desired.
  96  *
  97  * When you call into your shiny new hypervisor, sp_el2 will contain junk,
  98  * so you will need to set that to something sensible at the new hypervisor's
  99  * initialisation entry point.
 100  */
 101
 102 ENTRY(__hyp_get_vectors)
 103         mov     x0, xzr
 104         // fall through
 105 ENTRY(__hyp_set_vectors)
 106         hvc     #0
 107         ret
 108 ENDPROC(__hyp_get_vectors)
 109 ENDPROC(__hyp_set_vectors)