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linux-next/arch/arm64/kernel/hyp-stub.S
Marc Zyngier 712c6ff4db arm64: add hypervisor stub
If booted in EL2, install an dummy hypervisor whose only purpose
is to be replaced by a full fledged one.

A minimal API allows to:
- obtain the current HYP vectors (__hyp_get_vectors)
- set new HYP vectors (__hyp_set_vectors)

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2012-12-05 11:26:49 +00:00

110 lines
3.1 KiB
ArmAsm

/*
* Hypervisor stub
*
* Copyright (C) 2012 ARM Ltd.
* Author: Marc Zyngier <marc.zyngier@arm.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <linux/init.h>
#include <linux/linkage.h>
#include <asm/assembler.h>
#include <asm/ptrace.h>
#include <asm/virt.h>
.text
.align 11
ENTRY(__hyp_stub_vectors)
ventry el2_sync_invalid // Synchronous EL2t
ventry el2_irq_invalid // IRQ EL2t
ventry el2_fiq_invalid // FIQ EL2t
ventry el2_error_invalid // Error EL2t
ventry el2_sync_invalid // Synchronous EL2h
ventry el2_irq_invalid // IRQ EL2h
ventry el2_fiq_invalid // FIQ EL2h
ventry el2_error_invalid // Error EL2h
ventry el1_sync // Synchronous 64-bit EL1
ventry el1_irq_invalid // IRQ 64-bit EL1
ventry el1_fiq_invalid // FIQ 64-bit EL1
ventry el1_error_invalid // Error 64-bit EL1
ventry el1_sync_invalid // Synchronous 32-bit EL1
ventry el1_irq_invalid // IRQ 32-bit EL1
ventry el1_fiq_invalid // FIQ 32-bit EL1
ventry el1_error_invalid // Error 32-bit EL1
ENDPROC(__hyp_stub_vectors)
.align 11
el1_sync:
mrs x1, esr_el2
lsr x1, x1, #26
cmp x1, #0x16
b.ne 2f // Not an HVC trap
cbz x0, 1f
msr vbar_el2, x0 // Set vbar_el2
b 2f
1: mrs x0, vbar_el2 // Return vbar_el2
2: eret
ENDPROC(el1_sync)
.macro invalid_vector label
\label:
b \label
ENDPROC(\label)
.endm
invalid_vector el2_sync_invalid
invalid_vector el2_irq_invalid
invalid_vector el2_fiq_invalid
invalid_vector el2_error_invalid
invalid_vector el1_sync_invalid
invalid_vector el1_irq_invalid
invalid_vector el1_fiq_invalid
invalid_vector el1_error_invalid
/*
* __hyp_set_vectors: Call this after boot to set the initial hypervisor
* vectors as part of hypervisor installation. On an SMP system, this should
* be called on each CPU.
*
* x0 must be the physical address of the new vector table, and must be
* 2KB aligned.
*
* Before calling this, you must check that the stub hypervisor is installed
* everywhere, by waiting for any secondary CPUs to be brought up and then
* checking that is_hyp_mode_available() is true.
*
* If not, there is a pre-existing hypervisor, some CPUs failed to boot, or
* something else went wrong... in such cases, trying to install a new
* hypervisor is unlikely to work as desired.
*
* When you call into your shiny new hypervisor, sp_el2 will contain junk,
* so you will need to set that to something sensible at the new hypervisor's
* initialisation entry point.
*/
ENTRY(__hyp_get_vectors)
mov x0, xzr
// fall through
ENTRY(__hyp_set_vectors)
hvc #0
ret
ENDPROC(__hyp_get_vectors)
ENDPROC(__hyp_set_vectors)