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/*
* Copyright (C) 2012,2013 - 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/linkage.h>
#include <asm/assembler.h>
#include <asm/kvm_arm.h>
#include <asm/kvm_mmu.h>
#include <asm/pgtable-hwdef.h>
#include <asm/sysreg.h>
.text
.pushsection .hyp.idmap.text, "ax"
.align 11
ENTRY(__kvm_hyp_init)
ventry __invalid // Synchronous EL2t
ventry __invalid // IRQ EL2t
ventry __invalid // FIQ EL2t
ventry __invalid // Error EL2t
ventry __invalid // Synchronous EL2h
ventry __invalid // IRQ EL2h
ventry __invalid // FIQ EL2h
ventry __invalid // Error EL2h
ventry __do_hyp_init // Synchronous 64-bit EL1
ventry __invalid // IRQ 64-bit EL1
ventry __invalid // FIQ 64-bit EL1
ventry __invalid // Error 64-bit EL1
ventry __invalid // Synchronous 32-bit EL1
ventry __invalid // IRQ 32-bit EL1
ventry __invalid // FIQ 32-bit EL1
ventry __invalid // Error 32-bit EL1
__invalid:
b .
/*
* x0: HYP boot pgd
* x1: HYP pgd
* x2: HYP stack
* x3: HYP vectors
*/
__do_hyp_init:
msr ttbr0_el2, x0
mrs x4, tcr_el1
ldr x5, =TCR_EL2_MASK
and x4, x4, x5
mov x5, #TCR_EL2_RES1
orr x4, x4, x5
#ifndef CONFIG_ARM64_VA_BITS_48
/*
* If we are running with VA_BITS < 48, we may be running with an extra
* level of translation in the ID map. This is only the case if system
* RAM is out of range for the currently configured page size and number
* of translation levels, in which case we will also need the extra
* level for the HYP ID map, or we won't be able to enable the EL2 MMU.
*
* However, at EL2, there is only one TTBR register, and we can't switch
* between translation tables *and* update TCR_EL2.T0SZ at the same
* time. Bottom line: we need the extra level in *both* our translation
* tables.
*
* So use the same T0SZ value we use for the ID map.
*/
ldr_l x5, idmap_t0sz
bfi x4, x5, TCR_T0SZ_OFFSET, TCR_TxSZ_WIDTH
#endif
/*
* Read the PARange bits from ID_AA64MMFR0_EL1 and set the PS bits in
* TCR_EL2.
*/
mrs x5, ID_AA64MMFR0_EL1
bfi x4, x5, #16, #3
msr tcr_el2, x4
mrs x4, mair_el1
msr mair_el2, x4
isb
/* Invalidate the stale TLBs from Bootloader */
tlbi alle2
dsb sy
mrs x4, sctlr_el2
and x4, x4, #SCTLR_ELx_EE // preserve endianness of EL2
ldr x5, =SCTLR_ELx_FLAGS
orr x4, x4, x5
msr sctlr_el2, x4
isb
/* Skip the trampoline dance if we merged the boot and runtime PGDs */
cmp x0, x1
b.eq merged
/* MMU is now enabled. Get ready for the trampoline dance */
ldr x4, =TRAMPOLINE_VA
adr x5, target
bfi x4, x5, #0, #PAGE_SHIFT
br x4
target: /* We're now in the trampoline code, switch page tables */
msr ttbr0_el2, x1
isb
/* Invalidate the old TLBs */
tlbi alle2
dsb sy
merged:
/* Set the stack and new vectors */
kern_hyp_va x2
mov sp, x2
kern_hyp_va x3
msr vbar_el2, x3
/* Hello, World! */
eret
ENDPROC(__kvm_hyp_init)
/*
* Reset kvm back to the hyp stub. This is the trampoline dance in
* reverse. If kvm used an extended idmap, __extended_idmap_trampoline
* calls this code directly in the idmap. In this case switching to the
* boot tables is a no-op.
*
* x0: HYP boot pgd
* x1: HYP phys_idmap_start
*/
ENTRY(__kvm_hyp_reset)
/* We're in trampoline code in VA, switch back to boot page tables */
msr ttbr0_el2, x0
isb
/* Ensure the PA branch doesn't find a stale tlb entry or stale code. */
ic iallu
tlbi alle2
dsb sy
isb
/* Branch into PA space */
adr x0, 1f
bfi x1, x0, #0, #PAGE_SHIFT
br x1
/* We're now in idmap, disable MMU */
1: mrs x0, sctlr_el2
ldr x1, =SCTLR_ELx_FLAGS
bic x0, x0, x1 // Clear SCTL_M and etc
msr sctlr_el2, x0
isb
/* Invalidate the old TLBs */
tlbi alle2
dsb sy
/* Install stub vectors */
adr_l x0, __hyp_stub_vectors
msr vbar_el2, x0
eret
ENDPROC(__kvm_hyp_reset)
.ltorg
.popsection
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