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/*
* Copyright (C) 2012 - Virtual Open Systems and Columbia University
* Author: Christoffer Dall <c.dall@virtualopensystems.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, write to the Free Software
* Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
#include <linux/linkage.h>
#include <asm/assembler.h>
#include <asm/unified.h>
#include <asm/asm-offsets.h>
#include <asm/kvm_asm.h>
#include <asm/kvm_arm.h>
#include <asm/kvm_mmu.h>
#include <asm/virt.h>
/********************************************************************
* Hypervisor initialization
* - should be called with:
* r0 = top of Hyp stack (kernel VA)
* r1 = pointer to hyp vectors
* r2,r3 = Hypervisor pgd pointer
*
* The init scenario is:
* - We jump in HYP with 3 parameters: runtime HYP pgd, runtime stack,
* runtime vectors
* - Invalidate TLBs
* - Set stack and vectors
* - Setup the page tables
* - Enable the MMU
* - Profit! (or eret, if you only care about the code).
*
* Another possibility is to get a HYP stub hypercall.
* We discriminate between the two by checking if r0 contains a value
* that is less than HVC_STUB_HCALL_NR.
*/
.text
.pushsection .hyp.idmap.text,"ax"
.align 5
__kvm_hyp_init:
.globl __kvm_hyp_init
@ Hyp-mode exception vector
W(b) .
W(b) .
W(b) .
W(b) .
W(b) .
W(b) __do_hyp_init
W(b) .
W(b) .
__do_hyp_init:
@ Check for a stub hypercall
cmp r0, #HVC_STUB_HCALL_NR
blo __kvm_handle_stub_hvc
@ Set stack pointer
mov sp, r0
@ Set HVBAR to point to the HYP vectors
mcr p15, 4, r1, c12, c0, 0 @ HVBAR
@ Set the HTTBR to point to the hypervisor PGD pointer passed
mcrr p15, 4, rr_lo_hi(r2, r3), c2
@ Set the HTCR and VTCR to the same shareability and cacheability
@ settings as the non-secure TTBCR and with T0SZ == 0.
mrc p15, 4, r0, c2, c0, 2 @ HTCR
ldr r2, =HTCR_MASK
bic r0, r0, r2
mrc p15, 0, r1, c2, c0, 2 @ TTBCR
and r1, r1, #(HTCR_MASK & ~TTBCR_T0SZ)
orr r0, r0, r1
mcr p15, 4, r0, c2, c0, 2 @ HTCR
@ Use the same memory attributes for hyp. accesses as the kernel
@ (copy MAIRx ro HMAIRx).
mrc p15, 0, r0, c10, c2, 0
mcr p15, 4, r0, c10, c2, 0
mrc p15, 0, r0, c10, c2, 1
mcr p15, 4, r0, c10, c2, 1
@ Invalidate the stale TLBs from Bootloader
mcr p15, 4, r0, c8, c7, 0 @ TLBIALLH
dsb ish
@ Set the HSCTLR to:
@ - ARM/THUMB exceptions: Kernel config (Thumb-2 kernel)
@ - Endianness: Kernel config
@ - Fast Interrupt Features: Kernel config
@ - Write permission implies XN: disabled
@ - Instruction cache: enabled
@ - Data/Unified cache: enabled
@ - Memory alignment checks: enabled
@ - MMU: enabled (this code must be run from an identity mapping)
mrc p15, 4, r0, c1, c0, 0 @ HSCR
ldr r2, =HSCTLR_MASK
bic r0, r0, r2
mrc p15, 0, r1, c1, c0, 0 @ SCTLR
ldr r2, =(HSCTLR_EE | HSCTLR_FI | HSCTLR_I | HSCTLR_C)
and r1, r1, r2
ARM( ldr r2, =(HSCTLR_M | HSCTLR_A) )
THUMB( ldr r2, =(HSCTLR_M | HSCTLR_A | HSCTLR_TE) )
orr r1, r1, r2
orr r0, r0, r1
mcr p15, 4, r0, c1, c0, 0 @ HSCR
isb
eret
ENTRY(__kvm_handle_stub_hvc)
cmp r0, #HVC_GET_VECTORS
bne 1f
mrc p15, 4, r0, c12, c0, 0 @ get HVBAR
b exit
1: cmp r0, #HVC_SOFT_RESTART
bne 1f
/* The target is expected in r1 */
msr ELR_hyp, r1
mrs r0, cpsr
bic r0, r0, #MODE_MASK
orr r0, r0, #HYP_MODE
THUMB( orr r0, r0, #PSR_T_BIT )
msr spsr_cxsf, r0
b reset
1: cmp r0, #HVC_RESET_VECTORS
bne 1f
reset:
/* We're now in idmap, disable MMU */
mrc p15, 4, r1, c1, c0, 0 @ HSCTLR
ldr r0, =(HSCTLR_M | HSCTLR_A | HSCTLR_C | HSCTLR_I)
bic r1, r1, r0
mcr p15, 4, r1, c1, c0, 0 @ HSCTLR
/*
* Install stub vectors, using ardb's VA->PA trick.
*/
0: adr r0, 0b @ PA(0)
movw r1, #:lower16:__hyp_stub_vectors - 0b @ VA(stub) - VA(0)
movt r1, #:upper16:__hyp_stub_vectors - 0b
add r1, r1, r0 @ PA(stub)
mcr p15, 4, r1, c12, c0, 0 @ HVBAR
b exit
1: ldr r0, =HVC_STUB_ERR
exit:
eret
ENDPROC(__kvm_handle_stub_hvc)
.ltorg
.globl __kvm_hyp_init_end
__kvm_hyp_init_end:
.popsection
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