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kernel/linux-imx6_3.14.28/arch/arm/kvm/init.S 4.38 KB
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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/unified.h>
  #include <asm/asm-offsets.h>
  #include <asm/kvm_asm.h>
  #include <asm/kvm_arm.h>
  #include <asm/kvm_mmu.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 four parameters: boot HYP pgd, runtime HYP pgd,
   *   runtime stack, runtime vectors
   * - Enable the MMU with the boot pgd
   * - Jump to a target into the trampoline page (remember, this is the same
   *   physical page!)
   * - Now switch to the runtime pgd (same VA, and still the same physical
   *   page!)
   * - Invalidate TLBs
   * - Set stack and vectors
   * - Profit! (or eret, if you only care about the code).
   *
   * As we only have four registers available to pass parameters (and we
   * need six), we split the init in two phases:
   * - Phase 1: r0 = 0, r1 = 0, r2,r3 contain the boot PGD.
   *   Provides the basic HYP init, and enable the MMU.
   * - Phase 2: r0 = ToS, r1 = vectors, r2,r3 contain the runtime PGD.
   *   Switches to the runtime PGD, set stack and vectors.
   */
  
  	.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:
  	cmp	r0, #0			@ We have a SP?
  	bne	phase2			@ Yes, second stage init
  
  	@ Set the HTTBR to point to the hypervisor PGD pointer passed
  	mcrr	p15, 4, 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
  
  	mrc	p15, 4, r1, c2, c1, 2	@ VTCR
  	ldr	r2, =VTCR_MASK
  	bic	r1, r1, r2
  	bic	r0, r0, #(~VTCR_HTCR_SH)	@ clear non-reusable HTCR bits
  	orr	r1, r0, r1
  	orr	r1, r1, #(KVM_VTCR_SL0 | KVM_VTCR_T0SZ | KVM_VTCR_S)
  	mcr	p15, 4, r1, c2, c1, 2	@ VTCR
  
  	@ 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
  	isb
  	mcr	p15, 4, r0, c1, c0, 0	@ HSCR
  
  	@ End of init phase-1
  	eret
  
  phase2:
  	@ Set stack pointer
  	mov	sp, r0
  
  	@ Set HVBAR to point to the HYP vectors
  	mcr	p15, 4, r1, c12, c0, 0	@ HVBAR
  
  	@ Jump to the trampoline page
  	ldr	r0, =TRAMPOLINE_VA
  	adr	r1, target
  	bfi	r0, r1, #0, #PAGE_SHIFT
  	mov	pc, r0
  
  target:	@ We're now in the trampoline code, switch page tables
  	mcrr	p15, 4, r2, r3, c2
  	isb
  
  	@ Invalidate the old TLBs
  	mcr	p15, 4, r0, c8, c7, 0	@ TLBIALLH
  	dsb	ish
  
  	eret
  
  	.ltorg
  
  	.globl __kvm_hyp_init_end
  __kvm_hyp_init_end:
  
  	.popsection