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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>
+
+/********************************************************************
+ * 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, 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
+
+ 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
+ ret r0
+
+target: @ We're now in the trampoline code, switch page tables
+ mcrr p15, 4, rr_lo_hi(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