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Diffstat (limited to 'kernel/arch/arm/kvm/init.S')
| -rw-r--r-- | kernel/arch/arm/kvm/init.S | 159 |
1 files changed, 159 insertions, 0 deletions
diff --git a/kernel/arch/arm/kvm/init.S b/kernel/arch/arm/kvm/init.S new file mode 100644 index 000000000..3988e72d1 --- /dev/null +++ b/kernel/arch/arm/kvm/init.S @@ -0,0 +1,159 @@ +/* + * 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 |