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Diffstat (limited to 'arch/arm/kvm/init.S')
| -rw-r--r-- | arch/arm/kvm/init.S | 169 |
1 files changed, 169 insertions, 0 deletions
diff --git a/arch/arm/kvm/init.S b/arch/arm/kvm/init.S new file mode 100644 index 000000000..538652866 --- /dev/null +++ b/arch/arm/kvm/init.S @@ -0,0 +1,169 @@ +/* + * 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 + @ - 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) ) + THUMB( ldr r2, =(HSCTLR_M | 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_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 + eret + +exit: + mov r0, #0 + eret +ENDPROC(__kvm_handle_stub_hvc) + + .ltorg + + .globl __kvm_hyp_init_end +__kvm_hyp_init_end: + + .popsection |