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Diffstat (limited to 'arch/arm64/kvm/hyp-init.S')
| -rw-r--r-- | arch/arm64/kvm/hyp-init.S | 176 |
1 files changed, 176 insertions, 0 deletions
diff --git a/arch/arm64/kvm/hyp-init.S b/arch/arm64/kvm/hyp-init.S new file mode 100644 index 000000000..6ef670f18 --- /dev/null +++ b/arch/arm64/kvm/hyp-init.S @@ -0,0 +1,176 @@ +/* + * Copyright (C) 2012,2013 - ARM Ltd + * Author: Marc Zyngier <marc.zyngier@arm.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, see <http://www.gnu.org/licenses/>. + */ + +#include <linux/linkage.h> + +#include <asm/assembler.h> +#include <asm/kvm_arm.h> +#include <asm/kvm_mmu.h> +#include <asm/pgtable-hwdef.h> +#include <asm/sysreg.h> +#include <asm/virt.h> + + .text + .pushsection .hyp.idmap.text, "ax" + + .align 11 + +ENTRY(__kvm_hyp_init) + ventry __invalid // Synchronous EL2t + ventry __invalid // IRQ EL2t + ventry __invalid // FIQ EL2t + ventry __invalid // Error EL2t + + ventry __invalid // Synchronous EL2h + ventry __invalid // IRQ EL2h + ventry __invalid // FIQ EL2h + ventry __invalid // Error EL2h + + ventry __do_hyp_init // Synchronous 64-bit EL1 + ventry __invalid // IRQ 64-bit EL1 + ventry __invalid // FIQ 64-bit EL1 + ventry __invalid // Error 64-bit EL1 + + ventry __invalid // Synchronous 32-bit EL1 + ventry __invalid // IRQ 32-bit EL1 + ventry __invalid // FIQ 32-bit EL1 + ventry __invalid // Error 32-bit EL1 + +__invalid: + b . + + /* + * x0: HYP pgd + * x1: HYP stack + * x2: HYP vectors + * x3: per-CPU offset + */ +__do_hyp_init: + /* Check for a stub HVC call */ + cmp x0, #HVC_STUB_HCALL_NR + b.lo __kvm_handle_stub_hvc + + phys_to_ttbr x4, x0 + msr ttbr0_el2, x4 + + mrs x4, tcr_el1 + ldr x5, =TCR_EL2_MASK + and x4, x4, x5 + mov x5, #TCR_EL2_RES1 + orr x4, x4, x5 + + /* + * The ID map may be configured to use an extended virtual address + * range. This is only the case if system RAM is out of range for the + * currently configured page size and VA_BITS, in which case we will + * also need the extended virtual range for the HYP ID map, or we won't + * be able to enable the EL2 MMU. + * + * However, at EL2, there is only one TTBR register, and we can't switch + * between translation tables *and* update TCR_EL2.T0SZ at the same + * time. Bottom line: we need to use the extended range with *both* our + * translation tables. + * + * So use the same T0SZ value we use for the ID map. + */ + ldr_l x5, idmap_t0sz + bfi x4, x5, TCR_T0SZ_OFFSET, TCR_TxSZ_WIDTH + + /* + * Set the PS bits in TCR_EL2. + */ + tcr_compute_pa_size x4, #TCR_EL2_PS_SHIFT, x5, x6 + + msr tcr_el2, x4 + + mrs x4, mair_el1 + msr mair_el2, x4 + isb + + /* Invalidate the stale TLBs from Bootloader */ + tlbi alle2 + dsb sy + + /* + * Preserve all the RES1 bits while setting the default flags, + * as well as the EE bit on BE. Drop the A flag since the compiler + * is allowed to generate unaligned accesses. + */ + ldr x4, =(SCTLR_EL2_RES1 | (SCTLR_ELx_FLAGS & ~SCTLR_ELx_A)) +CPU_BE( orr x4, x4, #SCTLR_ELx_EE) + msr sctlr_el2, x4 + isb + + /* Set the stack and new vectors */ + kern_hyp_va x1 + mov sp, x1 + msr vbar_el2, x2 + + /* Set tpidr_el2 for use by HYP */ + msr tpidr_el2, x3 + + /* Hello, World! */ + eret +ENDPROC(__kvm_hyp_init) + +ENTRY(__kvm_handle_stub_hvc) + cmp x0, #HVC_SOFT_RESTART + b.ne 1f + + /* This is where we're about to jump, staying at EL2 */ + msr elr_el2, x1 + mov x0, #(PSR_F_BIT | PSR_I_BIT | PSR_A_BIT | PSR_D_BIT | PSR_MODE_EL2h) + msr spsr_el2, x0 + + /* Shuffle the arguments, and don't come back */ + mov x0, x2 + mov x1, x3 + mov x2, x4 + b reset + +1: cmp x0, #HVC_RESET_VECTORS + b.ne 1f + + /* + * Set the HVC_RESET_VECTORS return code before entering the common + * path so that we do not clobber x0-x2 in case we are coming via + * HVC_SOFT_RESTART. + */ + mov x0, xzr +reset: + /* Reset kvm back to the hyp stub. */ + mrs x5, sctlr_el2 + ldr x6, =SCTLR_ELx_FLAGS + bic x5, x5, x6 // Clear SCTL_M and etc + pre_disable_mmu_workaround + msr sctlr_el2, x5 + isb + + /* Install stub vectors */ + adr_l x5, __hyp_stub_vectors + msr vbar_el2, x5 + eret + +1: /* Bad stub call */ + ldr x0, =HVC_STUB_ERR + eret + +ENDPROC(__kvm_handle_stub_hvc) + + .ltorg + + .popsection |