| /* SPDX-License-Identifier: GPL-2.0-only */ |
| /* |
| * Hypervisor stub |
| * |
| * Copyright (C) 2012 ARM Ltd. |
| * Author: Marc Zyngier <marc.zyngier@arm.com> |
| */ |
| |
| #include <linux/init.h> |
| #include <linux/linkage.h> |
| |
| #include <asm/assembler.h> |
| #include <asm/el2_setup.h> |
| #include <asm/kvm_arm.h> |
| #include <asm/kvm_asm.h> |
| #include <asm/ptrace.h> |
| #include <asm/virt.h> |
| |
| .text |
| .pushsection .hyp.text, "ax" |
| |
| .align 11 |
| |
| SYM_CODE_START(__hyp_stub_vectors) |
| ventry el2_sync_invalid // Synchronous EL2t |
| ventry el2_irq_invalid // IRQ EL2t |
| ventry el2_fiq_invalid // FIQ EL2t |
| ventry el2_error_invalid // Error EL2t |
| |
| ventry elx_sync // Synchronous EL2h |
| ventry el2_irq_invalid // IRQ EL2h |
| ventry el2_fiq_invalid // FIQ EL2h |
| ventry el2_error_invalid // Error EL2h |
| |
| ventry elx_sync // Synchronous 64-bit EL1 |
| ventry el1_irq_invalid // IRQ 64-bit EL1 |
| ventry el1_fiq_invalid // FIQ 64-bit EL1 |
| ventry el1_error_invalid // Error 64-bit EL1 |
| |
| ventry el1_sync_invalid // Synchronous 32-bit EL1 |
| ventry el1_irq_invalid // IRQ 32-bit EL1 |
| ventry el1_fiq_invalid // FIQ 32-bit EL1 |
| ventry el1_error_invalid // Error 32-bit EL1 |
| SYM_CODE_END(__hyp_stub_vectors) |
| |
| .align 11 |
| |
| SYM_CODE_START_LOCAL(elx_sync) |
| cmp x0, #HVC_SET_VECTORS |
| b.ne 1f |
| msr vbar_el2, x1 |
| b 9f |
| |
| 1: cmp x0, #HVC_VHE_RESTART |
| b.eq mutate_to_vhe |
| |
| 2: cmp x0, #HVC_SOFT_RESTART |
| b.ne 3f |
| mov x0, x2 |
| mov x2, x4 |
| mov x4, x1 |
| mov x1, x3 |
| br x4 // no return |
| |
| 3: cmp x0, #HVC_RESET_VECTORS |
| beq 9f // Nothing to reset! |
| |
| /* Someone called kvm_call_hyp() against the hyp-stub... */ |
| mov_q x0, HVC_STUB_ERR |
| eret |
| |
| 9: mov x0, xzr |
| eret |
| SYM_CODE_END(elx_sync) |
| |
| // nVHE? No way! Give me the real thing! |
| SYM_CODE_START_LOCAL(mutate_to_vhe) |
| // Sanity check: MMU *must* be off |
| mrs x1, sctlr_el2 |
| tbnz x1, #0, 1f |
| |
| // Needs to be VHE capable, obviously |
| mrs x1, id_aa64mmfr1_el1 |
| ubfx x1, x1, #ID_AA64MMFR1_VHE_SHIFT, #4 |
| cbz x1, 1f |
| |
| // Check whether VHE is disabled from the command line |
| adr_l x1, id_aa64mmfr1_override |
| ldr x2, [x1, FTR_OVR_VAL_OFFSET] |
| ldr x1, [x1, FTR_OVR_MASK_OFFSET] |
| ubfx x2, x2, #ID_AA64MMFR1_VHE_SHIFT, #4 |
| ubfx x1, x1, #ID_AA64MMFR1_VHE_SHIFT, #4 |
| cmp x1, xzr |
| and x2, x2, x1 |
| csinv x2, x2, xzr, ne |
| cbnz x2, 2f |
| |
| 1: mov_q x0, HVC_STUB_ERR |
| eret |
| 2: |
| // Engage the VHE magic! |
| mov_q x0, HCR_HOST_VHE_FLAGS |
| msr hcr_el2, x0 |
| isb |
| |
| // Use the EL1 allocated stack, per-cpu offset |
| mrs x0, sp_el1 |
| mov sp, x0 |
| mrs x0, tpidr_el1 |
| msr tpidr_el2, x0 |
| |
| // FP configuration, vectors |
| mrs_s x0, SYS_CPACR_EL12 |
| msr cpacr_el1, x0 |
| mrs_s x0, SYS_VBAR_EL12 |
| msr vbar_el1, x0 |
| |
| // Use EL2 translations for SPE & TRBE and disable access from EL1 |
| mrs x0, mdcr_el2 |
| bic x0, x0, #(MDCR_EL2_E2PB_MASK << MDCR_EL2_E2PB_SHIFT) |
| bic x0, x0, #(MDCR_EL2_E2TB_MASK << MDCR_EL2_E2TB_SHIFT) |
| msr mdcr_el2, x0 |
| |
| // Transfer the MM state from EL1 to EL2 |
| mrs_s x0, SYS_TCR_EL12 |
| msr tcr_el1, x0 |
| mrs_s x0, SYS_TTBR0_EL12 |
| msr ttbr0_el1, x0 |
| mrs_s x0, SYS_TTBR1_EL12 |
| msr ttbr1_el1, x0 |
| mrs_s x0, SYS_MAIR_EL12 |
| msr mair_el1, x0 |
| isb |
| |
| // Hack the exception return to stay at EL2 |
| mrs x0, spsr_el1 |
| and x0, x0, #~PSR_MODE_MASK |
| mov x1, #PSR_MODE_EL2h |
| orr x0, x0, x1 |
| msr spsr_el1, x0 |
| |
| b enter_vhe |
| SYM_CODE_END(mutate_to_vhe) |
| |
| // At the point where we reach enter_vhe(), we run with |
| // the MMU off (which is enforced by mutate_to_vhe()). |
| // We thus need to be in the idmap, or everything will |
| // explode when enabling the MMU. |
| |
| .pushsection .idmap.text, "ax" |
| |
| SYM_CODE_START_LOCAL(enter_vhe) |
| // Invalidate TLBs before enabling the MMU |
| tlbi vmalle1 |
| dsb nsh |
| isb |
| |
| // Enable the EL2 S1 MMU, as set up from EL1 |
| mrs_s x0, SYS_SCTLR_EL12 |
| set_sctlr_el1 x0 |
| |
| // Disable the EL1 S1 MMU for a good measure |
| mov_q x0, INIT_SCTLR_EL1_MMU_OFF |
| msr_s SYS_SCTLR_EL12, x0 |
| |
| mov x0, xzr |
| |
| eret |
| SYM_CODE_END(enter_vhe) |
| |
| .popsection |
| |
| .macro invalid_vector label |
| SYM_CODE_START_LOCAL(\label) |
| b \label |
| SYM_CODE_END(\label) |
| .endm |
| |
| invalid_vector el2_sync_invalid |
| invalid_vector el2_irq_invalid |
| invalid_vector el2_fiq_invalid |
| invalid_vector el2_error_invalid |
| invalid_vector el1_sync_invalid |
| invalid_vector el1_irq_invalid |
| invalid_vector el1_fiq_invalid |
| invalid_vector el1_error_invalid |
| |
| .popsection |
| |
| /* |
| * __hyp_set_vectors: Call this after boot to set the initial hypervisor |
| * vectors as part of hypervisor installation. On an SMP system, this should |
| * be called on each CPU. |
| * |
| * x0 must be the physical address of the new vector table, and must be |
| * 2KB aligned. |
| * |
| * Before calling this, you must check that the stub hypervisor is installed |
| * everywhere, by waiting for any secondary CPUs to be brought up and then |
| * checking that is_hyp_mode_available() is true. |
| * |
| * If not, there is a pre-existing hypervisor, some CPUs failed to boot, or |
| * something else went wrong... in such cases, trying to install a new |
| * hypervisor is unlikely to work as desired. |
| * |
| * When you call into your shiny new hypervisor, sp_el2 will contain junk, |
| * so you will need to set that to something sensible at the new hypervisor's |
| * initialisation entry point. |
| */ |
| |
| SYM_FUNC_START(__hyp_set_vectors) |
| mov x1, x0 |
| mov x0, #HVC_SET_VECTORS |
| hvc #0 |
| ret |
| SYM_FUNC_END(__hyp_set_vectors) |
| |
| SYM_FUNC_START(__hyp_reset_vectors) |
| mov x0, #HVC_RESET_VECTORS |
| hvc #0 |
| ret |
| SYM_FUNC_END(__hyp_reset_vectors) |
| |
| /* |
| * Entry point to switch to VHE if deemed capable |
| */ |
| SYM_FUNC_START(switch_to_vhe) |
| // Need to have booted at EL2 |
| adr_l x1, __boot_cpu_mode |
| ldr w0, [x1] |
| cmp w0, #BOOT_CPU_MODE_EL2 |
| b.ne 1f |
| |
| // and still be at EL1 |
| mrs x0, CurrentEL |
| cmp x0, #CurrentEL_EL1 |
| b.ne 1f |
| |
| // Turn the world upside down |
| mov x0, #HVC_VHE_RESTART |
| hvc #0 |
| 1: |
| ret |
| SYM_FUNC_END(switch_to_vhe) |
