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+/* 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>
+
+// Warning, hardcoded register allocation
+// This will clobber x1 and x2, and expect x1 to contain
+// the id register value as read from the HW
+.macro __check_override idreg, fld, width, pass, fail
+ ubfx x1, x1, #\fld, #\width
+ cbz x1, \fail
+
+ adr_l x1, \idreg\()_override
+ ldr x2, [x1, FTR_OVR_VAL_OFFSET]
+ ldr x1, [x1, FTR_OVR_MASK_OFFSET]
+ ubfx x2, x2, #\fld, #\width
+ ubfx x1, x1, #\fld, #\width
+ cmp x1, xzr
+ and x2, x2, x1
+ csinv x2, x2, xzr, ne
+ cbnz x2, \pass
+ b \fail
+.endm
+
+.macro check_override idreg, fld, pass, fail
+ mrs x1, \idreg\()_el1
+ __check_override \idreg \fld 4 \pass \fail
+.endm
+
+ .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_FINALISE_EL2
+ b.eq __finalise_el2
+
+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)
+
+SYM_CODE_START_LOCAL(__finalise_el2)
+ check_override id_aa64pfr0 ID_AA64PFR0_EL1_SVE_SHIFT .Linit_sve .Lskip_sve
+
+.Linit_sve: /* SVE register access */
+ mrs x0, cptr_el2 // Disable SVE traps
+ bic x0, x0, #CPTR_EL2_TZ
+ msr cptr_el2, x0
+ isb
+ mov x1, #ZCR_ELx_LEN_MASK // SVE: Enable full vector
+ msr_s SYS_ZCR_EL2, x1 // length for EL1.
+
+.Lskip_sve:
+ check_override id_aa64pfr1 ID_AA64PFR1_EL1_SME_SHIFT .Linit_sme .Lskip_sme
+
+.Linit_sme: /* SME register access and priority mapping */
+ mrs x0, cptr_el2 // Disable SME traps
+ bic x0, x0, #CPTR_EL2_TSM
+ msr cptr_el2, x0
+ isb
+
+ mrs x1, sctlr_el2
+ orr x1, x1, #SCTLR_ELx_ENTP2 // Disable TPIDR2 traps
+ msr sctlr_el2, x1
+ isb
+
+ mov x0, #0 // SMCR controls
+
+ // Full FP in SM?
+ mrs_s x1, SYS_ID_AA64SMFR0_EL1
+ __check_override id_aa64smfr0 ID_AA64SMFR0_EL1_FA64_SHIFT 1 .Linit_sme_fa64 .Lskip_sme_fa64
+
+.Linit_sme_fa64:
+ orr x0, x0, SMCR_ELx_FA64_MASK
+.Lskip_sme_fa64:
+
+ orr x0, x0, #SMCR_ELx_LEN_MASK // Enable full SME vector
+ msr_s SYS_SMCR_EL2, x0 // length for EL1.
+
+ mrs_s x1, SYS_SMIDR_EL1 // Priority mapping supported?
+ ubfx x1, x1, #SMIDR_EL1_SMPS_SHIFT, #1
+ cbz x1, .Lskip_sme
+
+ msr_s SYS_SMPRIMAP_EL2, xzr // Make all priorities equal
+
+ mrs x1, id_aa64mmfr1_el1 // HCRX_EL2 present?
+ ubfx x1, x1, #ID_AA64MMFR1_EL1_HCX_SHIFT, #4
+ cbz x1, .Lskip_sme
+
+ mrs_s x1, SYS_HCRX_EL2
+ orr x1, x1, #HCRX_EL2_SMPME_MASK // Enable priority mapping
+ msr_s SYS_HCRX_EL2, x1
+
+.Lskip_sme:
+
+ // nVHE? No way! Give me the real thing!
+ // Sanity check: MMU *must* be off
+ mrs x1, sctlr_el2
+ tbnz x1, #0, 1f
+
+ // Needs to be VHE capable, obviously
+ check_override id_aa64mmfr1 ID_AA64MMFR1_EL1_VH_SHIFT 2f 1f
+
+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(__finalise_el2)
+
+ // At the point where we reach enter_vhe(), we run with
+ // the MMU off (which is enforced by __finalise_el2()).
+ // 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 finalise EL2 and switch to VHE if deemed capable
+ *
+ * w0: boot mode, as returned by init_kernel_el()
+ */
+SYM_FUNC_START(finalise_el2)
+ // Need to have booted at EL2
+ cmp w0, #BOOT_CPU_MODE_EL2
+ b.ne 1f
+
+ // and still be at EL1
+ mrs x0, CurrentEL
+ cmp x0, #CurrentEL_EL1
+ b.ne 1f
+
+ mov x0, #HVC_FINALISE_EL2
+ hvc #0
+1:
+ ret
+SYM_FUNC_END(finalise_el2)