260 lines
6.1 KiB
ArmAsm
260 lines
6.1 KiB
ArmAsm
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/*
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* Copyright (C) 2015 - ARM Ltd
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* Author: Marc Zyngier <marc.zyngier@arm.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <linux/arm-smccc.h>
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#include <linux/linkage.h>
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#include <asm/alternative.h>
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#include <asm/assembler.h>
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#include <asm/cpufeature.h>
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#include <asm/kvm_arm.h>
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#include <asm/kvm_asm.h>
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#include <asm/kvm_mmu.h>
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.text
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.pushsection .hyp.text, "ax"
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.macro do_el2_call
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/*
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* Shuffle the parameters before calling the function
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* pointed to in x0. Assumes parameters in x[1,2,3].
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*/
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mov lr, x0
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mov x0, x1
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mov x1, x2
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mov x2, x3
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blr lr
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.endm
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ENTRY(__vhe_hyp_call)
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str lr, [sp, #-16]!
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do_el2_call
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ldr lr, [sp], #16
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/*
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* We used to rely on having an exception return to get
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* an implicit isb. In the E2H case, we don't have it anymore.
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* rather than changing all the leaf functions, just do it here
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* before returning to the rest of the kernel.
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*/
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isb
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ret
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ENDPROC(__vhe_hyp_call)
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/*
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* Compute the idmap address of __kvm_hyp_reset based on the idmap
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* start passed as a parameter, and jump there.
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*
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* x0: HYP phys_idmap_start
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*/
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ENTRY(__kvm_hyp_teardown)
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mov x4, x0
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adr_l x3, __kvm_hyp_reset
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/* insert __kvm_hyp_reset()s offset into phys_idmap_start */
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bfi x4, x3, #0, #PAGE_SHIFT
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br x4
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ENDPROC(__kvm_hyp_teardown)
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el1_sync: // Guest trapped into EL2
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stp x0, x1, [sp, #-16]!
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mrs x0, esr_el2
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lsr x0, x0, #ESR_ELx_EC_SHIFT
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cmp x0, #ESR_ELx_EC_HVC64
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ccmp x0, #ESR_ELx_EC_HVC32, #4, ne
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b.ne el1_trap
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mrs x1, vttbr_el2 // If vttbr is valid, the guest
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cbnz x1, el1_hvc_guest // called HVC
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/* Here, we're pretty sure the host called HVC. */
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ldp x0, x1, [sp], #16
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cmp x0, #HVC_GET_VECTORS
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b.ne 1f
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mrs x0, vbar_el2
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b 2f
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1:
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/*
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* Perform the EL2 call
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*/
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kern_hyp_va x0
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do_el2_call
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2: eret
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el1_hvc_guest:
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/*
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* Fastest possible path for ARM_SMCCC_ARCH_WORKAROUND_1.
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* The workaround has already been applied on the host,
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* so let's quickly get back to the guest. We don't bother
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* restoring x1, as it can be clobbered anyway.
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*/
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ldr x1, [sp] // Guest's x0
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eor w1, w1, #ARM_SMCCC_ARCH_WORKAROUND_1
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cbz w1, wa_epilogue
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/* ARM_SMCCC_ARCH_WORKAROUND_2 handling */
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eor w1, w1, #(ARM_SMCCC_ARCH_WORKAROUND_1 ^ \
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ARM_SMCCC_ARCH_WORKAROUND_2)
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cbnz w1, el1_trap
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#ifdef CONFIG_ARM64_SSBD
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alternative_cb arm64_enable_wa2_handling
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b wa2_end
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alternative_cb_end
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get_vcpu_ptr x2, x0
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ldr x0, [x2, #VCPU_WORKAROUND_FLAGS]
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// Sanitize the argument and update the guest flags
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ldr x1, [sp, #8] // Guest's x1
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clz w1, w1 // Murphy's device:
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lsr w1, w1, #5 // w1 = !!w1 without using
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eor w1, w1, #1 // the flags...
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bfi x0, x1, #VCPU_WORKAROUND_2_FLAG_SHIFT, #1
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str x0, [x2, #VCPU_WORKAROUND_FLAGS]
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/* Check that we actually need to perform the call */
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hyp_ldr_this_cpu x0, arm64_ssbd_callback_required, x2
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cbz x0, wa2_end
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mov w0, #ARM_SMCCC_ARCH_WORKAROUND_2
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smc #0
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/* Don't leak data from the SMC call */
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mov x3, xzr
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wa2_end:
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mov x2, xzr
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mov x1, xzr
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#endif
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wa_epilogue:
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mov x0, xzr
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add sp, sp, #16
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eret
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el1_trap:
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get_vcpu_ptr x1, x0
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mrs x0, esr_el2
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lsr x0, x0, #ESR_ELx_EC_SHIFT
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/*
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* x0: ESR_EC
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* x1: vcpu pointer
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*/
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/* Guest accessed VFP/SIMD registers, save host, restore Guest */
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cmp x0, #ESR_ELx_EC_FP_ASIMD
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b.eq __fpsimd_guest_restore
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mov x0, #ARM_EXCEPTION_TRAP
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b __guest_exit
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el1_irq:
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stp x0, x1, [sp, #-16]!
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get_vcpu_ptr x1, x0
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mov x0, #ARM_EXCEPTION_IRQ
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b __guest_exit
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el1_error:
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stp x0, x1, [sp, #-16]!
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get_vcpu_ptr x1, x0
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mov x0, #ARM_EXCEPTION_EL1_SERROR
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b __guest_exit
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el2_error:
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/*
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* Only two possibilities:
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* 1) Either we come from the exit path, having just unmasked
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* PSTATE.A: change the return code to an EL2 fault, and
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* carry on, as we're already in a sane state to handle it.
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* 2) Or we come from anywhere else, and that's a bug: we panic.
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*
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* For (1), x0 contains the original return code and x1 doesn't
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* contain anything meaningful at that stage. We can reuse them
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* as temp registers.
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* For (2), who cares?
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*/
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mrs x0, elr_el2
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adr x1, abort_guest_exit_start
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cmp x0, x1
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adr x1, abort_guest_exit_end
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ccmp x0, x1, #4, ne
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b.ne __hyp_panic
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mov x0, #(1 << ARM_EXIT_WITH_SERROR_BIT)
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eret
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ENTRY(__hyp_do_panic)
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mov lr, #(PSR_F_BIT | PSR_I_BIT | PSR_A_BIT | PSR_D_BIT |\
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PSR_MODE_EL1h)
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msr spsr_el2, lr
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ldr lr, =panic
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msr elr_el2, lr
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eret
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ENDPROC(__hyp_do_panic)
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ENTRY(__hyp_panic)
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get_host_ctxt x0, x1
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b hyp_panic
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ENDPROC(__hyp_panic)
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.macro invalid_vector label, target = __hyp_panic
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.align 2
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\label:
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b \target
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ENDPROC(\label)
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.endm
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/* None of these should ever happen */
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invalid_vector el2t_sync_invalid
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invalid_vector el2t_irq_invalid
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invalid_vector el2t_fiq_invalid
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invalid_vector el2t_error_invalid
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invalid_vector el2h_sync_invalid
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invalid_vector el2h_irq_invalid
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invalid_vector el2h_fiq_invalid
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invalid_vector el1_sync_invalid
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invalid_vector el1_irq_invalid
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invalid_vector el1_fiq_invalid
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.ltorg
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.align 11
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ENTRY(__kvm_hyp_vector)
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ventry el2t_sync_invalid // Synchronous EL2t
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ventry el2t_irq_invalid // IRQ EL2t
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ventry el2t_fiq_invalid // FIQ EL2t
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ventry el2t_error_invalid // Error EL2t
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ventry el2h_sync_invalid // Synchronous EL2h
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ventry el2h_irq_invalid // IRQ EL2h
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ventry el2h_fiq_invalid // FIQ EL2h
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ventry el2_error // Error EL2h
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ventry el1_sync // Synchronous 64-bit EL1
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ventry el1_irq // IRQ 64-bit EL1
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ventry el1_fiq_invalid // FIQ 64-bit EL1
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ventry el1_error // Error 64-bit EL1
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ventry el1_sync // Synchronous 32-bit EL1
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ventry el1_irq // IRQ 32-bit EL1
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ventry el1_fiq_invalid // FIQ 32-bit EL1
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ventry el1_error // Error 32-bit EL1
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ENDPROC(__kvm_hyp_vector)
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