/* SPDX-License-Identifier: GPL-2.0-only */
/*
* Copyright (C) 2020 - Google Inc
* Author: Andrew Scull <[email protected]>
*/
#include <linux/linkage.h>
#include <asm/assembler.h>
#include <asm/kvm_arm.h>
#include <asm/kvm_asm.h>
#include <asm/kvm_mmu.h>
#include <asm/kvm_ptrauth.h>
.text
SYM_FUNC_START(__host_exit)
get_host_ctxt x0, x1
/* Store the host regs x2 and x3 */
stp x2, x3, [x0, #CPU_XREG_OFFSET(2)]
/* Retrieve the host regs x0-x1 from the stack */
ldp x2, x3, [sp], #16 // x0, x1
/* Store the host regs x0-x1 and x4-x17 */
stp x2, x3, [x0, #CPU_XREG_OFFSET(0)]
stp x4, x5, [x0, #CPU_XREG_OFFSET(4)]
stp x6, x7, [x0, #CPU_XREG_OFFSET(6)]
stp x8, x9, [x0, #CPU_XREG_OFFSET(8)]
stp x10, x11, [x0, #CPU_XREG_OFFSET(10)]
stp x12, x13, [x0, #CPU_XREG_OFFSET(12)]
stp x14, x15, [x0, #CPU_XREG_OFFSET(14)]
stp x16, x17, [x0, #CPU_XREG_OFFSET(16)]
/* Store the host regs x18-x29, lr */
save_callee_saved_regs x0
/* Save the host context pointer in x29 across the function call */
mov x29, x0
#ifdef CONFIG_ARM64_PTR_AUTH_KERNEL
alternative_if_not ARM64_HAS_ADDRESS_AUTH
b __skip_pauth_save
alternative_else_nop_endif
alternative_if ARM64_KVM_PROTECTED_MODE
/* Save kernel ptrauth keys. */
add x18, x29, #CPU_APIAKEYLO_EL1
ptrauth_save_state x18, x19, x20
/* Use hyp keys. */
adr_this_cpu x18, kvm_hyp_ctxt, x19
add x18, x18, #CPU_APIAKEYLO_EL1
ptrauth_restore_state x18, x19, x20
isb
alternative_else_nop_endif
__skip_pauth_save:
#endif /* CONFIG_ARM64_PTR_AUTH_KERNEL */
bl handle_trap
__host_enter_restore_full:
/* Restore kernel keys. */
#ifdef CONFIG_ARM64_PTR_AUTH_KERNEL
alternative_if_not ARM64_HAS_ADDRESS_AUTH
b __skip_pauth_restore
alternative_else_nop_endif
alternative_if ARM64_KVM_PROTECTED_MODE
add x18, x29, #CPU_APIAKEYLO_EL1
ptrauth_restore_state x18, x19, x20
alternative_else_nop_endif
__skip_pauth_restore:
#endif /* CONFIG_ARM64_PTR_AUTH_KERNEL */
/* Restore host regs x0-x17 */
ldp x0, x1, [x29, #CPU_XREG_OFFSET(0)]
ldp x2, x3, [x29, #CPU_XREG_OFFSET(2)]
ldp x4, x5, [x29, #CPU_XREG_OFFSET(4)]
ldp x6, x7, [x29, #CPU_XREG_OFFSET(6)]
/* x0-7 are use for panic arguments */
__host_enter_for_panic:
ldp x8, x9, [x29, #CPU_XREG_OFFSET(8)]
ldp x10, x11, [x29, #CPU_XREG_OFFSET(10)]
ldp x12, x13, [x29, #CPU_XREG_OFFSET(12)]
ldp x14, x15, [x29, #CPU_XREG_OFFSET(14)]
ldp x16, x17, [x29, #CPU_XREG_OFFSET(16)]
/* Restore host regs x18-x29, lr */
restore_callee_saved_regs x29
/* Do not touch any register after this! */
__host_enter_without_restoring:
eret
sb
SYM_FUNC_END(__host_exit)
/*
* void __noreturn __host_enter(struct kvm_cpu_context *host_ctxt);
*/
SYM_FUNC_START(__host_enter)
mov x29, x0
b __host_enter_restore_full
SYM_FUNC_END(__host_enter)
/*
* void __noreturn __hyp_do_panic(struct kvm_cpu_context *host_ctxt, u64 spsr,
* u64 elr, u64 par);
*/
SYM_FUNC_START(__hyp_do_panic)
/* Prepare and exit to the host's panic function. */
mov lr, #(PSR_F_BIT | PSR_I_BIT | PSR_A_BIT | PSR_D_BIT |\
PSR_MODE_EL1h)
msr spsr_el2, lr
adr_l lr, nvhe_hyp_panic_handler
hyp_kimg_va lr, x6
msr elr_el2, lr
mov x29, x0
#ifdef CONFIG_NVHE_EL2_DEBUG
/* Ensure host stage-2 is disabled */
mrs x0, hcr_el2
bic x0, x0, #HCR_VM
msr hcr_el2, x0
isb
tlbi vmalls12e1
dsb nsh
#endif
/* Load the panic arguments into x0-7 */
mrs x0, esr_el2
mov x4, x3
mov x3, x2
hyp_pa x3, x6
get_vcpu_ptr x5, x6
mrs x6, far_el2
mrs x7, hpfar_el2
/* Enter the host, conditionally restoring the host context. */
cbz x29, __host_enter_without_restoring
b __host_enter_for_panic
SYM_FUNC_END(__hyp_do_panic)
SYM_FUNC_START(__host_hvc)
ldp x0, x1, [sp] // Don't fixup the stack yet
/* No stub for you, sonny Jim */
alternative_if ARM64_KVM_PROTECTED_MODE
b __host_exit
alternative_else_nop_endif
/* Check for a stub HVC call */
cmp x0, #HVC_STUB_HCALL_NR
b.hs __host_exit
add sp, sp, #16
/*
* Compute the idmap address of __kvm_handle_stub_hvc and
* jump there.
*
* Preserve x0-x4, which may contain stub parameters.
*/
adr_l x5, __kvm_handle_stub_hvc
hyp_pa x5, x6
br x5
SYM_FUNC_END(__host_hvc)
.macro host_el1_sync_vect
.align 7
.L__vect_start\@:
stp x0, x1, [sp, #-16]!
mrs x0, esr_el2
ubfx x0, x0, #ESR_ELx_EC_SHIFT, #ESR_ELx_EC_WIDTH
cmp x0, #ESR_ELx_EC_HVC64
b.eq __host_hvc
b __host_exit
.L__vect_end\@:
.if ((.L__vect_end\@ - .L__vect_start\@) > 0x80)
.error "host_el1_sync_vect larger than vector entry"
.endif
.endm
.macro invalid_host_el2_vect
.align 7
/*
* Test whether the SP has overflowed, without corrupting a GPR.
* nVHE hypervisor stacks are aligned so that the PAGE_SHIFT bit
* of SP should always be 1.
*/
add sp, sp, x0 // sp' = sp + x0
sub x0, sp, x0 // x0' = sp' - x0 = (sp + x0) - x0 = sp
tbz x0, #PAGE_SHIFT, .L__hyp_sp_overflow\@
sub x0, sp, x0 // x0'' = sp' - x0' = (sp + x0) - sp = x0
sub sp, sp, x0 // sp'' = sp' - x0 = (sp + x0) - x0 = sp
/*
* The panic may not be clean if the exception is taken before the host
* context has been saved by __host_exit or after the hyp context has
* been partially clobbered by __host_enter.
*/
b hyp_panic
.L__hyp_sp_overflow\@:
/* Switch to the overflow stack */
adr_this_cpu sp, overflow_stack + OVERFLOW_STACK_SIZE, x0
b hyp_panic_bad_stack
ASM_BUG()
.endm
.macro invalid_host_el1_vect
.align 7
mov x0, xzr /* restore_host = false */
mrs x1, spsr_el2
mrs x2, elr_el2
mrs x3, par_el1
b __hyp_do_panic
.endm
/*
* The host vector does not use an ESB instruction in order to avoid consuming
* SErrors that should only be consumed by the host. Guest entry is deferred by
* __guest_enter if there are any pending asynchronous exceptions so hyp will
* always return to the host without having consumerd host SErrors.
*
* CONFIG_KVM_INDIRECT_VECTORS is not applied to the host vectors because the
* host knows about the EL2 vectors already, and there is no point in hiding
* them.
*/
.align 11
SYM_CODE_START(__kvm_hyp_host_vector)
invalid_host_el2_vect // Synchronous EL2t
invalid_host_el2_vect // IRQ EL2t
invalid_host_el2_vect // FIQ EL2t
invalid_host_el2_vect // Error EL2t
invalid_host_el2_vect // Synchronous EL2h
invalid_host_el2_vect // IRQ EL2h
invalid_host_el2_vect // FIQ EL2h
invalid_host_el2_vect // Error EL2h
host_el1_sync_vect // Synchronous 64-bit EL1/EL0
invalid_host_el1_vect // IRQ 64-bit EL1/EL0
invalid_host_el1_vect // FIQ 64-bit EL1/EL0
invalid_host_el1_vect // Error 64-bit EL1/EL0
host_el1_sync_vect // Synchronous 32-bit EL1/EL0
invalid_host_el1_vect // IRQ 32-bit EL1/EL0
invalid_host_el1_vect // FIQ 32-bit EL1/EL0
invalid_host_el1_vect // Error 32-bit EL1/EL0
SYM_CODE_END(__kvm_hyp_host_vector)
/*
* Forward SMC with arguments in struct kvm_cpu_context, and
* store the result into the same struct. Assumes SMCCC 1.2 or older.
*
* x0: struct kvm_cpu_context*
*/
SYM_CODE_START(__kvm_hyp_host_forward_smc)
/*
* Use x18 to keep the pointer to the host context because
* x18 is callee-saved in SMCCC but not in AAPCS64.
*/
mov x18, x0
ldp x0, x1, [x18, #CPU_XREG_OFFSET(0)]
ldp x2, x3, [x18, #CPU_XREG_OFFSET(2)]
ldp x4, x5, [x18, #CPU_XREG_OFFSET(4)]
ldp x6, x7, [x18, #CPU_XREG_OFFSET(6)]
ldp x8, x9, [x18, #CPU_XREG_OFFSET(8)]
ldp x10, x11, [x18, #CPU_XREG_OFFSET(10)]
ldp x12, x13, [x18, #CPU_XREG_OFFSET(12)]
ldp x14, x15, [x18, #CPU_XREG_OFFSET(14)]
ldp x16, x17, [x18, #CPU_XREG_OFFSET(16)]
smc #0
stp x0, x1, [x18, #CPU_XREG_OFFSET(0)]
stp x2, x3, [x18, #CPU_XREG_OFFSET(2)]
stp x4, x5, [x18, #CPU_XREG_OFFSET(4)]
stp x6, x7, [x18, #CPU_XREG_OFFSET(6)]
stp x8, x9, [x18, #CPU_XREG_OFFSET(8)]
stp x10, x11, [x18, #CPU_XREG_OFFSET(10)]
stp x12, x13, [x18, #CPU_XREG_OFFSET(12)]
stp x14, x15, [x18, #CPU_XREG_OFFSET(14)]
stp x16, x17, [x18, #CPU_XREG_OFFSET(16)]
ret
SYM_CODE_END(__kvm_hyp_host_forward_smc)
/*
* kvm_host_psci_cpu_entry is called through br instruction, which requires
* bti j instruction as compilers (gcc and llvm) doesn't insert bti j for external
* functions, but bti c instead.
*/
SYM_CODE_START(kvm_host_psci_cpu_entry)
bti j
b __kvm_host_psci_cpu_entry
SYM_CODE_END(kvm_host_psci_cpu_entry)
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