/* SPDX-License-Identifier: GPL-2.0-only */
/*
 * Copyright (C) 2012,2013 - ARM Ltd
 * Author: Marc Zyngier <marc.zyngier@arm.com>
 */

#include <linux/arm-smccc.h>
#include <linux/linkage.h>

#include <asm/alternative.h>
#include <asm/assembler.h>
#include <asm/el2_setup.h>
#include <asm/kvm_arm.h>
#include <asm/kvm_asm.h>
#include <asm/kvm_mmu.h>
#include <asm/pgtable-hwdef.h>
#include <asm/sysreg.h>
#include <asm/virt.h>

        .text
        .pushsection    .idmap.text, "ax"

        .align  11

SYM_CODE_START(__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       .

        /*
         * Only uses x0..x3 so as to not clobber callee-saved SMCCC registers.
         *
         * x0: SMCCC function ID
         * x1: struct kvm_nvhe_init_params PA
         */
__do_hyp_init:
        /* Check for a stub HVC call */
        cmp     x0, #HVC_STUB_HCALL_NR
        b.lo    __kvm_handle_stub_hvc

        mov     x3, #KVM_HOST_SMCCC_FUNC(__kvm_hyp_init)
        cmp     x0, x3
        b.eq    1f

        mov     x0, #SMCCC_RET_NOT_SUPPORTED
        eret

1:      mov     x0, x1
        mov     x3, lr
        bl      ___kvm_hyp_init                 // Clobbers x0..x2
        mov     lr, x3

        /* Hello, World! */
        mov     x0, #SMCCC_RET_SUCCESS
        eret
SYM_CODE_END(__kvm_hyp_init)

/*
 * Initialize the hypervisor in EL2.
 *
 * Only uses x0..x2 so as to not clobber callee-saved SMCCC registers
 * and leave x3 for the caller.
 *
 * x0: struct kvm_nvhe_init_params PA
 */
SYM_CODE_START_LOCAL(___kvm_hyp_init)
alternative_if ARM64_KVM_PROTECTED_MODE
        mov_q   x1, HCR_HOST_NVHE_PROTECTED_FLAGS
        msr     hcr_el2, x1
alternative_else_nop_endif

        ldr     x1, [x0, #NVHE_INIT_TPIDR_EL2]
        msr     tpidr_el2, x1

        ldr     x1, [x0, #NVHE_INIT_STACK_HYP_VA]
        mov     sp, x1

        ldr     x1, [x0, #NVHE_INIT_MAIR_EL2]
        msr     mair_el2, x1

        ldr     x1, [x0, #NVHE_INIT_PGD_PA]
        phys_to_ttbr x2, x1
alternative_if ARM64_HAS_CNP
        orr     x2, x2, #TTBR_CNP_BIT
alternative_else_nop_endif
        msr     ttbr0_el2, x2

        /*
         * Set the PS bits in TCR_EL2.
         */
        ldr     x0, [x0, #NVHE_INIT_TCR_EL2]
        tcr_compute_pa_size x0, #TCR_EL2_PS_SHIFT, x1, x2
        msr     tcr_el2, x0

        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.
         */
        mov_q   x0, (SCTLR_EL2_RES1 | (SCTLR_ELx_FLAGS & ~SCTLR_ELx_A))
CPU_BE( orr     x0, x0, #SCTLR_ELx_EE)
alternative_if ARM64_HAS_ADDRESS_AUTH
        mov_q   x1, (SCTLR_ELx_ENIA | SCTLR_ELx_ENIB | \
                     SCTLR_ELx_ENDA | SCTLR_ELx_ENDB)
        orr     x0, x0, x1
alternative_else_nop_endif
        msr     sctlr_el2, x0
        isb

        /* Set the host vector */
        ldr     x0, =__kvm_hyp_host_vector
        msr     vbar_el2, x0

        ret
SYM_CODE_END(___kvm_hyp_init)

/*
 * PSCI CPU_ON entry point
 *
 * x0: struct kvm_nvhe_init_params PA
 */
SYM_CODE_START(kvm_hyp_cpu_entry)
        mov     x1, #1                          // is_cpu_on = true
        b       __kvm_hyp_init_cpu
SYM_CODE_END(kvm_hyp_cpu_entry)

/*
 * PSCI CPU_SUSPEND / SYSTEM_SUSPEND entry point
 *
 * x0: struct kvm_nvhe_init_params PA
 */
SYM_CODE_START(kvm_hyp_cpu_resume)
        mov     x1, #0                          // is_cpu_on = false
        b       __kvm_hyp_init_cpu
SYM_CODE_END(kvm_hyp_cpu_resume)

/*
 * Common code for CPU entry points. Initializes EL2 state and
 * installs the hypervisor before handing over to a C handler.
 *
 * x0: struct kvm_nvhe_init_params PA
 * x1: bool is_cpu_on
 */
SYM_CODE_START_LOCAL(__kvm_hyp_init_cpu)
        mov     x28, x0                         // Stash arguments
        mov     x29, x1

        /* Check that the core was booted in EL2. */
        mrs     x0, CurrentEL
        cmp     x0, #CurrentEL_EL2
        b.eq    2f

        /* The core booted in EL1. KVM cannot be initialized on it. */
1:      wfe
        wfi
        b       1b

2:      msr     SPsel, #1                       // We want to use SP_EL{1,2}

        /* Initialize EL2 CPU state to sane values. */
        init_el2_state                          // Clobbers x0..x2

        /* Enable MMU, set vectors and stack. */
        mov     x0, x28
        bl      ___kvm_hyp_init                 // Clobbers x0..x2

        /* Leave idmap. */
        mov     x0, x29
        ldr     x1, =kvm_host_psci_cpu_entry
        br      x1
SYM_CODE_END(__kvm_hyp_init_cpu)

SYM_CODE_START(__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
        mov_q   x6, SCTLR_ELx_FLAGS
        bic     x5, x5, x6              // Clear SCTL_M and etc
        pre_disable_mmu_workaround
        msr     sctlr_el2, x5
        isb

alternative_if ARM64_KVM_PROTECTED_MODE
        mov_q   x5, HCR_HOST_NVHE_FLAGS
        msr     hcr_el2, x5
alternative_else_nop_endif

        /* Install stub vectors */
        adr_l   x5, __hyp_stub_vectors
        msr     vbar_el2, x5
        eret

1:      /* Bad stub call */
        mov_q   x0, HVC_STUB_ERR
        eret

SYM_CODE_END(__kvm_handle_stub_hvc)

        .popsection