/* SPDX-License-Identifier: GPL-2.0-only */
/*
 *
 * Copyright SUSE Linux Products GmbH 2010
 * Copyright 2010-2011 Freescale Semiconductor, Inc.
 *
 * Authors: Alexander Graf <agraf@suse.de>
 */

#include <asm/ppc_asm.h>
#include <asm/kvm_asm.h>
#include <asm/reg.h>
#include <asm/page.h>
#include <asm/asm-offsets.h>
#include <asm/asm-compat.h>

#define KVM_MAGIC_PAGE          (-4096)

#ifdef CONFIG_64BIT
#define LL64(reg, offs, reg2)   ld      reg, (offs)(reg2)
#define STL64(reg, offs, reg2)  std     reg, (offs)(reg2)
#else
#define LL64(reg, offs, reg2)   lwz     reg, (offs + 4)(reg2)
#define STL64(reg, offs, reg2)  stw     reg, (offs + 4)(reg2)
#endif

#define SCRATCH_SAVE                                                    \
        /* Enable critical section. We are critical if                  \
           shared->critical == r1 */                                    \
        STL64(r1, KVM_MAGIC_PAGE + KVM_MAGIC_CRITICAL, 0);              \
                                                                        \
        /* Save state */                                                \
        PPC_STL r31, (KVM_MAGIC_PAGE + KVM_MAGIC_SCRATCH1)(0);          \
        PPC_STL r30, (KVM_MAGIC_PAGE + KVM_MAGIC_SCRATCH2)(0);          \
        mfcr    r31;                                                    \
        stw     r31, (KVM_MAGIC_PAGE + KVM_MAGIC_SCRATCH3)(0);

#define SCRATCH_RESTORE                                                 \
        /* Restore state */                                             \
        PPC_LL  r31, (KVM_MAGIC_PAGE + KVM_MAGIC_SCRATCH1)(0);          \
        lwz     r30, (KVM_MAGIC_PAGE + KVM_MAGIC_SCRATCH3)(0);          \
        mtcr    r30;                                                    \
        PPC_LL  r30, (KVM_MAGIC_PAGE + KVM_MAGIC_SCRATCH2)(0);          \
                                                                        \
        /* Disable critical section. We are critical if                 \
           shared->critical == r1 and r2 is always != r1 */             \
        STL64(r2, KVM_MAGIC_PAGE + KVM_MAGIC_CRITICAL, 0);

.global kvm_template_start
kvm_template_start:

.global kvm_emulate_mtmsrd
kvm_emulate_mtmsrd:

        SCRATCH_SAVE

        /* Put MSR & ~(MSR_EE|MSR_RI) in r31 */
        LL64(r31, KVM_MAGIC_PAGE + KVM_MAGIC_MSR, 0)
        lis     r30, (~(MSR_EE | MSR_RI))@h
        ori     r30, r30, (~(MSR_EE | MSR_RI))@l
        and     r31, r31, r30

        /* OR the register's (MSR_EE|MSR_RI) on MSR */
kvm_emulate_mtmsrd_reg:
        ori     r30, r0, 0
        andi.   r30, r30, (MSR_EE|MSR_RI)
        or      r31, r31, r30

        /* Put MSR back into magic page */
        STL64(r31, KVM_MAGIC_PAGE + KVM_MAGIC_MSR, 0)

        /* Check if we have to fetch an interrupt */
        lwz     r31, (KVM_MAGIC_PAGE + KVM_MAGIC_INT)(0)
        cmpwi   r31, 0
        beq+    no_check

        /* Check if we may trigger an interrupt */
        andi.   r30, r30, MSR_EE
        beq     no_check

        SCRATCH_RESTORE

        /* Nag hypervisor */
kvm_emulate_mtmsrd_orig_ins:
        tlbsync

        b       kvm_emulate_mtmsrd_branch

no_check:

        SCRATCH_RESTORE

        /* Go back to caller */
kvm_emulate_mtmsrd_branch:
        b       .
kvm_emulate_mtmsrd_end:

.global kvm_emulate_mtmsrd_branch_offs
kvm_emulate_mtmsrd_branch_offs:
        .long (kvm_emulate_mtmsrd_branch - kvm_emulate_mtmsrd) / 4

.global kvm_emulate_mtmsrd_reg_offs
kvm_emulate_mtmsrd_reg_offs:
        .long (kvm_emulate_mtmsrd_reg - kvm_emulate_mtmsrd) / 4

.global kvm_emulate_mtmsrd_orig_ins_offs
kvm_emulate_mtmsrd_orig_ins_offs:
        .long (kvm_emulate_mtmsrd_orig_ins - kvm_emulate_mtmsrd) / 4

.global kvm_emulate_mtmsrd_len
kvm_emulate_mtmsrd_len:
        .long (kvm_emulate_mtmsrd_end - kvm_emulate_mtmsrd) / 4


#define MSR_SAFE_BITS (MSR_EE | MSR_RI)
#define MSR_CRITICAL_BITS ~MSR_SAFE_BITS

.global kvm_emulate_mtmsr
kvm_emulate_mtmsr:

        SCRATCH_SAVE

        /* Fetch old MSR in r31 */
        LL64(r31, KVM_MAGIC_PAGE + KVM_MAGIC_MSR, 0)

        /* Find the changed bits between old and new MSR */
kvm_emulate_mtmsr_reg1:
        ori     r30, r0, 0
        xor     r31, r30, r31

        /* Check if we need to really do mtmsr */
        LOAD_REG_IMMEDIATE(r30, MSR_CRITICAL_BITS)
        and.    r31, r31, r30

        /* No critical bits changed? Maybe we can stay in the guest. */
        beq     maybe_stay_in_guest

do_mtmsr:

        SCRATCH_RESTORE

        /* Just fire off the mtmsr if it's critical */
kvm_emulate_mtmsr_orig_ins:
        mtmsr   r0

        b       kvm_emulate_mtmsr_branch

maybe_stay_in_guest:

        /* Get the target register in r30 */
kvm_emulate_mtmsr_reg2:
        ori     r30, r0, 0

        /* Put MSR into magic page because we don't call mtmsr */
        STL64(r30, KVM_MAGIC_PAGE + KVM_MAGIC_MSR, 0)

        /* Check if we have to fetch an interrupt */
        lwz     r31, (KVM_MAGIC_PAGE + KVM_MAGIC_INT)(0)
        cmpwi   r31, 0
        beq+    no_mtmsr

        /* Check if we may trigger an interrupt */
        andi.   r31, r30, MSR_EE
        bne     do_mtmsr

no_mtmsr:

        SCRATCH_RESTORE

        /* Go back to caller */
kvm_emulate_mtmsr_branch:
        b       .
kvm_emulate_mtmsr_end:

.global kvm_emulate_mtmsr_branch_offs
kvm_emulate_mtmsr_branch_offs:
        .long (kvm_emulate_mtmsr_branch - kvm_emulate_mtmsr) / 4

.global kvm_emulate_mtmsr_reg1_offs
kvm_emulate_mtmsr_reg1_offs:
        .long (kvm_emulate_mtmsr_reg1 - kvm_emulate_mtmsr) / 4

.global kvm_emulate_mtmsr_reg2_offs
kvm_emulate_mtmsr_reg2_offs:
        .long (kvm_emulate_mtmsr_reg2 - kvm_emulate_mtmsr) / 4

.global kvm_emulate_mtmsr_orig_ins_offs
kvm_emulate_mtmsr_orig_ins_offs:
        .long (kvm_emulate_mtmsr_orig_ins - kvm_emulate_mtmsr) / 4

.global kvm_emulate_mtmsr_len
kvm_emulate_mtmsr_len:
        .long (kvm_emulate_mtmsr_end - kvm_emulate_mtmsr) / 4

#ifdef CONFIG_BOOKE

/* also used for wrteei 1 */
.global kvm_emulate_wrtee
kvm_emulate_wrtee:

        SCRATCH_SAVE

        /* Fetch old MSR in r31 */
        LL64(r31, KVM_MAGIC_PAGE + KVM_MAGIC_MSR, 0)

        /* Insert new MSR[EE] */
kvm_emulate_wrtee_reg:
        ori     r30, r0, 0
        rlwimi  r31, r30, 0, MSR_EE

        /*
         * If MSR[EE] is now set, check for a pending interrupt.
         * We could skip this if MSR[EE] was already on, but that
         * should be rare, so don't bother.
         */
        andi.   r30, r30, MSR_EE

        /* Put MSR into magic page because we don't call wrtee */
        STL64(r31, KVM_MAGIC_PAGE + KVM_MAGIC_MSR, 0)

        beq     no_wrtee

        /* Check if we have to fetch an interrupt */
        lwz     r30, (KVM_MAGIC_PAGE + KVM_MAGIC_INT)(0)
        cmpwi   r30, 0
        bne     do_wrtee

no_wrtee:
        SCRATCH_RESTORE

        /* Go back to caller */
kvm_emulate_wrtee_branch:
        b       .

do_wrtee:
        SCRATCH_RESTORE

        /* Just fire off the wrtee if it's critical */
kvm_emulate_wrtee_orig_ins:
        wrtee   r0

        b       kvm_emulate_wrtee_branch

kvm_emulate_wrtee_end:

.global kvm_emulate_wrtee_branch_offs
kvm_emulate_wrtee_branch_offs:
        .long (kvm_emulate_wrtee_branch - kvm_emulate_wrtee) / 4

.global kvm_emulate_wrtee_reg_offs
kvm_emulate_wrtee_reg_offs:
        .long (kvm_emulate_wrtee_reg - kvm_emulate_wrtee) / 4

.global kvm_emulate_wrtee_orig_ins_offs
kvm_emulate_wrtee_orig_ins_offs:
        .long (kvm_emulate_wrtee_orig_ins - kvm_emulate_wrtee) / 4

.global kvm_emulate_wrtee_len
kvm_emulate_wrtee_len:
        .long (kvm_emulate_wrtee_end - kvm_emulate_wrtee) / 4

.global kvm_emulate_wrteei_0
kvm_emulate_wrteei_0:
        SCRATCH_SAVE

        /* Fetch old MSR in r31 */
        LL64(r31, KVM_MAGIC_PAGE + KVM_MAGIC_MSR, 0)

        /* Remove MSR_EE from old MSR */
        rlwinm  r31, r31, 0, ~MSR_EE

        /* Write new MSR value back */
        STL64(r31, KVM_MAGIC_PAGE + KVM_MAGIC_MSR, 0)

        SCRATCH_RESTORE

        /* Go back to caller */
kvm_emulate_wrteei_0_branch:
        b       .
kvm_emulate_wrteei_0_end:

.global kvm_emulate_wrteei_0_branch_offs
kvm_emulate_wrteei_0_branch_offs:
        .long (kvm_emulate_wrteei_0_branch - kvm_emulate_wrteei_0) / 4

.global kvm_emulate_wrteei_0_len
kvm_emulate_wrteei_0_len:
        .long (kvm_emulate_wrteei_0_end - kvm_emulate_wrteei_0) / 4

#endif /* CONFIG_BOOKE */

#ifdef CONFIG_PPC_BOOK3S_32

.global kvm_emulate_mtsrin
kvm_emulate_mtsrin:

        SCRATCH_SAVE

        LL64(r31, KVM_MAGIC_PAGE + KVM_MAGIC_MSR, 0)
        andi.   r31, r31, MSR_DR | MSR_IR
        beq     kvm_emulate_mtsrin_reg1

        SCRATCH_RESTORE

kvm_emulate_mtsrin_orig_ins:
        nop
        b       kvm_emulate_mtsrin_branch

kvm_emulate_mtsrin_reg1:
        /* rX >> 26 */
        rlwinm  r30,r0,6,26,29

kvm_emulate_mtsrin_reg2:
        stw     r0, (KVM_MAGIC_PAGE + KVM_MAGIC_SR)(r30)

        SCRATCH_RESTORE

        /* Go back to caller */
kvm_emulate_mtsrin_branch:
        b       .
kvm_emulate_mtsrin_end:

.global kvm_emulate_mtsrin_branch_offs
kvm_emulate_mtsrin_branch_offs:
        .long (kvm_emulate_mtsrin_branch - kvm_emulate_mtsrin) / 4

.global kvm_emulate_mtsrin_reg1_offs
kvm_emulate_mtsrin_reg1_offs:
        .long (kvm_emulate_mtsrin_reg1 - kvm_emulate_mtsrin) / 4

.global kvm_emulate_mtsrin_reg2_offs
kvm_emulate_mtsrin_reg2_offs:
        .long (kvm_emulate_mtsrin_reg2 - kvm_emulate_mtsrin) / 4

.global kvm_emulate_mtsrin_orig_ins_offs
kvm_emulate_mtsrin_orig_ins_offs:
        .long (kvm_emulate_mtsrin_orig_ins - kvm_emulate_mtsrin) / 4

.global kvm_emulate_mtsrin_len
kvm_emulate_mtsrin_len:
        .long (kvm_emulate_mtsrin_end - kvm_emulate_mtsrin) / 4

#endif /* CONFIG_PPC_BOOK3S_32 */

        .balign 4
        .global kvm_tmp
kvm_tmp:
        .space  (64 * 1024)

.global kvm_tmp_end
kvm_tmp_end:

.global kvm_template_end
kvm_template_end: