// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2015 - ARM Ltd
 * Author: Marc Zyngier <marc.zyngier@arm.com>
 */

#include <hyp/debug-sr.h>

#include <linux/compiler.h>
#include <linux/kvm_host.h>

#include <asm/debug-monitors.h>
#include <asm/kvm_asm.h>
#include <asm/kvm_hyp.h>
#include <asm/kvm_mmu.h>

static void __debug_save_spe(u64 *pmscr_el1)
{
        u64 reg;

        /* Clear pmscr in case of early return */
        *pmscr_el1 = 0;

        /*
         * At this point, we know that this CPU implements
         * SPE and is available to the host.
         * Check if the host is actually using it ?
         */
        reg = read_sysreg_s(SYS_PMBLIMITR_EL1);
        if (!(reg & BIT(PMBLIMITR_EL1_E_SHIFT)))
                return;

        /* Yes; save the control register and disable data generation */
        *pmscr_el1 = read_sysreg_el1(SYS_PMSCR);
        write_sysreg_el1(0, SYS_PMSCR);
        isb();

        /* Now drain all buffered data to memory */
        psb_csync();
}

static void __debug_restore_spe(u64 pmscr_el1)
{
        if (!pmscr_el1)
                return;

        /* The host page table is installed, but not yet synchronised */
        isb();

        /* Re-enable data generation */
        write_sysreg_el1(pmscr_el1, SYS_PMSCR);
}

static void __trace_do_switch(u64 *saved_trfcr, u64 new_trfcr)
{
        *saved_trfcr = read_sysreg_el1(SYS_TRFCR);
        write_sysreg_el1(new_trfcr, SYS_TRFCR);
}

static bool __trace_needs_drain(void)
{
        if (is_protected_kvm_enabled() && host_data_test_flag(HAS_TRBE))
                return read_sysreg_s(SYS_TRBLIMITR_EL1) & TRBLIMITR_EL1_E;

        return host_data_test_flag(TRBE_ENABLED);
}

static bool __trace_needs_switch(void)
{
        return host_data_test_flag(TRBE_ENABLED) ||
               host_data_test_flag(EL1_TRACING_CONFIGURED);
}

static void __trace_switch_to_guest(void)
{
        /* Unsupported with TRBE so disable */
        if (host_data_test_flag(TRBE_ENABLED))
                *host_data_ptr(trfcr_while_in_guest) = 0;

        __trace_do_switch(host_data_ptr(host_debug_state.trfcr_el1),
                          *host_data_ptr(trfcr_while_in_guest));

        if (__trace_needs_drain()) {
                isb();
                tsb_csync();
        }
}

static void __trace_switch_to_host(void)
{
        __trace_do_switch(host_data_ptr(trfcr_while_in_guest),
                          *host_data_ptr(host_debug_state.trfcr_el1));
}

static void __debug_save_brbe(u64 *brbcr_el1)
{
        *brbcr_el1 = 0;

        /* Check if the BRBE is enabled */
        if (!(read_sysreg_el1(SYS_BRBCR) & (BRBCR_ELx_E0BRE | BRBCR_ELx_ExBRE)))
                return;

        /*
         * Prohibit branch record generation while we are in guest.
         * Since access to BRBCR_EL1 is trapped, the guest can't
         * modify the filtering set by the host.
         */
        *brbcr_el1 = read_sysreg_el1(SYS_BRBCR);
        write_sysreg_el1(0, SYS_BRBCR);
}

static void __debug_restore_brbe(u64 brbcr_el1)
{
        if (!brbcr_el1)
                return;

        /* Restore BRBE controls */
        write_sysreg_el1(brbcr_el1, SYS_BRBCR);
}

void __debug_save_host_buffers_nvhe(struct kvm_vcpu *vcpu)
{
        /* Disable and flush SPE data generation */
        if (host_data_test_flag(HAS_SPE))
                __debug_save_spe(host_data_ptr(host_debug_state.pmscr_el1));

        /* Disable BRBE branch records */
        if (host_data_test_flag(HAS_BRBE))
                __debug_save_brbe(host_data_ptr(host_debug_state.brbcr_el1));

        if (__trace_needs_switch())
                __trace_switch_to_guest();
}

void __debug_switch_to_guest(struct kvm_vcpu *vcpu)
{
        __debug_switch_to_guest_common(vcpu);
}

void __debug_restore_host_buffers_nvhe(struct kvm_vcpu *vcpu)
{
        if (host_data_test_flag(HAS_SPE))
                __debug_restore_spe(*host_data_ptr(host_debug_state.pmscr_el1));
        if (host_data_test_flag(HAS_BRBE))
                __debug_restore_brbe(*host_data_ptr(host_debug_state.brbcr_el1));
        if (__trace_needs_switch())
                __trace_switch_to_host();
}

void __debug_switch_to_host(struct kvm_vcpu *vcpu)
{
        __debug_switch_to_host_common(vcpu);
}