/*
 * Copyright (c) Atmosphère-NX
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
#include <mesosphere.hpp>
#if defined(ATMOSPHERE_ARCH_ARM64)
#include <mesosphere/arch/arm64/kern_secure_monitor_base.hpp>
#endif

namespace ams::kern {

    /* Initialization. */
    size_t KSystemControlBase::Init::GetRealMemorySize() {
        return ams::kern::MainMemorySize;
    }

    size_t KSystemControlBase::Init::GetIntendedMemorySize() {
        return ams::kern::MainMemorySize;
    }

    KPhysicalAddress KSystemControlBase::Init::GetKernelPhysicalBaseAddress(KPhysicalAddress base_address) {
        const size_t real_dram_size     = KSystemControl::Init::GetRealMemorySize();
        const size_t intended_dram_size = KSystemControl::Init::GetIntendedMemorySize();
        if (intended_dram_size * 2 < real_dram_size) {
            return base_address;
        } else {
            return base_address + ((real_dram_size - intended_dram_size) / 2);
        }
    }

    void KSystemControlBase::Init::GetInitialProcessBinaryLayout(InitialProcessBinaryLayout *out) {
        *out = {
            .address = GetInteger(KSystemControl::Init::GetKernelPhysicalBaseAddress(ams::kern::MainMemoryAddress)) + KSystemControl::Init::GetIntendedMemorySize() - KTraceBufferSize - InitialProcessBinarySizeMax,
            ._08     = 0,
        };
    }


    bool KSystemControlBase::Init::ShouldIncreaseThreadResourceLimit() {
        return true;
    }


    size_t KSystemControlBase::Init::GetApplicationPoolSize() {
        return 0;
    }

    size_t KSystemControlBase::Init::GetAppletPoolSize() {
        return 0;
    }

    size_t KSystemControlBase::Init::GetMinimumNonSecureSystemPoolSize() {
        return 0;
    }

    u8 KSystemControlBase::Init::GetDebugLogUartPort() {
        return 0;
    }

    void KSystemControlBase::Init::CpuOn(u64 core_id, uintptr_t entrypoint, uintptr_t arg) {
        #if defined(ATMOSPHERE_ARCH_ARM64)
        MESOSPHERE_INIT_ABORT_UNLESS((::ams::kern::arch::arm64::smc::CpuOn<0, false>(core_id, entrypoint, arg)) == 0);
        #else
        AMS_INFINITE_LOOP();
        #endif
    }

    /* Randomness for Initialization. */
    void KSystemControlBase::Init::GenerateRandom(u64 *dst, size_t count) {
        if (AMS_UNLIKELY(!s_initialized_random_generator)) {
            const u64 seed = KHardwareTimer::GetTick();
            s_random_generator.Initialize(reinterpret_cast<const u32*>(std::addressof(seed)), sizeof(seed) / sizeof(u32));
            s_initialized_random_generator = true;
        }

        for (size_t i = 0; i < count; ++i) {
            dst[i] = s_random_generator.GenerateRandomU64();
        }
    }

    u64 KSystemControlBase::Init::GenerateRandomRange(u64 min, u64 max) {
        if (AMS_UNLIKELY(!s_initialized_random_generator)) {
            const u64 seed = KHardwareTimer::GetTick();
            s_random_generator.Initialize(reinterpret_cast<const u32*>(std::addressof(seed)), sizeof(seed) / sizeof(u32));
            s_initialized_random_generator = true;
        }

        return KSystemControlBase::GenerateUniformRange(min, max, []() ALWAYS_INLINE_LAMBDA -> u64 { return s_random_generator.GenerateRandomU64(); });
    }

    /* System Initialization. */
    void KSystemControlBase::InitializePhase1(bool skip_target_system) {
        /* Initialize the rng, if we somehow haven't already. */
        if (AMS_UNLIKELY(!s_initialized_random_generator)) {
            const u64 seed = KHardwareTimer::GetTick();
            s_random_generator.Initialize(reinterpret_cast<const u32*>(std::addressof(seed)), sizeof(seed) / sizeof(u32));
            s_initialized_random_generator = true;
        }

        /* Configure KTargetSystem, if we haven't already by an implementation SystemControl. */
        if (!skip_target_system) {
            /* Set IsDebugMode. */
            {
                KTargetSystem::SetIsDebugMode(true);

                /* If debug mode, we want to initialize uart logging. */
                KTargetSystem::EnableDebugLogging(true);
                KDebugLog::Initialize();
            }

            /* Set Kernel Configuration. */
            {
                KTargetSystem::EnableDebugMemoryFill(false);
                KTargetSystem::EnableUserExceptionHandlers(true);
                KTargetSystem::EnableDynamicResourceLimits(true);
                KTargetSystem::EnableUserPmuAccess(false);
            }

            /* Set Kernel Debugging. */
            {
                /* NOTE: This is used to restrict access to SvcKernelDebug/SvcChangeKernelTraceState. */
                /* Mesosphere may wish to not require this, as we'd ideally keep ProgramVerification enabled for userland. */
                KTargetSystem::EnableKernelDebugging(true);
            }
        }

        /* System ResourceLimit initialization. */
        {
            /* Construct the resource limit object. */
            KResourceLimit &sys_res_limit = Kernel::GetSystemResourceLimit();
            KAutoObject::Create<KResourceLimit>(std::addressof(sys_res_limit));
            sys_res_limit.Initialize();

            /* Set the initial limits. */
            const auto [total_memory_size, kernel_memory_size] = KMemoryLayout::GetTotalAndKernelMemorySizes();
            const auto &slab_counts = init::GetSlabResourceCounts();
            MESOSPHERE_R_ABORT_UNLESS(sys_res_limit.SetLimitValue(ams::svc::LimitableResource_PhysicalMemoryMax,      total_memory_size));
            MESOSPHERE_R_ABORT_UNLESS(sys_res_limit.SetLimitValue(ams::svc::LimitableResource_ThreadCountMax,         slab_counts.num_KThread));
            MESOSPHERE_R_ABORT_UNLESS(sys_res_limit.SetLimitValue(ams::svc::LimitableResource_EventCountMax,          slab_counts.num_KEvent));
            MESOSPHERE_R_ABORT_UNLESS(sys_res_limit.SetLimitValue(ams::svc::LimitableResource_TransferMemoryCountMax, slab_counts.num_KTransferMemory));
            MESOSPHERE_R_ABORT_UNLESS(sys_res_limit.SetLimitValue(ams::svc::LimitableResource_SessionCountMax,        slab_counts.num_KSession));

            /* Reserve system memory. */
            MESOSPHERE_ABORT_UNLESS(sys_res_limit.Reserve(ams::svc::LimitableResource_PhysicalMemoryMax, kernel_memory_size));
        }
    }

    void KSystemControlBase::InitializePhase2() {
        /* Initialize KTrace. */
        if constexpr (IsKTraceEnabled) {
            const auto &ktrace = KMemoryLayout::GetKernelTraceBufferRegion();
            KTrace::Initialize(ktrace.GetAddress(), ktrace.GetSize());
        }
    }

    u32 KSystemControlBase::GetCreateProcessMemoryPool() {
        return KMemoryManager::Pool_System;
    }

    /* Privileged Access. */
    void KSystemControlBase::ReadWriteRegisterPrivileged(u32 *out, ams::svc::PhysicalAddress address, u32 mask, u32 value) {
        /* TODO */
        MESOSPHERE_UNUSED(out, address, mask, value);
        MESOSPHERE_UNIMPLEMENTED();
    }

    Result KSystemControlBase::ReadWriteRegister(u32 *out, ams::svc::PhysicalAddress address, u32 mask, u32 value) {
        MESOSPHERE_UNUSED(out, address, mask, value);
        return svc::ResultNotImplemented();
    }

    /* Randomness. */
    void KSystemControlBase::GenerateRandom(u64 *dst, size_t count) {
        KScopedInterruptDisable intr_disable;
        KScopedSpinLock lk(s_random_lock);

        for (size_t i = 0; i < count; ++i) {
            dst[i] = s_random_generator.GenerateRandomU64();
        }
    }

    u64 KSystemControlBase::GenerateRandomRange(u64 min, u64 max) {
        KScopedInterruptDisable intr_disable;
        KScopedSpinLock lk(s_random_lock);

        return KSystemControlBase::GenerateUniformRange(min, max, []() ALWAYS_INLINE_LAMBDA -> u64 { return s_random_generator.GenerateRandomU64(); });
    }

    u64 KSystemControlBase::GenerateRandomU64() {
        KScopedInterruptDisable intr_disable;
        KScopedSpinLock lk(s_random_lock);

        return s_random_generator.GenerateRandomU64();
    }

    void KSystemControlBase::SleepSystem() {
        MESOSPHERE_LOG("SleepSystem() was called\n");
    }

    void KSystemControlBase::StopSystem(void *) {
        MESOSPHERE_LOG("KSystemControlBase::StopSystem\n");
        AMS_INFINITE_LOOP();
    }

    /* User access. */
    #if defined(ATMOSPHERE_ARCH_ARM64)
    void KSystemControlBase::CallSecureMonitorFromUser(ams::svc::lp64::SecureMonitorArguments *args) {
        /* Get the function id for the current call. */
        u64 function_id = args->r[0];

        /* We'll need to map in pages if arguments are pointers. Prepare page groups to do so. */
        auto &page_table = GetCurrentProcess().GetPageTable();
        auto *bim = page_table.GetBlockInfoManager();

        constexpr size_t MaxMappedRegisters = 7;
        std::array<KPageGroup, MaxMappedRegisters> page_groups = { KPageGroup(bim), KPageGroup(bim), KPageGroup(bim), KPageGroup(bim), KPageGroup(bim), KPageGroup(bim), KPageGroup(bim), };

        for (size_t i = 0; i < MaxMappedRegisters; i++) {
            const size_t reg_id = i + 1;
            if (function_id & (1ul << (8 + reg_id))) {
                /* Create and open a new page group for the address. */
                KVirtualAddress virt_addr = args->r[reg_id];

                if (R_SUCCEEDED(page_table.MakeAndOpenPageGroup(std::addressof(page_groups[i]), util::AlignDown(GetInteger(virt_addr), PageSize), 1, KMemoryState_None, KMemoryState_None, KMemoryPermission_UserReadWrite, KMemoryPermission_UserReadWrite, KMemoryAttribute_None, KMemoryAttribute_None))) {
                    /* Translate the virtual address to a physical address. */
                    const auto it = page_groups[i].begin();
                    MESOSPHERE_ASSERT(it != page_groups[i].end());
                    MESOSPHERE_ASSERT(it->GetNumPages() == 1);

                    args->r[reg_id] = GetInteger(it->GetAddress()) | (GetInteger(virt_addr) & (PageSize - 1));
                } else {
                    /* If we couldn't map, we should clear the address. */
                    args->r[reg_id] = 0;
                }
            }
        }

        /* Invoke the secure monitor. */
        KSystemControl::CallSecureMonitorFromUserImpl(args);

        /* Make sure that we close any pages that we opened. */
        for (size_t i = 0; i < MaxMappedRegisters; i++) {
            page_groups[i].Close();
        }
    }

    void KSystemControlBase::CallSecureMonitorFromUserImpl(ams::svc::lp64::SecureMonitorArguments *args) {
        /* By default, we don't actually support secure monitor, so just set args to a failure code. */
        args->r[0] = 1;
    }
    #endif

    /* Secure Memory. */
    size_t KSystemControlBase::CalculateRequiredSecureMemorySize(size_t size, u32 pool) {
        MESOSPHERE_UNUSED(pool);
        return size;
    }

    Result KSystemControlBase::AllocateSecureMemory(KVirtualAddress *out, size_t size, u32 pool) {
        /* Ensure the size is aligned. */
        constexpr size_t Alignment = PageSize;
        R_UNLESS(util::IsAligned(size, Alignment), svc::ResultInvalidSize());

        /* Allocate the memory. */
        const size_t num_pages = size / PageSize;
        const KPhysicalAddress paddr = Kernel::GetMemoryManager().AllocateAndOpenContinuous(num_pages, Alignment / PageSize, KMemoryManager::EncodeOption(static_cast<KMemoryManager::Pool>(pool), KMemoryManager::Direction_FromFront));
        R_UNLESS(paddr != Null<KPhysicalAddress>, svc::ResultOutOfMemory());

        *out = KPageTable::GetHeapVirtualAddress(paddr);
        return ResultSuccess();
    }

    void KSystemControlBase::FreeSecureMemory(KVirtualAddress address, size_t size, u32 pool) {
        /* Ensure the size is aligned. */
        constexpr size_t Alignment = PageSize;
        MESOSPHERE_UNUSED(pool);
        MESOSPHERE_ABORT_UNLESS(util::IsAligned(GetInteger(address), Alignment));
        MESOSPHERE_ABORT_UNLESS(util::IsAligned(size, Alignment));

        /* Close the secure region's pages. */
        Kernel::GetMemoryManager().Close(KPageTable::GetHeapPhysicalAddress(address), size / PageSize);
    }

}