Atmosphere/libraries/libmesosphere/source/kern_k_device_address_space.cpp

/*
 * Copyright (c) 2018-2020 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>

namespace ams::kern {

    /* Static initializer. */
    void KDeviceAddressSpace::Initialize() {
        /* This just forwards to the device page table manager. */
        KDevicePageTable::Initialize();
    }

    /* Member functions. */
    Result KDeviceAddressSpace::Initialize(u64 address, u64 size) {
        MESOSPHERE_ASSERT_THIS();

        /* Initialize the device page table. */
        R_TRY(m_table.Initialize(address, size));

        /* Set member variables. */
        m_space_address  = address;
        m_space_size     = size;
        m_is_initialized = true;

        return ResultSuccess();
    }

    void KDeviceAddressSpace::Finalize() {
        MESOSPHERE_ASSERT_THIS();

        /* Finalize the table. */
        m_table.Finalize();

        /* Finalize base. */
        KAutoObjectWithSlabHeapAndContainer<KDeviceAddressSpace, KAutoObjectWithList>::Finalize();
    }

    Result KDeviceAddressSpace::Attach(ams::svc::DeviceName device_name) {
        /* Lock the address space. */
        KScopedLightLock lk(m_lock);

        /* Attach. */
        return m_table.Attach(device_name, m_space_address, m_space_size);
    }

    Result KDeviceAddressSpace::Detach(ams::svc::DeviceName device_name) {
        /* Lock the address space. */
        KScopedLightLock lk(m_lock);

        /* Detach. */
        return m_table.Detach(device_name);
    }

    Result KDeviceAddressSpace::Map(KProcessPageTable *page_table, KProcessAddress process_address, size_t size, u64 device_address, ams::svc::MemoryPermission device_perm, bool is_aligned) {
        /* Check that the address falls within the space. */
        R_UNLESS((m_space_address <= device_address && device_address + size - 1 <= m_space_address + m_space_size - 1), svc::ResultInvalidCurrentMemory());

        /* Lock the address space. */
        KScopedLightLock lk(m_lock);

        /* Lock the page table to prevent concurrent device mapping operations. */
        KScopedLightLock pt_lk = page_table->AcquireDeviceMapLock();

        /* Lock the pages. */
        R_TRY(page_table->LockForMapDeviceAddressSpace(process_address, size, ConvertToKMemoryPermission(device_perm), is_aligned));

        /* Ensure that if we fail, we don't keep unmapped pages locked. */
        auto unlock_guard = SCOPE_GUARD { MESOSPHERE_R_ABORT_UNLESS(page_table->UnlockForDeviceAddressSpace(process_address, size)); };

        /* Map the pages. */
        {
            /* Perform the mapping. */
            R_TRY(m_table.Map(page_table, process_address, size, device_address, device_perm, is_aligned));

            /* Ensure that we unmap the pages if we fail to update the protections. */
            /* NOTE: Nintendo does not check the result of this unmap call. */
            auto map_guard = SCOPE_GUARD { m_table.Unmap(device_address, size); };

            /* Update the protections in accordance with how much we mapped. */
            R_TRY(page_table->UnlockForDeviceAddressSpacePartialMap(process_address, size));

            /* We succeeded, so cancel our guard. */
            map_guard.Cancel();
        }

        /* We succeeded, so we don't need to unlock our pages. */
        unlock_guard.Cancel();
        return ResultSuccess();
    }

    Result KDeviceAddressSpace::Unmap(KProcessPageTable *page_table, KProcessAddress process_address, size_t size, u64 device_address) {
        /* Check that the address falls within the space. */
        R_UNLESS((m_space_address <= device_address && device_address + size - 1 <= m_space_address + m_space_size - 1), svc::ResultInvalidCurrentMemory());

        /* Lock the address space. */
        KScopedLightLock lk(m_lock);

        /* Lock the page table to prevent concurrent device mapping operations. */
        KScopedLightLock pt_lk = page_table->AcquireDeviceMapLock();

        /* Lock the pages. */
        R_TRY(page_table->LockForUnmapDeviceAddressSpace(process_address, size));

        /* If we fail to unmap, we want to do a partial unlock. */
        {
            auto unlock_guard = SCOPE_GUARD { MESOSPHERE_R_ABORT_UNLESS(page_table->UnlockForDeviceAddressSpacePartialMap(process_address, size)); };

            /* Unmap. */
            R_TRY(m_table.Unmap(page_table, process_address, size, device_address));

            unlock_guard.Cancel();
        }

        /* Unlock the pages. */
        MESOSPHERE_R_ABORT_UNLESS(page_table->UnlockForDeviceAddressSpace(process_address, size));

        return ResultSuccess();
    }

}