path: root/src/include/kernel/vmmmgr.H

/* IBM_PROLOG_BEGIN_TAG                                                   */
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/* $Source: src/include/kernel/vmmmgr.H $                                 */
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/* OpenPOWER HostBoot Project                                             */
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#ifndef __KERNEL_VMMMGR_H
#define __KERNEL_VMMMGR_H

#include <limits.h>
#include <sys/mmio.h>
#include <sys/mm.h>
#include <kernel/types.h>
#include <kernel/spinlock.H>


class MessageQueue;

class VmmManager
{
    public:
        /**
         * Constants used throughout the virtual memory management classes
         */
        enum VMM_CONSTS
        {
            INITIAL_MEM_SIZE = 4*MEGABYTE,

            // Place the page table at the top side of the cache, 256k in size.
            INITIAL_PT_OFFSET = INITIAL_MEM_SIZE - 1*MEGABYTE,
            PTSIZE = 256*KILOBYTE,
            HTABORG_OFFSET = INITIAL_PT_OFFSET,

            // Put the DMA Pages just after the Page Table
            MBOX_DMA_PAGES = 64,    // must be <= 64
            MBOX_DMA_PAGESIZE = (1 * KILOBYTE),
            MBOX_DMA_ADDR = INITIAL_PT_OFFSET + PTSIZE,
            MBOX_DMA_SIZE = MBOX_DMA_PAGES * MBOX_DMA_PAGESIZE,

            /** We need to reserve a hole in heap memory for the page table,
             *  etc.  Use these constants to define the hole. */
            FIRST_RESERVED_PAGE = INITIAL_PT_OFFSET,
            END_RESERVED_PAGE = INITIAL_PT_OFFSET +
                                 PTSIZE + MBOX_DMA_SIZE,

            // Tells processor to ignore HRMOR
            FORCE_PHYS_ADDR = 0x8000000000000000,
        };

        enum castout_t
        {
            NORMAL,
            CRITICAL,
        };

        /**
         * Kernel mapped page removal operations
         *
         * RELEASE : Writes dirty&write-tracked pages out to a storage device
         *           and removes other pages
         * FLUSH   : Only writes dirty&write-tracked pages out to a storage
         *           device
         * EVICT   : (Kernel) Writes dirty&write-tracked pages out to a storage
         *           device and removes other pages
         */
        enum PAGE_REMOVAL_OPS
        {
            RELEASE = 0,
            FLUSH = 1,
            EVICT = 2,
        };

        static void init();
        static void init_slb();

        /**
         * @brief Responsible for handling PTE misses.
         *
         * @param[in] t - Task causing the page fault.
         * @param[in] effAddr - Effective address accessed to cause fault.
         * @param[in] store - The PTE miss was due to a store.
         *
         * @return true - PTE miss was successfully handled.
         *
         * If the PTE miss is not successfully handled, the exception
         * handler should collect debug information and kill the task.
         */
        static bool pteMiss(task_t* t, uint64_t effAddr, bool store);

        /**
         * @brief Map a device into the device segment
         * @param ra[in] - Void pointer to real address to be mapped in
         * @param i_devDataSize[in] - Size of device segment block
         * @param i_nonCI[in] - Device should be mapped cacheable instead of CI
         * @return void* - Pointer to beginning virtual address, NULL otherwise
         */
        static void* devMap(void* ra, uint64_t i_devDataSize, bool i_nonCI);

        /**
         * @brief Unmap a device from the device segment
         * @param ea[in] - Void pointer to effective address
         * @return int - 0 for successful unmap, non-zero otherwise
         */
        static int devUnmap(void* ea);

        /**
         * @brief Allocates a block of virtual memory of the given size
         * @param i_mq[in] - Message queue to be associated with the block
         * @param i_va[in] - Page aligned base virtual address of the block
         *                   to be allocated
         * @param i_size[in] - Requested virtual memory size of the block
         * @return int - 0 for successful block allocation, non-zero otherwise
         */
        static int mmAllocBlock(MessageQueue* i_mq,void* i_va,uint64_t i_size);

        /**
         * @brief Find the physical address bound to the given address
         * @param[in] i_vaddr The address
         * @return the physical address or -EFAULT @see errno.h
         */
        static uint64_t findPhysicalAddress(uint64_t i_vaddr);

        /**
         * @brief Cast out older physical memory pages
         * @param[in] castout constraint
         */
        static void castOutPages(castout_t i_ct);

        /**
         * @brief Flush pagetable, Update shadow page info
         */
        static void flushPageTable( void);

        /**
         * @brief Remove pages by a specified operation of the given size
         * @param[in] i_op - Page removal operation to perform
         * @param[in] i_vaddr - Virtual address associated to page(s)
         * @param[in] i_size - Size of memory to perform page removal on
         * @param[in] i_task - OPTIONAL:Task requesting page removal.
         * @return int - 0 for successful page removal, non-zero otherwise
         *
         * The given virtual address will be 'rounded' down to the nearest page
         * boundary, along with the given size will be 'rounded' up to the
         * nearest divisible page size.
         *
         * When a task is given, it will be deferred until all pages requested
         * for removal have completed.
         */
        static int mmRemovePages(VmmManager::PAGE_REMOVAL_OPS i_op,
                                 void* i_vaddr, uint64_t i_size,
                                 task_t* i_task = NULL);
        /**
         * @brief Sets the permissions for a given page or range of pages
         * @param i_va[in] - Virtual address of the page to update permission
         * @param i_size[in] - range of memory that needs permissions updated...
         *             if i_size equals 0 then we only need to update an
         *            individual page.
         * @return int - 0 for successful permission update, non-zero otherwise
         *
         * The given virtual address will be 'rounded' down to the nearest page
         * boundary, along with the given size will be 'rounded' up to the
         * nearest divisible page size.
         */
        static int mmSetPermission(void* i_va,uint64_t i_size, uint64_t i_access_type);

        /**
         * @brief Retrieve the current HTABORG value
         * @return uint64_t - value of HTABORG
         */
        static uint64_t HTABORG();

        /**
         * @brief Find the kernel addressable address bound to the
         *     given virtual address
         * @param[in] i_vaddr The address
         * @return the kernel address or -EFAULT @see errno.h
         */
        static uint64_t findKernelAddress(uint64_t i_vaddr);

        /**
         * @brief Allocates a block of virtual memory that extends the VMM
         *          space upto 32MEG of Mainstore.
         */
        static int mmExtend( void);

        /** @fn mm_linear_map()
         *  @brief   Allocates a block of memory of the given size
         *           to at a specified address (direct pa to va  mapping)
         *  @param[in] i_paddr - physical address of the location for the block
         *  @param[in] i_size - size of the block requested
         *
         *  @return int - 0 for successful add, non-zero otherwise
         */
         static int mmLinearMap(void *i_paddr, uint64_t i_size);

    protected:
        VmmManager();
        ~VmmManager() {};

        /** @brief Get spinlock for memory subsystem.
         *  This is useful for passing to a deferred user-space message
         *  handler so that the subsystem code is SMP-safe when the message
         *  response is obtained.
         */
        static Spinlock* getLock();

    private:
        Spinlock lock;

        void initPTEs();
        void initSDR1();

        bool _pteMiss(task_t*, uint64_t, bool);

        /** See findPhysicalAddress */
        uint64_t _findPhysicalAddress(uint64_t i_vaddr);

        /* See mmSetPermission */
        int _mmSetPermission(void* i_va,uint64_t i_size, uint64_t i_access_type);

        /** See castOutPages */
        void _castOutPages(castout_t i_ct);

        /** See flushPageTable */
        void _flushPageTable( void );

        /** See mmAllocBlock */
        int _mmAllocBlock(MessageQueue* i_mq,void* i_va,uint64_t i_size);

        /** See mmRemovePages */
        int _mmRemovePages(VmmManager::PAGE_REMOVAL_OPS i_op,void* i_vaddr,
                           uint64_t i_size,task_t* i_task);

        /** See mmExtend */
        int _mmExtend( void );

        /** See devMap */
        void* _devMap(void* ra, uint64_t i_devDataSize, bool i_nonCI);
        /** See devUnmap */
        int _devUnmap(void* ea);

        /** See mmLinearMap */
        int _mmLinearMap(void*, uint64_t);

    public:
        friend class Block;
        friend class StackSegment;

};

#endif