source: mainline/kernel/generic/src/mm/km.c@ c142860

/*
 * Copyright (c) 2011 Jakub Jermar
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/** @addtogroup genericmm
 * @{
 */

/**
 * @file
 * @brief Kernel virtual memory setup.
 */

#include <mm/km.h>
#include <arch/mm/km.h>
#include <mm/page.h>
#include <mm/frame.h>
#include <mm/asid.h>
#include <config.h>
#include <typedefs.h>
#include <lib/ra.h>
#include <debug.h>
#include <arch.h>

static ra_arena_t *km_ni_arena;

#define DEFERRED_PAGES_MAX      (PAGE_SIZE / sizeof(uintptr_t)) 

/** Number of freed pages in the deferred buffer. */
static volatile unsigned deferred_pages;
/** Buffer of deferred freed pages. */
static uintptr_t deferred_page[DEFERRED_PAGES_MAX];

/** Flush the buffer of deferred freed pages.
 *
 * @return              Number of freed pages.
 */
static unsigned km_flush_deferred(void)
{
        unsigned i = 0;
        ipl_t ipl;

        ipl = tlb_shootdown_start(TLB_INVL_ASID, ASID_KERNEL, 0, 0);

        for (i = 0; i < deferred_pages; i++) {
                page_mapping_remove(AS_KERNEL, deferred_page[i]);
                km_page_free(deferred_page[i], PAGE_SIZE);
        }

        tlb_invalidate_asid(ASID_KERNEL);

        as_invalidate_translation_cache(AS_KERNEL, 0, -1);
        tlb_shootdown_finalize(ipl);

        return i;
}

/** Architecture dependent setup of identity-mapped kernel memory. */
void km_identity_init(void)
{
        km_identity_arch_init();
        config.identity_configured = true;
}

/** Architecture dependent setup of non-identity-mapped kernel memory. */
void km_non_identity_init(void)
{
        km_ni_arena = ra_arena_create();
        ASSERT(km_ni_arena != NULL);
        km_non_identity_arch_init();
        config.non_identity_configured = true;
}

bool km_is_non_identity(uintptr_t addr)
{
        return km_is_non_identity_arch(addr);
}

void km_non_identity_span_add(uintptr_t base, size_t size)
{
        bool span_added;

        page_mapping_make_global(base, size);

        span_added = ra_span_add(km_ni_arena, base, size);
        ASSERT(span_added);
}

uintptr_t km_page_alloc(size_t size, size_t align)
{
        return ra_alloc(km_ni_arena, size, align);
}

void km_page_free(uintptr_t page, size_t size)
{
        ra_free(km_ni_arena, page, size);
}

/** Unmap kernen non-identity page.
 *
 * @param[in] page      Non-identity page to be unmapped.
 */
static void km_unmap_deferred(uintptr_t page)
{
        page_table_lock(AS_KERNEL, true);

        if (deferred_pages == DEFERRED_PAGES_MAX) {
                (void) km_flush_deferred();
                deferred_pages = 0;
        }

        deferred_page[deferred_pages++] = page;

        page_table_unlock(AS_KERNEL, true);
}

/** Create a temporary page.
 *
 * The page is mapped read/write to a newly allocated frame of physical memory.
 * The page must be returned back to the system by a call to
 * km_temporary_page_put().
 *
 * @param[inout] framep Pointer to a variable which will receive the physical
 *                      address of the allocated frame.
 * @param[in] flags     Frame allocation flags. FRAME_NONE or FRAME_NO_RESERVE.
 * @return              Virtual address of the allocated frame.
 */
uintptr_t km_temporary_page_get(uintptr_t *framep, frame_flags_t flags)
{
        uintptr_t frame;
        uintptr_t page;

        ASSERT(THREAD);
        ASSERT(framep);
        ASSERT(!(flags & ~FRAME_NO_RESERVE));

        /*
         * Allocate a frame, preferably from high memory.
         */
        frame = (uintptr_t) frame_alloc(ONE_FRAME,
            FRAME_HIGHMEM | FRAME_ATOMIC | flags); 
        if (frame) {
                page = km_page_alloc(PAGE_SIZE, PAGE_SIZE);
                ASSERT(page);   // FIXME
                page_table_lock(AS_KERNEL, true);
                page_mapping_insert(AS_KERNEL, page, frame,
                    PAGE_CACHEABLE | PAGE_READ | PAGE_WRITE);
                page_table_unlock(AS_KERNEL, true);
        } else {
                frame = (uintptr_t) frame_alloc_noreserve(ONE_FRAME,
                    FRAME_LOWMEM);
                page = PA2KA(frame);
        }

        *framep = frame;
        return page;    
}

/** Destroy a temporary page.
 *
 * This function destroys a temporary page previously created by
 * km_temporary_page_get(). The page destruction may be immediate or deferred.
 * The frame mapped by the destroyed page is not freed.
 *
 * @param[in] page      Temporary page to be destroyed.
 */
void km_temporary_page_put(uintptr_t page)
{
        ASSERT(THREAD);

        if (km_is_non_identity(page))
                km_unmap_deferred(page);
}

/** @}
 */