source: rtems-libbsd/rtemsbsd/rtems/rtems-kernel-page.c @ 7533adc

/**
 * @file
 *
 * @ingroup rtems_bsd_rtems
 *
 * @brief TODO.
 */

/*
 * Copyright (c) 2015 embedded brains GmbH.  All rights reserved.
 *
 *  embedded brains GmbH
 *  Dornierstr. 4
 *  82178 Puchheim
 *  Germany
 *  <rtems@embedded-brains.de>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``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 OR CONTRIBUTORS 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.
 */

#include <machine/rtems-bsd-kernel-space.h>
#include <machine/rtems-bsd-page.h>

#include <sys/param.h>
#include <sys/types.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <vm/uma.h>

#include <stdlib.h>

#include <rtems/bsd/bsd.h>
#include <rtems/malloc.h>
#include <rtems/rbheap.h>

void **rtems_bsd_page_object_table;

uintptr_t rtems_bsd_page_area_begin;

static struct {
        struct mtx mtx;
        rtems_rbheap_control heap;
        size_t used;
} page_alloc;

void *
rtems_bsd_page_alloc(uintptr_t size_in_bytes, int wait)
{
        void *addr;

        mtx_lock(&page_alloc.mtx);

        addr = rtems_rbheap_allocate(&page_alloc.heap, size_in_bytes);
        if (addr == NULL && wait) {
                int i;

                for (i = 0; i < 8; i++) {
                        mtx_unlock(&page_alloc.mtx);
                        uma_reclaim();
                        mtx_lock(&page_alloc.mtx);

                        addr = rtems_rbheap_allocate(&page_alloc.heap,
                            size_in_bytes);
                        if (addr != NULL)
                                break;

                        msleep(&page_alloc.heap, &page_alloc.mtx, 0,
                            "page alloc", (hz / 4) * (i + 1));
                }

                if (i == 8) {
                        panic("rtems_bsd_page_alloc: page starvation");
                }
        }

        page_alloc.used += (addr != NULL) ? 1 : 0;
        mtx_unlock(&page_alloc.mtx);

#ifdef INVARIANTS
        wait |= M_ZERO;
#endif

        if (addr != NULL && (wait & M_ZERO) != 0) {
                memset(addr, 0, size_in_bytes);
        }

        return (addr);
}

void
rtems_bsd_page_free(void *addr)
{

        mtx_lock(&page_alloc.mtx);
        --page_alloc.used;
        rtems_rbheap_free(&page_alloc.heap, addr);
        wakeup(&page_alloc.heap);
        mtx_unlock(&page_alloc.mtx);
}

static void
rtems_bsd_page_init(void *arg)
{
        rtems_status_code sc;
        void *area;
        void **obj_table;
        rtems_rbheap_chunk *chunks;
        size_t i;
        size_t n;
        uintptr_t heap_size;

        mtx_init(&page_alloc.mtx, "page heap", NULL, MTX_DEF);

        heap_size = rtems_bsd_get_allocator_domain_size(
            RTEMS_BSD_ALLOCATOR_DOMAIN_PAGE);

        area = rtems_heap_allocate_aligned_with_boundary(heap_size, PAGE_SIZE,
            0);
        BSD_ASSERT(area != NULL);

        sc = rtems_rbheap_initialize(&page_alloc.heap, area, heap_size,
            PAGE_SIZE, rtems_rbheap_extend_descriptors_with_malloc, NULL);
        BSD_ASSERT(sc == RTEMS_SUCCESSFUL);

        rtems_rbheap_set_extend_descriptors(&page_alloc.heap,
            rtems_rbheap_extend_descriptors_never);

        n = heap_size / PAGE_SIZE;

        chunks = malloc(n * sizeof(*chunks), M_RTEMS_HEAP, M_NOWAIT);
        BSD_ASSERT(chunks != NULL);

        for (i = 0; i < n; ++i) {
                rtems_rbheap_add_to_spare_descriptor_chain(&page_alloc.heap,
                    &chunks[i]);
        }

        obj_table = calloc(n, sizeof(*obj_table));

        rtems_bsd_page_area_begin = (uintptr_t)area;
        rtems_bsd_page_object_table = obj_table;
}

SYSINIT(rtems_bsd_page, SI_SUB_VM, SI_ORDER_FIRST, rtems_bsd_page_init, NULL);