source: mainline/kernel/arch/arm32/src/mm/page.c@ dd0c8a0

/*
 * Copyright (c) 2007 Pavel Jancik, Michal Kebrt
 * 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 arm32mm
 * @{
 */
/** @file
 *  @brief Paging related functions.
 */

#include <arch/mm/page.h>
#include <genarch/mm/page_pt.h>
#include <mm/page.h>
#include <arch/mm/frame.h>
#include <align.h>
#include <config.h>
#include <arch/exception.h>
#include <typedefs.h>
#include <interrupt.h>
#include <macros.h>

/** Initializes page tables.
 *
 * 1:1 virtual-physical mapping is created in kernel address space. Mapping
 * for table with exception vectors is also created.
 */
void page_arch_init(void)
{
        int flags = PAGE_CACHEABLE | PAGE_EXEC;
        page_mapping_operations = &pt_mapping_operations;

#ifdef PROCESSOR_ARCH_armv6
        /* Select ARMv6 and ARMv7 memory model */
        SCTLR_write(SCTLR_read() | SCTLR_EXTENDED_PT_EN_FLAG);
#endif
        page_table_lock(AS_KERNEL, true);
        
        /* Kernel identity mapping */
        //FIXME: We need to consider the possibility that
        //identity_base > identity_size and physmem_end.
        //This might lead to overflow if identity_size is too big.
        for (uintptr_t cur = PHYSMEM_START_ADDR;
            cur < min(KA2PA(config.identity_base) +
                config.identity_size, config.physmem_end);
            cur += FRAME_SIZE)
                page_mapping_insert(AS_KERNEL, PA2KA(cur), cur, flags);
        
#ifdef HIGH_EXCEPTION_VECTORS
        /* Create mapping for exception table at high offset */
        uintptr_t ev_frame = frame_alloc(1, FRAME_NONE, 0);
        page_mapping_insert(AS_KERNEL, EXC_BASE_ADDRESS, ev_frame, flags);
#else
#error "Only high exception vector supported now"
#endif

        page_table_unlock(AS_KERNEL, true);
        
        as_switch(NULL, AS_KERNEL);
        
        boot_page_table_free();
}

/** @}
 */