/*
* Copyright (c) 2016 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 kernel_ia32
* @{
*/
/** @file
*/
#include <arch/vreg.h>
#include <arch/pm.h>
#include <config.h>
#include <typedefs.h>
#include <arch/asm.h>
#include <panic.h>
#include <mm/km.h>
#include <mm/frame.h>
/*
* During initialization, we need to make sure that context_save() and
* context_restore() touch some meaningful address when saving/restoring VREGs.
* When a processor is initialized, we set its GS base to a private page and
* vreg_ptr to zero.
*/
static uint32_t vreg_tp_dummy;
uint32_t *vreg_ptr = &vreg_tp_dummy;
/**
* Allocate and initialize a per-CPU user page to be accessible via the GS
* segment register and to hold the virtual registers.
*/
void vreg_init(void)
{
uintptr_t frame;
uint32_t *page;
descriptor_t *gdt_p = (descriptor_t *) gdtr.base;
frame = frame_alloc(1, FRAME_ATOMIC | FRAME_HIGHMEM, 0);
if (!frame)
panic("Cannot allocate VREG frame.");
page = (uint32_t *) km_map(frame, PAGE_SIZE, PAGE_SIZE,
PAGE_READ | PAGE_WRITE | PAGE_USER | PAGE_CACHEABLE);
gdt_setbase(&gdt_p[VREG_DES], (uintptr_t) page);
gdt_setlimit(&gdt_p[VREG_DES], sizeof(uint32_t));
gs_load(GDT_SELECTOR(VREG_DES));
vreg_ptr = NULL;
}
/** @}
*/