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/**************************************************************************
*
* This kernel module is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of the
* License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*
**************************************************************************/
/*
* This code provides access to unexported mm kernel features. It is necessary
* to use the new DRM memory manager code with kernels that don't support it
* directly.
*
* Authors: Thomas Hellstrom <thomas-at-tungstengraphics-dot-com>
* Linux kernel mm subsystem authors.
* (Most code taken from there).
*/
#include "drmP.h"
#if defined(CONFIG_X86) && (LINUX_VERSION_CODE < KERNEL_VERSION(2,6,15))
int drm_map_page_into_agp(struct page *page)
{
int i;
i = change_page_attr(page, 1, PAGE_KERNEL_NOCACHE);
/* Caller's responsibility to call global_flush_tlb() for
* performance reasons */
return i;
}
int drm_unmap_page_from_agp(struct page *page)
{
int i;
i = change_page_attr(page, 1, PAGE_KERNEL);
/* Caller's responsibility to call global_flush_tlb() for
* performance reasons */
return i;
}
#endif
pgprot_t vm_get_page_prot(unsigned long vm_flags)
{
#ifdef MODULE
static pgprot_t drm_protection_map[16] = {
__P000, __P001, __P010, __P011, __P100, __P101, __P110, __P111,
__S000, __S001, __S010, __S011, __S100, __S101, __S110, __S111
};
return drm_protection_map[vm_flags & 0x0F];
#else
extern pgprot_t protection_map[];
return protection_map[vm_flags & 0x0F];
#endif
};
int drm_pte_is_clear(struct vm_area_struct *vma,
unsigned long addr)
{
struct mm_struct *mm = vma->vm_mm;
int ret = 1;
pte_t *pte;
pmd_t *pmd;
pud_t *pud;
pgd_t *pgd;
#if (LINUX_VERSION_CODE < KERNEL_VERSION(2,6,15))
spin_lock(&mm->page_table_lock);
#else
spinlock_t ptl;
#endif
pgd = pgd_offset(mm, addr);
if (pgd_none(*pgd))
goto unlock;
pud = pud_offset(pgd, addr);
if (pud_none(*pud))
goto unlock;
pmd = pmd_offset(pud, addr);
if (pmd_none(*pmd))
goto unlock;
#if (LINUX_VERSION_CODE < KERNEL_VERSION(2,6,15))
pte = pte_offset_map(pmd, addr);
#else
pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
#endif
if (!pte)
goto unlock;
ret = pte_none(*pte);
#if (LINUX_VERSION_CODE < KERNEL_VERSION(2,6,15))
pte_unmap(pte);
unlock:
spin_unlock(&mm->page_table_lock);
#else
pte_unmap_unlock(pte, ptl);
unlock:
#endif
return ret;
}
static struct {
spinlock_t lock;
struct page *dummy_page;
atomic_t present;
} drm_np_retry =
{SPIN_LOCK_UNLOCKED, NOPAGE_OOM, ATOMIC_INIT(0)};
struct page * get_nopage_retry(void)
{
if (atomic_read(&drm_np_retry.present) == 0) {
struct page *page = alloc_page(GFP_KERNEL);
if (!page)
return NOPAGE_OOM;
spin_lock(&drm_np_retry.lock);
drm_np_retry.dummy_page = page;
atomic_set(&drm_np_retry.present,1);
spin_unlock(&drm_np_retry.lock);
}
get_page(drm_np_retry.dummy_page);
return drm_np_retry.dummy_page;
}
void free_nopage_retry(void)
{
if (atomic_read(&drm_np_retry.present) == 1) {
spin_lock(&drm_np_retry.lock);
__free_page(drm_np_retry.dummy_page);
drm_np_retry.dummy_page = NULL;
atomic_set(&drm_np_retry.present, 0);
spin_unlock(&drm_np_retry.lock);
}
}
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