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