3 files changed, 159 insertions, 1 deletions
diff --git a/linux-core/Makefile.kernel b/linux-core/Makefile.kernel
index 651e30b0..c7c47919 100644
--- a/linux-core/Makefile.kernel
+++ b/linux-core/Makefile.kernel
@@ -12,7 +12,7 @@ drm-objs    := drm_auth.o drm_bufs.o drm_context.o drm_dma.o drm_drawable.o \
 		drm_lock.o drm_memory.o drm_proc.o drm_stub.o drm_vm.o \
 		drm_sysfs.o drm_pci.o drm_agpsupport.o drm_scatter.o \
 		drm_memory_debug.o ati_pcigart.o drm_sman.o \
-		drm_hashtab.o drm_mm.o drm_object.o
+		drm_hashtab.o drm_mm.o drm_object.o drm_compat.o
 tdfx-objs   := tdfx_drv.o
 r128-objs   := r128_drv.o r128_cce.o r128_state.o r128_irq.o
 mga-objs    := mga_drv.o mga_dma.o mga_state.o mga_warp.o mga_irq.o
diff --git a/linux-core/drm_compat.c b/linux-core/drm_compat.c
new file mode 100644
index 00000000..cdef4b97
--- /dev/null
+++ b/linux-core/drm_compat.c
@@ -0,0 +1,140 @@
+/**************************************************************************
+ * 
+ * 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"
+#include <asm/pgtable.h>
+#include <asm/cacheflush.h>
+#include <asm/tlbflush.h>
+
+#ifdef MODULE
+void pgd_clear_bad(pgd_t * pgd)
+{
+	pgd_ERROR(*pgd);
+	pgd_clear(pgd);
+}
+
+void pud_clear_bad(pud_t * pud)
+{
+	pud_ERROR(*pud);
+	pud_clear(pud);
+}
+
+void pmd_clear_bad(pmd_t * pmd)
+{
+	pmd_ERROR(*pmd);
+	pmd_clear(pmd);
+}
+#endif
+
+static inline void change_pte_range(struct mm_struct *mm, pmd_t * pmd,
+				    unsigned long addr, unsigned long end)
+{
+	pte_t *pte;
+
+	pte = pte_offset_map(pmd, addr);
+	do {
+		if (pte_present(*pte)) {
+			pte_t ptent;
+			ptent = *pte;
+			ptep_get_and_clear(mm, addr, pte);
+			lazy_mmu_prot_update(ptent);
+		}
+	} while (pte++, addr += PAGE_SIZE, addr != end);
+	pte_unmap(pte - 1);
+}
+
+static inline void change_pmd_range(struct mm_struct *mm, pud_t * pud,
+				    unsigned long addr, unsigned long end)
+{
+	pmd_t *pmd;
+	unsigned long next;
+
+	pmd = pmd_offset(pud, addr);
+	do {
+		next = pmd_addr_end(addr, end);
+		if (pmd_none_or_clear_bad(pmd))
+			continue;
+		change_pte_range(mm, pmd, addr, next);
+	} while (pmd++, addr = next, addr != end);
+}
+
+static inline void change_pud_range(struct mm_struct *mm, pgd_t * pgd,
+				    unsigned long addr, unsigned long end)
+{
+	pud_t *pud;
+	unsigned long next;
+
+	pud = pud_offset(pgd, addr);
+	do {
+		next = pud_addr_end(addr, end);
+		if (pud_none_or_clear_bad(pud))
+			continue;
+		change_pmd_range(mm, pud, addr, next);
+	} while (pud++, addr = next, addr != end);
+}
+
+/*
+ * This function should be called with all relevant spinlocks held.
+ */
+
+void drm_clear_vma(struct vm_area_struct *vma,
+		   unsigned long addr, unsigned long end)
+{
+	struct mm_struct *mm = vma->vm_mm;
+	pgd_t *pgd;
+	unsigned long next;
+#if defined(flush_tlb_mm) || !defined(MODULE)
+	unsigned long start = addr;
+#endif
+	BUG_ON(addr >= end);
+	pgd = pgd_offset(mm, addr);
+	flush_cache_range(vma, addr, end);
+	do {
+		next = pgd_addr_end(addr, end);
+		if (pgd_none_or_clear_bad(pgd))
+			continue;
+		change_pud_range(mm, pgd, addr, next);
+	} while (pgd++, addr = next, addr != end);
+#if defined(flush_tlb_mm) || !defined(MODULE)
+	flush_tlb_range(vma, addr, end);
+#endif
+}
+
+pgprot_t drm_prot_map(uint32_t 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[flags & 0x0F];
+#else
+	extern pgprot_t protection_map[];
+	return protection_map[flags & 0x0F];
+#endif
+};
diff --git a/linux-core/drm_compat.h b/linux-core/drm_compat.h
index 407853d7..80928319 100644
--- a/linux-core/drm_compat.h
+++ b/linux-core/drm_compat.h
@@ -227,4 +227,22 @@ static inline int remap_pfn_range(struct vm_area_struct *vma, unsigned long from
 }
 #endif
 
+#include <linux/mm.h>
+#include <asm/page.h>
+
+/*
+ * Flush relevant caches and clear a VMA structure so that page references 
+ * will cause a page fault. Don't flush tlbs.
+ */
+
+extern void drm_clear_vma(struct vm_area_struct *vma,
+			  unsigned long addr, unsigned long end);
+
+/*
+ * Return the PTE protection map entries for the VMA flags given by 
+ * flags. This is a functional interface to the kernel's protection map.
+ */
+
+extern pgprot_t drm_prot_map(uint32_t flags);
+
 #endif