[PATCH] alpha_remap_area_pages

From Jeff.Wiedemeier@hp.com:

Add arch/alpha/mm/remap.c (__alpha_remap_area_pages).

arch/alpha/kernel/proto.h

@@ -153,6 +153,10 @@ extern void die_if_kernel(char *, struct pt_regs *, long, unsigned long *);
 extern void switch_to_system_map(void);
 extern void srm_paging_stop(void);
 
+/* ../mm/remap.c */
+extern int __alpha_remap_area_pages(unsigned long, unsigned long, 
+				    unsigned long, unsigned long);
+
 /* irq.c */
 
 #ifdef CONFIG_SMP

arch/alpha/mm/Makefile

@@ -2,6 +2,6 @@
 # Makefile for the linux alpha-specific parts of the memory manager.
 #
 
-obj-y	:= init.o fault.o extable.o
+obj-y	:= init.o fault.o extable.o remap.o
 
 obj-$(CONFIG_DISCONTIGMEM) += numa.o

arch/alpha/mm/remap.c

+#include <linux/vmalloc.h>
+#include <asm/pgalloc.h>
+#include <asm/cacheflush.h>
+
+/* called with the page_table_lock held */
+static inline void 
+remap_area_pte(pte_t * pte, unsigned long address, unsigned long size, 
+	       unsigned long phys_addr, unsigned long flags)
+{
+	unsigned long end;
+	unsigned long pfn;
+
+	address &= ~PMD_MASK;
+	end = address + size;
+	if (end > PMD_SIZE)
+		end = PMD_SIZE;
+	if (address >= end)
+		BUG();
+	pfn = phys_addr >> PAGE_SHIFT;
+	do {
+		if (!pte_none(*pte)) {
+			printk("remap_area_pte: page already exists\n");
+			BUG();
+		}
+		set_pte(pte, pfn_pte(pfn, 
+				     __pgprot(_PAGE_VALID | _PAGE_ASM | 
+				              _PAGE_KRE | _PAGE_KWE | flags)));
+		address += PAGE_SIZE;
+		pfn++;
+		pte++;
+	} while (address && (address < end));
+}
+
+/* called with the page_table_lock held */
+static inline int 
+remap_area_pmd(pmd_t * pmd, unsigned long address, unsigned long size, 
+	       unsigned long phys_addr, unsigned long flags)
+{
+	unsigned long end;
+
+	address &= ~PGDIR_MASK;
+	end = address + size;
+	if (end > PGDIR_SIZE)
+		end = PGDIR_SIZE;
+	phys_addr -= address;
+	if (address >= end)
+		BUG();
+	do {
+		pte_t * pte = pte_alloc_kernel(&init_mm, pmd, address);
+		if (!pte)
+			return -ENOMEM;
+		remap_area_pte(pte, address, end - address, 
+				     address + phys_addr, flags);
+		address = (address + PMD_SIZE) & PMD_MASK;
+		pmd++;
+	} while (address && (address < end));
+	return 0;
+}
+
+int
+__alpha_remap_area_pages(unsigned long address, unsigned long phys_addr,
+			 unsigned long size, unsigned long flags)
+{
+	pgd_t * dir;
+	int error = 0;
+	unsigned long end = address + size;
+
+	phys_addr -= address;
+	dir = pgd_offset(&init_mm, address);
+	flush_cache_all();
+	if (address >= end)
+		BUG();
+	spin_lock(&init_mm.page_table_lock);
+	do {
+		pmd_t *pmd;
+		pmd = pmd_alloc(&init_mm, dir, address);
+		error = -ENOMEM;
+		if (!pmd)
+			break;
+		if (remap_area_pmd(pmd, address, end - address,
+			           phys_addr + address, flags))
+			break;
+		error = 0;
+		address = (address + PGDIR_SIZE) & PGDIR_MASK;
+		dir++;
+	} while (address && (address < end));
+	spin_unlock(&init_mm.page_table_lock);
+	return error;
+}
+