[linuxsh-dev] New cache handling scheme

[NIIBE Y. <gn...@ch...>]

I've mistakenly removed the definitionn of flush_cache_page (the function
for flushing the cache for user space), which is reverted.

And as Documentation/cachetlb.txt says, now is the transition time
from flush_page_to_ram to copy_user_page/clear_user_page/flush_dcache_page.

I've implement copy_user_page and clear_user_page.

2000-09-18  NIIBE Yutaka  <gn...@m1...>

	Follow new cache handling scheme.  Because now is the transition
	time (I think it's not fully changed to use "flush_dcache_page"),
	let's leave flush_page_to_ram.

	* arch/sh/mm/cache.c (clear_user_page, copy_user_page): Implemented.
	(__flush_page_to_ram): New function.
	(flush_page_to_ram): Use __flush_page_to_ram.

	* include/asm-sh/page.h (clear_user_page, copy_user_page): Define
	function for SH-4.

	Revert the changes of 2000-09-09.
	* arch/sh/mm/cache.c (flush_cache_page): Reverted.
	* include/asm-sh/pgtable.h (flush_cache_page): Ditto.

Index: arch/sh/mm/cache.c
===================================================================
RCS file: /cvsroot/linuxsh/kernel/arch/sh/mm/cache.c,v
retrieving revision 1.20
diff -u -r1.20 cache.c
--- arch/sh/mm/cache.c	2000/09/09 01:49:39	1.20
+++ arch/sh/mm/cache.c	2000/09/18 05:04:57
@@ -354,6 +354,39 @@
 }
 
 /*
+ * Write back and invalidate D-caches for the page.
+ *
+ * ADDR: Virtual Address (U0 address)
+ *
+ * NOTE: We need to flush the _physical_ page entry.
+ * Flushing the cache lines for U0 only isn't enough.
+ * We need to flush for P1 too, which may contain aliases.
+ */
+void flush_cache_page(struct vm_area_struct *vma, unsigned long addr)
+{
+	pgd_t *dir;
+	pmd_t *pmd;
+	pte_t *pte;
+	pte_t entry;
+	unsigned long phys;
+	struct page *pg;
+
+	dir = pgd_offset(vma->vm_mm, addr);
+	pmd = pmd_offset(dir, addr);
+	if (pmd_none(*pmd))
+		return;
+	if (pmd_bad(*pmd))
+		return;
+	pte = pte_offset(pmd, addr);
+	entry = *pte;
+	if (pte_none(entry) || !pte_present(entry))
+		return;
+	phys = pte_val(entry)&PAGE_MASK;
+	pg = virt_to_page(__va(phys));
+	flush_dcache_page(pg);
+}
+
+/*
  * Write-back & invalidate the cache.
  *
  * After accessing the memory from kernel space (P1-area), we need to 
@@ -362,12 +395,12 @@
  * We search the D-cache to see if we have the entries corresponding to
  * the page, and if found, write back them.
  */
-void flush_page_to_ram(struct page *pg)
+void __flush_page_to_ram(void *kaddr)
 {
 	unsigned long phys, addr, data, i;
 
 	/* Physical address of this page */
-	phys = (pg - mem_map)*PAGE_SIZE + __MEMORY_START;
+	phys = PHYSADDR(kaddr);
 
 	jump_to_P2();
 	/* Loop all the D-cache */
@@ -382,6 +415,15 @@
 	back_to_P1();
 }
 
+void flush_page_to_ram(struct page *pg)
+{
+	unsigned long phys;
+
+	/* Physical address of this page */
+	phys = (pg - mem_map)*PAGE_SIZE + __MEMORY_START;
+	__flush_page_to_ram(phys_to_virt(phys));
+}
+
 /*
  * Check entries of the I-cache & D-cache of the page.
  * (To see "alias" issues)
@@ -437,5 +479,22 @@
 		dump_stack();
 		printk("--------------------\n");
 	}
+}
+
+/* Page is 4K, OC size is 16K, there are four lines. */
+#define CACHE_ALIAS 0x00003000
+
+void clear_user_page(void *to, unsigned long address)
+{
+	clear_page(to);
+	if (((address ^ (unsigned long)to) & CACHE_ALIAS))
+		__flush_page_to_ram(to);
+}
+
+void copy_user_page(void *to, void *from, unsigned long address)
+{
+	copy_page(to, from);
+	if (((address ^ (unsigned long)to) & CACHE_ALIAS))
+		__flush_page_to_ram(to);
 }
 #endif
Index: include/asm-sh/page.h
===================================================================
RCS file: /cvsroot/linuxsh/kernel/include/asm-sh/page.h,v
retrieving revision 1.4
diff -u -r1.4 page.h
--- include/asm-sh/page.h	2000/08/16 08:34:06	1.4
+++ include/asm-sh/page.h	2000/09/18 05:04:58
@@ -26,8 +26,14 @@
 
 #define clear_page(page)	memset((void *)(page), 0, PAGE_SIZE)
 #define copy_page(to,from)	memcpy((void *)(to), (void *)(from), PAGE_SIZE)
+
+#if defined(__sh3__)
 #define clear_user_page(page, vaddr)	clear_page(page)
 #define copy_user_page(to, from, vaddr)	copy_page(to, from)
+#elif defined(__SH4__)
+extern void clear_user_page(void *to, unsigned long address);
+extern void copy_user_page(void *to, void *from, unsigned long address);
+#endif
 
 /*
  * These are used to make use of C type-checking..
Index: include/asm-sh/pgtable.h
===================================================================
RCS file: /cvsroot/linuxsh/kernel/include/asm-sh/pgtable.h,v
retrieving revision 1.11
diff -u -r1.11 pgtable.h
--- include/asm-sh/pgtable.h	2000/09/09 01:49:40	1.11
+++ include/asm-sh/pgtable.h	2000/09/18 05:04:59
@@ -47,7 +47,7 @@
 extern void flush_cache_mm(struct mm_struct *mm);
 extern void flush_cache_range(struct mm_struct *mm, unsigned long start,
 			      unsigned long end);
-#define flush_cache_page(vma, vmaddr)		do { } while (0)
+extern void flush_cache_page(struct vm_area_struct *vma, unsigned long addr);
 extern void flush_page_to_ram(struct page *page);
 extern void flush_dcache_page(struct page *pg);
 extern void flush_icache_range(unsigned long start, unsigned long end);
Index: mm/vmscan.c
===================================================================
RCS file: /cvsroot/linuxsh/kernel/mm/vmscan.c,v
retrieving revision 1.13
diff -u -r1.13 vmscan.c
--- mm/vmscan.c	2000/09/04 06:41:54	1.13
+++ mm/vmscan.c	2000/09/18 05:05:05
@@ -138,7 +138,6 @@
 	 *
 	 * That would get rid of a lot of problems.
 	 */
-	flush_page_to_ram(page);
 	flush_cache_page(vma, address);
 	if (vma->vm_ops && (swapout = vma->vm_ops->swapout)) {
 		int error;