[XTENSA] Add support for cache-aliasing

Add support for processors that have cache-aliasing issues, such as
the Stretch S5000 processor. Cache-aliasing means that the size of
the cache (for one way) is larger than the page size, thus, a page
can end up in several places in cache depending on the virtual to
physical translation. The method used here is to map a user page
temporarily through the auto-refill way 0 and of of the DTLB.
We probably will want to revisit this issue and use a better
approach with kmap/kunmap.
Signed-off-by: Chris Zankel <chris@zankel.net>

arch/xtensa/kernel/asm-offsets.c

@@ -18,12 +18,13 @@
 #include <linux/stddef.h>
 #include <linux/thread_info.h>
 #include <linux/ptrace.h>
+#include <linux/mm.h>
+
 #include <asm/ptrace.h>
 #include <asm/processor.h>
 #include <asm/uaccess.h>
 
 #define DEFINE(sym, val) asm volatile("\n->" #sym " %0 " #val : : "i" (val))
-#define BLANK() asm volatile("\n->" : : )
 
 int main(void)
 {
@@ -63,7 +64,6 @@ int main(void)
 	DEFINE(PT_SIZE, sizeof(struct pt_regs));
 	DEFINE(PT_AREG_END, offsetof (struct pt_regs, areg[XCHAL_NUM_AREGS]));
 	DEFINE(PT_USER_SIZE, offsetof(struct pt_regs, areg[XCHAL_NUM_AREGS]));
-	BLANK();
 
 	/* struct task_struct */
 	DEFINE(TASK_PTRACE, offsetof (struct task_struct, ptrace));
@@ -73,27 +73,26 @@ int main(void)
 	DEFINE(TASK_THREAD, offsetof (struct task_struct, thread));
 	DEFINE(TASK_THREAD_INFO, offsetof (struct task_struct, stack));
 	DEFINE(TASK_STRUCT_SIZE, sizeof (struct task_struct));
-	BLANK();
 
 	/* struct thread_info (offset from start_struct) */
 	DEFINE(THREAD_RA, offsetof (struct task_struct, thread.ra));
 	DEFINE(THREAD_SP, offsetof (struct task_struct, thread.sp));
 	DEFINE(THREAD_CP_SAVE, offsetof (struct task_struct, thread.cp_save));
 	DEFINE(THREAD_CURRENT_DS, offsetof (struct task_struct, thread.current_ds));
-	BLANK();
 
 	/* struct mm_struct */
 	DEFINE(MM_USERS, offsetof(struct mm_struct, mm_users));
 	DEFINE(MM_PGD, offsetof (struct mm_struct, pgd));
 	DEFINE(MM_CONTEXT, offsetof (struct mm_struct, context));
-	BLANK();
-	DEFINE(PT_SINGLESTEP_BIT, PT_SINGLESTEP_BIT);
+
+	/* struct page */
+	DEFINE(PAGE_FLAGS, offsetof(struct page, flags));
 
 	/* constants */
 	DEFINE(_CLONE_VM, CLONE_VM);
 	DEFINE(_CLONE_UNTRACED, CLONE_UNTRACED);
+	DEFINE(PG_ARCH_1, PG_arch_1);
 
 	return 0;
 }
 
-

arch/xtensa/kernel/entry.S

@@ -7,7 +7,7 @@
  * License.  See the file "COPYING" in the main directory of this archive
  * for more details.
  *
- * Copyright (C) 2004-2005 by Tensilica Inc.
+ * Copyright (C) 2004-2007 by Tensilica Inc.
  *
  * Chris Zankel <chris@zankel.net>
  *
@@ -169,7 +169,7 @@ _user_exception:
 	 * We have to save all registers up to the first '1' from
 	 * the right, except the current frame (bit 0).
 	 * Assume a2 is:  001001000110001
-	 * All regiser frames starting from the top fiel to the marked '1'
+	 * All register frames starting from the top field to the marked '1'
 	 * must be saved.
 	 */
 
@@ -1590,7 +1590,7 @@ ENTRY(fast_second_level_miss)
 	 * The messy computation for 'pteval' above really simplifies
 	 * into the following:
 	 *
-	 * pteval = ((pmdval - PAGE_OFFSET) & PAGE_MASK) | PAGE_KERNEL
+	 * pteval = ((pmdval - PAGE_OFFSET) & PAGE_MASK) | PAGE_DIRECTORY
 	 */
 
 	movi	a1, -PAGE_OFFSET
@@ -1602,7 +1602,7 @@ ENTRY(fast_second_level_miss)
 	or	a0, a0, a1		# ... | PAGE_DIRECTORY
 
 	/*
-	 * We utilize all three wired-ways (7-9( to hold pmd translations.
+	 * We utilize all three wired-ways (7-9) to hold pmd translations.
 	 * Memory regions are mapped to the DTLBs according to bits 28 and 29.
 	 * This allows to map the three most common regions to three different
 	 * DTLBs:
@@ -1652,6 +1652,73 @@ ENTRY(fast_second_level_miss)
 9:	l32i	a0, a1, TASK_ACTIVE_MM	# unlikely case mm == 0
 	j	8b
 
+#if (DCACHE_WAY_SIZE > PAGE_SIZE)
+
+2:	/* Special case for cache aliasing.
+	 * We (should) only get here if a clear_user_page, copy_user_page
+	 * or the aliased cache flush functions got preemptively interrupted 
+	 * by another task. Re-establish temporary mapping to the 
+	 * TLBTEMP_BASE areas.
+	 */
+
+	/* We shouldn't be in a double exception */
+
+	l32i	a0, a2, PT_DEPC
+	bgeui	a0, VALID_DOUBLE_EXCEPTION_ADDRESS, 2f
+
+	/* Make sure the exception originated in the special functions */
+
+	movi	a0, __tlbtemp_mapping_start
+	rsr	a3, EPC_1
+	bltu	a3, a0, 2f
+	movi	a0, __tlbtemp_mapping_end
+	bgeu	a3, a0, 2f
+
+	/* Check if excvaddr was in one of the TLBTEMP_BASE areas. */
+
+	movi	a3, TLBTEMP_BASE_1
+	rsr	a0, EXCVADDR
+	bltu	a0, a3, 2f
+
+	addi	a1, a0, -(2 << (DCACHE_ALIAS_ORDER + PAGE_SHIFT))
+	bgeu	a1, a3, 2f
+
+	/* Check if we have to restore an ITLB mapping. */
+
+	movi	a1, __tlbtemp_mapping_itlb
+	rsr	a3, EPC_1
+	sub	a3, a3, a1
+
+	/* Calculate VPN */
+
+	movi	a1, PAGE_MASK
+	and	a1, a1, a0
+
+	/* Jump for ITLB entry */
+
+	bgez	a3, 1f
+
+	/* We can use up to two TLBTEMP areas, one for src and one for dst. */
+
+	extui	a3, a0, PAGE_SHIFT + DCACHE_ALIAS_ORDER, 1
+	add	a1, a3, a1
+
+	/* PPN is in a6 for the first TLBTEMP area and in a7 for the second. */
+
+	mov	a0, a6
+	movnez	a0, a7, a3
+	j	3b
+
+	/* ITLB entry. We only use dst in a6. */
+
+1:	witlb	a6, a1
+	isync
+	j	4b
+
+
+#endif	// DCACHE_WAY_SIZE > PAGE_SIZE
+
+
 2:	/* Invalid PGD, default exception handling */
 
 	movi	a3, exc_table

arch/xtensa/mm/Makefile

@@ -5,9 +5,5 @@
 # removes any old dependencies. DON'T put your own dependencies here
 # unless it's something special (ie not a .c file).
 #
-# Note 2! The CFLAGS definition is now in the main makefile...
 
-obj-y	 := init.o fault.o tlb.o misc.o
-obj-m	 :=
-obj-n	 :=
-obj-	 :=
+obj-y	 := init.o fault.o tlb.o misc.o cache.o

arch/xtensa/mm/cache.c

+/*
+ * arch/xtensa/mm/cache.c
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 2001-2006 Tensilica Inc.
+ *
+ * Chris Zankel	<chris@zankel.net>
+ * Joe Taylor
+ * Marc Gauthier
+ *
+ */
+
+#include <linux/init.h>
+#include <linux/signal.h>
+#include <linux/sched.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/string.h>
+#include <linux/types.h>
+#include <linux/ptrace.h>
+#include <linux/bootmem.h>
+#include <linux/swap.h>
+#include <linux/pagemap.h>
+
+#include <asm/pgtable.h>
+#include <asm/bootparam.h>
+#include <asm/mmu_context.h>
+#include <asm/tlb.h>
+#include <asm/tlbflush.h>
+#include <asm/page.h>
+#include <asm/pgalloc.h>
+#include <asm/pgtable.h>
+
+//#define printd(x...) printk(x)
+#define printd(x...) do { } while(0)
+
+/* 
+ * Note:
+ * The kernel provides one architecture bit PG_arch_1 in the page flags that 
+ * can be used for cache coherency.
+ *
+ * I$-D$ coherency.
+ *
+ * The Xtensa architecture doesn't keep the instruction cache coherent with
+ * the data cache. We use the architecture bit to indicate if the caches
+ * are coherent. The kernel clears this bit whenever a page is added to the
+ * page cache. At that time, the caches might not be in sync. We, therefore,
+ * define this flag as 'clean' if set.
+ *
+ * D-cache aliasing.
+ *
+ * With cache aliasing, we have to always flush the cache when pages are
+ * unmapped (see tlb_start_vma(). So, we use this flag to indicate a dirty
+ * page.
+ * 
+ *
+ *
+ */
+
+#if (DCACHE_WAY_SIZE > PAGE_SIZE) && XCHAL_DCACHE_IS_WRITEBACK
+
+/*
+ * Any time the kernel writes to a user page cache page, or it is about to
+ * read from a page cache page this routine is called.
+ *
+ */
+
+void flush_dcache_page(struct page *page)
+{
+	struct address_space *mapping = page_mapping(page);
+
+	/*
+	 * If we have a mapping but the page is not mapped to user-space
+	 * yet, we simply mark this page dirty and defer flushing the 
+	 * caches until update_mmu().
+	 */
+
+	if (mapping && !mapping_mapped(mapping)) {
+		if (!test_bit(PG_arch_1, &page->flags))
+			set_bit(PG_arch_1, &page->flags);
+		return;
+
+	} else {
+
+		unsigned long phys = page_to_phys(page);
+		unsigned long temp = page->index << PAGE_SHIFT;
+		unsigned long alias = !(DCACHE_ALIAS_EQ(temp, phys));
+		unsigned long virt;
+
+		/* 
+		 * Flush the page in kernel space and user space.
+		 * Note that we can omit that step if aliasing is not
+		 * an issue, but we do have to synchronize I$ and D$
+		 * if we have a mapping.
+		 */
+
+		if (!alias && !mapping)
+			return;
+
+		__flush_invalidate_dcache_page((long)page_address(page));
+
+		virt = TLBTEMP_BASE_1 + (temp & DCACHE_ALIAS_MASK);
+
+		if (alias)
+			__flush_invalidate_dcache_page_alias(virt, phys);
+
+		if (mapping)
+			__invalidate_icache_page_alias(virt, phys);
+	}
+
+	/* There shouldn't be an entry in the cache for this page anymore. */
+}
+
+
+/*
+ * For now, flush the whole cache. FIXME??
+ */
+
+void flush_cache_range(struct vm_area_struct* vma, 
+		       unsigned long start, unsigned long end)
+{
+	__flush_invalidate_dcache_all();
+	__invalidate_icache_all();
+}
+
+/* 
+ * Remove any entry in the cache for this page. 
+ *
+ * Note that this function is only called for user pages, so use the
+ * alias versions of the cache flush functions.
+ */
+
+void flush_cache_page(struct vm_area_struct* vma, unsigned long address,
+    		      unsigned long pfn)
+{
+	/* Note that we have to use the 'alias' address to avoid multi-hit */
+
+	unsigned long phys = page_to_phys(pfn_to_page(pfn));
+	unsigned long virt = TLBTEMP_BASE_1 + (address & DCACHE_ALIAS_MASK);
+
+	__flush_invalidate_dcache_page_alias(virt, phys);
+	__invalidate_icache_page_alias(virt, phys);
+}
+
+#endif
+
+void
+update_mmu_cache(struct vm_area_struct * vma, unsigned long addr, pte_t pte)
+{
+	unsigned long pfn = pte_pfn(pte);
+	struct page *page;
+
+	if (!pfn_valid(pfn))
+		return;
+
+	page = pfn_to_page(pfn);
+
+	/* Invalidate old entry in TLBs */
+
+	invalidate_itlb_mapping(addr);
+	invalidate_dtlb_mapping(addr);
+
+#if (DCACHE_WAY_SIZE > PAGE_SIZE) && XCHAL_DCACHE_IS_WRITEBACK
+
+	if (!PageReserved(page) && test_bit(PG_arch_1, &page->flags)) {
+
+		unsigned long vaddr = TLBTEMP_BASE_1 + (addr & DCACHE_ALIAS_MASK);
+		unsigned long paddr = (unsigned long) page_address(page);
+		unsigned long phys = page_to_phys(page);
+
+		__flush_invalidate_dcache_page(paddr);
+
+		__flush_invalidate_dcache_page_alias(vaddr, phys);
+		__invalidate_icache_page_alias(vaddr, phys);
+
+		clear_bit(PG_arch_1, &page->flags);
+	}
+#else
+	if (!PageReserved(page) && !test_bit(PG_arch_1, &page->flags)
+	    && (vma->vm_flags & VM_EXEC) != 0) {
+		unsigned long vaddr = addr & PAGE_MASK;
+		__flush_dcache_page(vaddr);
+		__invalidate_icache_page(vaddr);
+		set_bit(PG_arch_1, &page->flags);
+	}
+#endif
+}
+
+/*
+ * access_process_vm() has called get_user_pages(), which has done a
+ * flush_dcache_page() on the page.
+ */
+
+#if (DCACHE_WAY_SIZE > PAGE_SIZE) && XCHAL_DCACHE_IS_WRITEBACK
+
+void copy_to_user_page(struct vm_area_struct *vma, struct page *page, 
+		unsigned long vaddr, void *dst, const void *src,
+		unsigned long len)
+{
+	unsigned long phys = page_to_phys(page);
+	unsigned long alias = !(DCACHE_ALIAS_EQ(vaddr, phys));
+
+	/* Flush and invalidate user page if aliased. */
+
+	if (alias) {
+		unsigned long temp = TLBTEMP_BASE_1 + (vaddr & DCACHE_ALIAS_MASK);
+		__flush_invalidate_dcache_page_alias(temp, phys);
+	}
+
+	/* Copy data */
+	
+	memcpy(dst, src, len);
+
+	/*
+	 * Flush and invalidate kernel page if aliased and synchronize 
+	 * data and instruction caches for executable pages. 
+	 */
+
+	if (alias) {
+		unsigned long temp = TLBTEMP_BASE_1 + (vaddr & DCACHE_ALIAS_MASK);
+
+		__flush_invalidate_dcache_range((unsigned long) dst, len);
+		if ((vma->vm_flags & VM_EXEC) != 0) {
+			__invalidate_icache_page_alias(temp, phys);
+		}
+
+	} else if ((vma->vm_flags & VM_EXEC) != 0) {
+		__flush_dcache_range((unsigned long)dst,len);
+		__invalidate_icache_range((unsigned long) dst, len);
+	}
+}
+
+extern void copy_from_user_page(struct vm_area_struct *vma, struct page *page,
+		unsigned long vaddr, void *dst, const void *src,
+		unsigned long len)
+{
+	unsigned long phys = page_to_phys(page);
+	unsigned long alias = !(DCACHE_ALIAS_EQ(vaddr, phys));
+
+	/*
+	 * Flush user page if aliased. 
+	 * (Note: a simply flush would be sufficient) 
+	 */
+
+	if (alias) {
+		unsigned long temp = TLBTEMP_BASE_1 + (vaddr & DCACHE_ALIAS_MASK);
+		__flush_invalidate_dcache_page_alias(temp, phys);
+	}
+
+	memcpy(dst, src, len);
+}
+
+#endif

arch/xtensa/mm/fault.c

@@ -24,6 +24,8 @@
 unsigned long asid_cache = ASID_USER_FIRST;
 void bad_page_fault(struct pt_regs*, unsigned long, int);
 
+#undef DEBUG_PAGE_FAULT
+
 /*
  * This routine handles page faults.  It determines the address,
  * and the problem, and then passes it off to one of the appropriate
@@ -64,7 +66,7 @@ void do_page_fault(struct pt_regs *regs)
 		    exccause == EXCCAUSE_ITLB_MISS ||
 		    exccause == EXCCAUSE_FETCH_CACHE_ATTRIBUTE) ? 1 : 0;
 
-#if 0
+#ifdef DEBUG_PAGE_FAULT
 	printk("[%s:%d:%08x:%d:%08x:%s%s]\n", current->comm, current->pid,
 	       address, exccause, regs->pc, is_write? "w":"", is_exec? "x":"");
 #endif
@@ -219,7 +221,7 @@ bad_page_fault(struct pt_regs *regs, unsigned long address, int sig)
 
 	/* Are we prepared to handle this kernel fault?  */
 	if ((entry = search_exception_tables(regs->pc)) != NULL) {
-#if 1
+#ifdef DEBUG_PAGE_FAULT
 		printk(KERN_DEBUG "%s: Exception at pc=%#010lx (%lx)\n",
 				current->comm, regs->pc, entry->fixup);
 #endif

arch/xtensa/mm/init.c

@@ -15,40 +15,24 @@
  * Kevin Chea
  */
 
-#include <linux/init.h>
-#include <linux/signal.h>
-#include <linux/sched.h>
 #include <linux/kernel.h>
 #include <linux/errno.h>
-#include <linux/string.h>
-#include <linux/types.h>
-#include <linux/ptrace.h>
 #include <linux/bootmem.h>
 #include <linux/swap.h>
+#include <linux/mman.h>
+#include <linux/nodemask.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
 
 #include <asm/pgtable.h>
 #include <asm/bootparam.h>
 #include <asm/mmu_context.h>
 #include <asm/tlb.h>
-#include <asm/tlbflush.h>
 #include <asm/page.h>
 #include <asm/pgalloc.h>
-#include <asm/pgtable.h>
-
 
-#define DEBUG 0
 
 DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
-//static DEFINE_SPINLOCK(tlb_lock);
-
-/*
- * This flag is used to indicate that the page was mapped and modified in
- * kernel space, so the cache is probably dirty at that address.
- * If cache aliasing is enabled and the page color mismatches, update_mmu_cache
- * synchronizes the caches if this bit is set.
- */
-
-#define PG_cache_clean PG_arch_1
 
 /* References to section boundaries */
 
@@ -323,228 +307,22 @@ void show_mem(void)
 	printk("%d free pages\n", free);
 }
 
-/* ------------------------------------------------------------------------- */
-
-#if (DCACHE_WAY_SIZE > PAGE_SIZE)
-
-/*
- * With cache aliasing, the page color of the page in kernel space and user
- * space might mismatch. We temporarily map the page to a different virtual
- * address with the same color and clear the page there.
- */
-
-void clear_user_page(void *kaddr, unsigned long vaddr, struct page* page)
-{
-
-  	/*  There shouldn't be any entries for this page. */
-
-	__flush_invalidate_dcache_page_phys(__pa(page_address(page)));
-
-	if (!PAGE_COLOR_EQ(vaddr, kaddr)) {
-		unsigned long v, p;
-
-		/* Temporarily map page to DTLB_WAY_DCACHE_ALIAS0. */
-
-		spin_lock(&tlb_lock);
-
-		p = (unsigned long)pte_val((mk_pte(page,PAGE_KERNEL)));
-		kaddr = (void*)PAGE_COLOR_MAP0(vaddr);
-		v = (unsigned long)kaddr | DTLB_WAY_DCACHE_ALIAS0;
-		__asm__ __volatile__("wdtlb %0,%1; dsync" : :"a" (p), "a" (v));
-
-		clear_page(kaddr);
-
-		spin_unlock(&tlb_lock);
-	} else {
-		clear_page(kaddr);
-	}
-
-	/* We need to make sure that i$ and d$ are coherent. */
-
-	clear_bit(PG_cache_clean, &page->flags);
-}
-
-/*
- * With cache aliasing, we have to make sure that the page color of the page
- * in kernel space matches that of the virtual user address before we read
- * the page. If the page color differ, we create a temporary DTLB entry with
- * the corrent page color and use this 'temporary' address as the source.
- * We then use the same approach as in clear_user_page and copy the data
- * to the kernel space and clear the PG_cache_clean bit to synchronize caches
- * later.
- *
- * Note:
- * Instead of using another 'way' for the temporary DTLB entry, we could
- * probably use the same entry that points to the kernel address (after
- * saving the original value and restoring it when we are done).
- */
+struct kmem_cache *pgtable_cache __read_mostly;
 
-void copy_user_page(void* to, void* from, unsigned long vaddr,
-    		    struct page* to_page)
+static void pgd_ctor(void *addr, struct kmem_cache *cache, unsigned long flags)
 {
-	/* There shouldn't be any entries for the new page. */
-
-	__flush_invalidate_dcache_page_phys(__pa(page_address(to_page)));
-
-	spin_lock(&tlb_lock);
-
-	if (!PAGE_COLOR_EQ(vaddr, from)) {
-		unsigned long v, p, t;
-
-		__asm__ __volatile__ ("pdtlb %1,%2; rdtlb1 %0,%1"
-				      : "=a"(p), "=a"(t) : "a"(from));
-		from = (void*)PAGE_COLOR_MAP0(vaddr);
-		v = (unsigned long)from | DTLB_WAY_DCACHE_ALIAS0;
-		__asm__ __volatile__ ("wdtlb %0,%1; dsync" ::"a" (p), "a" (v));
-	}
-
-	if (!PAGE_COLOR_EQ(vaddr, to)) {
-		unsigned long v, p;
-
-		p = (unsigned long)pte_val((mk_pte(to_page,PAGE_KERNEL)));
-		to = (void*)PAGE_COLOR_MAP1(vaddr);
-		v = (unsigned long)to | DTLB_WAY_DCACHE_ALIAS1;
-		__asm__ __volatile__ ("wdtlb %0,%1; dsync" ::"a" (p), "a" (v));
-	}
-	copy_page(to, from);
-
-	spin_unlock(&tlb_lock);
-
-	/* We need to make sure that i$ and d$ are coherent. */
-
-	clear_bit(PG_cache_clean, &to_page->flags);
-}
-
-
-
-/*
- * Any time the kernel writes to a user page cache page, or it is about to
- * read from a page cache page this routine is called.
- *
- * Note:
- * The kernel currently only provides one architecture bit in the page
- * flags that we use for I$/D$ coherency. Maybe, in future, we can
- * use a sepearte bit for deferred dcache aliasing:
- * If the page is not mapped yet, we only need to set a flag,
- * if mapped, we need to invalidate the page.
- */
-// FIXME: we probably need this for WB caches not only for Page Coloring..
-
-void flush_dcache_page(struct page *page)
-{
-	unsigned long addr = __pa(page_address(page));
-	struct address_space *mapping = page_mapping(page);
-
-	__flush_invalidate_dcache_page_phys(addr);
-
-	if (!test_bit(PG_cache_clean, &page->flags))
-		return;
-
-	/* If this page hasn't been mapped, yet, handle I$/D$ coherency later.*/
-#if 0
-	if (mapping && !mapping_mapped(mapping))
-		clear_bit(PG_cache_clean, &page->flags);
-	else
-#endif
-		__invalidate_icache_page_phys(addr);
-}
-
-void flush_cache_range(struct vm_area_struct* vma, unsigned long s,
-		       unsigned long e)
-{
-	__flush_invalidate_cache_all();
-}
-
-void flush_cache_page(struct vm_area_struct* vma, unsigned long address,
-    		      unsigned long pfn)
-{
-	struct page *page = pfn_to_page(pfn);
-
-	/* Remove any entry for the old mapping. */
-
-	if (current->active_mm == vma->vm_mm) {
-		unsigned long addr = __pa(page_address(page));
-		__flush_invalidate_dcache_page_phys(addr);
-		if ((vma->vm_flags & VM_EXEC) != 0)
-			__invalidate_icache_page_phys(addr);
-	} else {
-		BUG();
-	}
-}
-
-#endif	/* (DCACHE_WAY_SIZE > PAGE_SIZE) */
-
-
-pte_t* pte_alloc_one_kernel (struct mm_struct* mm, unsigned long addr)
-{
-	pte_t* pte = (pte_t*)__get_free_pages(GFP_KERNEL|__GFP_REPEAT, 0);
-	if (likely(pte)) {
-	       	pte_t* ptep = (pte_t*)(pte_val(*pte) + PAGE_OFFSET);
-		int i;
-		for (i = 0; i < 1024; i++, ptep++)
-			pte_clear(mm, addr, ptep);
-	}
-	return pte;
-}
-
-struct page* pte_alloc_one(struct mm_struct *mm, unsigned long addr)
-{
-	struct page *page;
-
-	page = alloc_pages(GFP_KERNEL | __GFP_REPEAT, 0);
-
-	if (likely(page)) {
-		pte_t* ptep = kmap_atomic(page, KM_USER0);
-		int i;
+	pte_t* ptep = (pte_t*)addr;
+	int i;
 
-		for (i = 0; i < 1024; i++, ptep++)
-			pte_clear(mm, addr, ptep);
+	for (i = 0; i < 1024; i++, ptep++)
+		pte_clear(NULL, 0, ptep);
 
-		kunmap_atomic(ptep, KM_USER0);
-	}
-	return page;
 }
 
-
-/*
- * Handle D$/I$ coherency.
- *
- * Note:
- * We only have one architecture bit for the page flags, so we cannot handle
- * cache aliasing, yet.
- */
-
-void
-update_mmu_cache(struct vm_area_struct * vma, unsigned long addr, pte_t pte)
+void __init pgtable_cache_init(void)
 {
-	unsigned long pfn = pte_pfn(pte);
-	struct page *page;
-	unsigned long vaddr = addr & PAGE_MASK;
-
-	if (!pfn_valid(pfn))
-		return;
-
-	page = pfn_to_page(pfn);
-
-	invalidate_itlb_mapping(addr);
-	invalidate_dtlb_mapping(addr);
-
-	/* We have a new mapping. Use it. */
-
-	write_dtlb_entry(pte, dtlb_probe(addr));
-
-	/* If the processor can execute from this page, synchronize D$/I$. */
-
-	if ((vma->vm_flags & VM_EXEC) != 0) {
-
-		write_itlb_entry(pte, itlb_probe(addr));
-
-		/* Synchronize caches, if not clean. */
-
-		if (!test_and_set_bit(PG_cache_clean, &page->flags)) {
-			__flush_dcache_page(vaddr);
-			__invalidate_icache_page(vaddr);
-		}
-	}
+	pgtable_cache = kmem_cache_create("pgd",
+			PAGE_SIZE, PAGE_SIZE,
+			SLAB_HWCACHE_ALIGN,
+			pgd_ctor);
 }
-

arch/xtensa/mm/misc.S

@@ -7,29 +7,33 @@
  * License.  See the file "COPYING" in the main directory of this archive
  * for more details.
  *
- * Copyright (C) 2001 - 2005 Tensilica Inc.
+ * Copyright (C) 2001 - 2007 Tensilica Inc.
  *
  * Chris Zankel	<chris@zankel.net>
  */
 
-/* Note: we might want to implement some of the loops as zero-overhead-loops,
- *	 where applicable and if supported by the processor.
- */
 
 #include <linux/linkage.h>
 #include <asm/page.h>
 #include <asm/pgtable.h>
 #include <asm/asmmacro.h>
 #include <asm/cacheasm.h>
+#include <asm/tlbflush.h>
+
 
-/* clear_page (page) */
+/*
+ * clear_page and clear_user_page are the same for non-cache-aliased configs.
+ *
+ * clear_page (unsigned long page)
+ *                    a2
+ */
 
 ENTRY(clear_page)
 	entry	a1, 16
-	addi	a4, a2, PAGE_SIZE
-	movi	a3, 0
 
-1:	s32i	a3, a2, 0
+	movi	a3, 0
+	__loopi	a2, a7, PAGE_SIZE, 32
+	s32i	a3, a2, 0
 	s32i	a3, a2, 4
 	s32i	a3, a2, 8
 	s32i	a3, a2, 12
@@ -37,42 +41,277 @@ ENTRY(clear_page)
 	s32i	a3, a2, 20
 	s32i	a3, a2, 24
 	s32i	a3, a2, 28
-	addi	a2, a2, 32
-	blt	a2, a4, 1b
+	__endla	a2, a7, 32
 
 	retw
 
 /*
+ * copy_page and copy_user_page are the same for non-cache-aliased configs.
+ *
  * copy_page (void *to, void *from)
- *                  a2        a3
+ *               a2          a3
  */
 
 ENTRY(copy_page)
 	entry	a1, 16
-	addi	a4, a2, PAGE_SIZE
-
-1:	l32i	a5, a3, 0
-	l32i	a6, a3, 4
-	l32i	a7, a3, 8
-	s32i	a5, a2, 0
-	s32i	a6, a2, 4
-	s32i	a7, a2, 8
-	l32i	a5, a3, 12
-	l32i	a6, a3, 16
-	l32i	a7, a3, 20
-	s32i	a5, a2, 12
-	s32i	a6, a2, 16
-	s32i	a7, a2, 20
-	l32i	a5, a3, 24
-	l32i	a6, a3, 28
-	s32i	a5, a2, 24
-	s32i	a6, a2, 28
-	addi	a2, a2, 32
-	addi	a3, a3, 32
-	blt	a2, a4, 1b
 
+	__loopi a2, a4, PAGE_SIZE, 32
+
+	l32i    a8, a3, 0
+	l32i    a9, a3, 4
+	s32i    a8, a2, 0
+	s32i    a9, a2, 4
+
+	l32i    a8, a3, 8
+	l32i    a9, a3, 12
+	s32i    a8, a2, 8
+	s32i    a9, a2, 12
+
+	l32i    a8, a3, 16
+	l32i    a9, a3, 20
+	s32i    a8, a2, 16
+	s32i    a9, a2, 20
+
+	l32i    a8, a3, 24
+	l32i    a9, a3, 28
+	s32i    a8, a2, 24
+	s32i    a9, a2, 28
+
+	addi    a2, a2, 32
+	addi    a3, a3, 32
+
+	__endl  a2, a4
+
+	retw
+
+/*
+ * If we have to deal with cache aliasing, we use temporary memory mappings
+ * to ensure that the source and destination pages have the same color as
+ * the virtual address. We use way 0 and 1 for temporary mappings in such cases.
+ *
+ * The temporary DTLB entries shouldn't be flushed by interrupts, but are
+ * flushed by preemptive task switches. Special code in the 
+ * fast_second_level_miss handler re-established the temporary mapping. 
+ * It requires that the PPNs for the destination and source addresses are
+ * in a6, and a7, respectively.
+ */
+
+/* TLB miss exceptions are treated special in the following region */
+
+ENTRY(__tlbtemp_mapping_start)
+
+#if (DCACHE_WAY_SIZE > PAGE_SIZE)
+
+/*
+ * clear_user_page (void *addr, unsigned long vaddr, struct page *page)
+ *                     a2              a3                 a4
+ */
+
+ENTRY(clear_user_page)
+	entry	a1, 32
+
+	/* Mark page dirty and determine alias. */
+
+	movi	a7, (1 << PG_ARCH_1)
+	l32i	a5, a4, PAGE_FLAGS
+	xor	a6, a2, a3
+	extui	a3, a3, PAGE_SHIFT, DCACHE_ALIAS_ORDER
+	extui	a6, a6, PAGE_SHIFT, DCACHE_ALIAS_ORDER
+	or	a5, a5, a7
+	slli	a3, a3, PAGE_SHIFT
+	s32i	a5, a4, PAGE_FLAGS
+
+	/* Skip setting up a temporary DTLB if not aliased. */
+
+	beqz	a6, 1f
+
+	/* Invalidate kernel page. */
+
+	mov	a10, a2
+	call8	__invalidate_dcache_page
+
+	/* Setup a temporary DTLB with the color of the VPN */
+
+	movi	a4, -PAGE_OFFSET + (PAGE_KERNEL | _PAGE_HW_WRITE)
+	movi	a5, TLBTEMP_BASE_1			# virt
+	add	a6, a2, a4				# ppn
+	add	a2, a5, a3				# add 'color'
+
+	wdtlb	a6, a2
+	dsync
+
+1:	movi	a3, 0
+	__loopi	a2, a7, PAGE_SIZE, 32
+	s32i	a3, a2, 0
+	s32i	a3, a2, 4
+	s32i	a3, a2, 8
+	s32i	a3, a2, 12
+	s32i	a3, a2, 16
+	s32i	a3, a2, 20
+	s32i	a3, a2, 24
+	s32i	a3, a2, 28
+	__endla	a2, a7, 32
+
+	bnez	a6, 1f
+	retw
+
+	/* We need to invalidate the temporary idtlb entry, if any. */
+
+1:	addi	a2, a2, -PAGE_SIZE
+	idtlb	a2
+	dsync
+
+	retw
+
+/*
+ * copy_page_user (void *to, void *from, unsigned long vaddr, struct page *page)
+ *                    a2          a3	        a4		    a5
+ */
+
+ENTRY(copy_user_page)
+
+	entry	a1, 32 
+
+	/* Mark page dirty and determine alias for destination. */
+
+	movi	a8, (1 << PG_ARCH_1)
+	l32i	a9, a5, PAGE_FLAGS
+	xor	a6, a2, a4
+	xor	a7, a3, a4
+	extui	a4, a4, PAGE_SHIFT, DCACHE_ALIAS_ORDER
+	extui	a6, a6, PAGE_SHIFT, DCACHE_ALIAS_ORDER
+	extui	a7, a7, PAGE_SHIFT, DCACHE_ALIAS_ORDER
+	or	a9, a9, a8
+	slli	a4, a4, PAGE_SHIFT
+	s32i	a9, a5, PAGE_FLAGS
+	movi	a5, -PAGE_OFFSET + (PAGE_KERNEL | _PAGE_HW_WRITE)
+
+	beqz	a6, 1f
+
+	/* Invalidate dcache */
+
+	mov	a10, a2
+	call8	__invalidate_dcache_page
+
+	/* Setup a temporary DTLB with a matching color. */
+
+	movi	a8, TLBTEMP_BASE_1			# base
+	add	a6, a2, a5				# ppn
+	add	a2, a8, a4				# add 'color'
+
+	wdtlb	a6, a2
+	dsync
+
+	/* Skip setting up a temporary DTLB for destination if not aliased. */
+
+1:	beqz	a7, 1f
+
+	/* Setup a temporary DTLB with a matching color. */
+
+	movi	a8, TLBTEMP_BASE_2			# base
+	add	a7, a3, a5				# ppn
+	add	a3, a8, a4
+	addi	a8, a3, 1				# way1
+
+	wdtlb	a7, a8
+	dsync
+
+1:	__loopi a2, a4, PAGE_SIZE, 32
+
+	l32i    a8, a3, 0
+	l32i    a9, a3, 4
+	s32i    a8, a2, 0
+	s32i    a9, a2, 4
+
+	l32i    a8, a3, 8
+	l32i    a9, a3, 12
+	s32i    a8, a2, 8
+	s32i    a9, a2, 12
+
+	l32i    a8, a3, 16
+	l32i    a9, a3, 20
+	s32i    a8, a2, 16
+	s32i    a9, a2, 20
+
+	l32i    a8, a3, 24
+	l32i    a9, a3, 28
+	s32i    a8, a2, 24
+	s32i    a9, a2, 28
+
+	addi    a2, a2, 32
+	addi    a3, a3, 32
+
+	__endl  a2, a4
+
+	/* We need to invalidate any temporary mapping! */
+
+	bnez	a6, 1f
+	bnez	a7, 2f
+	retw
+
+1:	addi	a2, a2, -PAGE_SIZE
+	idtlb	a2
+	dsync
+	bnez	a7, 2f
+	retw
+
+2:	addi	a3, a3, -PAGE_SIZE+1
+	idtlb	a3
+	dsync
+
+	retw
+
+#endif
+
+#if (DCACHE_WAY_SIZE > PAGE_SIZE)
+
+/*
+ * void __flush_invalidate_dcache_page_alias (addr, phys)
+ *                                             a2    a3
+ */
+
+ENTRY(__flush_invalidate_dcache_page_alias)
+	entry	sp, 16
+
+	movi	a7, 0			# required for exception handler
+	addi	a6, a3, (PAGE_KERNEL | _PAGE_HW_WRITE)
+	mov	a4, a2
+	wdtlb	a6, a2
+	dsync
+
+	___flush_invalidate_dcache_page a2 a3
+
+	idtlb	a4
+	dsync
+
+	retw
+
+#endif
+
+ENTRY(__tlbtemp_mapping_itlb)
+
+#if (ICACHE_WAY_SIZE > PAGE_SIZE)
+	
+ENTRY(__invalidate_icache_page_alias)
+	entry	sp, 16
+
+	addi	a6, a3, (PAGE_KERNEL | _PAGE_HW_WRITE)
+	mov	a4, a2
+	witlb	a6, a2
+	isync
+
+	___invalidate_icache_page a2 a3
+
+	iitlb	a4
+	isync
 	retw
 
+#endif
+
+/* End of special treatment in tlb miss exception */
+
+ENTRY(__tlbtemp_mapping_end)
+
 /*
  * void __invalidate_icache_page(ulong start)
  */
@@ -121,8 +360,6 @@ ENTRY(__flush_dcache_page)
 	dsync
 	retw
 
-
-
 /*
  * void __invalidate_icache_range(ulong start, ulong size)
  */
@@ -168,7 +405,6 @@ ENTRY(__invalidate_dcache_range)
 
 	___invalidate_dcache_range a2 a3 a4
 
-
 	retw
 
 /*

include/asm-xtensa/cache.h

@@ -19,6 +19,15 @@
 
 #define DCACHE_WAY_SIZE	(XCHAL_DCACHE_SIZE/XCHAL_DCACHE_WAYS)
 #define ICACHE_WAY_SIZE	(XCHAL_ICACHE_SIZE/XCHAL_ICACHE_WAYS)
+#define DCACHE_WAY_SHIFT (XCHAL_DCACHE_SETWIDTH + XCHAL_DCACHE_LINEWIDTH)
+#define ICACHE_WAY_SHIFT (XCHAL_ICACHE_SETWIDTH + XCHAL_ICACHE_LINEWIDTH)
+
+/* Maximum cache size per way. */
+#if DCACHE_WAY_SIZE >= ICACHE_WAY_SIZE
+# define CACHE_WAY_SIZE DCACHE_WAY_SIZE
+#else
+# define CACHE_WAY_SIZE ICACHE_WAY_SIZE
+#endif
 
 
 #endif	/* _XTENSA_CACHE_H */

include/asm-xtensa/cacheflush.h

@@ -5,7 +5,7 @@
  * License.  See the file "COPYING" in the main directory of this archive
  * for more details.
  *
- * (C) 2001 - 2006 Tensilica Inc.
+ * (C) 2001 - 2007 Tensilica Inc.
  */
 
 #ifndef _XTENSA_CACHEFLUSH_H
@@ -18,10 +18,7 @@
 #include <asm/page.h>
 
 /*
- * flush and invalidate data cache, invalidate instruction cache:
- *
- * __flush_invalidate_cache_all()
- * __flush_invalidate_cache_range(from,sze)
+ * Lo-level routines for cache flushing.
  *
  * invalidate data or instruction cache:
  *
@@ -40,26 +37,39 @@
  * __flush_invalidate_dcache_all()
  * __flush_invalidate_dcache_page(adr)
  * __flush_invalidate_dcache_range(from,size)
+ *
+ * specials for cache aliasing:
+ *
+ * __flush_invalidate_dcache_page_alias(vaddr,paddr)
+ * __invalidate_icache_page_alias(vaddr,paddr)
  */
 
-extern void __flush_invalidate_cache_all(void);
-extern void __flush_invalidate_cache_range(unsigned long, unsigned long);
-extern void __flush_invalidate_dcache_all(void);
+extern void __invalidate_dcache_all(void);
 extern void __invalidate_icache_all(void);
-
 extern void __invalidate_dcache_page(unsigned long);
 extern void __invalidate_icache_page(unsigned long);
 extern void __invalidate_icache_range(unsigned long, unsigned long);
 extern void __invalidate_dcache_range(unsigned long, unsigned long);
 
+
 #if XCHAL_DCACHE_IS_WRITEBACK
+extern void __flush_invalidate_dcache_all(void);
 extern void __flush_dcache_page(unsigned long);
+extern void __flush_dcache_range(unsigned long, unsigned long);
 extern void __flush_invalidate_dcache_page(unsigned long);
 extern void __flush_invalidate_dcache_range(unsigned long, unsigned long);
 #else
-# define __flush_dcache_page(p)				do { } while(0)
-# define __flush_invalidate_dcache_page(p) 		do { } while(0)
-# define __flush_invalidate_dcache_range(p,s)		do { } while(0)
+# define __flush_dcache_range(p,s)		do { } while(0)
+# define __flush_dcache_page(p)			do { } while(0)
+# define __flush_invalidate_dcache_page(p) 	__invalidate_dcache_page(p)
+# define __flush_invalidate_dcache_range(p,s)	__invalidate_dcache_range(p,s)
+#endif
+
+#if (DCACHE_WAY_SIZE > PAGE_SIZE)
+extern void __flush_invalidate_dcache_page_alias(unsigned long, unsigned long);
+#endif
+#if (ICACHE_WAY_SIZE > PAGE_SIZE)
+extern void __invalidate_icache_page_alias(unsigned long, unsigned long);
 #endif
 
 /*
@@ -71,17 +81,21 @@ extern void __flush_invalidate_dcache_range(unsigned long, unsigned long);
  * (see also Documentation/cachetlb.txt)
  */
 
-#if (DCACHE_WAY_SIZE > PAGE_SIZE) && XCHAL_DCACHE_IS_WRITEBACK
+#if (DCACHE_WAY_SIZE > PAGE_SIZE)
 
-#define flush_cache_all()		__flush_invalidate_cache_all();
-#define flush_cache_mm(mm)		__flush_invalidate_cache_all();
-#define flush_cache_dup_mm(mm)		__flush_invalidate_cache_all();
+#define flush_cache_all()						\
+	do {								\
+		__flush_invalidate_dcache_all();			\
+		__invalidate_icache_all();				\
+	} while (0)
 
-#define flush_cache_vmap(start,end)	__flush_invalidate_cache_all();
-#define flush_cache_vunmap(start,end)	__flush_invalidate_cache_all();
+#define flush_cache_mm(mm)		flush_cache_all()
+#define flush_cache_dup_mm(mm)		flush_cache_mm(mm)
 
-extern void flush_dcache_page(struct page*);
+#define flush_cache_vmap(start,end)	flush_cache_all()
+#define flush_cache_vunmap(start,end)	flush_cache_all()
 
+extern void flush_dcache_page(struct page*);
 extern void flush_cache_range(struct vm_area_struct*, ulong, ulong);
 extern void flush_cache_page(struct vm_area_struct*, unsigned long, unsigned long);
 
@@ -101,24 +115,39 @@ extern void flush_cache_page(struct vm_area_struct*, unsigned long, unsigned lon
 
 #endif
 
+/* Ensure consistency between data and instruction cache. */
 #define flush_icache_range(start,end) 					\
-	__invalidate_icache_range(start,(end)-(start))
+	do {								\
+		__flush_dcache_range(start, (end) - (start));		\
+		__invalidate_icache_range(start,(end) - (start));	\
+	} while (0)
 
 /* This is not required, see Documentation/cachetlb.txt */
-
-#define	flush_icache_page(vma,page)			do { } while(0)
+#define	flush_icache_page(vma,page)			do { } while (0)
 
 #define flush_dcache_mmap_lock(mapping)			do { } while (0)
 #define flush_dcache_mmap_unlock(mapping)		do { } while (0)
 
+#if (DCACHE_WAY_SIZE > PAGE_SIZE)
 
-#define copy_to_user_page(vma, page, vaddr, dst, src, len) \
-	memcpy(dst, src, len)
+extern void copy_to_user_page(struct vm_area_struct*, struct page*,
+		unsigned long, void*, const void*, unsigned long);
+extern void copy_from_user_page(struct vm_area_struct*, struct page*,
+		unsigned long, void*, const void*, unsigned long);
+
+#else
+
+#define copy_to_user_page(vma, page, vaddr, dst, src, len)		\
+	do {								\
+		memcpy(dst, src, len);					\
+		__flush_dcache_range((unsigned long) dst, len);		\
+		__invalidate_icache_range((unsigned long) dst, len);	\
+	} while (0)
 
 #define copy_from_user_page(vma, page, vaddr, dst, src, len) \
 	memcpy(dst, src, len)
 
-#endif /* __KERNEL__ */
+#endif
 
+#endif /* __KERNEL__ */
 #endif /* _XTENSA_CACHEFLUSH_H */
-

include/asm-xtensa/io.h

@@ -14,6 +14,7 @@
 #ifdef __KERNEL__
 #include <asm/byteorder.h>
 #include <asm/page.h>
+#include <linux/kernel.h>
 
 #include <linux/types.h>
 

include/asm-xtensa/page.h

@@ -15,6 +15,7 @@
 
 #include <asm/processor.h>
 #include <asm/types.h>
+#include <asm/cache.h>
 
 /*
  * Fixed TLB translations in the processor.
@@ -39,6 +40,53 @@
 #define MAX_MEM_PFN		XCHAL_KSEG_SIZE
 #define PGTABLE_START		0x80000000
 
+/*
+ * Cache aliasing:
+ *
+ * If the cache size for one way is greater than the page size, we have to
+ * deal with cache aliasing. The cache index is wider than the page size:
+ *
+ * |    |cache| cache index
+ * | pfn  |off|	virtual address
+ * |xxxx:X|zzz|
+ * |    : |   |
+ * | \  / |   |
+ * |trans.|   |
+ * | /  \ |   |
+ * |yyyy:Y|zzz|	physical address
+ *
+ * When the page number is translated to the physical page address, the lowest
+ * bit(s) (X) that are part of the cache index are also translated (Y).
+ * If this translation changes bit(s) (X), the cache index is also afected,
+ * thus resulting in a different cache line than before.
+ * The kernel does not provide a mechanism to ensure that the page color
+ * (represented by this bit) remains the same when allocated or when pages
+ * are remapped. When user pages are mapped into kernel space, the color of
+ * the page might also change.
+ *
+ * We use the address space VMALLOC_END ... VMALLOC_END + DCACHE_WAY_SIZE * 2
+ * to temporarily map a patch so we can match the color.
+ */
+
+#if DCACHE_WAY_SIZE > PAGE_SIZE
+# define DCACHE_ALIAS_ORDER	(DCACHE_WAY_SHIFT - PAGE_SHIFT)
+# define DCACHE_ALIAS_MASK	(PAGE_MASK & (DCACHE_WAY_SIZE - 1))
+# define DCACHE_ALIAS(a)	(((a) & DCACHE_ALIAS_MASK) >> PAGE_SHIFT)
+# define DCACHE_ALIAS_EQ(a,b)	((((a) ^ (b)) & DCACHE_ALIAS_MASK) == 0)
+#else
+# define DCACHE_ALIAS_ORDER	0
+#endif
+
+#if ICACHE_WAY_SIZE > PAGE_SIZE
+# define ICACHE_ALIAS_ORDER	(ICACHE_WAY_SHIFT - PAGE_SHIFT)
+# define ICACHE_ALIAS_MASK	(PAGE_MASK & (ICACHE_WAY_SIZE - 1))
+# define ICACHE_ALIAS(a)	(((a) & ICACHE_ALIAS_MASK) >> PAGE_SHIFT)
+# define ICACHE_ALIAS_EQ(a,b)	((((a) ^ (b)) & ICACHE_ALIAS_MASK) == 0)
+#else
+# define ICACHE_ALIAS_ORDER	0
+#endif
+
+
 #ifdef __ASSEMBLY__
 
 #define __pgprot(x)	(x)
@@ -90,11 +138,11 @@ extern void copy_page(void *to, void *from);
  * some extra work
  */
 
-#if (DCACHE_WAY_SIZE > PAGE_SIZE)
-void clear_user_page(void *addr, unsigned long vaddr, struct page* page);
-void copy_user_page(void *to,void* from,unsigned long vaddr,struct page* page);
+#if DCACHE_WAY_SIZE > PAGE_SIZE
+extern void clear_user_page(void*, unsigned long, struct page*);
+extern void copy_user_page(void*, void*, unsigned long, struct page*);
 #else
-# define clear_user_page(page,vaddr,pg)		clear_page(page)
+# define clear_user_page(page, vaddr, pg)	clear_page(page)
 # define copy_user_page(to, from, vaddr, pg)	copy_page(to, from)
 #endif
 

include/asm-xtensa/pgalloc.h

 /*
- * linux/include/asm-xtensa/pgalloc.h
+ * include/asm-xtensa/pgalloc.h
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation.
  *
- * Copyright (C) 2001-2005 Tensilica Inc.
+ * Copyright (C) 2001-2007 Tensilica Inc.
  */
 
 #ifndef _XTENSA_PGALLOC_H
@@ -13,103 +13,54 @@
 
 #ifdef __KERNEL__
 
-#include <linux/threads.h>
 #include <linux/highmem.h>
-#include <asm/processor.h>
-#include <asm/cacheflush.h>
-
-
-/* Cache aliasing:
- *
- * If the cache size for one way is greater than the page size, we have to
- * deal with cache aliasing. The cache index is wider than the page size:
- *
- *      |cache |
- * |pgnum |page|	virtual address
- * |xxxxxX|zzzz|
- * |      |    |
- *   \  / |    |
- *  trans.|    |
- *   /  \ |    |
- * |yyyyyY|zzzz|	physical address
- *
- * When the page number is translated to the physical page address, the lowest
- * bit(s) (X) that are also part of the cache index are also translated (Y).
- * If this translation changes this bit (X), the cache index is also afected,
- * thus resulting in a different cache line than before.
- * The kernel does not provide a mechanism to ensure that the page color
- * (represented by this bit) remains the same when allocated or when pages
- * are remapped. When user pages are mapped into kernel space, the color of
- * the page might also change.
- *
- * We use the address space VMALLOC_END ... VMALLOC_END + DCACHE_WAY_SIZE * 2
- * to temporarily map a patch so we can match the color.
- */
-
-#if (DCACHE_WAY_SIZE > PAGE_SIZE)
-# define PAGE_COLOR_MASK	(PAGE_MASK & (DCACHE_WAY_SIZE-1))
-# define PAGE_COLOR(a)		\
-	(((unsigned long)(a)&PAGE_COLOR_MASK) >> PAGE_SHIFT)
-# define PAGE_COLOR_EQ(a,b)	\
-	((((unsigned long)(a) ^ (unsigned long)(b)) & PAGE_COLOR_MASK) == 0)
-# define PAGE_COLOR_MAP0(v)	\
-	(VMALLOC_END + ((unsigned long)(v) & PAGE_COLOR_MASK))
-# define PAGE_COLOR_MAP1(v)	\
-	(VMALLOC_END + ((unsigned long)(v) & PAGE_COLOR_MASK) + DCACHE_WAY_SIZE)
-#endif
 
 /*
  * Allocating and freeing a pmd is trivial: the 1-entry pmd is
  * inside the pgd, so has no extra memory associated with it.
  */
 
-#define pgd_free(pgd)	free_page((unsigned long)(pgd))
-
-#if (DCACHE_WAY_SIZE > PAGE_SIZE) && XCHAL_DCACHE_IS_WRITEBACK
+#define pmd_populate_kernel(mm, pmdp, ptep)				     \
+	(pmd_val(*(pmdp)) = ((unsigned long)ptep))
+#define pmd_populate(mm, pmdp, page)					     \
+	(pmd_val(*(pmdp)) = ((unsigned long)page_to_virt(page)))
 
-static inline void
-pmd_populate_kernel(struct mm_struct *mm, pmd_t *pmdp, pte_t *pte)
+static inline pgd_t*
+pgd_alloc(struct mm_struct *mm)
 {
-	pmd_val(*(pmdp)) = (unsigned long)(pte);
-	__asm__ __volatile__ ("memw; dhwb %0, 0; dsync" :: "a" (pmdp));
+	return (pgd_t*) __get_free_pages(GFP_KERNEL | __GFP_ZERO, PGD_ORDER);
 }
 
-static inline void
-pmd_populate(struct mm_struct *mm, pmd_t *pmdp, struct page *page)
+static inline void pgd_free(pgd_t *pgd)
 {
-	pmd_val(*(pmdp)) = (unsigned long)page_to_virt(page);
-	__asm__ __volatile__ ("memw; dhwb %0, 0; dsync" :: "a" (pmdp));
+	free_page((unsigned long)pgd);
 }
 
+/* Use a slab cache for the pte pages (see also sparc64 implementation) */
 
+extern struct kmem_cache *pgtable_cache;
 
-#else
-
-# define pmd_populate_kernel(mm, pmdp, pte)				     \
-	(pmd_val(*(pmdp)) = (unsigned long)(pte))
-# define pmd_populate(mm, pmdp, page)					     \
-	(pmd_val(*(pmdp)) = (unsigned long)page_to_virt(page))
-
-#endif
-
-static inline pgd_t*
-pgd_alloc(struct mm_struct *mm)
+static inline pte_t *pte_alloc_one_kernel(struct mm_struct *mm, 
+					 unsigned long address)
 {
-	pgd_t *pgd;
-
-	pgd = (pgd_t *)__get_free_pages(GFP_KERNEL|__GFP_ZERO, PGD_ORDER);
-
-	if (likely(pgd != NULL))
-		__flush_dcache_page((unsigned long)pgd);
+	return kmem_cache_alloc(pgtable_cache, GFP_KERNEL|__GFP_REPEAT);
+}
 
-	return pgd;
+static inline struct page *pte_alloc_one(struct mm_struct *mm, 
+					 unsigned long addr)
+{
+	return virt_to_page(pte_alloc_one_kernel(mm, addr));
 }
 
-extern pte_t* pte_alloc_one_kernel(struct mm_struct* mm, unsigned long addr);
-extern struct page* pte_alloc_one(struct mm_struct* mm, unsigned long addr);
+static inline void pte_free_kernel(pte_t *pte)
+{
+	kmem_cache_free(pgtable_cache, pte);
+}
 
-#define pte_free_kernel(pte) free_page((unsigned long)pte)
-#define pte_free(pte) __free_page(pte)
+static inline void pte_free(struct page *page)
+{
+	kmem_cache_free(pgtable_cache, page_address(page));
+}
 
 #endif /* __KERNEL__ */
 #endif /* _XTENSA_PGALLOC_H */

include/asm-xtensa/pgtable.h

 /*
- * linux/include/asm-xtensa/pgtable.h
+ * include/asm-xtensa/pgtable.h
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
@@ -60,16 +60,20 @@
 #define FIRST_USER_ADDRESS	0
 #define FIRST_USER_PGD_NR	(FIRST_USER_ADDRESS >> PGDIR_SHIFT)
 
-/* virtual memory area. We keep a distance to other memory regions to be
+/*
+ * Virtual memory area. We keep a distance to other memory regions to be
  * on the safe side. We also use this area for cache aliasing.
  */
 
-// FIXME: virtual memory area must be configuration-dependent
-
 #define VMALLOC_START		0xC0000000
-#define VMALLOC_END		0xC7FF0000
+#define VMALLOC_END		0xC6FEFFFF
+#define TLBTEMP_BASE_1		0xC6FF0000
+#define TLBTEMP_BASE_2		0xC6FF8000
+#define MODULE_START		0xC7000000
+#define MODULE_END		0xC7FFFFFF
 
-/* Xtensa Linux config PTE layout (when present):
+/*
+ * Xtensa Linux config PTE layout (when present):
  *	31-12:	PPN
  *	11-6:	Software
  *	5-4:	RING
@@ -126,12 +130,13 @@
 #define PAGE_SHARED	   __pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_WRITABLE)
 #define PAGE_SHARED_EXEC \
 	__pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_WRITABLE | _PAGE_HW_EXEC)
-#define PAGE_KERNEL	   __pgprot(_PAGE_PRESENT)
+#define PAGE_KERNEL	   __pgprot(_PAGE_PRESENT | _PAGE_HW_WRITE)
+#define PAGE_KERNEL_EXEC   __pgprot(_PAGE_PRESENT|_PAGE_HW_WRITE|_PAGE_HW_EXEC)
 
 #if (DCACHE_WAY_SIZE > PAGE_SIZE)
-# define _PAGE_DIRECTORY (_PAGE_VALID | _PAGE_ACCESSED | _PAGE_HW_WRITE)
+# define _PAGE_DIRECTORY (_PAGE_VALID | _PAGE_ACCESSED)
 #else
-# define _PAGE_DIRECTORY (_PAGE_VALID|_PAGE_ACCESSED|_PAGE_HW_WRITE|_PAGE_CA_WB)
+# define _PAGE_DIRECTORY (_PAGE_VALID | _PAGE_ACCESSED | _PAGE_CA_WB)
 #endif
 
 #else /* no mmu */
@@ -244,6 +249,10 @@ static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
 static inline void update_pte(pte_t *ptep, pte_t pteval)
 {
 	*ptep = pteval;
+#if (DCACHE_WAY_SIZE > PAGE_SIZE) && XCHAL_DCACHE_IS_WRITEBACK
+	__asm__ __volatile__ ("dhwb %0, 0" :: "a" (ptep));
+#endif
+
 }
 
 struct mm_struct;
@@ -383,13 +392,12 @@ extern  void update_mmu_cache(struct vm_area_struct * vma,
  * remap a physical page `pfn' of size `size' with page protection `prot'
  * into virtual address `from'
  */
+
 #define io_remap_pfn_range(vma,from,pfn,size,prot) \
                 remap_pfn_range(vma, from, pfn, size, prot)
 
 
-/* No page table caches to init */
-
-#define pgtable_cache_init()	do { } while (0)
+extern void pgtable_cache_init(void);
 
 typedef pte_t *pte_addr_t;
 

include/asm-xtensa/tlb.h

@@ -11,14 +11,36 @@
 #ifndef _XTENSA_TLB_H
 #define _XTENSA_TLB_H
 
-#define tlb_start_vma(tlb,vma)			do { } while (0)
-#define tlb_end_vma(tlb,vma)			do { } while (0)
-#define __tlb_remove_tlb_entry(tlb,pte,addr)	do { } while (0)
+#include <asm/cache.h>
+#include <asm/page.h>
+
+#if (DCACHE_WAY_SIZE <= PAGE_SIZE)
+
+/* Note, read http://lkml.org/lkml/2004/1/15/6 */
+
+# define tlb_start_vma(tlb,vma)			do { } while (0)
+# define tlb_end_vma(tlb,vma)			do { } while (0)
+
+#else
 
+# define tlb_start_vma(tlb, vma)					      \
+	do {								      \
+		if (!tlb->fullmm)					      \
+			flush_cache_range(vma, vma->vm_start, vma->vm_end);   \
+	} while(0)
+
+# define tlb_end_vma(tlb, vma)						      \
+	do {								      \
+		if (!tlb->fullmm)					      \
+			flush_tlb_range(vma, vma->vm_start, vma->vm_end);     \
+	} while(0)
+
+#endif
+
+#define __tlb_remove_tlb_entry(tlb,pte,addr)	do { } while (0)
 #define tlb_flush(tlb)				flush_tlb_mm((tlb)->mm)
 
 #include <asm-generic/tlb.h>
-#include <asm/page.h>
 
 #define __pte_free_tlb(tlb,pte)			pte_free(pte)