Merge branch 'sh/cachetlb'

arch/sh/include/asm/fixmap.h

@@ -14,9 +14,9 @@
 #define _ASM_FIXMAP_H
 
 #include <linux/kernel.h>
+#include <linux/threads.h>
 #include <asm/page.h>
 #ifdef CONFIG_HIGHMEM
-#include <linux/threads.h>
 #include <asm/kmap_types.h>
 #endif
 
@@ -46,9 +46,9 @@
  * fix-mapped?
  */
 enum fixed_addresses {
-#define FIX_N_COLOURS 16
+#define FIX_N_COLOURS 8
 	FIX_CMAP_BEGIN,
-	FIX_CMAP_END = FIX_CMAP_BEGIN + FIX_N_COLOURS,
+	FIX_CMAP_END = FIX_CMAP_BEGIN + (FIX_N_COLOURS * NR_CPUS),
 	FIX_UNCACHED,
 #ifdef CONFIG_HIGHMEM
 	FIX_KMAP_BEGIN,	/* reserved pte's for temporary kernel mappings */

arch/sh/mm/cache-sh4.c

@@ -2,7 +2,7 @@
  * arch/sh/mm/cache-sh4.c
  *
  * Copyright (C) 1999, 2000, 2002  Niibe Yutaka
- * Copyright (C) 2001 - 2007  Paul Mundt
+ * Copyright (C) 2001 - 2009  Paul Mundt
  * Copyright (C) 2003  Richard Curnow
  * Copyright (c) 2007 STMicroelectronics (R&D) Ltd.
  *
@@ -15,6 +15,8 @@
 #include <linux/io.h>
 #include <linux/mutex.h>
 #include <linux/fs.h>
+#include <linux/highmem.h>
+#include <asm/pgtable.h>
 #include <asm/mmu_context.h>
 #include <asm/cacheflush.h>
 
@@ -23,20 +25,11 @@
  * flushing. Anything exceeding this will simply flush the dcache in its
  * entirety.
  */
-#define MAX_DCACHE_PAGES	64	/* XXX: Tune for ways */
 #define MAX_ICACHE_PAGES	32
 
 static void __flush_cache_4096(unsigned long addr, unsigned long phys,
 			       unsigned long exec_offset);
 
-/*
- * This is initialised here to ensure that it is not placed in the BSS.  If
- * that were to happen, note that cache_init gets called before the BSS is
- * cleared, so this would get nulled out which would be hopeless.
- */
-static void (*__flush_dcache_segment_fn)(unsigned long, unsigned long) =
-	(void (*)(unsigned long, unsigned long))0xdeadbeef;
-
 /*
  * Write back the range of D-cache, and purge the I-cache.
  *
@@ -123,12 +116,12 @@ static void sh4_flush_dcache_page(void *arg)
 	else
 #endif
 	{
-		unsigned long phys = PHYSADDR(page_address(page));
+		unsigned long phys = page_to_phys(page);
 		unsigned long addr = CACHE_OC_ADDRESS_ARRAY;
 		int i, n;
 
 		/* Loop all the D-cache */
-		n = boot_cpu_data.dcache.n_aliases;
+		n = boot_cpu_data.dcache.way_incr >> 12;
 		for (i = 0; i < n; i++, addr += 4096)
 			flush_cache_4096(addr, phys);
 	}
@@ -158,10 +151,27 @@ static void __uses_jump_to_uncached flush_icache_all(void)
 	local_irq_restore(flags);
 }
 
-static inline void flush_dcache_all(void)
+static void flush_dcache_all(void)
 {
-	(*__flush_dcache_segment_fn)(0UL, boot_cpu_data.dcache.way_size);
-	wmb();
+	unsigned long addr, end_addr, entry_offset;
+
+	end_addr = CACHE_OC_ADDRESS_ARRAY +
+		(current_cpu_data.dcache.sets <<
+		 current_cpu_data.dcache.entry_shift) *
+			current_cpu_data.dcache.ways;
+
+	entry_offset = 1 << current_cpu_data.dcache.entry_shift;
+
+	for (addr = CACHE_OC_ADDRESS_ARRAY; addr < end_addr; ) {
+		__raw_writel(0, addr); addr += entry_offset;
+		__raw_writel(0, addr); addr += entry_offset;
+		__raw_writel(0, addr); addr += entry_offset;
+		__raw_writel(0, addr); addr += entry_offset;
+		__raw_writel(0, addr); addr += entry_offset;
+		__raw_writel(0, addr); addr += entry_offset;
+		__raw_writel(0, addr); addr += entry_offset;
+		__raw_writel(0, addr); addr += entry_offset;
+	}
 }
 
 static void sh4_flush_cache_all(void *unused)
@@ -170,89 +180,13 @@ static void sh4_flush_cache_all(void *unused)
 	flush_icache_all();
 }
 
-static void __flush_cache_mm(struct mm_struct *mm, unsigned long start,
-			     unsigned long end)
-{
-	unsigned long d = 0, p = start & PAGE_MASK;
-	unsigned long alias_mask = boot_cpu_data.dcache.alias_mask;
-	unsigned long n_aliases = boot_cpu_data.dcache.n_aliases;
-	unsigned long select_bit;
-	unsigned long all_aliases_mask;
-	unsigned long addr_offset;
-	pgd_t *dir;
-	pmd_t *pmd;
-	pud_t *pud;
-	pte_t *pte;
-	int i;
-
-	dir = pgd_offset(mm, p);
-	pud = pud_offset(dir, p);
-	pmd = pmd_offset(pud, p);
-	end = PAGE_ALIGN(end);
-
-	all_aliases_mask = (1 << n_aliases) - 1;
-
-	do {
-		if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd))) {
-			p &= PMD_MASK;
-			p += PMD_SIZE;
-			pmd++;
-
-			continue;
-		}
-
-		pte = pte_offset_kernel(pmd, p);
-
-		do {
-			unsigned long phys;
-			pte_t entry = *pte;
-
-			if (!(pte_val(entry) & _PAGE_PRESENT)) {
-				pte++;
-				p += PAGE_SIZE;
-				continue;
-			}
-
-			phys = pte_val(entry) & PTE_PHYS_MASK;
-
-			if ((p ^ phys) & alias_mask) {
-				d |= 1 << ((p & alias_mask) >> PAGE_SHIFT);
-				d |= 1 << ((phys & alias_mask) >> PAGE_SHIFT);
-
-				if (d == all_aliases_mask)
-					goto loop_exit;
-			}
-
-			pte++;
-			p += PAGE_SIZE;
-		} while (p < end && ((unsigned long)pte & ~PAGE_MASK));
-		pmd++;
-	} while (p < end);
-
-loop_exit:
-	addr_offset = 0;
-	select_bit = 1;
-
-	for (i = 0; i < n_aliases; i++) {
-		if (d & select_bit) {
-			(*__flush_dcache_segment_fn)(addr_offset, PAGE_SIZE);
-			wmb();
-		}
-
-		select_bit <<= 1;
-		addr_offset += PAGE_SIZE;
-	}
-}
-
 /*
  * Note : (RPC) since the caches are physically tagged, the only point
  * of flush_cache_mm for SH-4 is to get rid of aliases from the
  * D-cache.  The assumption elsewhere, e.g. flush_cache_range, is that
  * lines can stay resident so long as the virtual address they were
  * accessed with (hence cache set) is in accord with the physical
- * address (i.e. tag).  It's no different here.  So I reckon we don't
- * need to flush the I-cache, since aliases don't matter for that.  We
- * should try that.
+ * address (i.e. tag).  It's no different here.
  *
  * Caller takes mm->mmap_sem.
  */
@@ -263,33 +197,7 @@ static void sh4_flush_cache_mm(void *arg)
 	if (cpu_context(smp_processor_id(), mm) == NO_CONTEXT)
 		return;
 
-	/*
-	 * If cache is only 4k-per-way, there are never any 'aliases'.  Since
-	 * the cache is physically tagged, the data can just be left in there.
-	 */
-	if (boot_cpu_data.dcache.n_aliases == 0)
-		return;
-
-	/*
-	 * Don't bother groveling around the dcache for the VMA ranges
-	 * if there are too many PTEs to make it worthwhile.
-	 */
-	if (mm->nr_ptes >= MAX_DCACHE_PAGES)
-		flush_dcache_all();
-	else {
-		struct vm_area_struct *vma;
-
-		/*
-		 * In this case there are reasonably sized ranges to flush,
-		 * iterate through the VMA list and take care of any aliases.
-		 */
-		for (vma = mm->mmap; vma; vma = vma->vm_next)
-			__flush_cache_mm(mm, vma->vm_start, vma->vm_end);
-	}
-
-	/* Only touch the icache if one of the VMAs has VM_EXEC set. */
-	if (mm->exec_vm)
-		flush_icache_all();
+	flush_dcache_all();
 }
 
 /*
@@ -302,44 +210,64 @@ static void sh4_flush_cache_page(void *args)
 {
 	struct flusher_data *data = args;
 	struct vm_area_struct *vma;
+	struct page *page;
 	unsigned long address, pfn, phys;
-	unsigned int alias_mask;
+	int map_coherent = 0;
+	pgd_t *pgd;
+	pud_t *pud;
+	pmd_t *pmd;
+	pte_t *pte;
+	void *vaddr;
 
 	vma = data->vma;
 	address = data->addr1;
 	pfn = data->addr2;
 	phys = pfn << PAGE_SHIFT;
+	page = pfn_to_page(pfn);
 
 	if (cpu_context(smp_processor_id(), vma->vm_mm) == NO_CONTEXT)
 		return;
 
-	alias_mask = boot_cpu_data.dcache.alias_mask;
-
-	/* We only need to flush D-cache when we have alias */
-	if ((address^phys) & alias_mask) {
-		/* Loop 4K of the D-cache */
-		flush_cache_4096(
-			CACHE_OC_ADDRESS_ARRAY | (address & alias_mask),
-			phys);
-		/* Loop another 4K of the D-cache */
-		flush_cache_4096(
-			CACHE_OC_ADDRESS_ARRAY | (phys & alias_mask),
-			phys);
-	}
+	address &= PAGE_MASK;
+	pgd = pgd_offset(vma->vm_mm, address);
+	pud = pud_offset(pgd, address);
+	pmd = pmd_offset(pud, address);
+	pte = pte_offset_kernel(pmd, address);
+
+	/* If the page isn't present, there is nothing to do here. */
+	if (!(pte_val(*pte) & _PAGE_PRESENT))
+		return;
 
-	alias_mask = boot_cpu_data.icache.alias_mask;
-	if (vma->vm_flags & VM_EXEC) {
+	if ((vma->vm_mm == current->active_mm))
+		vaddr = NULL;
+	else {
 		/*
-		 * Evict entries from the portion of the cache from which code
-		 * may have been executed at this address (virtual).  There's
-		 * no need to evict from the portion corresponding to the
-		 * physical address as for the D-cache, because we know the
-		 * kernel has never executed the code through its identity
-		 * translation.
+		 * Use kmap_coherent or kmap_atomic to do flushes for
+		 * another ASID than the current one.
 		 */
-		flush_cache_4096(
-			CACHE_IC_ADDRESS_ARRAY | (address & alias_mask),
-			phys);
+		map_coherent = (current_cpu_data.dcache.n_aliases &&
+			!test_bit(PG_dcache_dirty, &page->flags) &&
+			page_mapped(page));
+		if (map_coherent)
+			vaddr = kmap_coherent(page, address);
+		else
+			vaddr = kmap_atomic(page, KM_USER0);
+
+		address = (unsigned long)vaddr;
+	}
+
+	if (pages_do_alias(address, phys))
+		flush_cache_4096(CACHE_OC_ADDRESS_ARRAY |
+			(address & shm_align_mask), phys);
+
+	if (vma->vm_flags & VM_EXEC)
+		flush_icache_all();
+
+	if (vaddr) {
+		if (map_coherent)
+			kunmap_coherent(vaddr);
+		else
+			kunmap_atomic(vaddr, KM_USER0);
 	}
 }
 
@@ -372,24 +300,10 @@ static void sh4_flush_cache_range(void *args)
 	if (boot_cpu_data.dcache.n_aliases == 0)
 		return;
 
-	/*
-	 * Don't bother with the lookup and alias check if we have a
-	 * wide range to cover, just blow away the dcache in its
-	 * entirety instead. -- PFM.
-	 */
-	if (((end - start) >> PAGE_SHIFT) >= MAX_DCACHE_PAGES)
-		flush_dcache_all();
-	else
-		__flush_cache_mm(vma->vm_mm, start, end);
+	flush_dcache_all();
 
-	if (vma->vm_flags & VM_EXEC) {
-		/*
-		 * TODO: Is this required???  Need to look at how I-cache
-		 * coherency is assured when new programs are loaded to see if
-		 * this matters.
-		 */
+	if (vma->vm_flags & VM_EXEC)
 		flush_icache_all();
-	}
 }
 
 /**
@@ -443,7 +357,7 @@ static void __flush_cache_4096(unsigned long addr, unsigned long phys,
 	 * pointless nead-of-loop check for 0 iterations.
 	 */
 	do {
-		ea = base_addr + PAGE_SIZE;
+		ea = base_addr + 4096;
 		a = base_addr;
 		p = phys;
 
@@ -463,245 +377,6 @@ static void __flush_cache_4096(unsigned long addr, unsigned long phys,
 	} while (--way_count != 0);
 }
 
-/*
- * Break the 1, 2 and 4 way variants of this out into separate functions to
- * avoid nearly all the overhead of having the conditional stuff in the function
- * bodies (+ the 1 and 2 way cases avoid saving any registers too).
- *
- * We want to eliminate unnecessary bus transactions, so this code uses
- * a non-obvious technique.
- *
- * Loop over a cache way sized block of, one cache line at a time. For each
- * line, use movca.a to cause the current cache line contents to be written
- * back, but without reading anything from main memory. However this has the
- * side effect that the cache is now caching that memory location. So follow
- * this with a cache invalidate to mark the cache line invalid. And do all
- * this with interrupts disabled, to avoid the cache line being accidently
- * evicted while it is holding garbage.
- *
- * This also breaks in a number of circumstances:
- * - if there are modifications to the region of memory just above
- *   empty_zero_page (for example because a breakpoint has been placed
- *   there), then these can be lost.
- *
- *   This is because the the memory address which the cache temporarily
- *   caches in the above description is empty_zero_page. So the
- *   movca.l hits the cache (it is assumed that it misses, or at least
- *   isn't dirty), modifies the line and then invalidates it, losing the
- *   required change.
- *
- * - If caches are disabled or configured in write-through mode, then
- *   the movca.l writes garbage directly into memory.
- */
-static void __flush_dcache_segment_writethrough(unsigned long start,
-					        unsigned long extent_per_way)
-{
-	unsigned long addr;
-	int i;
-
-	addr = CACHE_OC_ADDRESS_ARRAY | (start & cpu_data->dcache.entry_mask);
-
-	while (extent_per_way) {
-		for (i = 0; i < cpu_data->dcache.ways; i++)
-			__raw_writel(0, addr + cpu_data->dcache.way_incr * i);
-
-		addr += cpu_data->dcache.linesz;
-		extent_per_way -= cpu_data->dcache.linesz;
-	}
-}
-
-static void __flush_dcache_segment_1way(unsigned long start,
-					unsigned long extent_per_way)
-{
-	unsigned long orig_sr, sr_with_bl;
-	unsigned long base_addr;
-	unsigned long way_incr, linesz, way_size;
-	struct cache_info *dcache;
-	register unsigned long a0, a0e;
-
-	asm volatile("stc sr, %0" : "=r" (orig_sr));
-	sr_with_bl = orig_sr | (1<<28);
-	base_addr = ((unsigned long)&empty_zero_page[0]);
-
-	/*
-	 * The previous code aligned base_addr to 16k, i.e. the way_size of all
-	 * existing SH-4 D-caches.  Whilst I don't see a need to have this
-	 * aligned to any better than the cache line size (which it will be
-	 * anyway by construction), let's align it to at least the way_size of
-	 * any existing or conceivable SH-4 D-cache.  -- RPC
-	 */
-	base_addr = ((base_addr >> 16) << 16);
-	base_addr |= start;
-
-	dcache = &boot_cpu_data.dcache;
-	linesz = dcache->linesz;
-	way_incr = dcache->way_incr;
-	way_size = dcache->way_size;
-
-	a0 = base_addr;
-	a0e = base_addr + extent_per_way;
-	do {
-		asm volatile("ldc %0, sr" : : "r" (sr_with_bl));
-		asm volatile("movca.l r0, @%0\n\t"
-			     "ocbi @%0" : : "r" (a0));
-		a0 += linesz;
-		asm volatile("movca.l r0, @%0\n\t"
-			     "ocbi @%0" : : "r" (a0));
-		a0 += linesz;
-		asm volatile("movca.l r0, @%0\n\t"
-			     "ocbi @%0" : : "r" (a0));
-		a0 += linesz;
-		asm volatile("movca.l r0, @%0\n\t"
-			     "ocbi @%0" : : "r" (a0));
-		asm volatile("ldc %0, sr" : : "r" (orig_sr));
-		a0 += linesz;
-	} while (a0 < a0e);
-}
-
-static void __flush_dcache_segment_2way(unsigned long start,
-					unsigned long extent_per_way)
-{
-	unsigned long orig_sr, sr_with_bl;
-	unsigned long base_addr;
-	unsigned long way_incr, linesz, way_size;
-	struct cache_info *dcache;
-	register unsigned long a0, a1, a0e;
-
-	asm volatile("stc sr, %0" : "=r" (orig_sr));
-	sr_with_bl = orig_sr | (1<<28);
-	base_addr = ((unsigned long)&empty_zero_page[0]);
-
-	/* See comment under 1-way above */
-	base_addr = ((base_addr >> 16) << 16);
-	base_addr |= start;
-
-	dcache = &boot_cpu_data.dcache;
-	linesz = dcache->linesz;
-	way_incr = dcache->way_incr;
-	way_size = dcache->way_size;
-
-	a0 = base_addr;
-	a1 = a0 + way_incr;
-	a0e = base_addr + extent_per_way;
-	do {
-		asm volatile("ldc %0, sr" : : "r" (sr_with_bl));
-		asm volatile("movca.l r0, @%0\n\t"
-			     "movca.l r0, @%1\n\t"
-			     "ocbi @%0\n\t"
-			     "ocbi @%1" : :
-			     "r" (a0), "r" (a1));
-		a0 += linesz;
-		a1 += linesz;
-		asm volatile("movca.l r0, @%0\n\t"
-			     "movca.l r0, @%1\n\t"
-			     "ocbi @%0\n\t"
-			     "ocbi @%1" : :
-			     "r" (a0), "r" (a1));
-		a0 += linesz;
-		a1 += linesz;
-		asm volatile("movca.l r0, @%0\n\t"
-			     "movca.l r0, @%1\n\t"
-			     "ocbi @%0\n\t"
-			     "ocbi @%1" : :
-			     "r" (a0), "r" (a1));
-		a0 += linesz;
-		a1 += linesz;
-		asm volatile("movca.l r0, @%0\n\t"
-			     "movca.l r0, @%1\n\t"
-			     "ocbi @%0\n\t"
-			     "ocbi @%1" : :
-			     "r" (a0), "r" (a1));
-		asm volatile("ldc %0, sr" : : "r" (orig_sr));
-		a0 += linesz;
-		a1 += linesz;
-	} while (a0 < a0e);
-}
-
-static void __flush_dcache_segment_4way(unsigned long start,
-					unsigned long extent_per_way)
-{
-	unsigned long orig_sr, sr_with_bl;
-	unsigned long base_addr;
-	unsigned long way_incr, linesz, way_size;
-	struct cache_info *dcache;
-	register unsigned long a0, a1, a2, a3, a0e;
-
-	asm volatile("stc sr, %0" : "=r" (orig_sr));
-	sr_with_bl = orig_sr | (1<<28);
-	base_addr = ((unsigned long)&empty_zero_page[0]);
-
-	/* See comment under 1-way above */
-	base_addr = ((base_addr >> 16) << 16);
-	base_addr |= start;
-
-	dcache = &boot_cpu_data.dcache;
-	linesz = dcache->linesz;
-	way_incr = dcache->way_incr;
-	way_size = dcache->way_size;
-
-	a0 = base_addr;
-	a1 = a0 + way_incr;
-	a2 = a1 + way_incr;
-	a3 = a2 + way_incr;
-	a0e = base_addr + extent_per_way;
-	do {
-		asm volatile("ldc %0, sr" : : "r" (sr_with_bl));
-		asm volatile("movca.l r0, @%0\n\t"
-			     "movca.l r0, @%1\n\t"
-			     "movca.l r0, @%2\n\t"
-			     "movca.l r0, @%3\n\t"
-			     "ocbi @%0\n\t"
-			     "ocbi @%1\n\t"
-			     "ocbi @%2\n\t"
-			     "ocbi @%3\n\t" : :
-			     "r" (a0), "r" (a1), "r" (a2), "r" (a3));
-		a0 += linesz;
-		a1 += linesz;
-		a2 += linesz;
-		a3 += linesz;
-		asm volatile("movca.l r0, @%0\n\t"
-			     "movca.l r0, @%1\n\t"
-			     "movca.l r0, @%2\n\t"
-			     "movca.l r0, @%3\n\t"
-			     "ocbi @%0\n\t"
-			     "ocbi @%1\n\t"
-			     "ocbi @%2\n\t"
-			     "ocbi @%3\n\t" : :
-			     "r" (a0), "r" (a1), "r" (a2), "r" (a3));
-		a0 += linesz;
-		a1 += linesz;
-		a2 += linesz;
-		a3 += linesz;
-		asm volatile("movca.l r0, @%0\n\t"
-			     "movca.l r0, @%1\n\t"
-			     "movca.l r0, @%2\n\t"
-			     "movca.l r0, @%3\n\t"
-			     "ocbi @%0\n\t"
-			     "ocbi @%1\n\t"
-			     "ocbi @%2\n\t"
-			     "ocbi @%3\n\t" : :
-			     "r" (a0), "r" (a1), "r" (a2), "r" (a3));
-		a0 += linesz;
-		a1 += linesz;
-		a2 += linesz;
-		a3 += linesz;
-		asm volatile("movca.l r0, @%0\n\t"
-			     "movca.l r0, @%1\n\t"
-			     "movca.l r0, @%2\n\t"
-			     "movca.l r0, @%3\n\t"
-			     "ocbi @%0\n\t"
-			     "ocbi @%1\n\t"
-			     "ocbi @%2\n\t"
-			     "ocbi @%3\n\t" : :
-			     "r" (a0), "r" (a1), "r" (a2), "r" (a3));
-		asm volatile("ldc %0, sr" : : "r" (orig_sr));
-		a0 += linesz;
-		a1 += linesz;
-		a2 += linesz;
-		a3 += linesz;
-	} while (a0 < a0e);
-}
-
 extern void __weak sh4__flush_region_init(void);
 
 /*
@@ -709,32 +384,11 @@ extern void __weak sh4__flush_region_init(void);
  */
 void __init sh4_cache_init(void)
 {
-	unsigned int wt_enabled = !!(__raw_readl(CCR) & CCR_CACHE_WT);
-
 	printk("PVR=%08x CVR=%08x PRR=%08x\n",
 		ctrl_inl(CCN_PVR),
 		ctrl_inl(CCN_CVR),
 		ctrl_inl(CCN_PRR));
 
-	if (wt_enabled)
-		__flush_dcache_segment_fn = __flush_dcache_segment_writethrough;
-	else {
-		switch (boot_cpu_data.dcache.ways) {
-		case 1:
-			__flush_dcache_segment_fn = __flush_dcache_segment_1way;
-			break;
-		case 2:
-			__flush_dcache_segment_fn = __flush_dcache_segment_2way;
-			break;
-		case 4:
-			__flush_dcache_segment_fn = __flush_dcache_segment_4way;
-			break;
-		default:
-			panic("unknown number of cache ways\n");
-			break;
-		}
-	}
-
 	local_flush_icache_range	= sh4_flush_icache_range;
 	local_flush_dcache_page		= sh4_flush_dcache_page;
 	local_flush_cache_all		= sh4_flush_cache_all;

arch/sh/mm/cache.c

@@ -164,11 +164,17 @@ void flush_cache_all(void)
 
 void flush_cache_mm(struct mm_struct *mm)
 {
+	if (boot_cpu_data.dcache.n_aliases == 0)
+		return;
+
 	cacheop_on_each_cpu(local_flush_cache_mm, mm, 1);
 }
 
 void flush_cache_dup_mm(struct mm_struct *mm)
 {
+	if (boot_cpu_data.dcache.n_aliases == 0)
+		return;
+
 	cacheop_on_each_cpu(local_flush_cache_dup_mm, mm, 1);
 }
 

arch/sh/mm/kmap.c

@@ -39,7 +39,9 @@ void *kmap_coherent(struct page *page, unsigned long addr)
 	pagefault_disable();
 
 	idx = FIX_CMAP_END -
-		((addr & current_cpu_data.dcache.alias_mask) >> PAGE_SHIFT);
+		(((addr >> PAGE_SHIFT) & (FIX_N_COLOURS - 1)) +
+		 (FIX_N_COLOURS * smp_processor_id()));
+
 	vaddr = __fix_to_virt(idx);
 
 	BUG_ON(!pte_none(*(kmap_coherent_pte - idx)));