[PATCH] xtensa: Architecture support for Tensilica Xtensa Part 6

The attached patches provides part 6 of an architecture implementation for the
Tensilica Xtensa CPU series.

Signed-off-by: Chris Zankel <chris@zankel.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 116 insertions, 0 deletions

diff --git a/include/asm-xtensa/pgalloc.h b/include/asm-xtensa/pgalloc.h
new file mode 100644
index 0000000..734a8d0
--- /dev/null
+++ b/include/asm-xtensa/pgalloc.h
@@ -0,0 +1,116 @@
+/*
+ * linux/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.
+ */
+
+#ifndef _XTENSA_PGALLOC_H
+#define _XTENSA_PGALLOC_H
+
+#ifdef __KERNEL__
+
+#include <linux/config.h>
+#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
+
+static inline void
+pmd_populate_kernel(struct mm_struct *mm, pmd_t *pmdp, pte_t *pte)
+{
+	pmd_val(*(pmdp)) = (unsigned long)(pte);
+	__asm__ __volatile__ ("memw; dhwb %0, 0; dsync" :: "a" (pmdp));
+}
+
+static inline void
+pmd_populate(struct mm_struct *mm, pmd_t *pmdp, struct page *page)
+{
+	pmd_val(*(pmdp)) = (unsigned long)page_to_virt(page);
+	__asm__ __volatile__ ("memw; dhwb %0, 0; dsync" :: "a" (pmdp));
+}
+
+
+
+#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)
+{
+	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 pgd;
+}
+
+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);
+
+#define pte_free_kernel(pte) free_page((unsigned long)pte)
+#define pte_free(pte) __free_page(pte)
+
+#endif /* __KERNEL__ */
+#endif /* _XTENSA_PGALLOC_H */