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authorIlya Yanok <yanok@emcraft.com>2008-12-11 04:55:41 +0300
committerPaul Mackerras <paulus@samba.org>2008-12-29 09:53:25 +1100
commitca9153a3a2a7556d091dfe080e42b0e67881fff6 (patch)
tree35b5ce24f190690cf7a726cbb97980da51704855 /arch/powerpc/include/asm/highmem.h
parent6ca4f7494bde078b2b730e28e4ea1dc36a772f70 (diff)
powerpc/44x: Support 16K/64K base page sizes on 44x
This adds support for 16k and 64k page sizes on PowerPC 44x processors. The PGDIR table is much smaller than a page when using 16k or 64k pages (512 and 32 bytes respectively) so we allocate the PGDIR with kzalloc() instead of __get_free_pages(). One PTE table covers rather a large memory area when using 16k or 64k pages (32MB or 512MB respectively), so we can easily put FIXMAP and PKMAP in the area covered by one PTE table. Signed-off-by: Yuri Tikhonov <yur@emcraft.com> Signed-off-by: Vladimir Panfilov <pvr@emcraft.com> Signed-off-by: Ilya Yanok <yanok@emcraft.com> Acked-by: Josh Boyer <jwboyer@linux.vnet.ibm.com> Signed-off-by: Paul Mackerras <paulus@samba.org>
Diffstat (limited to 'arch/powerpc/include/asm/highmem.h')
-rw-r--r--arch/powerpc/include/asm/highmem.h19
1 files changed, 17 insertions, 2 deletions
diff --git a/arch/powerpc/include/asm/highmem.h b/arch/powerpc/include/asm/highmem.h
index fd97e501aa6a..04e4a620952e 100644
--- a/arch/powerpc/include/asm/highmem.h
+++ b/arch/powerpc/include/asm/highmem.h
@@ -38,9 +38,24 @@ extern pte_t *pkmap_page_table;
* easily, subsequent pte tables have to be allocated in one physical
* chunk of RAM.
*/
-#define LAST_PKMAP (1 << PTE_SHIFT)
-#define LAST_PKMAP_MASK (LAST_PKMAP-1)
+/*
+ * We use one full pte table with 4K pages. And with 16K/64K pages pte
+ * table covers enough memory (32MB and 512MB resp.) that both FIXMAP
+ * and PKMAP can be placed in single pte table. We use 1024 pages for
+ * PKMAP in case of 16K/64K pages.
+ */
+#ifdef CONFIG_PPC_4K_PAGES
+#define PKMAP_ORDER PTE_SHIFT
+#else
+#define PKMAP_ORDER 10
+#endif
+#define LAST_PKMAP (1 << PKMAP_ORDER)
+#ifndef CONFIG_PPC_4K_PAGES
+#define PKMAP_BASE (FIXADDR_START - PAGE_SIZE*(LAST_PKMAP + 1))
+#else
#define PKMAP_BASE ((FIXADDR_START - PAGE_SIZE*(LAST_PKMAP + 1)) & PMD_MASK)
+#endif
+#define LAST_PKMAP_MASK (LAST_PKMAP-1)
#define PKMAP_NR(virt) ((virt-PKMAP_BASE) >> PAGE_SHIFT)
#define PKMAP_ADDR(nr) (PKMAP_BASE + ((nr) << PAGE_SHIFT))