7 files changed, 55 insertions, 9 deletions
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index ccdd8de3c55..2d6d133c0ed 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -409,6 +409,18 @@ config PPC_HAS_HASH_64K
 	depends on PPC64
 	default n
 
+config STDBINUTILS
+	bool "Using standard binutils settings"
+	depends on 44x
+	default y
+	help
+	  Turning this option off allows you to select 256KB PAGE_SIZE on 44x.
+	  Note, that kernel will be able to run only those applications,
+	  which had been compiled using binutils later than 2.17.50.0.3 with
+	  '-zmax-page-size' set to 256K (the default is 64K). Or, if using
+	  the older binutils, you can patch them with a trivial patch, which
+	  changes the ELF_MAXPAGESIZE definition from 0x10000 to 0x40000.
+
 choice
 	prompt "Page size"
 	default PPC_4K_PAGES
@@ -444,6 +456,19 @@ config PPC_64K_PAGES
 	bool "64k page size" if 44x || PPC_STD_MMU_64
 	select PPC_HAS_HASH_64K if PPC_STD_MMU_64
 
+config PPC_256K_PAGES
+	bool "256k page size" if 44x
+	depends on !STDBINUTILS && (!SHMEM || BROKEN)
+	help
+	  Make the page size 256k.
+
+	  As the ELF standard only requires alignment to support page
+	  sizes up to 64k, you will need to compile all of your user
+	  space applications with a non-standard binutils settings
+	  (see the STDBINUTILS description for details).
+
+	  Say N unless you know what you are doing.
+
 endchoice
 
 config FORCE_MAX_ZONEORDER
@@ -456,6 +481,8 @@ config FORCE_MAX_ZONEORDER
 	default "9" if PPC_STD_MMU_32 && PPC_16K_PAGES
 	range 7 64 if PPC_STD_MMU_32 && PPC_64K_PAGES
 	default "7" if PPC_STD_MMU_32 && PPC_64K_PAGES
+	range 5 64 if PPC_STD_MMU_32 && PPC_256K_PAGES
+	default "5" if PPC_STD_MMU_32 && PPC_256K_PAGES
 	range 11 64
 	default "11"
 	help
diff --git a/arch/powerpc/include/asm/highmem.h b/arch/powerpc/include/asm/highmem.h
index 04e4a620952..a2907595067 100644
--- a/arch/powerpc/include/asm/highmem.h
+++ b/arch/powerpc/include/asm/highmem.h
@@ -39,15 +39,15 @@ extern pte_t *pkmap_page_table;
  * chunk of RAM.
  */
 /*
- * 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.
+ * We use one full pte table with 4K pages. And with 16K/64K/256K pages pte
+ * table covers enough memory (32MB/512MB/2GB resp.), so that both FIXMAP
+ * and PKMAP can be placed in a single pte table. We use 512 pages for PKMAP
+ * in case of 16K/64K/256K page sizes.
  */
 #ifdef CONFIG_PPC_4K_PAGES
 #define PKMAP_ORDER	PTE_SHIFT
 #else
-#define PKMAP_ORDER	10
+#define PKMAP_ORDER	9
 #endif
 #define LAST_PKMAP	(1 << PKMAP_ORDER)
 #ifndef CONFIG_PPC_4K_PAGES
diff --git a/arch/powerpc/include/asm/mmu-44x.h b/arch/powerpc/include/asm/mmu-44x.h
index 27cc6fdcd3b..3c86576bfef 100644
--- a/arch/powerpc/include/asm/mmu-44x.h
+++ b/arch/powerpc/include/asm/mmu-44x.h
@@ -83,6 +83,8 @@ typedef struct {
 #define PPC44x_TLBE_SIZE	PPC44x_TLB_16K
 #elif (PAGE_SHIFT == 16)
 #define PPC44x_TLBE_SIZE	PPC44x_TLB_64K
+#elif (PAGE_SHIFT == 18)
+#define PPC44x_TLBE_SIZE	PPC44x_TLB_256K
 #else
 #error "Unsupported PAGE_SIZE"
 #endif
diff --git a/arch/powerpc/include/asm/page.h b/arch/powerpc/include/asm/page.h
index 197d569f5bd..32cbf16f10e 100644
--- a/arch/powerpc/include/asm/page.h
+++ b/arch/powerpc/include/asm/page.h
@@ -19,12 +19,14 @@
 #include <asm/kdump.h>
 
 /*
- * On regular PPC32 page size is 4K (but we support 4K/16K/64K pages
+ * On regular PPC32 page size is 4K (but we support 4K/16K/64K/256K pages
  * on PPC44x). For PPC64 we support either 4K or 64K software
  * page size. When using 64K pages however, whether we are really supporting
  * 64K pages in HW or not is irrelevant to those definitions.
  */
-#if defined(CONFIG_PPC_64K_PAGES)
+#if defined(CONFIG_PPC_256K_PAGES)
+#define PAGE_SHIFT		18
+#elif defined(CONFIG_PPC_64K_PAGES)
 #define PAGE_SHIFT		16
 #elif defined(CONFIG_PPC_16K_PAGES)
 #define PAGE_SHIFT		14
diff --git a/arch/powerpc/include/asm/page_32.h b/arch/powerpc/include/asm/page_32.h
index 1458d950038..a0e3f6e6b4e 100644
--- a/arch/powerpc/include/asm/page_32.h
+++ b/arch/powerpc/include/asm/page_32.h
@@ -19,7 +19,11 @@
 #define PTE_FLAGS_OFFSET	0
 #endif
 
+#ifdef CONFIG_PPC_256K_PAGES
+#define PTE_SHIFT	(PAGE_SHIFT - PTE_T_LOG2 - 2)	/* 1/4 of a page */
+#else
 #define PTE_SHIFT	(PAGE_SHIFT - PTE_T_LOG2)	/* full page */
+#endif
 
 #ifndef __ASSEMBLY__
 /*
diff --git a/arch/powerpc/include/asm/thread_info.h b/arch/powerpc/include/asm/thread_info.h
index 9665a26a253..e04286f92f6 100644
--- a/arch/powerpc/include/asm/thread_info.h
+++ b/arch/powerpc/include/asm/thread_info.h
@@ -12,8 +12,10 @@
 
 /* We have 8k stacks on ppc32 and 16k on ppc64 */
 
-#ifdef CONFIG_PPC64
+#if defined(CONFIG_PPC64)
 #define THREAD_SHIFT		14
+#elif defined(CONFIG_PPC_256K_PAGES)
+#define THREAD_SHIFT		15
 #else
 #define THREAD_SHIFT		13
 #endif
diff --git a/arch/powerpc/kernel/head_booke.h b/arch/powerpc/kernel/head_booke.h
index bec18078239..69a4489bc86 100644
--- a/arch/powerpc/kernel/head_booke.h
+++ b/arch/powerpc/kernel/head_booke.h
@@ -10,6 +10,15 @@
 		mtspr	SPRN_IVOR##vector_number,r26;	\
 		sync
 
+#if (THREAD_SHIFT < 15)
+#define ALLOC_STACK_FRAME(reg, val)			\
+	addi reg,reg,val
+#else
+#define ALLOC_STACK_FRAME(reg, val)			\
+	addis	reg,reg,val@ha;				\
+	addi	reg,reg,val@l
+#endif
+
 #define NORMAL_EXCEPTION_PROLOG						     \
 	mtspr	SPRN_SPRG0,r10;		/* save two registers to work with */\
 	mtspr	SPRN_SPRG1,r11;						     \
@@ -20,7 +29,7 @@
 	beq	1f;							     \
 	mfspr	r1,SPRN_SPRG3;		/* if from user, start at top of   */\
 	lwz	r1,THREAD_INFO-THREAD(r1); /* this thread's kernel stack   */\
-	addi	r1,r1,THREAD_SIZE;					     \
+	ALLOC_STACK_FRAME(r1, THREAD_SIZE);				     \
 1:	subi	r1,r1,INT_FRAME_SIZE;	/* Allocate an exception frame     */\
 	mr	r11,r1;							     \
 	stw	r10,_CCR(r11);          /* save various registers	   */\