[PATCH] sh: hugetlb support

From: Paul Mundt <lethal@linux-sh.org>

This implements hugetlb support for SH-4.  SH-4 supports 1k/4k/64k/1MB pages,
since we're only interested in the 64k/1MB sizes, this is what we support.

The sh hugetlbpage code borrows heavily off of the sparc64 port, which works
fine for these cases at this point in time.

arch/sh/Kconfig

@@ -244,6 +244,19 @@ config MMU
 	  turning this off will boot the kernel on these machines with the
 	  MMU implicitly switched off.
 
+choice
+	prompt "HugeTLB page size"
+	depends on HUGETLB_PAGE && CPU_SH4 && MMU
+	default HUGETLB_PAGE_SIZE_64K
+
+config HUGETLB_PAGE_SIZE_64K
+	bool "64K"
+
+config HUGETLB_PAGE_SIZE_1MB
+	bool "1MB"
+
+endchoice
+
 config CMDLINE_BOOL
 	bool "Default bootloader kernel arguments"
 

arch/sh/mm/Makefile

@@ -2,13 +2,14 @@
 # Makefile for the Linux SuperH-specific parts of the memory manager.
 #
 
-obj-y			:= init.o extable.o
+obj-y			:= init.o extable.o consistent.o
 
 obj-$(CONFIG_CPU_SH2)	+= cache-sh2.o
 obj-$(CONFIG_CPU_SH3)	+= cache-sh3.o
 obj-$(CONFIG_CPU_SH4)	+= cache-sh4.o pg-sh4.o
 
 obj-$(CONFIG_DMA_PAGE_OPS)	+= pg-dma.o
+obj-$(CONFIG_HUGETLB_PAGE)	+= hugetlbpage.o
 
 mmu-y			:= fault-nommu.o tlb-nommu.o pg-nommu.o
 mmu-$(CONFIG_MMU)	:= fault.o clear_page.o copy_page.o

arch/sh/mm/tlb-sh4.c

@@ -68,7 +68,7 @@ void update_mmu_cache(struct vm_area_struct * vma,
 	/* Set PTEL register */
 	pteval &= _PAGE_FLAGS_HARDWARE_MASK; /* drop software flags */
 #ifdef CONFIG_SH_WRITETHROUGH
-	pteval |= 1;
+	pteval |= _PAGE_WT;
 #endif
 	/* conveniently, we want all the software flags to be 0 anyway */
 	ctrl_outl(pteval, MMU_PTEL);

fs/Kconfig

@@ -866,7 +866,7 @@ config TMPFS
 
 config HUGETLBFS
 	bool "HugeTLB file system support"
-	depends X86 || IA64 || PPC64 || SPARC64 || X86_64 || BROKEN
+	depends X86 || IA64 || PPC64 || SPARC64 || SUPERH || X86_64 || BROKEN
 
 config HUGETLB_PAGE
 	def_bool HUGETLBFS

include/asm-sh/page.h

@@ -21,6 +21,18 @@
 #define PAGE_MASK	(~(PAGE_SIZE-1))
 #define PTE_MASK	PAGE_MASK
 
+#if defined(CONFIG_HUGETLB_PAGE_SIZE_64K)
+#define HPAGE_SHIFT	16
+#elif defined(CONFIG_HUGETLB_PAGE_SIZE_1MB)
+#define HPAGE_SHIFT	20
+#endif
+
+#ifdef CONFIG_HUGETLB_PAGE
+#define HPAGE_SIZE		(1UL << HPAGE_SHIFT)
+#define HPAGE_MASK		(~(HPAGE_SIZE-1))
+#define HUGETLB_PAGE_ORDER	(HPAGE_SHIFT-PAGE_SHIFT)
+#endif
+
 #ifdef __KERNEL__
 #ifndef __ASSEMBLY__
 

include/asm-sh/pgtable.h

@@ -53,20 +53,20 @@ extern unsigned long empty_zero_page[1024];
 #define VMALLOC_START	(P3SEG+0x00100000)
 #define VMALLOC_END	P4SEG
 
-/*			0x001     WT-bit on SH-4, 0 on SH-3 */
+#define	_PAGE_WT	0x001  /* WT-bit on SH-4, 0 on SH-3 */
 #define _PAGE_HW_SHARED	0x002  /* SH-bit  : page is shared among processes */
 #define _PAGE_DIRTY	0x004  /* D-bit   : page changed */
 #define _PAGE_CACHABLE	0x008  /* C-bit   : cachable */
-/*			0x010     SZ0-bit : Size of page */
+#define _PAGE_SZ0	0x010  /* SZ0-bit : Size of page */
 #define _PAGE_RW	0x020  /* PR0-bit : write access allowed */
 #define _PAGE_USER	0x040  /* PR1-bit : user space access allowed */
-/*			0x080     SZ1-bit : Size of page (on SH-4) */
+#define _PAGE_SZ1	0x080  /* SZ1-bit : Size of page (on SH-4) */
 #define _PAGE_PRESENT	0x100  /* V-bit   : page is valid */
 #define _PAGE_PROTNONE	0x200  /* software: if not present  */
 #define _PAGE_ACCESSED 	0x400  /* software: page referenced */
 #define _PAGE_U0_SHARED 0x800  /* software: page is shared in user space */
 
-#define	_PAGE_FILE	0x080  /* software: pagecache or swap? */
+#define	_PAGE_FILE	_PAGE_WT  /* software: pagecache or swap? */
 
 /* software: moves to PTEA.TC (Timing Control) */
 #define _PAGE_PCC_AREA5	0x00000000	/* use BSC registers for area5 */
@@ -83,20 +83,29 @@ extern unsigned long empty_zero_page[1024];
 
 
 /* Mask which drop software flags
- * We also drop SZ1 bit since it is always 0 and used for _PAGE_FILE
+ * We also drop WT bit since it is used for _PAGE_FILE
  * bit in this implementation.
  */
+#define _PAGE_CLEAR_FLAGS	(_PAGE_WT | _PAGE_PROTNONE | _PAGE_ACCESSED | _PAGE_U0_SHARED)
+
 #if defined(CONFIG_CPU_SH3)
 /*
  * MMU on SH-3 has bug on SH-bit: We can't use it if MMUCR.IX=1.
  * Work around: Just drop SH-bit.
  */
-#define _PAGE_FLAGS_HARDWARE_MASK	0x1ffff17c
+#define _PAGE_FLAGS_HARDWARE_MASK	(0x1fffffff & ~(_PAGE_CLEAR_FLAGS | _PAGE_HW_SHARED))
 #else
-#define _PAGE_FLAGS_HARDWARE_MASK	0x1ffff17e
+#define _PAGE_FLAGS_HARDWARE_MASK	(0x1fffffff & ~(_PAGE_CLEAR_FLAGS))
+#endif
+
+/* Hardware flags: SZ0=1 (4k-byte) */
+#define _PAGE_FLAGS_HARD	_PAGE_SZ0
+
+#if defined(CONFIG_HUGETLB_PAGE_SIZE_64K)
+#define _PAGE_SZHUGE	(_PAGE_SZ1)
+#elif defined(CONFIG_HUGETLB_PAGE_SIZE_1MB)
+#define _PAGE_SZHUGE	(_PAGE_SZ0 | _PAGE_SZ1)
 #endif
-/* Hardware flags: SZ=1 (4k-byte) */
-#define _PAGE_FLAGS_HARD		0x00000010
 
 #define _PAGE_SHARED	_PAGE_U0_SHARED