sh: Preliminary support for SH-X2 MMU.

This adds some preliminary support for the SH-X2 MMU, used by
newer SH-4A parts (particularly SH7785).

This MMU implements a 'compat' mode with SH-X MMUs and an
'extended' mode for SH-X2 extended features. Extended features
include additional page sizes (8kB, 4MB, 64MB), as well as the
addition of page execute permissions.

The extended mode attributes are placed in a second data array,
which requires us to switch to 64-bit PTEs when in X2 mode.

With the addition of the exec perms, we also overhaul the mmap
prots somewhat, now that it's possible to handle them more
intelligently.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

arch/sh/mm/Kconfig

@@ -235,13 +235,22 @@ config MEMORY_SIZE
 
 config 32BIT
 	bool "Support 32-bit physical addressing through PMB"
-	depends on CPU_SH4A && MMU
+	depends on CPU_SH4A && MMU && (!X2TLB || BROKEN)
 	default y
 	help
 	  If you say Y here, physical addressing will be extended to
 	  32-bits through the SH-4A PMB. If this is not set, legacy
 	  29-bit physical addressing will be used.
 
+config X2TLB
+	bool "Enable extended TLB mode"
+	depends on CPU_SUBTYPE_SH7785 && MMU && EXPERIMENTAL
+	help
+	  Selecting this option will enable the extended mode of the SH-X2
+	  TLB. For legacy SH-X behaviour and interoperability, say N. For
+	  all of the fun new features and a willingless to submit bug reports,
+	  say Y.
+
 config VSYSCALL
 	bool "Support vsyscall page"
 	depends on MMU
@@ -255,17 +264,53 @@ config VSYSCALL
 	  For systems with an MMU that can afford to give up a page,
 	  (the default value) say Y.
 
+choice
+	prompt "Kernel page size"
+	default PAGE_SIZE_4KB
+
+config PAGE_SIZE_4KB
+	bool "4kB"
+	help
+	  This is the default page size used by all SuperH CPUs.
+
+config PAGE_SIZE_8KB
+	bool "8kB"
+	depends on EXPERIMENTAL && X2TLB
+	help
+	  This enables 8kB pages as supported by SH-X2 and later MMUs.
+
+config PAGE_SIZE_64KB
+	bool "64kB"
+	depends on EXPERIMENTAL && CPU_SH4
+	help
+	  This enables support for 64kB pages, possible on all SH-4
+	  CPUs and later. Highly experimental, not recommended.
+
+endchoice
+
 choice
 	prompt "HugeTLB page size"
 	depends on HUGETLB_PAGE && CPU_SH4 && MMU
 	default HUGETLB_PAGE_SIZE_64K
 
 config HUGETLB_PAGE_SIZE_64K
-	bool "64K"
+	bool "64kB"
+
+config HUGETLB_PAGE_SIZE_256K
+	bool "256kB"
+	depends on X2TLB
 
 config HUGETLB_PAGE_SIZE_1MB
 	bool "1MB"
 
+config HUGETLB_PAGE_SIZE_4MB
+	bool "4MB"
+	depends on X2TLB
+
+config HUGETLB_PAGE_SIZE_64MB
+	bool "64MB"
+	depends on X2TLB
+
 endchoice
 
 source "mm/Kconfig"

arch/sh/mm/init.c

@@ -93,7 +93,7 @@ static void set_pte_phys(unsigned long addr, unsigned long phys, pgprot_t prot)
 	pud = pud_offset(pgd, addr);
 	if (pud_none(*pud)) {
 		pmd = (pmd_t *)get_zeroed_page(GFP_ATOMIC);
-		set_pud(pud, __pud(__pa(pmd) | _KERNPG_TABLE | _PAGE_USER));
+		set_pud(pud, __pud(__pa(pmd) | _PAGE_TABLE));
 		if (pmd != pmd_offset(pud, 0)) {
 			pud_ERROR(*pud);
 			return;
@@ -103,7 +103,7 @@ static void set_pte_phys(unsigned long addr, unsigned long phys, pgprot_t prot)
 	pmd = pmd_offset(pud, addr);
 	if (pmd_none(*pmd)) {
 		pte = (pte_t *)get_zeroed_page(GFP_ATOMIC);
-		set_pmd(pmd, __pmd(__pa(pte) | _KERNPG_TABLE | _PAGE_USER));
+		set_pmd(pmd, __pmd(__pa(pte) | _PAGE_TABLE));
 		if (pte != pte_offset_kernel(pmd, 0)) {
 			pmd_ERROR(*pmd);
 			return;

arch/sh/mm/ioremap.c

@@ -28,9 +28,7 @@ static inline void remap_area_pte(pte_t * pte, unsigned long address,
 {
 	unsigned long end;
 	unsigned long pfn;
-	pgprot_t pgprot = __pgprot(_PAGE_PRESENT | _PAGE_RW |
-				   _PAGE_DIRTY | _PAGE_ACCESSED |
-				   _PAGE_HW_SHARED | _PAGE_FLAGS_HARD | flags);
+	pgprot_t pgprot = __pgprot(pgprot_val(PAGE_KERNEL_NOCACHE) | flags);
 
 	address &= ~PMD_MASK;
 	end = address + size;

arch/sh/mm/pg-sh4.c

@@ -37,10 +37,6 @@ void clear_user_page(void *to, unsigned long address, struct page *page)
 	if (((address ^ (unsigned long)to) & CACHE_ALIAS) == 0)
 		clear_page(to);
 	else {
-		pgprot_t pgprot = __pgprot(_PAGE_PRESENT |
-					   _PAGE_RW | _PAGE_CACHABLE |
-					   _PAGE_DIRTY | _PAGE_ACCESSED |
-					   _PAGE_HW_SHARED | _PAGE_FLAGS_HARD);
 		unsigned long phys_addr = PHYSADDR(to);
 		unsigned long p3_addr = P3SEG + (address & CACHE_ALIAS);
 		pgd_t *pgd = pgd_offset_k(p3_addr);
@@ -50,7 +46,7 @@ void clear_user_page(void *to, unsigned long address, struct page *page)
 		pte_t entry;
 		unsigned long flags;
 
-		entry = pfn_pte(phys_addr >> PAGE_SHIFT, pgprot);
+		entry = pfn_pte(phys_addr >> PAGE_SHIFT, PAGE_KERNEL);
 		down(&p3map_sem[(address & CACHE_ALIAS)>>12]);
 		set_pte(pte, entry);
 		local_irq_save(flags);
@@ -77,10 +73,6 @@ void copy_user_page(void *to, void *from, unsigned long address,
 	if (((address ^ (unsigned long)to) & CACHE_ALIAS) == 0)
 		copy_page(to, from);
 	else {
-		pgprot_t pgprot = __pgprot(_PAGE_PRESENT |
-					   _PAGE_RW | _PAGE_CACHABLE |
-					   _PAGE_DIRTY | _PAGE_ACCESSED |
-					   _PAGE_HW_SHARED | _PAGE_FLAGS_HARD);
 		unsigned long phys_addr = PHYSADDR(to);
 		unsigned long p3_addr = P3SEG + (address & CACHE_ALIAS);
 		pgd_t *pgd = pgd_offset_k(p3_addr);
@@ -90,7 +82,7 @@ void copy_user_page(void *to, void *from, unsigned long address,
 		pte_t entry;
 		unsigned long flags;
 
-		entry = pfn_pte(phys_addr >> PAGE_SHIFT, pgprot);
+		entry = pfn_pte(phys_addr >> PAGE_SHIFT, PAGE_KERNEL);
 		down(&p3map_sem[(address & CACHE_ALIAS)>>12]);
 		set_pte(pte, entry);
 		local_irq_save(flags);

include/asm-sh/elf.h

@@ -74,7 +74,7 @@ typedef struct user_fpu_struct elf_fpregset_t;
 #define ELF_ARCH	EM_SH
 
 #define USE_ELF_CORE_DUMP
-#define ELF_EXEC_PAGESIZE	4096
+#define ELF_EXEC_PAGESIZE	PAGE_SIZE
 
 /* This is the location that an ET_DYN program is loaded if exec'ed.  Typical
    use of this is to invoke "./ld.so someprog" to test out a new version of

include/asm-sh/page.h

@@ -13,9 +13,16 @@
    [ P4 control   ]		0xE0000000
  */
 
-
 /* PAGE_SHIFT determines the page size */
-#define PAGE_SHIFT	12
+#if defined(CONFIG_PAGE_SIZE_4KB)
+# define PAGE_SHIFT	12
+#elif defined(CONFIG_PAGE_SIZE_8KB)
+# define PAGE_SHIFT	13
+#elif defined(CONFIG_PAGE_SIZE_64KB)
+# define PAGE_SHIFT	16
+#else
+# error "Bogus kernel page size?"
+#endif
 
 #ifdef __ASSEMBLY__
 #define PAGE_SIZE	(1 << PAGE_SHIFT)
@@ -28,8 +35,14 @@
 
 #if defined(CONFIG_HUGETLB_PAGE_SIZE_64K)
 #define HPAGE_SHIFT	16
+#elif defined(CONFIG_HUGETLB_PAGE_SIZE_256K)
+#define HPAGE_SHIFT	18
 #elif defined(CONFIG_HUGETLB_PAGE_SIZE_1MB)
 #define HPAGE_SHIFT	20
+#elif defined(CONFIG_HUGETLB_PAGE_SIZE_4MB)
+#define HPAGE_SHIFT	22
+#elif defined(CONFIG_HUGETLB_PAGE_SIZE_64MB)
+#define HPAGE_SHIFT	26
 #endif
 
 #ifdef CONFIG_HUGETLB_PAGE
@@ -69,15 +82,25 @@ extern void __copy_user_page(void *to, void *from, void *orig_to);
 /*
  * These are used to make use of C type-checking..
  */
-typedef struct { unsigned long pte; } pte_t;
-typedef struct { unsigned long pgd; } pgd_t;
+#ifdef CONFIG_X2TLB
+typedef struct { unsigned long pte_low, pte_high; } pte_t;
+typedef struct { unsigned long long pgprot; } pgprot_t;
+#define pte_val(x) \
+	((x).pte_low | ((unsigned long long)(x).pte_high << 32))
+#define __pte(x) \
+	({ pte_t __pte = {(x), ((unsigned long long)(x)) >> 32}; __pte; })
+#else
+typedef struct { unsigned long pte_low; } pte_t;
 typedef struct { unsigned long pgprot; } pgprot_t;
+#define pte_val(x)	((x).pte_low)
+#define __pte(x) ((pte_t) { (x) } )
+#endif
+
+typedef struct { unsigned long pgd; } pgd_t;
 
-#define pte_val(x)	((x).pte)
 #define pgd_val(x)	((x).pgd)
 #define pgprot_val(x)	((x).pgprot)
 
-#define __pte(x) ((pte_t) { (x) } )
 #define __pgd(x) ((pgd_t) { (x) } )
 #define __pgprot(x)	((pgprot_t) { (x) } )