[PATCH] ppc64: support 64k pages

Adds a new CONFIG_PPC_64K_PAGES which, when enabled, changes the kernel
base page size to 64K.  The resulting kernel still boots on any
hardware.  On current machines with 4K pages support only, the kernel
will maintain 16 "subpages" for each 64K page transparently.

Note that while real 64K capable HW has been tested, the current patch
will not enable it yet as such hardware is not released yet, and I'm
still verifying with the firmware architects the proper to get the
information from the newer hypervisors.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 53 insertions, 107 deletions

diff --git a/include/asm-ppc64/pgtable.h b/include/asm-ppc64/pgtable.h
index 8c3f574046b6..fde93ec36abc 100644
--- a/include/asm-ppc64/pgtable.h
+++ b/include/asm-ppc64/pgtable.h
@@ -15,40 +15,11 @@
 #include <asm/tlbflush.h>
 #endif /* __ASSEMBLY__ */
 
-/*
- * Entries per page directory level.  The PTE level must use a 64b record
- * for each page table entry.  The PMD and PGD level use a 32b record for 
- * each entry by assuming that each entry is page aligned.
- */
-#define PTE_INDEX_SIZE  9
-#define PMD_INDEX_SIZE  7
-#define PUD_INDEX_SIZE  7
-#define PGD_INDEX_SIZE  9
-
-#define PTE_TABLE_SIZE	(sizeof(pte_t) << PTE_INDEX_SIZE)
-#define PMD_TABLE_SIZE	(sizeof(pmd_t) << PMD_INDEX_SIZE)
-#define PUD_TABLE_SIZE	(sizeof(pud_t) << PUD_INDEX_SIZE)
-#define PGD_TABLE_SIZE	(sizeof(pgd_t) << PGD_INDEX_SIZE)
-
-#define PTRS_PER_PTE	(1 << PTE_INDEX_SIZE)
-#define PTRS_PER_PMD	(1 << PMD_INDEX_SIZE)
-#define PTRS_PER_PUD	(1 << PMD_INDEX_SIZE)
-#define PTRS_PER_PGD	(1 << PGD_INDEX_SIZE)
-
-/* PMD_SHIFT determines what a second-level page table entry can map */
-#define PMD_SHIFT	(PAGE_SHIFT + PTE_INDEX_SIZE)
-#define PMD_SIZE	(1UL << PMD_SHIFT)
-#define PMD_MASK	(~(PMD_SIZE-1))
-
-/* PUD_SHIFT determines what a third-level page table entry can map */
-#define PUD_SHIFT	(PMD_SHIFT + PMD_INDEX_SIZE)
-#define PUD_SIZE	(1UL << PUD_SHIFT)
-#define PUD_MASK	(~(PUD_SIZE-1))
-
-/* PGDIR_SHIFT determines what a fourth-level page table entry can map */
-#define PGDIR_SHIFT	(PUD_SHIFT + PUD_INDEX_SIZE)
-#define PGDIR_SIZE	(1UL << PGDIR_SHIFT)
-#define PGDIR_MASK	(~(PGDIR_SIZE-1))
+#ifdef CONFIG_PPC_64K_PAGES
+#include <asm/pgtable-64k.h>
+#else
+#include <asm/pgtable-4k.h>
+#endif
 
 #define FIRST_USER_ADDRESS	0
 
@@ -75,8 +46,9 @@
 #define VMALLOC_END   (VMALLOC_START + VMALLOC_SIZE)
 
 /*
- * Bits in a linux-style PTE.  These match the bits in the
- * (hardware-defined) PowerPC PTE as closely as possible.
+ * Common bits in a linux-style PTE.  These match the bits in the
+ * (hardware-defined) PowerPC PTE as closely as possible. Additional
+ * bits may be defined in pgtable-*.h
  */
 #define _PAGE_PRESENT	0x0001 /* software: pte contains a translation */
 #define _PAGE_USER	0x0002 /* matches one of the PP bits */
@@ -91,15 +63,6 @@
 #define _PAGE_RW	0x0200 /* software: user write access allowed */
 #define _PAGE_HASHPTE	0x0400 /* software: pte has an associated HPTE */
 #define _PAGE_BUSY	0x0800 /* software: PTE & hash are busy */ 
-#define _PAGE_SECONDARY 0x8000 /* software: HPTE is in secondary group */
-#define _PAGE_GROUP_IX  0x7000 /* software: HPTE index within group */
-#define _PAGE_HUGE	0x10000 /* 16MB page */
-/* Bits 0x7000 identify the index within an HPT Group */
-#define _PAGE_HPTEFLAGS (_PAGE_BUSY | _PAGE_HASHPTE | _PAGE_SECONDARY | _PAGE_GROUP_IX)
-/* PAGE_MASK gives the right answer below, but only by accident */
-/* It should be preserving the high 48 bits and then specifically */
-/* preserving _PAGE_SECONDARY | _PAGE_GROUP_IX */
-#define _PAGE_CHG_MASK	(PAGE_MASK | _PAGE_ACCESSED | _PAGE_DIRTY | _PAGE_HPTEFLAGS)
 
 #define _PAGE_BASE	(_PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_COHERENT)
 
@@ -122,10 +85,10 @@
 #define PAGE_AGP	__pgprot(_PAGE_BASE | _PAGE_WRENABLE | _PAGE_NO_CACHE)
 #define HAVE_PAGE_AGP
 
-/*
- * This bit in a hardware PTE indicates that the page is *not* executable.
- */
-#define HW_NO_EXEC	_PAGE_EXEC
+/* PTEIDX nibble */
+#define _PTEIDX_SECONDARY	0x8
+#define _PTEIDX_GROUP_IX	0x7
+
 
 /*
  * POWER4 and newer have per page execute protection, older chips can only
@@ -164,21 +127,10 @@ extern unsigned long empty_zero_page[PAGE_SIZE/sizeof(unsigned long)];
 #define ZERO_PAGE(vaddr) (virt_to_page(empty_zero_page))
 #endif /* __ASSEMBLY__ */
 
-/* shift to put page number into pte */
-#define PTE_SHIFT (17)
-
 #ifdef CONFIG_HUGETLB_PAGE
 
-#ifndef __ASSEMBLY__
-int hash_huge_page(struct mm_struct *mm, unsigned long access,
-		   unsigned long ea, unsigned long vsid, int local);
-#endif /* __ASSEMBLY__ */
-
 #define HAVE_ARCH_UNMAPPED_AREA
 #define HAVE_ARCH_UNMAPPED_AREA_TOPDOWN
-#else
-
-#define hash_huge_page(mm,a,ea,vsid,local)	-1
 
 #endif
 
@@ -197,7 +149,7 @@ static inline pte_t pfn_pte(unsigned long pfn, pgprot_t pgprot)
 	pte_t pte;
 
 
-	pte_val(pte) = (pfn << PTE_SHIFT) | pgprot_val(pgprot);
+	pte_val(pte) = (pfn << PTE_RPN_SHIFT) | pgprot_val(pgprot);
 	return pte;
 }
 
@@ -209,30 +161,25 @@ static inline pte_t pfn_pte(unsigned long pfn, pgprot_t pgprot)
 
 /* pte_clear moved to later in this file */
 
-#define pte_pfn(x)		((unsigned long)((pte_val(x) >> PTE_SHIFT)))
+#define pte_pfn(x)		((unsigned long)((pte_val(x)>>PTE_RPN_SHIFT)))
 #define pte_page(x)		pfn_to_page(pte_pfn(x))
 
-#define pmd_set(pmdp, ptep) 	({BUG_ON((u64)ptep < KERNELBASE); pmd_val(*(pmdp)) = (unsigned long)(ptep);})
+#define pmd_set(pmdp, pmdval) 	(pmd_val(*(pmdp)) = (pmdval))
 #define pmd_none(pmd)		(!pmd_val(pmd))
 #define	pmd_bad(pmd)		(pmd_val(pmd) == 0)
 #define	pmd_present(pmd)	(pmd_val(pmd) != 0)
 #define	pmd_clear(pmdp)		(pmd_val(*(pmdp)) = 0)
-#define pmd_page_kernel(pmd)	(pmd_val(pmd))
+#define pmd_page_kernel(pmd)	(pmd_val(pmd) & ~PMD_MASKED_BITS)
 #define pmd_page(pmd)		virt_to_page(pmd_page_kernel(pmd))
 
-#define pud_set(pudp, pmdp)	(pud_val(*(pudp)) = (unsigned long)(pmdp))
+#define pud_set(pudp, pudval)	(pud_val(*(pudp)) = (pudval))
 #define pud_none(pud)		(!pud_val(pud))
 #define pud_bad(pud)		((pud_val(pud)) == 0)
 #define pud_present(pud)	(pud_val(pud) != 0)
 #define pud_clear(pudp)		(pud_val(*(pudp)) = 0)
-#define pud_page(pud)		(pud_val(pud))
+#define pud_page(pud)		(pud_val(pud) & ~PUD_MASKED_BITS)
 
 #define pgd_set(pgdp, pudp)	({pgd_val(*(pgdp)) = (unsigned long)(pudp);})
-#define pgd_none(pgd)		(!pgd_val(pgd))
-#define pgd_bad(pgd)		(pgd_val(pgd) == 0)
-#define pgd_present(pgd)	(pgd_val(pgd) != 0)
-#define pgd_clear(pgdp)		(pgd_val(*(pgdp)) = 0)
-#define pgd_page(pgd)		(pgd_val(pgd))
 
 /* 
  * Find an entry in a page-table-directory.  We combine the address region 
@@ -243,9 +190,6 @@ static inline pte_t pfn_pte(unsigned long pfn, pgprot_t pgprot)
 
 #define pgd_offset(mm, address)	 ((mm)->pgd + pgd_index(address))
 
-#define pud_offset(pgdp, addr)	\
-  (((pud_t *) pgd_page(*(pgdp))) + (((addr) >> PUD_SHIFT) & (PTRS_PER_PUD - 1)))
-
 #define pmd_offset(pudp,addr) \
   (((pmd_t *) pud_page(*(pudp))) + (((addr) >> PMD_SHIFT) & (PTRS_PER_PMD - 1)))
 
@@ -271,7 +215,6 @@ static inline int pte_exec(pte_t pte)  { return pte_val(pte) & _PAGE_EXEC;}
 static inline int pte_dirty(pte_t pte) { return pte_val(pte) & _PAGE_DIRTY;}
 static inline int pte_young(pte_t pte) { return pte_val(pte) & _PAGE_ACCESSED;}
 static inline int pte_file(pte_t pte) { return pte_val(pte) & _PAGE_FILE;}
-static inline int pte_huge(pte_t pte) { return pte_val(pte) & _PAGE_HUGE;}
 
 static inline void pte_uncache(pte_t pte) { pte_val(pte) |= _PAGE_NO_CACHE; }
 static inline void pte_cache(pte_t pte)   { pte_val(pte) &= ~_PAGE_NO_CACHE; }
@@ -286,7 +229,6 @@ static inline pte_t pte_mkclean(pte_t pte) {
 	pte_val(pte) &= ~(_PAGE_DIRTY); return pte; }
 static inline pte_t pte_mkold(pte_t pte) {
 	pte_val(pte) &= ~_PAGE_ACCESSED; return pte; }
-
 static inline pte_t pte_mkread(pte_t pte) {
 	pte_val(pte) |= _PAGE_USER; return pte; }
 static inline pte_t pte_mkexec(pte_t pte) {
@@ -298,7 +240,7 @@ static inline pte_t pte_mkdirty(pte_t pte) {
 static inline pte_t pte_mkyoung(pte_t pte) {
 	pte_val(pte) |= _PAGE_ACCESSED; return pte; }
 static inline pte_t pte_mkhuge(pte_t pte) {
-	pte_val(pte) |= _PAGE_HUGE; return pte; }
+	return pte; }
 
 /* Atomic PTE updates */
 static inline unsigned long pte_update(pte_t *p, unsigned long clr)
@@ -321,11 +263,13 @@ static inline unsigned long pte_update(pte_t *p, unsigned long clr)
 /* PTE updating functions, this function puts the PTE in the
  * batch, doesn't actually triggers the hash flush immediately,
  * you need to call flush_tlb_pending() to do that.
+ * Pass -1 for "normal" size (4K or 64K)
  */
-extern void hpte_update(struct mm_struct *mm, unsigned long addr, unsigned long pte,
-			int wrprot);
+extern void hpte_update(struct mm_struct *mm, unsigned long addr,
+			pte_t *ptep, unsigned long pte, int huge);
 
-static inline int __ptep_test_and_clear_young(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
+static inline int __ptep_test_and_clear_young(struct mm_struct *mm,
+					      unsigned long addr, pte_t *ptep)
 {
 	unsigned long old;
 
@@ -333,7 +277,7 @@ static inline int __ptep_test_and_clear_young(struct mm_struct *mm, unsigned lon
 		return 0;
 	old = pte_update(ptep, _PAGE_ACCESSED);
 	if (old & _PAGE_HASHPTE) {
-		hpte_update(mm, addr, old, 0);
+		hpte_update(mm, addr, ptep, old, 0);
 		flush_tlb_pending();
 	}
 	return (old & _PAGE_ACCESSED) != 0;
@@ -351,7 +295,8 @@ static inline int __ptep_test_and_clear_young(struct mm_struct *mm, unsigned lon
  * moment we always flush but we need to fix hpte_update and test if the
  * optimisation is worth it.
  */
-static inline int __ptep_test_and_clear_dirty(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
+static inline int __ptep_test_and_clear_dirty(struct mm_struct *mm,
+					      unsigned long addr, pte_t *ptep)
 {
 	unsigned long old;
 
@@ -359,7 +304,7 @@ static inline int __ptep_test_and_clear_dirty(struct mm_struct *mm, unsigned lon
 		return 0;
 	old = pte_update(ptep, _PAGE_DIRTY);
 	if (old & _PAGE_HASHPTE)
-		hpte_update(mm, addr, old, 0);
+		hpte_update(mm, addr, ptep, old, 0);
 	return (old & _PAGE_DIRTY) != 0;
 }
 #define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_DIRTY
@@ -371,7 +316,8 @@ static inline int __ptep_test_and_clear_dirty(struct mm_struct *mm, unsigned lon
 })
 
 #define __HAVE_ARCH_PTEP_SET_WRPROTECT
-static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
+static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long addr,
+				      pte_t *ptep)
 {
 	unsigned long old;
 
@@ -379,7 +325,7 @@ static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long addr,
        		return;
 	old = pte_update(ptep, _PAGE_RW);
 	if (old & _PAGE_HASHPTE)
-		hpte_update(mm, addr, old, 0);
+		hpte_update(mm, addr, ptep, old, 0);
 }
 
 /*
@@ -408,21 +354,23 @@ static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long addr,
 })
 
 #define __HAVE_ARCH_PTEP_GET_AND_CLEAR
-static inline pte_t ptep_get_and_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
+static inline pte_t ptep_get_and_clear(struct mm_struct *mm,
+				       unsigned long addr, pte_t *ptep)
 {
 	unsigned long old = pte_update(ptep, ~0UL);
 
 	if (old & _PAGE_HASHPTE)
-		hpte_update(mm, addr, old, 0);
+		hpte_update(mm, addr, ptep, old, 0);
 	return __pte(old);
 }
 
-static inline void pte_clear(struct mm_struct *mm, unsigned long addr, pte_t * ptep)
+static inline void pte_clear(struct mm_struct *mm, unsigned long addr,
+			     pte_t * ptep)
 {
 	unsigned long old = pte_update(ptep, ~0UL);
 
 	if (old & _PAGE_HASHPTE)
-		hpte_update(mm, addr, old, 0);
+		hpte_update(mm, addr, ptep, old, 0);
 }
 
 /*
@@ -435,7 +383,14 @@ static inline void set_pte_at(struct mm_struct *mm, unsigned long addr,
 		pte_clear(mm, addr, ptep);
 		flush_tlb_pending();
 	}
-	*ptep = __pte(pte_val(pte) & ~_PAGE_HPTEFLAGS);
+	pte = __pte(pte_val(pte) & ~_PAGE_HPTEFLAGS);
+
+#ifdef CONFIG_PPC_64K_PAGES
+	if (mmu_virtual_psize != MMU_PAGE_64K)
+		pte = __pte(pte_val(pte) | _PAGE_COMBO);
+#endif /* CONFIG_PPC_64K_PAGES */
+
+	*ptep = pte;
 }
 
 /* Set the dirty and/or accessed bits atomically in a linux PTE, this
@@ -482,8 +437,6 @@ extern pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
 	printk("%s:%d: bad pte %08lx.\n", __FILE__, __LINE__, pte_val(e))
 #define pmd_ERROR(e) \
 	printk("%s:%d: bad pmd %08lx.\n", __FILE__, __LINE__, pmd_val(e))
-#define pud_ERROR(e) \
-	printk("%s:%d: bad pud %08lx.\n", __FILE__, __LINE__, pud_val(e))
 #define pgd_ERROR(e) \
 	printk("%s:%d: bad pgd %08lx.\n", __FILE__, __LINE__, pgd_val(e))
 
@@ -509,12 +462,12 @@ extern void update_mmu_cache(struct vm_area_struct *, unsigned long, pte_t);
 /* Encode and de-code a swap entry */
 #define __swp_type(entry)	(((entry).val >> 1) & 0x3f)
 #define __swp_offset(entry)	((entry).val >> 8)
-#define __swp_entry(type, offset) ((swp_entry_t) { ((type) << 1) | ((offset) << 8) })
-#define __pte_to_swp_entry(pte)	((swp_entry_t) { pte_val(pte) >> PTE_SHIFT })
-#define __swp_entry_to_pte(x)	((pte_t) { (x).val << PTE_SHIFT })
-#define pte_to_pgoff(pte)	(pte_val(pte) >> PTE_SHIFT)
-#define pgoff_to_pte(off)	((pte_t) {((off) << PTE_SHIFT)|_PAGE_FILE})
-#define PTE_FILE_MAX_BITS	(BITS_PER_LONG - PTE_SHIFT)
+#define __swp_entry(type, offset) ((swp_entry_t){((type)<< 1)|((offset)<<8)})
+#define __pte_to_swp_entry(pte)	((swp_entry_t){pte_val(pte) >> PTE_RPN_SHIFT})
+#define __swp_entry_to_pte(x)	((pte_t) { (x).val << PTE_RPN_SHIFT })
+#define pte_to_pgoff(pte)	(pte_val(pte) >> PTE_RPN_SHIFT)
+#define pgoff_to_pte(off)	((pte_t) {((off) << PTE_RPN_SHIFT)|_PAGE_FILE})
+#define PTE_FILE_MAX_BITS	(BITS_PER_LONG - PTE_RPN_SHIFT)
 
 /*
  * kern_addr_valid is intended to indicate whether an address is a valid
@@ -532,29 +485,22 @@ void pgtable_cache_init(void);
 /*
  * find_linux_pte returns the address of a linux pte for a given 
  * effective address and directory.  If not found, it returns zero.
- */
-static inline pte_t *find_linux_pte(pgd_t *pgdir, unsigned long ea)
+ */static inline pte_t *find_linux_pte(pgd_t *pgdir, unsigned long ea)
 {
 	pgd_t *pg;
 	pud_t *pu;
 	pmd_t *pm;
 	pte_t *pt = NULL;
-	pte_t pte;
 
 	pg = pgdir + pgd_index(ea);
 	if (!pgd_none(*pg)) {
 		pu = pud_offset(pg, ea);
 		if (!pud_none(*pu)) {
 			pm = pmd_offset(pu, ea);
-			if (pmd_present(*pm)) {
+			if (pmd_present(*pm))
 				pt = pte_offset_kernel(pm, ea);
-				pte = *pt;
-				if (!pte_present(pte))
-					pt = NULL;
-			}
 		}
 	}
-
 	return pt;
 }