1 files changed, 366 insertions, 0 deletions
diff --git a/arch/alpha/include/asm/pgtable.h b/arch/alpha/include/asm/pgtable.h
new file mode 100644
index 0000000000..635f0a5f5b
--- /dev/null
+++ b/arch/alpha/include/asm/pgtable.h
@@ -0,0 +1,366 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ALPHA_PGTABLE_H
+#define _ALPHA_PGTABLE_H
+
+#include <asm-generic/pgtable-nopud.h>
+
+/*
+ * This file contains the functions and defines necessary to modify and use
+ * the Alpha page table tree.
+ *
+ * This hopefully works with any standard Alpha page-size, as defined
+ * in <asm/page.h> (currently 8192).
+ */
+#include <linux/mmzone.h>
+
+#include <asm/page.h>
+#include <asm/processor.h>	/* For TASK_SIZE */
+#include <asm/machvec.h>
+#include <asm/setup.h>
+
+struct mm_struct;
+struct vm_area_struct;
+
+/* Certain architectures need to do special things when PTEs
+ * within a page table are directly modified.  Thus, the following
+ * hook is made available.
+ */
+#define set_pte(pteptr, pteval) ((*(pteptr)) = (pteval))
+
+/* PMD_SHIFT determines the size of the area a second-level page table can map */
+#define PMD_SHIFT	(PAGE_SHIFT + (PAGE_SHIFT-3))
+#define PMD_SIZE	(1UL << PMD_SHIFT)
+#define PMD_MASK	(~(PMD_SIZE-1))
+
+/* PGDIR_SHIFT determines what a third-level page table entry can map */
+#define PGDIR_SHIFT	(PAGE_SHIFT + 2*(PAGE_SHIFT-3))
+#define PGDIR_SIZE	(1UL << PGDIR_SHIFT)
+#define PGDIR_MASK	(~(PGDIR_SIZE-1))
+
+/*
+ * Entries per page directory level:  the Alpha is three-level, with
+ * all levels having a one-page page table.
+ */
+#define PTRS_PER_PTE	(1UL << (PAGE_SHIFT-3))
+#define PTRS_PER_PMD	(1UL << (PAGE_SHIFT-3))
+#define PTRS_PER_PGD	(1UL << (PAGE_SHIFT-3))
+#define USER_PTRS_PER_PGD	(TASK_SIZE / PGDIR_SIZE)
+
+/* Number of pointers that fit on a page:  this will go away. */
+#define PTRS_PER_PAGE	(1UL << (PAGE_SHIFT-3))
+
+#ifdef CONFIG_ALPHA_LARGE_VMALLOC
+#define VMALLOC_START		0xfffffe0000000000
+#else
+#define VMALLOC_START		(-2*PGDIR_SIZE)
+#endif
+#define VMALLOC_END		(-PGDIR_SIZE)
+
+/*
+ * OSF/1 PAL-code-imposed page table bits
+ */
+#define _PAGE_VALID	0x0001
+#define _PAGE_FOR	0x0002	/* used for page protection (fault on read) */
+#define _PAGE_FOW	0x0004	/* used for page protection (fault on write) */
+#define _PAGE_FOE	0x0008	/* used for page protection (fault on exec) */
+#define _PAGE_ASM	0x0010
+#define _PAGE_KRE	0x0100	/* xxx - see below on the "accessed" bit */
+#define _PAGE_URE	0x0200	/* xxx */
+#define _PAGE_KWE	0x1000	/* used to do the dirty bit in software */
+#define _PAGE_UWE	0x2000	/* used to do the dirty bit in software */
+
+/* .. and these are ours ... */
+#define _PAGE_DIRTY	0x20000
+#define _PAGE_ACCESSED	0x40000
+
+/* We borrow bit 39 to store the exclusive marker in swap PTEs. */
+#define _PAGE_SWP_EXCLUSIVE	0x8000000000UL
+
+/*
+ * NOTE! The "accessed" bit isn't necessarily exact:  it can be kept exactly
+ * by software (use the KRE/URE/KWE/UWE bits appropriately), but I'll fake it.
+ * Under Linux/AXP, the "accessed" bit just means "read", and I'll just use
+ * the KRE/URE bits to watch for it. That way we don't need to overload the
+ * KWE/UWE bits with both handling dirty and accessed.
+ *
+ * Note that the kernel uses the accessed bit just to check whether to page
+ * out a page or not, so it doesn't have to be exact anyway.
+ */
+
+#define __DIRTY_BITS	(_PAGE_DIRTY | _PAGE_KWE | _PAGE_UWE)
+#define __ACCESS_BITS	(_PAGE_ACCESSED | _PAGE_KRE | _PAGE_URE)
+
+#define _PFN_MASK	0xFFFFFFFF00000000UL
+
+#define _PAGE_TABLE	(_PAGE_VALID | __DIRTY_BITS | __ACCESS_BITS)
+#define _PAGE_CHG_MASK	(_PFN_MASK | __DIRTY_BITS | __ACCESS_BITS)
+
+/*
+ * All the normal masks have the "page accessed" bits on, as any time they are used,
+ * the page is accessed. They are cleared only by the page-out routines
+ */
+#define PAGE_NONE	__pgprot(_PAGE_VALID | __ACCESS_BITS | _PAGE_FOR | _PAGE_FOW | _PAGE_FOE)
+#define PAGE_SHARED	__pgprot(_PAGE_VALID | __ACCESS_BITS)
+#define PAGE_COPY	__pgprot(_PAGE_VALID | __ACCESS_BITS | _PAGE_FOW)
+#define PAGE_READONLY	__pgprot(_PAGE_VALID | __ACCESS_BITS | _PAGE_FOW)
+#define PAGE_KERNEL	__pgprot(_PAGE_VALID | _PAGE_ASM | _PAGE_KRE | _PAGE_KWE)
+
+#define _PAGE_NORMAL(x) __pgprot(_PAGE_VALID | __ACCESS_BITS | (x))
+
+#define _PAGE_P(x) _PAGE_NORMAL((x) | (((x) & _PAGE_FOW)?0:_PAGE_FOW))
+#define _PAGE_S(x) _PAGE_NORMAL(x)
+
+/*
+ * The hardware can handle write-only mappings, but as the Alpha
+ * architecture does byte-wide writes with a read-modify-write
+ * sequence, it's not practical to have write-without-read privs.
+ * Thus the "-w- -> rw-" and "-wx -> rwx" mapping here (and in
+ * arch/alpha/mm/fault.c)
+ */
+	/* xwr */
+
+/*
+ * pgprot_noncached() is only for infiniband pci support, and a real
+ * implementation for RAM would be more complicated.
+ */
+#define pgprot_noncached(prot)	(prot)
+
+/*
+ * BAD_PAGETABLE is used when we need a bogus page-table, while
+ * BAD_PAGE is used for a bogus page.
+ *
+ * ZERO_PAGE is a global shared page that is always zero:  used
+ * for zero-mapped memory areas etc..
+ */
+extern pte_t __bad_page(void);
+extern pmd_t * __bad_pagetable(void);
+
+extern unsigned long __zero_page(void);
+
+#define BAD_PAGETABLE	__bad_pagetable()
+#define BAD_PAGE	__bad_page()
+#define ZERO_PAGE(vaddr)	(virt_to_page(ZERO_PGE))
+
+/* number of bits that fit into a memory pointer */
+#define BITS_PER_PTR			(8*sizeof(unsigned long))
+
+/* to align the pointer to a pointer address */
+#define PTR_MASK			(~(sizeof(void*)-1))
+
+/* sizeof(void*)==1<<SIZEOF_PTR_LOG2 */
+#define SIZEOF_PTR_LOG2			3
+
+/* to find an entry in a page-table */
+#define PAGE_PTR(address)		\
+  ((unsigned long)(address)>>(PAGE_SHIFT-SIZEOF_PTR_LOG2)&PTR_MASK&~PAGE_MASK)
+
+/*
+ * On certain platforms whose physical address space can overlap KSEG,
+ * namely EV6 and above, we must re-twiddle the physaddr to restore the
+ * correct high-order bits.
+ *
+ * This is extremely confusing until you realize that this is actually
+ * just working around a userspace bug.  The X server was intending to
+ * provide the physical address but instead provided the KSEG address.
+ * Or tried to, except it's not representable.
+ * 
+ * On Tsunami there's nothing meaningful at 0x40000000000, so this is
+ * a safe thing to do.  Come the first core logic that does put something
+ * in this area -- memory or whathaveyou -- then this hack will have
+ * to go away.  So be prepared!
+ */
+
+#if defined(CONFIG_ALPHA_GENERIC) && defined(USE_48_BIT_KSEG)
+#error "EV6-only feature in a generic kernel"
+#endif
+#if defined(CONFIG_ALPHA_GENERIC) || \
+    (defined(CONFIG_ALPHA_EV6) && !defined(USE_48_BIT_KSEG))
+#define KSEG_PFN	(0xc0000000000UL >> PAGE_SHIFT)
+#define PHYS_TWIDDLE(pfn) \
+  ((((pfn) & KSEG_PFN) == (0x40000000000UL >> PAGE_SHIFT)) \
+  ? ((pfn) ^= KSEG_PFN) : (pfn))
+#else
+#define PHYS_TWIDDLE(pfn) (pfn)
+#endif
+
+/*
+ * Conversion functions:  convert a page and protection to a page entry,
+ * and a page entry and page directory to the page they refer to.
+ */
+#define page_to_pa(page)	(page_to_pfn(page) << PAGE_SHIFT)
+#define PFN_PTE_SHIFT		32
+#define pte_pfn(pte)		(pte_val(pte) >> PFN_PTE_SHIFT)
+
+#define pte_page(pte)	pfn_to_page(pte_pfn(pte))
+#define mk_pte(page, pgprot)						\
+({									\
+	pte_t pte;							\
+									\
+	pte_val(pte) = (page_to_pfn(page) << 32) | pgprot_val(pgprot);	\
+	pte;								\
+})
+
+extern inline pte_t pfn_pte(unsigned long physpfn, pgprot_t pgprot)
+{ pte_t pte; pte_val(pte) = (PHYS_TWIDDLE(physpfn) << 32) | pgprot_val(pgprot); return pte; }
+
+extern inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
+{ pte_val(pte) = (pte_val(pte) & _PAGE_CHG_MASK) | pgprot_val(newprot); return pte; }
+
+extern inline void pmd_set(pmd_t * pmdp, pte_t * ptep)
+{ pmd_val(*pmdp) = _PAGE_TABLE | ((((unsigned long) ptep) - PAGE_OFFSET) << (32-PAGE_SHIFT)); }
+
+extern inline void pud_set(pud_t * pudp, pmd_t * pmdp)
+{ pud_val(*pudp) = _PAGE_TABLE | ((((unsigned long) pmdp) - PAGE_OFFSET) << (32-PAGE_SHIFT)); }
+
+
+extern inline unsigned long
+pmd_page_vaddr(pmd_t pmd)
+{
+	return ((pmd_val(pmd) & _PFN_MASK) >> (32-PAGE_SHIFT)) + PAGE_OFFSET;
+}
+
+#define pmd_pfn(pmd)	(pmd_val(pmd) >> 32)
+#define pmd_page(pmd)	(pfn_to_page(pmd_val(pmd) >> 32))
+#define pud_page(pud)	(pfn_to_page(pud_val(pud) >> 32))
+
+extern inline pmd_t *pud_pgtable(pud_t pgd)
+{
+	return (pmd_t *)(PAGE_OFFSET + ((pud_val(pgd) & _PFN_MASK) >> (32-PAGE_SHIFT)));
+}
+
+extern inline int pte_none(pte_t pte)		{ return !pte_val(pte); }
+extern inline int pte_present(pte_t pte)	{ return pte_val(pte) & _PAGE_VALID; }
+extern inline void pte_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep)
+{
+	pte_val(*ptep) = 0;
+}
+
+extern inline int pmd_none(pmd_t pmd)		{ return !pmd_val(pmd); }
+extern inline int pmd_bad(pmd_t pmd)		{ return (pmd_val(pmd) & ~_PFN_MASK) != _PAGE_TABLE; }
+extern inline int pmd_present(pmd_t pmd)	{ return pmd_val(pmd) & _PAGE_VALID; }
+extern inline void pmd_clear(pmd_t * pmdp)	{ pmd_val(*pmdp) = 0; }
+
+extern inline int pud_none(pud_t pud)		{ return !pud_val(pud); }
+extern inline int pud_bad(pud_t pud)		{ return (pud_val(pud) & ~_PFN_MASK) != _PAGE_TABLE; }
+extern inline int pud_present(pud_t pud)	{ return pud_val(pud) & _PAGE_VALID; }
+extern inline void pud_clear(pud_t * pudp)	{ pud_val(*pudp) = 0; }
+
+/*
+ * The following only work if pte_present() is true.
+ * Undefined behaviour if not..
+ */
+extern inline int pte_write(pte_t pte)		{ return !(pte_val(pte) & _PAGE_FOW); }
+extern inline int pte_dirty(pte_t pte)		{ return pte_val(pte) & _PAGE_DIRTY; }
+extern inline int pte_young(pte_t pte)		{ return pte_val(pte) & _PAGE_ACCESSED; }
+
+extern inline pte_t pte_wrprotect(pte_t pte)	{ pte_val(pte) |= _PAGE_FOW; return pte; }
+extern inline pte_t pte_mkclean(pte_t pte)	{ pte_val(pte) &= ~(__DIRTY_BITS); return pte; }
+extern inline pte_t pte_mkold(pte_t pte)	{ pte_val(pte) &= ~(__ACCESS_BITS); return pte; }
+extern inline pte_t pte_mkwrite_novma(pte_t pte){ pte_val(pte) &= ~_PAGE_FOW; return pte; }
+extern inline pte_t pte_mkdirty(pte_t pte)	{ pte_val(pte) |= __DIRTY_BITS; return pte; }
+extern inline pte_t pte_mkyoung(pte_t pte)	{ pte_val(pte) |= __ACCESS_BITS; return pte; }
+
+/*
+ * The smp_rmb() in the following functions are required to order the load of
+ * *dir (the pointer in the top level page table) with any subsequent load of
+ * the returned pmd_t *ret (ret is data dependent on *dir).
+ *
+ * If this ordering is not enforced, the CPU might load an older value of
+ * *ret, which may be uninitialized data. See mm/memory.c:__pte_alloc for
+ * more details.
+ *
+ * Note that we never change the mm->pgd pointer after the task is running, so
+ * pgd_offset does not require such a barrier.
+ */
+
+/* Find an entry in the second-level page table.. */
+extern inline pmd_t * pmd_offset(pud_t * dir, unsigned long address)
+{
+	pmd_t *ret = pud_pgtable(*dir) + ((address >> PMD_SHIFT) & (PTRS_PER_PAGE - 1));
+	smp_rmb(); /* see above */
+	return ret;
+}
+#define pmd_offset pmd_offset
+
+/* Find an entry in the third-level page table.. */
+extern inline pte_t * pte_offset_kernel(pmd_t * dir, unsigned long address)
+{
+	pte_t *ret = (pte_t *) pmd_page_vaddr(*dir)
+		+ ((address >> PAGE_SHIFT) & (PTRS_PER_PAGE - 1));
+	smp_rmb(); /* see above */
+	return ret;
+}
+#define pte_offset_kernel pte_offset_kernel
+
+extern pgd_t swapper_pg_dir[1024];
+
+/*
+ * The Alpha doesn't have any external MMU info:  the kernel page
+ * tables contain all the necessary information.
+ */
+extern inline void update_mmu_cache(struct vm_area_struct * vma,
+	unsigned long address, pte_t *ptep)
+{
+}
+
+static inline void update_mmu_cache_range(struct vm_fault *vmf,
+		struct vm_area_struct *vma, unsigned long address,
+		pte_t *ptep, unsigned int nr)
+{
+}
+
+/*
+ * Encode/decode swap entries and swap PTEs. Swap PTEs are all PTEs that
+ * are !pte_none() && !pte_present().
+ *
+ * Format of swap PTEs:
+ *
+ *   6 6 6 6 5 5 5 5 5 5 5 5 5 5 4 4 4 4 4 4 4 4 4 4 3 3 3 3 3 3 3 3
+ *   3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2
+ *   <------------------- offset ------------------> E <--- type -->
+ *
+ *   3 3 2 2 2 2 2 2 2 2 2 2 1 1 1 1 1 1 1 1 1 1
+ *   1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0
+ *   <--------------------------- zeroes -------------------------->
+ *
+ *   E is the exclusive marker that is not stored in swap entries.
+ */
+extern inline pte_t mk_swap_pte(unsigned long type, unsigned long offset)
+{ pte_t pte; pte_val(pte) = ((type & 0x7f) << 32) | (offset << 40); return pte; }
+
+#define __swp_type(x)		(((x).val >> 32) & 0x7f)
+#define __swp_offset(x)		((x).val >> 40)
+#define __swp_entry(type, off)	((swp_entry_t) { pte_val(mk_swap_pte((type), (off))) })
+#define __pte_to_swp_entry(pte)	((swp_entry_t) { pte_val(pte) })
+#define __swp_entry_to_pte(x)	((pte_t) { (x).val })
+
+static inline int pte_swp_exclusive(pte_t pte)
+{
+	return pte_val(pte) & _PAGE_SWP_EXCLUSIVE;
+}
+
+static inline pte_t pte_swp_mkexclusive(pte_t pte)
+{
+	pte_val(pte) |= _PAGE_SWP_EXCLUSIVE;
+	return pte;
+}
+
+static inline pte_t pte_swp_clear_exclusive(pte_t pte)
+{
+	pte_val(pte) &= ~_PAGE_SWP_EXCLUSIVE;
+	return pte;
+}
+
+#define pte_ERROR(e) \
+	printk("%s:%d: bad pte %016lx.\n", __FILE__, __LINE__, pte_val(e))
+#define pmd_ERROR(e) \
+	printk("%s:%d: bad pmd %016lx.\n", __FILE__, __LINE__, pmd_val(e))
+#define pgd_ERROR(e) \
+	printk("%s:%d: bad pgd %016lx.\n", __FILE__, __LINE__, pgd_val(e))
+
+extern void paging_init(void);
+
+/* We have our own get_unmapped_area to cope with ADDR_LIMIT_32BIT.  */
+#define HAVE_ARCH_UNMAPPED_AREA
+
+#endif /* _ALPHA_PGTABLE_H */