Hexagon: Add page table header files & etc.

Signed-off-by: Richard Kuo <rkuo@codeaurora.org>
Signed-off-by: Linas Vepstas <linas@codeaurora.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/hexagon/include/asm/fixmap.h

+/*
+ * Fixmap support for Hexagon - enough to support highmem features
+ *
+ * Copyright (c) 2010-2011, Code Aurora Forum. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+#ifndef _ASM_FIXMAP_H
+#define _ASM_FIXMAP_H
+
+/*
+ * A lot of the fixmap info is already in mem-layout.h
+ */
+#include <asm/mem-layout.h>
+
+/*
+ * Full fixmap support involves set_fixmap() functions, but
+ * these may not be needed if all we're after is an area for
+ * highmem kernel mappings.
+ */
+#define	__fix_to_virt(x)	(FIXADDR_TOP - ((x) << PAGE_SHIFT))
+#define	__virt_to_fix(x)	((FIXADDR_TOP - ((x)&PAGE_MASK)) >> PAGE_SHIFT)
+
+extern void __this_fixmap_does_not_exist(void);
+
+/**
+ * fix_to_virt -- "index to address" translation.
+ *
+ * If anyone tries to use the idx directly without translation,
+ * we catch the bug with a NULL-deference kernel oops. Illegal
+ * ranges of incoming indices are caught too.
+ */
+static inline unsigned long fix_to_virt(const unsigned int idx)
+{
+	/*
+	 * This branch gets completely eliminated after inlining,
+	 * except when someone tries to use fixaddr indices in an
+	 * illegal way. (such as mixing up address types or using
+	 * out-of-range indices).
+	 *
+	 * If it doesn't get removed, the linker will complain
+	 * loudly with a reasonably clear error message..
+	 */
+	if (idx >= __end_of_fixed_addresses)
+		__this_fixmap_does_not_exist();
+
+	return __fix_to_virt(idx);
+}
+
+static inline unsigned long virt_to_fix(const unsigned long vaddr)
+{
+	BUG_ON(vaddr >= FIXADDR_TOP || vaddr < FIXADDR_START);
+	return __virt_to_fix(vaddr);
+}
+
+#define kmap_get_fixmap_pte(vaddr) \
+	pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr), \
+				(vaddr)), (vaddr)), (vaddr))
+
+#endif

arch/hexagon/include/asm/mmu.h

+/*
+ * Copyright (c) 2010-2011, Code Aurora Forum. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+#ifndef _ASM_MMU_H
+#define _ASM_MMU_H
+
+#include <asm/vdso.h>
+
+/*
+ * Architecture-specific state for a mm_struct.
+ * For the Hexagon Virtual Machine, it can be a copy
+ * of the pointer to the page table base.
+ */
+struct mm_context {
+	unsigned long long generation;
+	unsigned long ptbase;
+	struct hexagon_vdso *vdso;
+};
+
+typedef struct mm_context mm_context_t;
+
+#endif

arch/hexagon/include/asm/mmu_context.h

+/*
+ * MM context support for the Hexagon architecture
+ *
+ * Copyright (c) 2010-2011, Code Aurora Forum. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+#ifndef _ASM_MMU_CONTEXT_H
+#define _ASM_MMU_CONTEXT_H
+
+#include <asm/setup.h>
+#include <asm/page.h>
+#include <asm/pgalloc.h>
+#include <asm/mem-layout.h>
+
+static inline void destroy_context(struct mm_struct *mm)
+{
+}
+
+/*
+ * VM port hides all TLB management, so "lazy TLB" isn't very
+ * meaningful.  Even for ports to architectures with visble TLBs,
+ * this is almost invariably a null function.
+ */
+static inline void enter_lazy_tlb(struct mm_struct *mm,
+	struct task_struct *tsk)
+{
+}
+
+/*
+ * Architecture-specific actions, if any, for memory map deactivation.
+ */
+static inline void deactivate_mm(struct task_struct *tsk,
+	struct mm_struct *mm)
+{
+}
+
+/**
+ * init_new_context - initialize context related info for new mm_struct instance
+ * @tsk: pointer to a task struct
+ * @mm: pointer to a new mm struct
+ */
+static inline int init_new_context(struct task_struct *tsk,
+					struct mm_struct *mm)
+{
+	/* mm->context is set up by pgd_alloc */
+	return 0;
+}
+
+/*
+ *  Switch active mm context
+ */
+static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
+				struct task_struct *tsk)
+{
+	int l1;
+
+	/*
+	 * For virtual machine, we have to update system map if it's been
+	 * touched.
+	 */
+	if (next->context.generation < prev->context.generation) {
+		for (l1 = MIN_KERNEL_SEG; l1 <= max_kernel_seg; l1++)
+			next->pgd[l1] = init_mm.pgd[l1];
+
+		next->context.generation = prev->context.generation;
+	}
+
+	__vmnewmap((void *)next->context.ptbase);
+}
+
+/*
+ *  Activate new memory map for task
+ */
+static inline void activate_mm(struct mm_struct *prev, struct mm_struct *next)
+{
+	unsigned long flags;
+
+	local_irq_save(flags);
+	switch_mm(prev, next, current_thread_info()->task);
+	local_irq_restore(flags);
+}
+
+/*  Generic hooks for arch_dup_mmap and arch_exit_mmap  */
+#include <asm-generic/mm_hooks.h>
+
+#endif

arch/hexagon/include/asm/page.h

+/*
+ * Page management definitions for the Hexagon architecture
+ *
+ * Copyright (c) 2010-2011, Code Aurora Forum. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+#ifndef _ASM_PAGE_H
+#define _ASM_PAGE_H
+
+#include <linux/const.h>
+
+/*  This is probably not the most graceful way to handle this.  */
+
+#ifdef CONFIG_PAGE_SIZE_4KB
+#define PAGE_SHIFT 12
+#define HEXAGON_L1_PTE_SIZE __HVM_PDE_S_4KB
+#endif
+
+#ifdef CONFIG_PAGE_SIZE_16KB
+#define PAGE_SHIFT 14
+#define HEXAGON_L1_PTE_SIZE __HVM_PDE_S_16KB
+#endif
+
+#ifdef CONFIG_PAGE_SIZE_64KB
+#define PAGE_SHIFT 16
+#define HEXAGON_L1_PTE_SIZE __HVM_PDE_S_64KB
+#endif
+
+#ifdef CONFIG_PAGE_SIZE_256KB
+#define PAGE_SHIFT 18
+#define HEXAGON_L1_PTE_SIZE __HVM_PDE_S_256KB
+#endif
+
+#ifdef CONFIG_PAGE_SIZE_1MB
+#define PAGE_SHIFT 20
+#define HEXAGON_L1_PTE_SIZE __HVM_PDE_S_1MB
+#endif
+
+/*
+ *  These should be defined in hugetlb.h, but apparently not.
+ *  "Huge" for us should be 4MB or 16MB, which are both represented
+ *  in L1 PTE's.  Right now, it's set up for 4MB.
+ */
+#ifdef CONFIG_HUGETLB_PAGE
+#define HPAGE_SHIFT 22
+#define HPAGE_SIZE (1UL << HPAGE_SHIFT)
+#define HPAGE_MASK (~(HPAGE_SIZE-1))
+#define HUGETLB_PAGE_ORDER (HPAGE_SHIFT-PAGE_SHIFT)
+#define HVM_HUGEPAGE_SIZE 0x5
+#endif
+
+#define PAGE_SIZE  (1UL << PAGE_SHIFT)
+#define PAGE_MASK  (~((1 << PAGE_SHIFT) - 1))
+
+#ifdef __KERNEL__
+#ifndef __ASSEMBLY__
+
+/*
+ * This is for PFN_DOWN, which mm.h needs.  Seems the right place to pull it in.
+ */
+#include <linux/pfn.h>
+
+/*
+ * We implement a two-level architecture-specific page table structure.
+ * Null intermediate page table level (pmd, pud) definitions will come from
+ * asm-generic/pagetable-nopmd.h and asm-generic/pagetable-nopud.h
+ */
+typedef struct { unsigned long pte; } pte_t;
+typedef struct { unsigned long pgd; } pgd_t;
+typedef struct { unsigned long pgprot; } pgprot_t;
+typedef struct page *pgtable_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) })
+
+/*
+ * We need a __pa and a __va routine for kernel space.
+ * MIPS says they're only used during mem_init.
+ * also, check if we need a PHYS_OFFSET.
+ */
+#define __pa(x) ((unsigned long)(x) - PAGE_OFFSET)
+#define __va(x) ((void *)((unsigned long)(x) + PAGE_OFFSET))
+
+/* The "page frame" descriptor is defined in linux/mm.h */
+struct page;
+
+/* Returns page frame descriptor for virtual address. */
+#define virt_to_page(kaddr) pfn_to_page(PFN_DOWN(__pa(kaddr)))
+
+/* Default vm area behavior is non-executable.  */
+#define VM_DATA_DEFAULT_FLAGS (VM_READ | VM_WRITE | \
+				VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC)
+
+#define pfn_valid(pfn) ((pfn) < max_mapnr)
+#define virt_addr_valid(kaddr) pfn_valid(__pa(kaddr) >> PAGE_SHIFT)
+
+/*  Need to not use a define for linesize; may move this to another file.  */
+static inline void clear_page(void *page)
+{
+	/*  This can only be done on pages with L1 WB cache */
+	asm volatile(
+		"	loop0(1f,%1);\n"
+		"1:	{ dczeroa(%0);\n"
+		"	  %0 = add(%0,#32); }:endloop0\n"
+		: "+r" (page)
+		: "r" (PAGE_SIZE/32)
+		: "lc0", "sa0", "memory"
+	);
+}
+
+#define copy_page(to, from)	memcpy((to), (from), PAGE_SIZE)
+
+/*
+ * Under assumption that kernel always "sees" user map...
+ */
+#define clear_user_page(page, vaddr, pg)	clear_page(page)
+#define copy_user_page(to, from, vaddr, pg)	copy_page(to, from)
+
+/*
+ * page_to_phys - convert page to physical address
+ * @page - pointer to page entry in mem_map
+ */
+#define page_to_phys(page)      (page_to_pfn(page) << PAGE_SHIFT)
+
+/*
+ * For port to Hexagon Virtual Machine, MAYBE we check for attempts
+ * to reference reserved HVM space, but in any case, the VM will be
+ * protected.
+ */
+#define kern_addr_valid(addr)   (1)
+
+#include <asm-generic/memory_model.h>
+/* XXX Todo: implement assembly-optimized version of getorder. */
+#include <asm-generic/getorder.h>
+
+#endif /* ifdef __ASSEMBLY__ */
+#endif /* ifdef __KERNEL__ */
+
+#endif

arch/hexagon/include/asm/pgalloc.h

+/*
+ * Page table support for the Hexagon architecture
+ *
+ * Copyright (c) 2010-2011, Code Aurora Forum. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+#ifndef _ASM_PGALLOC_H
+#define _ASM_PGALLOC_H
+
+#include <asm/mem-layout.h>
+#include <asm/atomic.h>
+
+#define check_pgt_cache() do {} while (0)
+
+extern unsigned long long kmap_generation;
+
+/*
+ * Page table creation interface
+ */
+static inline pgd_t *pgd_alloc(struct mm_struct *mm)
+{
+	pgd_t *pgd;
+
+	pgd = (pgd_t *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
+
+	/*
+	 * There may be better ways to do this, but to ensure
+	 * that new address spaces always contain the kernel
+	 * base mapping, and to ensure that the user area is
+	 * initially marked invalid, initialize the new map
+	 * map with a copy of the kernel's persistent map.
+	 */
+
+	memcpy(pgd, swapper_pg_dir, PTRS_PER_PGD*sizeof(pgd_t *));
+	mm->context.generation = kmap_generation;
+
+	/* Physical version is what is passed to virtual machine on switch */
+	mm->context.ptbase = __pa(pgd);
+
+	return pgd;
+}
+
+static inline void pgd_free(struct mm_struct *mm, pgd_t *pgd)
+{
+	free_page((unsigned long) pgd);
+}
+
+static inline struct page *pte_alloc_one(struct mm_struct *mm,
+					 unsigned long address)
+{
+	struct page *pte;
+
+	pte = alloc_page(GFP_KERNEL | __GFP_REPEAT | __GFP_ZERO);
+
+	if (pte)
+		pgtable_page_ctor(pte);
+
+	return pte;
+}
+
+/* _kernel variant gets to use a different allocator */
+static inline pte_t *pte_alloc_one_kernel(struct mm_struct *mm,
+					  unsigned long address)
+{
+	gfp_t flags =  GFP_KERNEL | __GFP_REPEAT | __GFP_ZERO;
+	return (pte_t *) __get_free_page(flags);
+}
+
+static inline void pte_free(struct mm_struct *mm, struct page *pte)
+{
+	pgtable_page_dtor(pte);
+	__free_page(pte);
+}
+
+static inline void pte_free_kernel(struct mm_struct *mm, pte_t *pte)
+{
+	free_page((unsigned long)pte);
+}
+
+static inline void pmd_populate(struct mm_struct *mm, pmd_t *pmd,
+				pgtable_t pte)
+{
+	/*
+	 * Conveniently, zero in 3 LSB means indirect 4K page table.
+	 * Not so convenient when you're trying to vary the page size.
+	 */
+	set_pmd(pmd, __pmd(((unsigned long)page_to_pfn(pte) << PAGE_SHIFT) |
+		HEXAGON_L1_PTE_SIZE));
+}
+
+/*
+ * Other architectures seem to have ways of making all processes
+ * share the same pmd's for their kernel mappings, but the v0.3
+ * Hexagon VM spec has a "monolithic" L1 table for user and kernel
+ * segments.  We track "generations" of the kernel map to minimize
+ * overhead, and update the "slave" copies of the kernel mappings
+ * as part of switch_mm.  However, we still need to update the
+ * kernel map of the active thread who's calling pmd_populate_kernel...
+ */
+static inline void pmd_populate_kernel(struct mm_struct *mm, pmd_t *pmd,
+				       pte_t *pte)
+{
+	extern spinlock_t kmap_gen_lock;
+	pmd_t *ppmd;
+	int pmdindex;
+
+	spin_lock(&kmap_gen_lock);
+	kmap_generation++;
+	mm->context.generation = kmap_generation;
+	current->active_mm->context.generation = kmap_generation;
+	spin_unlock(&kmap_gen_lock);
+
+	set_pmd(pmd, __pmd(((unsigned long)__pa(pte)) | HEXAGON_L1_PTE_SIZE));
+
+	/*
+	 * Now the "slave" copy of the current thread.
+	 * This is pointer arithmetic, not byte addresses!
+	 */
+	pmdindex = (pgd_t *)pmd - mm->pgd;
+	ppmd = (pmd_t *)current->active_mm->pgd + pmdindex;
+	set_pmd(ppmd, __pmd(((unsigned long)__pa(pte)) | HEXAGON_L1_PTE_SIZE));
+	if (pmdindex > max_kernel_seg)
+		max_kernel_seg = pmdindex;
+}
+
+#define __pte_free_tlb(tlb, pte, addr)		\
+do {						\
+	pgtable_page_dtor((pte));		\
+	tlb_remove_page((tlb), (pte));		\
+} while (0)
+
+#endif

arch/hexagon/mm/pgalloc.c

+/*
+ * Copyright (c) 2010-2011, Code Aurora Forum. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+#include <linux/init.h>
+
+void __init pgtable_cache_init(void)
+{
+}