arch/arm64/mm/hugetlbpage.c - linux/kernel/git/viro/vfs - Git at Google

 /*
  * arch/arm64/mm/hugetlbpage.c
  *
  * Copyright (C) 2013 Linaro Ltd.
  *
  * Based on arch/x86/mm/hugetlbpage.c.
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License 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.
  */

 #include <linux/init.h>
 #include <linux/fs.h>
 #include <linux/mm.h>
 #include <linux/hugetlb.h>
 #include <linux/pagemap.h>
 #include <linux/err.h>
 #include <linux/sysctl.h>
 #include <asm/mman.h>
 #include <asm/tlb.h>
 #include <asm/tlbflush.h>
 #include <asm/pgalloc.h>

 int pmd_huge(pmd_t pmd)
 {
 	return pmd_val(pmd) && !(pmd_val(pmd) & PMD_TABLE_BIT);
 }

 int pud_huge(pud_t pud)
 {
 #ifndef __PAGETABLE_PMD_FOLDED
 	return pud_val(pud) && !(pud_val(pud) & PUD_TABLE_BIT);
 #else
 	return 0;
 #endif
 }

 static int find_num_contig(struct mm_struct *mm, unsigned long addr,
 			   pte_t *ptep, pte_t pte, size_t *pgsize)
 {
 	pgd_t *pgd = pgd_offset(mm, addr);
 	pud_t *pud;
 	pmd_t *pmd;

 	*pgsize = PAGE_SIZE;
 	if (!pte_cont(pte))
 		return 1;
 	pud = pud_offset(pgd, addr);
 	pmd = pmd_offset(pud, addr);
 	if ((pte_t *)pmd == ptep) {
 		*pgsize = PMD_SIZE;
 		return CONT_PMDS;
 	}
 	return CONT_PTES;
 }

 void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
 			    pte_t *ptep, pte_t pte)
 {
 	size_t pgsize;
 	int i;
 	int ncontig = find_num_contig(mm, addr, ptep, pte, &pgsize);
 	unsigned long pfn;
 	pgprot_t hugeprot;

 	if (ncontig == 1) {
 		set_pte_at(mm, addr, ptep, pte);
 		return;
 	}

 	pfn = pte_pfn(pte);
 	hugeprot = __pgprot(pte_val(pfn_pte(pfn, __pgprot(0))) ^ pte_val(pte));
 	for (i = 0; i < ncontig; i++) {
 		pr_debug("%s: set pte %p to 0x%llx\n", __func__, ptep,
 			 pte_val(pfn_pte(pfn, hugeprot)));
 		set_pte_at(mm, addr, ptep, pfn_pte(pfn, hugeprot));
 		ptep++;
 		pfn += pgsize >> PAGE_SHIFT;
 		addr += pgsize;
 	}
 }

 pte_t *huge_pte_alloc(struct mm_struct *mm,
 		      unsigned long addr, unsigned long sz)
 {
 	pgd_t *pgd;
 	pud_t *pud;
 	pte_t *pte = NULL;

 	pr_debug("%s: addr:0x%lx sz:0x%lx\n", __func__, addr, sz);
 	pgd = pgd_offset(mm, addr);
 	pud = pud_alloc(mm, pgd, addr);
 	if (!pud)
 		return NULL;

 	if (sz == PUD_SIZE) {
 		pte = (pte_t *)pud;
 	} else if (sz == (PAGE_SIZE * CONT_PTES)) {
 		pmd_t *pmd = pmd_alloc(mm, pud, addr);

 		WARN_ON(addr & (sz - 1));
 		/*
 		 * Note that if this code were ever ported to the
 		 * 32-bit arm platform then it will cause trouble in
 		 * the case where CONFIG_HIGHPTE is set, since there
 		 * will be no pte_unmap() to correspond with this
 		 * pte_alloc_map().
 		 */
 		pte = pte_alloc_map(mm, pmd, addr);
 	} else if (sz == PMD_SIZE) {
 		if (IS_ENABLED(CONFIG_ARCH_WANT_HUGE_PMD_SHARE) &&
 		    pud_none(*pud))
 			pte = huge_pmd_share(mm, addr, pud);
 		else
 			pte = (pte_t *)pmd_alloc(mm, pud, addr);
 	} else if (sz == (PMD_SIZE * CONT_PMDS)) {
 		pmd_t *pmd;

 		pmd = pmd_alloc(mm, pud, addr);
 		WARN_ON(addr & (sz - 1));
 		return (pte_t *)pmd;
 	}

 	pr_debug("%s: addr:0x%lx sz:0x%lx ret pte=%p/0x%llx\n", __func__, addr,
 	       sz, pte, pte_val(*pte));
 	return pte;
 }

 pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
 {
 	pgd_t *pgd;
 	pud_t *pud;
 	pmd_t *pmd = NULL;
 	pte_t *pte = NULL;

 	pgd = pgd_offset(mm, addr);
 	pr_debug("%s: addr:0x%lx pgd:%p\n", __func__, addr, pgd);
 	if (!pgd_present(*pgd))
 		return NULL;
 	pud = pud_offset(pgd, addr);
 	if (!pud_present(*pud))
 		return NULL;

 	if (pud_huge(*pud))
 		return (pte_t *)pud;
 	pmd = pmd_offset(pud, addr);
 	if (!pmd_present(*pmd))
 		return NULL;

 	if (pte_cont(pmd_pte(*pmd))) {
 		pmd = pmd_offset(
 			pud, (addr & CONT_PMD_MASK));
 		return (pte_t *)pmd;
 	}
 	if (pmd_huge(*pmd))
 		return (pte_t *)pmd;
 	pte = pte_offset_kernel(pmd, addr);
 	if (pte_present(*pte) && pte_cont(*pte)) {
 		pte = pte_offset_kernel(
 			pmd, (addr & CONT_PTE_MASK));
 		return pte;
 	}
 	return NULL;
 }

 pte_t arch_make_huge_pte(pte_t entry, struct vm_area_struct *vma,
 			 struct page *page, int writable)
 {
 	size_t pagesize = huge_page_size(hstate_vma(vma));

 	if (pagesize == CONT_PTE_SIZE) {
 		entry = pte_mkcont(entry);
 	} else if (pagesize == CONT_PMD_SIZE) {
 		entry = pmd_pte(pmd_mkcont(pte_pmd(entry)));
 	} else if (pagesize != PUD_SIZE && pagesize != PMD_SIZE) {
 		pr_warn("%s: unrecognized huge page size 0x%lx\n",
 			__func__, pagesize);
 	}
 	return entry;
 }

 pte_t huge_ptep_get_and_clear(struct mm_struct *mm,
 			      unsigned long addr, pte_t *ptep)
 {
 	pte_t pte;

 	if (pte_cont(*ptep)) {
 		int ncontig, i;
 		size_t pgsize;
 		pte_t *cpte;
 		bool is_dirty = false;

 		cpte = huge_pte_offset(mm, addr);
 		ncontig = find_num_contig(mm, addr, cpte, *cpte, &pgsize);
 		/* save the 1st pte to return */
 		pte = ptep_get_and_clear(mm, addr, cpte);
 		for (i = 1, addr += pgsize; i < ncontig; ++i, addr += pgsize) {
 			/*
 			 * If HW_AFDBM is enabled, then the HW could
 			 * turn on the dirty bit for any of the page
 			 * in the set, so check them all.
 			 */
 			++cpte;
 			if (pte_dirty(ptep_get_and_clear(mm, addr, cpte)))
 				is_dirty = true;
 		}
 		if (is_dirty)
 			return pte_mkdirty(pte);
 		else
 			return pte;
 	} else {
 		return ptep_get_and_clear(mm, addr, ptep);
 	}
 }

 int huge_ptep_set_access_flags(struct vm_area_struct *vma,
 			       unsigned long addr, pte_t *ptep,
 			       pte_t pte, int dirty)
 {
 	pte_t *cpte;

 	if (pte_cont(pte)) {
 		int ncontig, i, changed = 0;
 		size_t pgsize = 0;
 		unsigned long pfn = pte_pfn(pte);
 		/* Select all bits except the pfn */
 		pgprot_t hugeprot =
 			__pgprot(pte_val(pfn_pte(pfn, __pgprot(0))) ^
 				 pte_val(pte));

 		cpte = huge_pte_offset(vma->vm_mm, addr);
 		pfn = pte_pfn(*cpte);
 		ncontig = find_num_contig(vma->vm_mm, addr, cpte,
 					  *cpte, &pgsize);
 		for (i = 0; i < ncontig; ++i, ++cpte, addr += pgsize) {
 			changed |= ptep_set_access_flags(vma, addr, cpte,
 							pfn_pte(pfn,
 								hugeprot),
 							dirty);
 			pfn += pgsize >> PAGE_SHIFT;
 		}
 		return changed;
 	} else {
 		return ptep_set_access_flags(vma, addr, ptep, pte, dirty);
 	}
 }

 void huge_ptep_set_wrprotect(struct mm_struct *mm,
 			     unsigned long addr, pte_t *ptep)
 {
 	if (pte_cont(*ptep)) {
 		int ncontig, i;
 		pte_t *cpte;
 		size_t pgsize = 0;

 		cpte = huge_pte_offset(mm, addr);
 		ncontig = find_num_contig(mm, addr, cpte, *cpte, &pgsize);
 		for (i = 0; i < ncontig; ++i, ++cpte, addr += pgsize)
 			ptep_set_wrprotect(mm, addr, cpte);
 	} else {
 		ptep_set_wrprotect(mm, addr, ptep);
 	}
 }

 void huge_ptep_clear_flush(struct vm_area_struct *vma,
 			   unsigned long addr, pte_t *ptep)
 {
 	if (pte_cont(*ptep)) {
 		int ncontig, i;
 		pte_t *cpte;
 		size_t pgsize = 0;

 		cpte = huge_pte_offset(vma->vm_mm, addr);
 		ncontig = find_num_contig(vma->vm_mm, addr, cpte,
 					  *cpte, &pgsize);
 		for (i = 0; i < ncontig; ++i, ++cpte, addr += pgsize)
 			ptep_clear_flush(vma, addr, cpte);
 	} else {
 		ptep_clear_flush(vma, addr, ptep);
 	}
 }

 static __init int setup_hugepagesz(char *opt)
 {
 	unsigned long ps = memparse(opt, &opt);

 	if (ps == PMD_SIZE) {
 		hugetlb_add_hstate(PMD_SHIFT - PAGE_SHIFT);
 	} else if (ps == PUD_SIZE) {
 		hugetlb_add_hstate(PUD_SHIFT - PAGE_SHIFT);
 	} else if (ps == (PAGE_SIZE * CONT_PTES)) {
 		hugetlb_add_hstate(CONT_PTE_SHIFT);
 	} else if (ps == (PMD_SIZE * CONT_PMDS)) {
 		hugetlb_add_hstate((PMD_SHIFT + CONT_PMD_SHIFT) - PAGE_SHIFT);
 	} else {
 		hugetlb_bad_size();
 		pr_err("hugepagesz: Unsupported page size %lu K\n", ps >> 10);
 		return 0;
 	}
 	return 1;
 }
 __setup("hugepagesz=", setup_hugepagesz);

 #ifdef CONFIG_ARM64_64K_PAGES
 static __init int add_default_hugepagesz(void)
 {
 	if (size_to_hstate(CONT_PTES * PAGE_SIZE) == NULL)
 		hugetlb_add_hstate(CONT_PTE_SHIFT);
 	return 0;
 }
 arch_initcall(add_default_hugepagesz);
 #endif
	/*
	* arch/arm64/mm/hugetlbpage.c
	*
	* Copyright (C) 2013 Linaro Ltd.
	*
	* Based on arch/x86/mm/hugetlbpage.c.
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License 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.
	*/

	#include <linux/init.h>
	#include <linux/fs.h>
	#include <linux/mm.h>
	#include <linux/hugetlb.h>
	#include <linux/pagemap.h>
	#include <linux/err.h>
	#include <linux/sysctl.h>
	#include <asm/mman.h>
	#include <asm/tlb.h>
	#include <asm/tlbflush.h>
	#include <asm/pgalloc.h>

	int pmd_huge(pmd_t pmd)
	{
	return pmd_val(pmd) && !(pmd_val(pmd) & PMD_TABLE_BIT);
	}

	int pud_huge(pud_t pud)
	{
	#ifndef __PAGETABLE_PMD_FOLDED
	return pud_val(pud) && !(pud_val(pud) & PUD_TABLE_BIT);
	#else
	return 0;
	#endif
	}

	static int find_num_contig(struct mm_struct *mm, unsigned long addr,
	pte_t ptep, pte_t pte, size_t pgsize)
	{
	pgd_t *pgd = pgd_offset(mm, addr);
	pud_t *pud;
	pmd_t *pmd;

	*pgsize = PAGE_SIZE;
	if (!pte_cont(pte))
	return 1;
	pud = pud_offset(pgd, addr);
	pmd = pmd_offset(pud, addr);
	if ((pte_t *)pmd == ptep) {
	*pgsize = PMD_SIZE;
	return CONT_PMDS;
	}
	return CONT_PTES;
	}

	void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
	pte_t *ptep, pte_t pte)
	{
	size_t pgsize;
	int i;
	int ncontig = find_num_contig(mm, addr, ptep, pte, &pgsize);
	unsigned long pfn;
	pgprot_t hugeprot;

	if (ncontig == 1) {
	set_pte_at(mm, addr, ptep, pte);
	return;
	}

	pfn = pte_pfn(pte);
	hugeprot = __pgprot(pte_val(pfn_pte(pfn, __pgprot(0))) ^ pte_val(pte));
	for (i = 0; i < ncontig; i++) {
	pr_debug("%s: set pte %p to 0x%llx\n", __func__, ptep,
	pte_val(pfn_pte(pfn, hugeprot)));
	set_pte_at(mm, addr, ptep, pfn_pte(pfn, hugeprot));
	ptep++;
	pfn += pgsize >> PAGE_SHIFT;
	addr += pgsize;
	}
	}

	pte_t huge_pte_alloc(struct mm_struct mm,
	unsigned long addr, unsigned long sz)
	{
	pgd_t *pgd;
	pud_t *pud;
	pte_t *pte = NULL;

	pr_debug("%s: addr:0x%lx sz:0x%lx\n", __func__, addr, sz);
	pgd = pgd_offset(mm, addr);
	pud = pud_alloc(mm, pgd, addr);
	if (!pud)
	return NULL;

	if (sz == PUD_SIZE) {
	pte = (pte_t *)pud;
	} else if (sz == (PAGE_SIZE * CONT_PTES)) {
	pmd_t *pmd = pmd_alloc(mm, pud, addr);

	WARN_ON(addr & (sz - 1));
	/*
	* Note that if this code were ever ported to the
	* 32-bit arm platform then it will cause trouble in
	* the case where CONFIG_HIGHPTE is set, since there
	* will be no pte_unmap() to correspond with this
	* pte_alloc_map().
	*/
	pte = pte_alloc_map(mm, pmd, addr);
	} else if (sz == PMD_SIZE) {
	if (IS_ENABLED(CONFIG_ARCH_WANT_HUGE_PMD_SHARE) &&
	pud_none(*pud))
	pte = huge_pmd_share(mm, addr, pud);
	else
	pte = (pte_t *)pmd_alloc(mm, pud, addr);
	} else if (sz == (PMD_SIZE * CONT_PMDS)) {
	pmd_t *pmd;

	pmd = pmd_alloc(mm, pud, addr);
	WARN_ON(addr & (sz - 1));
	return (pte_t *)pmd;
	}

	pr_debug("%s: addr:0x%lx sz:0x%lx ret pte=%p/0x%llx\n", __func__, addr,
	sz, pte, pte_val(*pte));
	return pte;
	}

	pte_t huge_pte_offset(struct mm_struct mm, unsigned long addr)
	{
	pgd_t *pgd;
	pud_t *pud;
	pmd_t *pmd = NULL;
	pte_t *pte = NULL;

	pgd = pgd_offset(mm, addr);
	pr_debug("%s: addr:0x%lx pgd:%p\n", __func__, addr, pgd);
	if (!pgd_present(*pgd))
	return NULL;
	pud = pud_offset(pgd, addr);
	if (!pud_present(*pud))
	return NULL;

	if (pud_huge(*pud))
	return (pte_t *)pud;
	pmd = pmd_offset(pud, addr);
	if (!pmd_present(*pmd))
	return NULL;

	if (pte_cont(pmd_pte(*pmd))) {
	pmd = pmd_offset(
	pud, (addr & CONT_PMD_MASK));
	return (pte_t *)pmd;
	}
	if (pmd_huge(*pmd))
	return (pte_t *)pmd;
	pte = pte_offset_kernel(pmd, addr);
	if (pte_present(pte) && pte_cont(pte)) {
	pte = pte_offset_kernel(
	pmd, (addr & CONT_PTE_MASK));
	return pte;
	}
	return NULL;
	}

	pte_t arch_make_huge_pte(pte_t entry, struct vm_area_struct *vma,
	struct page *page, int writable)
	{
	size_t pagesize = huge_page_size(hstate_vma(vma));

	if (pagesize == CONT_PTE_SIZE) {
	entry = pte_mkcont(entry);
	} else if (pagesize == CONT_PMD_SIZE) {
	entry = pmd_pte(pmd_mkcont(pte_pmd(entry)));
	} else if (pagesize != PUD_SIZE && pagesize != PMD_SIZE) {
	pr_warn("%s: unrecognized huge page size 0x%lx\n",
	__func__, pagesize);
	}
	return entry;
	}

	pte_t huge_ptep_get_and_clear(struct mm_struct *mm,
	unsigned long addr, pte_t *ptep)
	{
	pte_t pte;

	if (pte_cont(*ptep)) {
	int ncontig, i;
	size_t pgsize;
	pte_t *cpte;
	bool is_dirty = false;

	cpte = huge_pte_offset(mm, addr);
	ncontig = find_num_contig(mm, addr, cpte, *cpte, &pgsize);
	/* save the 1st pte to return */
	pte = ptep_get_and_clear(mm, addr, cpte);
	for (i = 1, addr += pgsize; i < ncontig; ++i, addr += pgsize) {
	/*
	* If HW_AFDBM is enabled, then the HW could
	* turn on the dirty bit for any of the page
	* in the set, so check them all.
	*/
	++cpte;
	if (pte_dirty(ptep_get_and_clear(mm, addr, cpte)))
	is_dirty = true;
	}
	if (is_dirty)
	return pte_mkdirty(pte);
	else
	return pte;
	} else {
	return ptep_get_and_clear(mm, addr, ptep);
	}
	}

	int huge_ptep_set_access_flags(struct vm_area_struct *vma,
	unsigned long addr, pte_t *ptep,
	pte_t pte, int dirty)
	{
	pte_t *cpte;

	if (pte_cont(pte)) {
	int ncontig, i, changed = 0;
	size_t pgsize = 0;
	unsigned long pfn = pte_pfn(pte);
	/* Select all bits except the pfn */
	pgprot_t hugeprot =
	__pgprot(pte_val(pfn_pte(pfn, __pgprot(0))) ^
	pte_val(pte));

	cpte = huge_pte_offset(vma->vm_mm, addr);
	pfn = pte_pfn(*cpte);
	ncontig = find_num_contig(vma->vm_mm, addr, cpte,
	*cpte, &pgsize);
	for (i = 0; i < ncontig; ++i, ++cpte, addr += pgsize) {
	changed \|= ptep_set_access_flags(vma, addr, cpte,
	pfn_pte(pfn,
	hugeprot),
	dirty);
	pfn += pgsize >> PAGE_SHIFT;
	}
	return changed;
	} else {
	return ptep_set_access_flags(vma, addr, ptep, pte, dirty);
	}
	}

	void huge_ptep_set_wrprotect(struct mm_struct *mm,
	unsigned long addr, pte_t *ptep)
	{
	if (pte_cont(*ptep)) {
	int ncontig, i;
	pte_t *cpte;
	size_t pgsize = 0;

	cpte = huge_pte_offset(mm, addr);
	ncontig = find_num_contig(mm, addr, cpte, *cpte, &pgsize);
	for (i = 0; i < ncontig; ++i, ++cpte, addr += pgsize)
	ptep_set_wrprotect(mm, addr, cpte);
	} else {
	ptep_set_wrprotect(mm, addr, ptep);
	}
	}

	void huge_ptep_clear_flush(struct vm_area_struct *vma,
	unsigned long addr, pte_t *ptep)
	{
	if (pte_cont(*ptep)) {
	int ncontig, i;
	pte_t *cpte;
	size_t pgsize = 0;

	cpte = huge_pte_offset(vma->vm_mm, addr);
	ncontig = find_num_contig(vma->vm_mm, addr, cpte,
	*cpte, &pgsize);
	for (i = 0; i < ncontig; ++i, ++cpte, addr += pgsize)
	ptep_clear_flush(vma, addr, cpte);
	} else {
	ptep_clear_flush(vma, addr, ptep);
	}
	}

	static __init int setup_hugepagesz(char *opt)
	{
	unsigned long ps = memparse(opt, &opt);

	if (ps == PMD_SIZE) {
	hugetlb_add_hstate(PMD_SHIFT - PAGE_SHIFT);
	} else if (ps == PUD_SIZE) {
	hugetlb_add_hstate(PUD_SHIFT - PAGE_SHIFT);
	} else if (ps == (PAGE_SIZE * CONT_PTES)) {
	hugetlb_add_hstate(CONT_PTE_SHIFT);
	} else if (ps == (PMD_SIZE * CONT_PMDS)) {
	hugetlb_add_hstate((PMD_SHIFT + CONT_PMD_SHIFT) - PAGE_SHIFT);
	} else {
	hugetlb_bad_size();
	pr_err("hugepagesz: Unsupported page size %lu K\n", ps >> 10);
	return 0;
	}
	return 1;
	}
	__setup("hugepagesz=", setup_hugepagesz);

	#ifdef CONFIG_ARM64_64K_PAGES
	static __init int add_default_hugepagesz(void)
	{
	if (size_to_hstate(CONT_PTES * PAGE_SIZE) == NULL)
	hugetlb_add_hstate(CONT_PTE_SHIFT);
	return 0;
	}
	arch_initcall(add_default_hugepagesz);
	#endif