cregit-Linux how code gets into the kernel

Release 4.14 arch/hexagon/include/asm/pgalloc.h

/*
 * Page table support for the Hexagon architecture
 *
 * Copyright (c) 2010-2011, The Linux Foundation. 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; }

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Richard Kuo68100.00%1100.00%
Total68100.00%1100.00%


static inline void pgd_free(struct mm_struct *mm, pgd_t *pgd) { free_page((unsigned long) pgd); }

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Richard Kuo25100.00%1100.00%
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static inline struct page *pte_alloc_one(struct mm_struct *mm, unsigned long address) { struct page *pte; pte = alloc_page(GFP_KERNEL | __GFP_ZERO); if (!pte) return NULL; if (!pgtable_page_ctor(pte)) { __free_page(pte); return NULL; } return pte; }

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Richard Kuo4472.13%150.00%
Kirill A. Shutemov1727.87%150.00%
Total61100.00%2100.00%

/* _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_ZERO; return (pte_t *) __get_free_page(flags); }

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Richard Kuo34100.00%1100.00%
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static inline void pte_free(struct mm_struct *mm, struct page *pte) { pgtable_page_dtor(pte); __free_page(pte); }

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Richard Kuo27100.00%1100.00%
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static inline void pte_free_kernel(struct mm_struct *mm, pte_t *pte) { free_page((unsigned long)pte); }

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Richard Kuo25100.00%1100.00%
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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)); }

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Richard Kuo43100.00%1100.00%
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/* * 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; }

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Richard Kuo143100.00%1100.00%
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#define __pte_free_tlb(tlb, pte, addr) \ do { \ pgtable_page_dtor((pte)); \ tlb_remove_page((tlb), (pte)); \ } while (0) #endif

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Richard Kuo45096.36%266.67%
Kirill A. Shutemov173.64%133.33%
Total467100.00%3100.00%
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