flush.c

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/*
 * Based on arch/arm/mm/flush.c
 *
 * Copyright (C) 1995-2002 Russell King
 * Copyright (C) 2012 ARM Ltd.
 *
 * 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.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <linux/export.h>
#include <linux/mm.h>
#include <linux/pagemap.h>

#include <asm/cacheflush.h>
#include <asm/cachetype.h>
#include <asm/tlbflush.h>

#include "mm.h"

void flush_cache_mm(struct mm_struct *mm)
{
}

void flush_cache_range(struct vm_area_struct *vma, unsigned long start,
               unsigned long end)
{
    if (vma->vm_flags & VM_EXEC)
        __flush_icache_all();
}

void flush_cache_page(struct vm_area_struct *vma, unsigned long user_addr,
              unsigned long pfn)
{
}

static void flush_ptrace_access(struct vm_area_struct *vma, struct page *page,
                unsigned long uaddr, void *kaddr,
                unsigned long len)
{
    if (vma->vm_flags & VM_EXEC) {
        unsigned long addr = (unsigned long)kaddr;
        if (icache_is_aliasing()) {
            __flush_dcache_area(kaddr, len);
            __flush_icache_all();
        } else {
            flush_icache_range(addr, addr + len);
        }
    }
}

/*
 * Copy user data from/to a page which is mapped into a different processes
 * address space.  Really, we want to allow our "user space" model to handle
 * this.
 *
 * Note that this code needs to run on the current CPU.
 */
void copy_to_user_page(struct vm_area_struct *vma, struct page *page,
               unsigned long uaddr, void *dst, const void *src,
               unsigned long len)
{
#ifdef CONFIG_SMP
    preempt_disable();
#endif
    memcpy(dst, src, len);
    flush_ptrace_access(vma, page, uaddr, dst, len);
#ifdef CONFIG_SMP
    preempt_enable();
#endif
}

void __flush_dcache_page(struct page *page)
{
    __flush_dcache_area(page_address(page), PAGE_SIZE);
}

void __sync_icache_dcache(pte_t pte, unsigned long addr)
{
    unsigned long pfn;
    struct page *page;

    pfn = pte_pfn(pte);
    if (!pfn_valid(pfn))
        return;

    page = pfn_to_page(pfn);
    if (!test_and_set_bit(PG_dcache_clean, &page->flags)) {
        __flush_dcache_page(page);
        __flush_icache_all();
    } else if (icache_is_aivivt()) {
        __flush_icache_all();
    }
}

/*
 * Ensure cache coherency between kernel mapping and userspace mapping of this
 * page.
 */
void flush_dcache_page(struct page *page)
{
    struct address_space *mapping;

    /*
     * The zero page is never written to, so never has any dirty cache
     * lines, and therefore never needs to be flushed.
     */
    if (page == ZERO_PAGE(0))
        return;

    mapping = page_mapping(page);
    if (mapping && mapping_mapped(mapping)) {
        __flush_dcache_page(page);
        __flush_icache_all();
        set_bit(PG_dcache_clean, &page->flags);
    } else {
        clear_bit(PG_dcache_clean, &page->flags);
    }
}
EXPORT_SYMBOL(flush_dcache_page);

/*
 * Additional functions defined in assembly.
 */
EXPORT_SYMBOL(flush_cache_all);
EXPORT_SYMBOL(flush_icache_range);