cache.c

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/*
 * Copyright (C) 2004-2006 Atmel Corporation
 *
 * 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.
 */

#include <linux/highmem.h>
#include <linux/unistd.h>

#include <asm/cacheflush.h>
#include <asm/cachectl.h>
#include <asm/processor.h>
#include <asm/uaccess.h>
#include <asm/syscalls.h>

/*
 * If you attempt to flush anything more than this, you need superuser
 * privileges.  The value is completely arbitrary.
 */
#define CACHEFLUSH_MAX_LEN  1024

void invalidate_dcache_region(void *start, size_t size)
{
    unsigned long v, begin, end, linesz, mask;

    linesz = boot_cpu_data.dcache.linesz;
    mask = linesz - 1;

    /* when first and/or last cachelines are shared, flush them
     * instead of invalidating ... never discard valid data!
     */
    begin = (unsigned long)start;
    end = begin + size;

    if (begin & mask) {
        flush_dcache_line(start);
        begin += linesz;
    }
    if (end & mask) {
        flush_dcache_line((void *)end);
        end &= ~mask;
    }

    /* remaining cachelines only need invalidation */
    for (v = begin; v < end; v += linesz)
        invalidate_dcache_line((void *)v);
    flush_write_buffer();
}

void clean_dcache_region(void *start, size_t size)
{
    unsigned long v, begin, end, linesz;

    linesz = boot_cpu_data.dcache.linesz;
    begin = (unsigned long)start & ~(linesz - 1);
    end = ((unsigned long)start + size + linesz - 1) & ~(linesz - 1);

    for (v = begin; v < end; v += linesz)
        clean_dcache_line((void *)v);
    flush_write_buffer();
}

void flush_dcache_region(void *start, size_t size)
{
    unsigned long v, begin, end, linesz;

    linesz = boot_cpu_data.dcache.linesz;
    begin = (unsigned long)start & ~(linesz - 1);
    end = ((unsigned long)start + size + linesz - 1) & ~(linesz - 1);

    for (v = begin; v < end; v += linesz)
        flush_dcache_line((void *)v);
    flush_write_buffer();
}

void invalidate_icache_region(void *start, size_t size)
{
    unsigned long v, begin, end, linesz;

    linesz = boot_cpu_data.icache.linesz;
    begin = (unsigned long)start & ~(linesz - 1);
    end = ((unsigned long)start + size + linesz - 1) & ~(linesz - 1);

    for (v = begin; v < end; v += linesz)
        invalidate_icache_line((void *)v);
}

static inline void __flush_icache_range(unsigned long start, unsigned long end)
{
    unsigned long v, linesz;

    linesz = boot_cpu_data.dcache.linesz;
    for (v = start; v < end; v += linesz) {
        clean_dcache_line((void *)v);
        invalidate_icache_line((void *)v);
    }

    flush_write_buffer();
}

/*
 * This one is called after a module has been loaded.
 */
void flush_icache_range(unsigned long start, unsigned long end)
{
    unsigned long linesz;

    linesz = boot_cpu_data.dcache.linesz;
    __flush_icache_range(start & ~(linesz - 1),
                 (end + linesz - 1) & ~(linesz - 1));
}

/*
 * This one is called from __do_fault() and do_swap_page().
 */
void flush_icache_page(struct vm_area_struct *vma, struct page *page)
{
    if (vma->vm_flags & VM_EXEC) {
        void *v = page_address(page);
        __flush_icache_range((unsigned long)v, (unsigned long)v + PAGE_SIZE);
    }
}

asmlinkage int sys_cacheflush(int operation, void __user *addr, size_t len)
{
    int ret;

    if (len > CACHEFLUSH_MAX_LEN) {
        ret = -EPERM;
        if (!capable(CAP_SYS_ADMIN))
            goto out;
    }

    ret = -EFAULT;
    if (!access_ok(VERIFY_WRITE, addr, len))
        goto out;

    switch (operation) {
    case CACHE_IFLUSH:
        flush_icache_range((unsigned long)addr,
                   (unsigned long)addr + len);
        ret = 0;
        break;
    default:
        ret = -EINVAL;
    }

out:
    return ret;
}

void copy_to_user_page(struct vm_area_struct *vma, struct page *page,
        unsigned long vaddr, void *dst, const void *src,
        unsigned long len)
{
    memcpy(dst, src, len);
    if (vma->vm_flags & VM_EXEC)
        flush_icache_range((unsigned long)dst,
                (unsigned long)dst + len);
}