/*
 * Copyright 2002-2019 Intel Corporation.
 * 
 * This software is provided to you as Sample Source Code as defined in the accompanying
 * End User License Agreement for the Intel(R) Software Development Products ("Agreement")
 * section 1.L.
 * 
 * This software and the related documents are provided as is, with no express or implied
 * warranties, other than those that are expressly stated in the License.
 */

/*
 * See "swizzleapp.c" for a description of this test.
 */

#include <sys/mman.h>
#include <stdlib.h>
#include <unistd.h>

ADDRINT page_mask;
ADDRINT page_offset_mask;
ADDRINT swizzle_space = 0;
ADDRINT target_space = 0;

static void make_swizzle_space(ADDRINT val)
{
    int page_size = getpagesize();
    page_offset_mask = page_size-1;
    page_mask = ~page_offset_mask;
    // Get swizzle space by allocating memory and rounding up
    ADDRINT mem = (ADDRINT)malloc(2 * page_size);
    swizzle_space = (mem + page_size - 1) & page_mask;
    if (0 != mprotect((void*)swizzle_space, page_size, 0))
    {
        perror("mprotect");
        exit(1);
    }
    target_space = val & page_mask;
#if defined(DEBUG_OUTPUT)
    fprintf(stderr,"page mask %p page_offset_mask %p swizzle_space %p target_space %p\n",
            (void*)page_mask,(void*)page_offset_mask,(void*)swizzle_space,(void*)target_space);
#endif
}

static VOID SwizzleRef(ADDRINT *val)
{
#if defined(DEBUG_OUTPUT)
    fprintf(stderr,"swizzle: in %p\n",(void*)*val);
#endif
    if (target_space == 0)
    {
        make_swizzle_space(*val);
    }
    
    if ((*val & page_mask) != target_space)
    {
        fprintf(stderr,"Multiple target space pages\n");
        exit(1);
    }
    *val = swizzle_space | (*val & page_offset_mask);
#if defined(DEBUG_OUTPUT)
    fprintf(stderr,"  out %p\n",(void*)*val);
#endif
}

static ADDRINT Unswizzle(ADDRINT val)
{
    if (page_mask == 0)
        return val;
    
#if defined(DEBUG_OUTPUT)
    fprintf(stderr,"unswizzle: in %p\n",(void*)val);
#endif
    if ((val & page_mask) == swizzle_space)
        val = target_space | (val & page_offset_mask);
#if defined(DEBUG_OUTPUT)
    fprintf(stderr,"  out %p\n",(void*)val);
#endif
    return val;
}

static void UnswizzleRef(ADDRINT * val)
{
    *val = Unswizzle(*val);
}