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/**
* Copyright (C) ARM Limited 2010-2011. 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 as
* published by the Free Software Foundation.
*
*/
#define COOKIEMAP_ENTRIES 1024 /* must be power of 2 */
#define MAX_COLLISIONS 2
static DEFINE_PER_CPU(uint32_t, cookie_next_key);
static DEFINE_PER_CPU(uint64_t *, cookie_keys);
static DEFINE_PER_CPU(uint32_t *, cookie_values);
static uint32_t *gator_crc32_table;
static uint32_t cookiemap_code(uint32_t value) {
uint32_t cookiecode = (value >> 24) & 0xff;
cookiecode = cookiecode * 31 + ((value >> 16) & 0xff);
cookiecode = cookiecode * 31 + ((value >> 8) & 0xff);
cookiecode = cookiecode * 31 + ((value >> 0) & 0xff);
cookiecode &= (COOKIEMAP_ENTRIES-1);
return cookiecode * MAX_COLLISIONS;
}
static uint32_t gator_chksum_crc32(char *data)
{
register unsigned long crc;
unsigned char *block = data;
int i, length = strlen(data);
crc = 0xFFFFFFFF;
for (i = 0; i < length; i++) {
crc = ((crc >> 8) & 0x00FFFFFF) ^ gator_crc32_table[(crc ^ *block++) & 0xFF];
}
return (crc ^ 0xFFFFFFFF);
}
/*
* Exists
* Pre: [0][1][v][3]..[n-1]
* Post: [v][0][1][3]..[n-1]
*/
static uint32_t cookiemap_exists(uint64_t key) {
int cpu = raw_smp_processor_id();
uint32_t cookiecode = cookiemap_code(key);
uint64_t *keys = &(per_cpu(cookie_keys, cpu)[cookiecode]);
uint32_t *values = &(per_cpu(cookie_values, cpu)[cookiecode]);
int x;
for (x = 0; x < MAX_COLLISIONS; x++) {
if (keys[x] == key) {
uint32_t value = values[x];
for (; x > 0; x--) {
keys[x] = keys[x-1];
values[x] = values[x-1];
}
keys[0] = key;
values[0] = value;
return value;
}
}
return 0;
}
/*
* Add
* Pre: [0][1][2][3]..[n-1]
* Post: [v][0][1][2]..[n-2]
*/
static void cookiemap_add(uint64_t key, uint32_t value) {
int cpu = raw_smp_processor_id();
int cookiecode = cookiemap_code(key);
uint64_t *keys = &(per_cpu(cookie_keys, cpu)[cookiecode]);
uint32_t *values = &(per_cpu(cookie_values, cpu)[cookiecode]);
int x;
for (x = MAX_COLLISIONS-1; x > 0; x--) {
keys[x] = keys[x-1];
values[x] = keys[x-1];
}
keys[0] = key;
values[0] = value;
}
static inline uint32_t get_cookie(int cpu, int tgid, struct vm_area_struct *vma)
{
struct path *path;
uint64_t key;
int cookie;
char *text;
if (!vma || !vma->vm_file) {
return INVALID_COOKIE;
}
path = &vma->vm_file->f_path;
if (!path || !path->dentry) {
return INVALID_COOKIE;
}
text = (char*)path->dentry->d_name.name;
key = gator_chksum_crc32(text);
key = (key << 32) | (uint32_t)text;
cookie = cookiemap_exists(key);
if (cookie) {
goto output;
}
cookie = per_cpu(cookie_next_key, cpu)+=nr_cpu_ids;
cookiemap_add(key, cookie);
gator_buffer_write_packed_int(cpu, PROTOCOL_COOKIE);
gator_buffer_write_packed_int(cpu, cookie);
gator_buffer_write_string(cpu, text);
output:
return cookie;
}
static int get_exec_cookie(int cpu, struct task_struct *task)
{
unsigned long cookie = NO_COOKIE;
struct mm_struct *mm = task->mm;
struct vm_area_struct *vma;
if (!mm)
return cookie;
for (vma = mm->mmap; vma; vma = vma->vm_next) {
if (!vma->vm_file)
continue;
if (!(vma->vm_flags & VM_EXECUTABLE))
continue;
cookie = get_cookie(cpu, task->tgid, vma);
break;
}
return cookie;
}
static unsigned long get_address_cookie(int cpu, struct task_struct *task, unsigned long addr, off_t *offset)
{
unsigned long cookie = NO_COOKIE;
struct mm_struct *mm = task->mm;
struct vm_area_struct *vma;
if (!mm)
return cookie;
for (vma = find_vma(mm, addr); vma; vma = vma->vm_next) {
if (addr < vma->vm_start || addr >= vma->vm_end)
continue;
if (vma->vm_file) {
cookie = get_cookie(cpu, task->tgid, vma);
*offset = (vma->vm_pgoff << PAGE_SHIFT) + addr - vma->vm_start;
} else {
/* must be an anonymous map */
*offset = addr;
}
break;
}
if (!vma)
cookie = INVALID_COOKIE;
return cookie;
}
static void cookies_initialize(void)
{
uint32_t crc, poly;
int cpu, size;
int i, j;
for_each_present_cpu(cpu) {
per_cpu(cookie_next_key, cpu) = nr_cpu_ids + cpu;
size = COOKIEMAP_ENTRIES * MAX_COLLISIONS * sizeof(uint64_t);
per_cpu(cookie_keys, cpu) = (uint64_t*)kmalloc(size, GFP_KERNEL);
memset(per_cpu(cookie_keys, cpu), 0, size);
size = COOKIEMAP_ENTRIES * MAX_COLLISIONS * sizeof(uint32_t);
per_cpu(cookie_values, cpu) = (uint32_t*)kmalloc(size, GFP_KERNEL);
memset(per_cpu(cookie_values, cpu), 0, size);
}
// build CRC32 table
poly = 0x04c11db7;
gator_crc32_table = (uint32_t*)kmalloc(256 * sizeof(uint32_t), GFP_KERNEL);
for (i = 0; i < 256; i++) {
crc = i;
for (j = 8; j > 0; j--) {
if (crc & 1) {
crc = (crc >> 1) ^ poly;
} else {
crc >>= 1;
}
}
gator_crc32_table[i] = crc;
}
}
static void cookies_release(void)
{
int cpu;
for_each_present_cpu(cpu) {
kfree(per_cpu(cookie_keys, cpu));
per_cpu(cookie_keys, cpu) = NULL;
kfree(per_cpu(cookie_values, cpu));
per_cpu(cookie_values, cpu) = NULL;
}
kfree(gator_crc32_table);
gator_crc32_table = NULL;
}
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