diff options
Diffstat (limited to 'driver/gator_cookies.c')
| -rw-r--r-- | driver/gator_cookies.c | 224 |
1 files changed, 224 insertions, 0 deletions
diff --git a/driver/gator_cookies.c b/driver/gator_cookies.c new file mode 100644 index 0000000..4e39667 --- /dev/null +++ b/driver/gator_cookies.c @@ -0,0 +1,224 @@ +/** + * 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; +} |