diff options
Diffstat (limited to 'drivers/gator/gator_cookies.c')
| -rw-r--r-- | drivers/gator/gator_cookies.c | 433 |
1 files changed, 433 insertions, 0 deletions
diff --git a/drivers/gator/gator_cookies.c b/drivers/gator/gator_cookies.c new file mode 100644 index 000000000000..eb9b946170c1 --- /dev/null +++ b/drivers/gator/gator_cookies.c @@ -0,0 +1,433 @@ +/** + * Copyright (C) ARM Limited 2010-2013. 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 TRANSLATE_BUFFER_SIZE 512 // must be a power of 2 - 512/4 = 128 entries +#define TRANSLATE_TEXT_SIZE 256 +#define MAX_COLLISIONS 2 + +static uint32_t *gator_crc32_table; +static unsigned int translate_buffer_mask; + +struct cookie_args { + struct task_struct *task; + const char *text; +}; + +static DEFINE_PER_CPU(char *, translate_text); +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 DEFINE_PER_CPU(int, translate_buffer_read); +static DEFINE_PER_CPU(int, translate_buffer_write); +static DEFINE_PER_CPU(struct cookie_args *, translate_buffer); + +static uint32_t get_cookie(int cpu, struct task_struct *task, const char *text, bool from_wq); +static void wq_cookie_handler(struct work_struct *unused); +DECLARE_WORK(cookie_work, wq_cookie_handler); +static struct timer_list app_process_wake_up_timer; +static void app_process_wake_up_handler(unsigned long unused_data); + +static uint32_t cookiemap_code(uint64_t value64) +{ + uint32_t value = (uint32_t)((value64 >> 32) + value64); + 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(const char *data) +{ + register unsigned long crc; + const 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) +{ + unsigned long x, flags, retval = 0; + int cpu = get_physical_cpu(); + uint32_t cookiecode = cookiemap_code(key); + uint64_t *keys = &(per_cpu(cookie_keys, cpu)[cookiecode]); + uint32_t *values = &(per_cpu(cookie_values, cpu)[cookiecode]); + + // Can be called from interrupt handler or from work queue + local_irq_save(flags); + 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; + retval = value; + break; + } + } + local_irq_restore(flags); + + return retval; +} + +/* + * 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 = get_physical_cpu(); + 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] = values[x - 1]; + } + keys[0] = key; + values[0] = value; +} + +#ifndef CONFIG_PREEMPT_RT_FULL +static void translate_buffer_write_args(int cpu, struct task_struct *task, const char *text) +{ + unsigned long flags; + int write; + int next_write; + struct cookie_args *args; + + local_irq_save(flags); + + write = per_cpu(translate_buffer_write, cpu); + next_write = (write + 1) & translate_buffer_mask; + + // At least one entry must always remain available as when read == write, the queue is empty not full + if (next_write != per_cpu(translate_buffer_read, cpu)) { + args = &per_cpu(translate_buffer, cpu)[write]; + args->task = task; + args->text = text; + get_task_struct(task); + per_cpu(translate_buffer_write, cpu) = next_write; + } + + local_irq_restore(flags); +} +#endif + +static void translate_buffer_read_args(int cpu, struct cookie_args *args) +{ + unsigned long flags; + int read; + + local_irq_save(flags); + + read = per_cpu(translate_buffer_read, cpu); + *args = per_cpu(translate_buffer, cpu)[read]; + per_cpu(translate_buffer_read, cpu) = (read + 1) & translate_buffer_mask; + + local_irq_restore(flags); +} + +static void wq_cookie_handler(struct work_struct *unused) +{ + struct cookie_args args; + int cpu = get_physical_cpu(), cookie; + + mutex_lock(&start_mutex); + + if (gator_started != 0) { + while (per_cpu(translate_buffer_read, cpu) != per_cpu(translate_buffer_write, cpu)) { + translate_buffer_read_args(cpu, &args); + cookie = get_cookie(cpu, args.task, args.text, true); + marshal_link(cookie, args.task->tgid, args.task->pid); + put_task_struct(args.task); + } + } + + mutex_unlock(&start_mutex); +} + +static void app_process_wake_up_handler(unsigned long unused_data) +{ + // had to delay scheduling work as attempting to schedule work during the context switch is illegal in kernel versions 3.5 and greater + schedule_work(&cookie_work); +} + +// Retrieve full name from proc/pid/cmdline for java processes on Android +static int translate_app_process(const char **text, int cpu, struct task_struct *task, bool from_wq) +{ + void *maddr; + unsigned int len; + unsigned long addr; + struct mm_struct *mm; + struct page *page = NULL; + struct vm_area_struct *page_vma; + int bytes, offset, retval = 0; + char *buf = per_cpu(translate_text, cpu); + +#ifndef CONFIG_PREEMPT_RT_FULL + // Push work into a work queue if in atomic context as the kernel functions below might sleep + // Rely on the in_interrupt variable rather than in_irq() or in_interrupt() kernel functions, as the value of these functions seems + // inconsistent during a context switch between android/linux versions + if (!from_wq) { + // Check if already in buffer + int pos = per_cpu(translate_buffer_read, cpu); + while (pos != per_cpu(translate_buffer_write, cpu)) { + if (per_cpu(translate_buffer, cpu)[pos].task == task) + goto out; + pos = (pos + 1) & translate_buffer_mask; + } + + translate_buffer_write_args(cpu, task, *text); + + // Not safe to call in RT-Preempt full in schedule switch context + mod_timer(&app_process_wake_up_timer, jiffies + 1); + goto out; + } +#endif + + mm = get_task_mm(task); + if (!mm) + goto out; + if (!mm->arg_end) + goto outmm; + addr = mm->arg_start; + len = mm->arg_end - mm->arg_start; + + if (len > TRANSLATE_TEXT_SIZE) + len = TRANSLATE_TEXT_SIZE; + + down_read(&mm->mmap_sem); + while (len) { + if (get_user_pages(task, mm, addr, 1, 0, 1, &page, &page_vma) <= 0) + goto outsem; + + maddr = kmap(page); + offset = addr & (PAGE_SIZE - 1); + bytes = len; + if (bytes > PAGE_SIZE - offset) + bytes = PAGE_SIZE - offset; + + copy_from_user_page(page_vma, page, addr, buf, maddr + offset, bytes); + + kunmap(page); // release page allocated by get_user_pages() + page_cache_release(page); + + len -= bytes; + buf += bytes; + addr += bytes; + + *text = per_cpu(translate_text, cpu); + retval = 1; + } + + // On app_process startup, /proc/pid/cmdline is initially "zygote" then "<pre-initialized>" but changes after an initial startup period + if (strcmp(*text, "zygote") == 0 || strcmp(*text, "<pre-initialized>") == 0) + retval = 0; + +outsem: + up_read(&mm->mmap_sem); +outmm: + mmput(mm); +out: + return retval; +} + +static uint32_t get_cookie(int cpu, struct task_struct *task, const char *text, bool from_wq) +{ + unsigned long flags, cookie; + uint64_t key; + + key = gator_chksum_crc32(text); + key = (key << 32) | (uint32_t)task->tgid; + + cookie = cookiemap_exists(key); + if (cookie) { + return cookie; + } + + if (strcmp(text, "app_process") == 0) { + if (!translate_app_process(&text, cpu, task, from_wq)) + return UNRESOLVED_COOKIE; + } + + // Can be called from interrupt handler or from work queue or from scheduler trace + local_irq_save(flags); + + cookie = UNRESOLVED_COOKIE; + if (marshal_cookie_header(text)) { + cookie = per_cpu(cookie_next_key, cpu) += nr_cpu_ids; + cookiemap_add(key, cookie); + marshal_cookie(cookie, text); + } + + local_irq_restore(flags); + + return cookie; +} + +static int get_exec_cookie(int cpu, struct task_struct *task) +{ + struct mm_struct *mm = task->mm; + const char *text; + + // kernel threads have no address space + if (!mm) + return NO_COOKIE; + + if (task && task->mm && task->mm->exe_file) { + text = task->mm->exe_file->f_path.dentry->d_name.name; + return get_cookie(cpu, task, text, false); + } + + return UNRESOLVED_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; + const char *text; + + 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) { + text = vma->vm_file->f_path.dentry->d_name.name; + cookie = get_cookie(cpu, task, text, false); + *offset = (vma->vm_pgoff << PAGE_SHIFT) + addr - vma->vm_start; + } else { + /* must be an anonymous map */ + *offset = addr; + } + + break; + } + + if (!vma) + cookie = UNRESOLVED_COOKIE; + + return cookie; +} + +static int cookies_initialize(void) +{ + uint32_t crc, poly; + int i, j, cpu, size, err = 0; + + translate_buffer_mask = TRANSLATE_BUFFER_SIZE / sizeof(per_cpu(translate_buffer, 0)[0]) - 1; + + 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); + if (!per_cpu(cookie_keys, cpu)) { + err = -ENOMEM; + goto cookie_setup_error; + } + 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); + if (!per_cpu(cookie_values, cpu)) { + err = -ENOMEM; + goto cookie_setup_error; + } + memset(per_cpu(cookie_values, cpu), 0, size); + + per_cpu(translate_buffer, cpu) = (struct cookie_args *)kmalloc(TRANSLATE_BUFFER_SIZE, GFP_KERNEL); + if (!per_cpu(translate_buffer, cpu)) { + err = -ENOMEM; + goto cookie_setup_error; + } + + per_cpu(translate_buffer_write, cpu) = 0; + per_cpu(translate_buffer_read, cpu) = 0; + + per_cpu(translate_text, cpu) = (char *)kmalloc(TRANSLATE_TEXT_SIZE, GFP_KERNEL); + if (!per_cpu(translate_text, cpu)) { + err = -ENOMEM; + goto cookie_setup_error; + } + } + + // build CRC32 table + poly = 0x04c11db7; + gator_crc32_table = (uint32_t *)kmalloc(256 * sizeof(uint32_t), GFP_KERNEL); + if (!gator_crc32_table) { + err = -ENOMEM; + goto cookie_setup_error; + } + 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; + } + + setup_timer(&app_process_wake_up_timer, app_process_wake_up_handler, 0); + +cookie_setup_error: + return err; +} + +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(per_cpu(translate_buffer, cpu)); + per_cpu(translate_buffer, cpu) = NULL; + per_cpu(translate_buffer_read, cpu) = 0; + per_cpu(translate_buffer_write, cpu) = 0; + + kfree(per_cpu(translate_text, cpu)); + per_cpu(translate_text, cpu) = NULL; + } + + del_timer_sync(&app_process_wake_up_timer); + kfree(gator_crc32_table); + gator_crc32_table = NULL; +} |