diff options
Diffstat (limited to 'drivers/acpi/acpi_dbg.c')
| -rw-r--r-- | drivers/acpi/acpi_dbg.c | 785 |
1 files changed, 785 insertions, 0 deletions
diff --git a/drivers/acpi/acpi_dbg.c b/drivers/acpi/acpi_dbg.c new file mode 100644 index 000000000..d50261d05 --- /dev/null +++ b/drivers/acpi/acpi_dbg.c @@ -0,0 +1,785 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * ACPI AML interfacing support + * + * Copyright (C) 2015, Intel Corporation + * Authors: Lv Zheng <lv.zheng@intel.com> + */ + +/* #define DEBUG */ +#define pr_fmt(fmt) "ACPI: AML: " fmt + +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/wait.h> +#include <linux/poll.h> +#include <linux/sched.h> +#include <linux/kthread.h> +#include <linux/proc_fs.h> +#include <linux/debugfs.h> +#include <linux/circ_buf.h> +#include <linux/acpi.h> +#include "internal.h" + +#define ACPI_AML_BUF_ALIGN (sizeof (acpi_size)) +#define ACPI_AML_BUF_SIZE PAGE_SIZE + +#define circ_count(circ) \ + (CIRC_CNT((circ)->head, (circ)->tail, ACPI_AML_BUF_SIZE)) +#define circ_count_to_end(circ) \ + (CIRC_CNT_TO_END((circ)->head, (circ)->tail, ACPI_AML_BUF_SIZE)) +#define circ_space(circ) \ + (CIRC_SPACE((circ)->head, (circ)->tail, ACPI_AML_BUF_SIZE)) +#define circ_space_to_end(circ) \ + (CIRC_SPACE_TO_END((circ)->head, (circ)->tail, ACPI_AML_BUF_SIZE)) + +#define ACPI_AML_OPENED 0x0001 +#define ACPI_AML_CLOSED 0x0002 +#define ACPI_AML_IN_USER 0x0004 /* user space is writing cmd */ +#define ACPI_AML_IN_KERN 0x0008 /* kernel space is reading cmd */ +#define ACPI_AML_OUT_USER 0x0010 /* user space is reading log */ +#define ACPI_AML_OUT_KERN 0x0020 /* kernel space is writing log */ +#define ACPI_AML_USER (ACPI_AML_IN_USER | ACPI_AML_OUT_USER) +#define ACPI_AML_KERN (ACPI_AML_IN_KERN | ACPI_AML_OUT_KERN) +#define ACPI_AML_BUSY (ACPI_AML_USER | ACPI_AML_KERN) +#define ACPI_AML_OPEN (ACPI_AML_OPENED | ACPI_AML_CLOSED) + +struct acpi_aml_io { + wait_queue_head_t wait; + unsigned long flags; + unsigned long users; + struct mutex lock; + struct task_struct *thread; + char out_buf[ACPI_AML_BUF_SIZE] __aligned(ACPI_AML_BUF_ALIGN); + struct circ_buf out_crc; + char in_buf[ACPI_AML_BUF_SIZE] __aligned(ACPI_AML_BUF_ALIGN); + struct circ_buf in_crc; + acpi_osd_exec_callback function; + void *context; + unsigned long usages; +}; + +static struct acpi_aml_io acpi_aml_io; +static bool acpi_aml_initialized; +static struct file *acpi_aml_active_reader; +static struct dentry *acpi_aml_dentry; + +static inline bool __acpi_aml_running(void) +{ + return acpi_aml_io.thread ? true : false; +} + +static inline bool __acpi_aml_access_ok(unsigned long flag) +{ + /* + * The debugger interface is in opened state (OPENED && !CLOSED), + * then it is allowed to access the debugger buffers from either + * user space or the kernel space. + * In addition, for the kernel space, only the debugger thread + * (thread ID matched) is allowed to access. + */ + if (!(acpi_aml_io.flags & ACPI_AML_OPENED) || + (acpi_aml_io.flags & ACPI_AML_CLOSED) || + !__acpi_aml_running()) + return false; + if ((flag & ACPI_AML_KERN) && + current != acpi_aml_io.thread) + return false; + return true; +} + +static inline bool __acpi_aml_readable(struct circ_buf *circ, unsigned long flag) +{ + /* + * Another read is not in progress and there is data in buffer + * available for read. + */ + if (!(acpi_aml_io.flags & flag) && circ_count(circ)) + return true; + return false; +} + +static inline bool __acpi_aml_writable(struct circ_buf *circ, unsigned long flag) +{ + /* + * Another write is not in progress and there is buffer space + * available for write. + */ + if (!(acpi_aml_io.flags & flag) && circ_space(circ)) + return true; + return false; +} + +static inline bool __acpi_aml_busy(void) +{ + if (acpi_aml_io.flags & ACPI_AML_BUSY) + return true; + return false; +} + +static inline bool __acpi_aml_used(void) +{ + return acpi_aml_io.usages ? true : false; +} + +static inline bool acpi_aml_running(void) +{ + bool ret; + + mutex_lock(&acpi_aml_io.lock); + ret = __acpi_aml_running(); + mutex_unlock(&acpi_aml_io.lock); + return ret; +} + +static bool acpi_aml_busy(void) +{ + bool ret; + + mutex_lock(&acpi_aml_io.lock); + ret = __acpi_aml_busy(); + mutex_unlock(&acpi_aml_io.lock); + return ret; +} + +static bool acpi_aml_used(void) +{ + bool ret; + + /* + * The usage count is prepared to avoid race conditions between the + * starts and the stops of the debugger thread. + */ + mutex_lock(&acpi_aml_io.lock); + ret = __acpi_aml_used(); + mutex_unlock(&acpi_aml_io.lock); + return ret; +} + +static bool acpi_aml_kern_readable(void) +{ + bool ret; + + mutex_lock(&acpi_aml_io.lock); + ret = !__acpi_aml_access_ok(ACPI_AML_IN_KERN) || + __acpi_aml_readable(&acpi_aml_io.in_crc, ACPI_AML_IN_KERN); + mutex_unlock(&acpi_aml_io.lock); + return ret; +} + +static bool acpi_aml_kern_writable(void) +{ + bool ret; + + mutex_lock(&acpi_aml_io.lock); + ret = !__acpi_aml_access_ok(ACPI_AML_OUT_KERN) || + __acpi_aml_writable(&acpi_aml_io.out_crc, ACPI_AML_OUT_KERN); + mutex_unlock(&acpi_aml_io.lock); + return ret; +} + +static bool acpi_aml_user_readable(void) +{ + bool ret; + + mutex_lock(&acpi_aml_io.lock); + ret = !__acpi_aml_access_ok(ACPI_AML_OUT_USER) || + __acpi_aml_readable(&acpi_aml_io.out_crc, ACPI_AML_OUT_USER); + mutex_unlock(&acpi_aml_io.lock); + return ret; +} + +static bool acpi_aml_user_writable(void) +{ + bool ret; + + mutex_lock(&acpi_aml_io.lock); + ret = !__acpi_aml_access_ok(ACPI_AML_IN_USER) || + __acpi_aml_writable(&acpi_aml_io.in_crc, ACPI_AML_IN_USER); + mutex_unlock(&acpi_aml_io.lock); + return ret; +} + +static int acpi_aml_lock_write(struct circ_buf *circ, unsigned long flag) +{ + int ret = 0; + + mutex_lock(&acpi_aml_io.lock); + if (!__acpi_aml_access_ok(flag)) { + ret = -EFAULT; + goto out; + } + if (!__acpi_aml_writable(circ, flag)) { + ret = -EAGAIN; + goto out; + } + acpi_aml_io.flags |= flag; +out: + mutex_unlock(&acpi_aml_io.lock); + return ret; +} + +static int acpi_aml_lock_read(struct circ_buf *circ, unsigned long flag) +{ + int ret = 0; + + mutex_lock(&acpi_aml_io.lock); + if (!__acpi_aml_access_ok(flag)) { + ret = -EFAULT; + goto out; + } + if (!__acpi_aml_readable(circ, flag)) { + ret = -EAGAIN; + goto out; + } + acpi_aml_io.flags |= flag; +out: + mutex_unlock(&acpi_aml_io.lock); + return ret; +} + +static void acpi_aml_unlock_fifo(unsigned long flag, bool wakeup) +{ + mutex_lock(&acpi_aml_io.lock); + acpi_aml_io.flags &= ~flag; + if (wakeup) + wake_up_interruptible(&acpi_aml_io.wait); + mutex_unlock(&acpi_aml_io.lock); +} + +static int acpi_aml_write_kern(const char *buf, int len) +{ + int ret; + struct circ_buf *crc = &acpi_aml_io.out_crc; + int n; + char *p; + + ret = acpi_aml_lock_write(crc, ACPI_AML_OUT_KERN); + if (ret < 0) + return ret; + /* sync tail before inserting logs */ + smp_mb(); + p = &crc->buf[crc->head]; + n = min(len, circ_space_to_end(crc)); + memcpy(p, buf, n); + /* sync head after inserting logs */ + smp_wmb(); + crc->head = (crc->head + n) & (ACPI_AML_BUF_SIZE - 1); + acpi_aml_unlock_fifo(ACPI_AML_OUT_KERN, true); + return n; +} + +static int acpi_aml_readb_kern(void) +{ + int ret; + struct circ_buf *crc = &acpi_aml_io.in_crc; + char *p; + + ret = acpi_aml_lock_read(crc, ACPI_AML_IN_KERN); + if (ret < 0) + return ret; + /* sync head before removing cmds */ + smp_rmb(); + p = &crc->buf[crc->tail]; + ret = (int)*p; + /* sync tail before inserting cmds */ + smp_mb(); + crc->tail = (crc->tail + 1) & (ACPI_AML_BUF_SIZE - 1); + acpi_aml_unlock_fifo(ACPI_AML_IN_KERN, true); + return ret; +} + +/* + * acpi_aml_write_log() - Capture debugger output + * @msg: the debugger output + * + * This function should be used to implement acpi_os_printf() to filter out + * the debugger output and store the output into the debugger interface + * buffer. Return the size of stored logs or errno. + */ +static ssize_t acpi_aml_write_log(const char *msg) +{ + int ret = 0; + int count = 0, size = 0; + + if (!acpi_aml_initialized) + return -ENODEV; + if (msg) + count = strlen(msg); + while (count > 0) { +again: + ret = acpi_aml_write_kern(msg + size, count); + if (ret == -EAGAIN) { + ret = wait_event_interruptible(acpi_aml_io.wait, + acpi_aml_kern_writable()); + /* + * We need to retry when the condition + * becomes true. + */ + if (ret == 0) + goto again; + break; + } + if (ret < 0) + break; + size += ret; + count -= ret; + } + return size > 0 ? size : ret; +} + +/* + * acpi_aml_read_cmd() - Capture debugger input + * @msg: the debugger input + * @size: the size of the debugger input + * + * This function should be used to implement acpi_os_get_line() to capture + * the debugger input commands and store the input commands into the + * debugger interface buffer. Return the size of stored commands or errno. + */ +static ssize_t acpi_aml_read_cmd(char *msg, size_t count) +{ + int ret = 0; + int size = 0; + + /* + * This is ensured by the running fact of the debugger thread + * unless a bug is introduced. + */ + BUG_ON(!acpi_aml_initialized); + while (count > 0) { +again: + /* + * Check each input byte to find the end of the command. + */ + ret = acpi_aml_readb_kern(); + if (ret == -EAGAIN) { + ret = wait_event_interruptible(acpi_aml_io.wait, + acpi_aml_kern_readable()); + /* + * We need to retry when the condition becomes + * true. + */ + if (ret == 0) + goto again; + } + if (ret < 0) + break; + *(msg + size) = (char)ret; + size++; + count--; + if (ret == '\n') { + /* + * acpi_os_get_line() requires a zero terminated command + * string. + */ + *(msg + size - 1) = '\0'; + break; + } + } + return size > 0 ? size : ret; +} + +static int acpi_aml_thread(void *unused) +{ + acpi_osd_exec_callback function = NULL; + void *context; + + mutex_lock(&acpi_aml_io.lock); + if (acpi_aml_io.function) { + acpi_aml_io.usages++; + function = acpi_aml_io.function; + context = acpi_aml_io.context; + } + mutex_unlock(&acpi_aml_io.lock); + + if (function) + function(context); + + mutex_lock(&acpi_aml_io.lock); + acpi_aml_io.usages--; + if (!__acpi_aml_used()) { + acpi_aml_io.thread = NULL; + wake_up(&acpi_aml_io.wait); + } + mutex_unlock(&acpi_aml_io.lock); + + return 0; +} + +/* + * acpi_aml_create_thread() - Create AML debugger thread + * @function: the debugger thread callback + * @context: the context to be passed to the debugger thread + * + * This function should be used to implement acpi_os_execute() which is + * used by the ACPICA debugger to create the debugger thread. + */ +static int acpi_aml_create_thread(acpi_osd_exec_callback function, void *context) +{ + struct task_struct *t; + + mutex_lock(&acpi_aml_io.lock); + acpi_aml_io.function = function; + acpi_aml_io.context = context; + mutex_unlock(&acpi_aml_io.lock); + + t = kthread_create(acpi_aml_thread, NULL, "aml"); + if (IS_ERR(t)) { + pr_err("Failed to create AML debugger thread.\n"); + return PTR_ERR(t); + } + + mutex_lock(&acpi_aml_io.lock); + acpi_aml_io.thread = t; + acpi_set_debugger_thread_id((acpi_thread_id)(unsigned long)t); + wake_up_process(t); + mutex_unlock(&acpi_aml_io.lock); + return 0; +} + +static int acpi_aml_wait_command_ready(bool single_step, + char *buffer, size_t length) +{ + acpi_status status; + + if (single_step) + acpi_os_printf("\n%1c ", ACPI_DEBUGGER_EXECUTE_PROMPT); + else + acpi_os_printf("\n%1c ", ACPI_DEBUGGER_COMMAND_PROMPT); + + status = acpi_os_get_line(buffer, length, NULL); + if (ACPI_FAILURE(status)) + return -EINVAL; + return 0; +} + +static int acpi_aml_notify_command_complete(void) +{ + return 0; +} + +static int acpi_aml_open(struct inode *inode, struct file *file) +{ + int ret = 0; + acpi_status status; + + mutex_lock(&acpi_aml_io.lock); + /* + * The debugger interface is being closed, no new user is allowed + * during this period. + */ + if (acpi_aml_io.flags & ACPI_AML_CLOSED) { + ret = -EBUSY; + goto err_lock; + } + if ((file->f_flags & O_ACCMODE) != O_WRONLY) { + /* + * Only one reader is allowed to initiate the debugger + * thread. + */ + if (acpi_aml_active_reader) { + ret = -EBUSY; + goto err_lock; + } else { + pr_debug("Opening debugger reader.\n"); + acpi_aml_active_reader = file; + } + } else { + /* + * No writer is allowed unless the debugger thread is + * ready. + */ + if (!(acpi_aml_io.flags & ACPI_AML_OPENED)) { + ret = -ENODEV; + goto err_lock; + } + } + if (acpi_aml_active_reader == file) { + pr_debug("Opening debugger interface.\n"); + mutex_unlock(&acpi_aml_io.lock); + + pr_debug("Initializing debugger thread.\n"); + status = acpi_initialize_debugger(); + if (ACPI_FAILURE(status)) { + pr_err("Failed to initialize debugger.\n"); + ret = -EINVAL; + goto err_exit; + } + pr_debug("Debugger thread initialized.\n"); + + mutex_lock(&acpi_aml_io.lock); + acpi_aml_io.flags |= ACPI_AML_OPENED; + acpi_aml_io.out_crc.head = acpi_aml_io.out_crc.tail = 0; + acpi_aml_io.in_crc.head = acpi_aml_io.in_crc.tail = 0; + pr_debug("Debugger interface opened.\n"); + } + acpi_aml_io.users++; +err_lock: + if (ret < 0) { + if (acpi_aml_active_reader == file) + acpi_aml_active_reader = NULL; + } + mutex_unlock(&acpi_aml_io.lock); +err_exit: + return ret; +} + +static int acpi_aml_release(struct inode *inode, struct file *file) +{ + mutex_lock(&acpi_aml_io.lock); + acpi_aml_io.users--; + if (file == acpi_aml_active_reader) { + pr_debug("Closing debugger reader.\n"); + acpi_aml_active_reader = NULL; + + pr_debug("Closing debugger interface.\n"); + acpi_aml_io.flags |= ACPI_AML_CLOSED; + + /* + * Wake up all user space/kernel space blocked + * readers/writers. + */ + wake_up_interruptible(&acpi_aml_io.wait); + mutex_unlock(&acpi_aml_io.lock); + /* + * Wait all user space/kernel space readers/writers to + * stop so that ACPICA command loop of the debugger thread + * should fail all its command line reads after this point. + */ + wait_event(acpi_aml_io.wait, !acpi_aml_busy()); + + /* + * Then we try to terminate the debugger thread if it is + * not terminated. + */ + pr_debug("Terminating debugger thread.\n"); + acpi_terminate_debugger(); + wait_event(acpi_aml_io.wait, !acpi_aml_used()); + pr_debug("Debugger thread terminated.\n"); + + mutex_lock(&acpi_aml_io.lock); + acpi_aml_io.flags &= ~ACPI_AML_OPENED; + } + if (acpi_aml_io.users == 0) { + pr_debug("Debugger interface closed.\n"); + acpi_aml_io.flags &= ~ACPI_AML_CLOSED; + } + mutex_unlock(&acpi_aml_io.lock); + return 0; +} + +static int acpi_aml_read_user(char __user *buf, int len) +{ + int ret; + struct circ_buf *crc = &acpi_aml_io.out_crc; + int n; + char *p; + + ret = acpi_aml_lock_read(crc, ACPI_AML_OUT_USER); + if (ret < 0) + return ret; + /* sync head before removing logs */ + smp_rmb(); + p = &crc->buf[crc->tail]; + n = min(len, circ_count_to_end(crc)); + if (copy_to_user(buf, p, n)) { + ret = -EFAULT; + goto out; + } + /* sync tail after removing logs */ + smp_mb(); + crc->tail = (crc->tail + n) & (ACPI_AML_BUF_SIZE - 1); + ret = n; +out: + acpi_aml_unlock_fifo(ACPI_AML_OUT_USER, ret >= 0); + return ret; +} + +static ssize_t acpi_aml_read(struct file *file, char __user *buf, + size_t count, loff_t *ppos) +{ + int ret = 0; + int size = 0; + + if (!count) + return 0; + if (!access_ok(buf, count)) + return -EFAULT; + + while (count > 0) { +again: + ret = acpi_aml_read_user(buf + size, count); + if (ret == -EAGAIN) { + if (file->f_flags & O_NONBLOCK) + break; + else { + ret = wait_event_interruptible(acpi_aml_io.wait, + acpi_aml_user_readable()); + /* + * We need to retry when the condition + * becomes true. + */ + if (ret == 0) + goto again; + } + } + if (ret < 0) { + if (!acpi_aml_running()) + ret = 0; + break; + } + if (ret) { + size += ret; + count -= ret; + *ppos += ret; + break; + } + } + return size > 0 ? size : ret; +} + +static int acpi_aml_write_user(const char __user *buf, int len) +{ + int ret; + struct circ_buf *crc = &acpi_aml_io.in_crc; + int n; + char *p; + + ret = acpi_aml_lock_write(crc, ACPI_AML_IN_USER); + if (ret < 0) + return ret; + /* sync tail before inserting cmds */ + smp_mb(); + p = &crc->buf[crc->head]; + n = min(len, circ_space_to_end(crc)); + if (copy_from_user(p, buf, n)) { + ret = -EFAULT; + goto out; + } + /* sync head after inserting cmds */ + smp_wmb(); + crc->head = (crc->head + n) & (ACPI_AML_BUF_SIZE - 1); + ret = n; +out: + acpi_aml_unlock_fifo(ACPI_AML_IN_USER, ret >= 0); + return n; +} + +static ssize_t acpi_aml_write(struct file *file, const char __user *buf, + size_t count, loff_t *ppos) +{ + int ret = 0; + int size = 0; + + if (!count) + return 0; + if (!access_ok(buf, count)) + return -EFAULT; + + while (count > 0) { +again: + ret = acpi_aml_write_user(buf + size, count); + if (ret == -EAGAIN) { + if (file->f_flags & O_NONBLOCK) + break; + else { + ret = wait_event_interruptible(acpi_aml_io.wait, + acpi_aml_user_writable()); + /* + * We need to retry when the condition + * becomes true. + */ + if (ret == 0) + goto again; + } + } + if (ret < 0) { + if (!acpi_aml_running()) + ret = 0; + break; + } + if (ret) { + size += ret; + count -= ret; + *ppos += ret; + } + } + return size > 0 ? size : ret; +} + +static __poll_t acpi_aml_poll(struct file *file, poll_table *wait) +{ + __poll_t masks = 0; + + poll_wait(file, &acpi_aml_io.wait, wait); + if (acpi_aml_user_readable()) + masks |= EPOLLIN | EPOLLRDNORM; + if (acpi_aml_user_writable()) + masks |= EPOLLOUT | EPOLLWRNORM; + + return masks; +} + +static const struct file_operations acpi_aml_operations = { + .read = acpi_aml_read, + .write = acpi_aml_write, + .poll = acpi_aml_poll, + .open = acpi_aml_open, + .release = acpi_aml_release, + .llseek = generic_file_llseek, +}; + +static const struct acpi_debugger_ops acpi_aml_debugger = { + .create_thread = acpi_aml_create_thread, + .read_cmd = acpi_aml_read_cmd, + .write_log = acpi_aml_write_log, + .wait_command_ready = acpi_aml_wait_command_ready, + .notify_command_complete = acpi_aml_notify_command_complete, +}; + +static int __init acpi_aml_init(void) +{ + int ret; + + if (acpi_disabled) + return -ENODEV; + + /* Initialize AML IO interface */ + mutex_init(&acpi_aml_io.lock); + init_waitqueue_head(&acpi_aml_io.wait); + acpi_aml_io.out_crc.buf = acpi_aml_io.out_buf; + acpi_aml_io.in_crc.buf = acpi_aml_io.in_buf; + + acpi_aml_dentry = debugfs_create_file("acpidbg", + S_IFREG | S_IRUGO | S_IWUSR, + acpi_debugfs_dir, NULL, + &acpi_aml_operations); + + ret = acpi_register_debugger(THIS_MODULE, &acpi_aml_debugger); + if (ret) { + debugfs_remove(acpi_aml_dentry); + acpi_aml_dentry = NULL; + return ret; + } + + acpi_aml_initialized = true; + return 0; +} + +static void __exit acpi_aml_exit(void) +{ + if (acpi_aml_initialized) { + acpi_unregister_debugger(&acpi_aml_debugger); + debugfs_remove(acpi_aml_dentry); + acpi_aml_dentry = NULL; + acpi_aml_initialized = false; + } +} + +module_init(acpi_aml_init); +module_exit(acpi_aml_exit); + +MODULE_AUTHOR("Lv Zheng"); +MODULE_DESCRIPTION("ACPI debugger userspace IO driver"); +MODULE_LICENSE("GPL"); |