/*
   * Copyright (C) 2002-2003 Hewlett-Packard Co
   *               Stephane Eranian <eranian@hpl.hp.com>
   *
   * This file implements the default sampling buffer format
   * for the Linux/ia64 perfmon-2 subsystem.
   */
  #include <linux/kernel.h>
  #include <linux/types.h>
  #include <linux/module.h>

  #include <linux/init.h>
  #include <asm/delay.h>
  #include <linux/smp.h>
  
  #include <asm/perfmon.h>
  #include <asm/perfmon_default_smpl.h>
  
  MODULE_AUTHOR("Stephane Eranian <eranian@hpl.hp.com>");
  MODULE_DESCRIPTION("perfmon default sampling format");
  MODULE_LICENSE("GPL");

  #define DEFAULT_DEBUG 1
  
  #ifdef DEFAULT_DEBUG
  #define DPRINT(a) \
  	do { \

  		if (unlikely(pfm_sysctl.debug >0)) { printk("%s.%d: CPU%d ", __func__, __LINE__, smp_processor_id()); printk a; } \

  	} while (0)
  
  #define DPRINT_ovfl(a) \
  	do { \

  		if (unlikely(pfm_sysctl.debug > 0 && pfm_sysctl.debug_ovfl >0)) { printk("%s.%d: CPU%d ", __func__, __LINE__, smp_processor_id()); printk a; } \

  	} while (0)
  
  #else
  #define DPRINT(a)
  #define DPRINT_ovfl(a)
  #endif

  static int
  default_validate(struct task_struct *task, unsigned int flags, int cpu, void *data)
  {
  	pfm_default_smpl_arg_t *arg = (pfm_default_smpl_arg_t*)data;
  	int ret = 0;
  
  	if (data == NULL) {

  		DPRINT(("[%d] no argument passed
  ", task_pid_nr(task)));

  		return -EINVAL;
  	}

  	DPRINT(("[%d] validate flags=0x%x CPU%d
  ", task_pid_nr(task), flags, cpu));

  
  	/*
  	 * must hold at least the buffer header + one minimally sized entry
  	 */
  	if (arg->buf_size < PFM_DEFAULT_SMPL_MIN_BUF_SIZE) return -EINVAL;
  
  	DPRINT(("buf_size=%lu
  ", arg->buf_size));
  
  	return ret;
  }
  
  static int
  default_get_size(struct task_struct *task, unsigned int flags, int cpu, void *data, unsigned long *size)
  {
  	pfm_default_smpl_arg_t *arg = (pfm_default_smpl_arg_t *)data;
  
  	/*
  	 * size has been validated in default_validate
  	 */
  	*size = arg->buf_size;
  
  	return 0;
  }
  
  static int
  default_init(struct task_struct *task, void *buf, unsigned int flags, int cpu, void *data)
  {
  	pfm_default_smpl_hdr_t *hdr;
  	pfm_default_smpl_arg_t *arg = (pfm_default_smpl_arg_t *)data;
  
  	hdr = (pfm_default_smpl_hdr_t *)buf;
  
  	hdr->hdr_version      = PFM_DEFAULT_SMPL_VERSION;
  	hdr->hdr_buf_size     = arg->buf_size;
  	hdr->hdr_cur_offs     = sizeof(*hdr);
  	hdr->hdr_overflows    = 0UL;
  	hdr->hdr_count        = 0UL;
  
  	DPRINT(("[%d] buffer=%p buf_size=%lu hdr_size=%lu hdr_version=%u cur_offs=%lu
  ",

  		task_pid_nr(task),

  		buf,
  		hdr->hdr_buf_size,
  		sizeof(*hdr),
  		hdr->hdr_version,
  		hdr->hdr_cur_offs));
  
  	return 0;
  }
  
  static int
  default_handler(struct task_struct *task, void *buf, pfm_ovfl_arg_t *arg, struct pt_regs *regs, unsigned long stamp)
  {
  	pfm_default_smpl_hdr_t *hdr;
  	pfm_default_smpl_entry_t *ent;
  	void *cur, *last;
  	unsigned long *e, entry_size;
  	unsigned int npmds, i;
  	unsigned char ovfl_pmd;
  	unsigned char ovfl_notify;
  
  	if (unlikely(buf == NULL || arg == NULL|| regs == NULL || task == NULL)) {
  		DPRINT(("[%d] invalid arguments buf=%p arg=%p
  ", task->pid, buf, arg));
  		return -EINVAL;
  	}
  
  	hdr         = (pfm_default_smpl_hdr_t *)buf;
  	cur         = buf+hdr->hdr_cur_offs;
  	last        = buf+hdr->hdr_buf_size;
  	ovfl_pmd    = arg->ovfl_pmd;
  	ovfl_notify = arg->ovfl_notify;
  
  	/*
  	 * precheck for sanity
  	 */
  	if ((last - cur) < PFM_DEFAULT_MAX_ENTRY_SIZE) goto full;
  
  	npmds = hweight64(arg->smpl_pmds[0]);
  
  	ent = (pfm_default_smpl_entry_t *)cur;
  
  	prefetch(arg->smpl_pmds_values);
  
  	entry_size = sizeof(*ent) + (npmds << 3);
  
  	/* position for first pmd */
  	e = (unsigned long *)(ent+1);
  
  	hdr->hdr_count++;
  
  	DPRINT_ovfl(("[%d] count=%lu cur=%p last=%p free_bytes=%lu ovfl_pmd=%d ovfl_notify=%d npmds=%u
  ",
  			task->pid,
  			hdr->hdr_count,
  			cur, last,
  			last-cur,
  			ovfl_pmd,
  			ovfl_notify, npmds));
  
  	/*
  	 * current = task running at the time of the overflow.
  	 *
  	 * per-task mode:

  	 * 	- this is usually the task being monitored.

  	 * 	  Under certain conditions, it might be a different task
  	 *
  	 * system-wide:
  	 * 	- this is not necessarily the task controlling the session
  	 */
  	ent->pid            = current->pid;
  	ent->ovfl_pmd  	    = ovfl_pmd;
  	ent->last_reset_val = arg->pmd_last_reset; //pmd[0].reg_last_reset_val;
  
  	/*
  	 * where did the fault happen (includes slot number)
  	 */
  	ent->ip = regs->cr_iip | ((regs->cr_ipsr >> 41) & 0x3);
  
  	ent->tstamp    = stamp;
  	ent->cpu       = smp_processor_id();
  	ent->set       = arg->active_set;
  	ent->tgid      = current->tgid;
  
  	/*
  	 * selectively store PMDs in increasing index number
  	 */
  	if (npmds) {
  		unsigned long *val = arg->smpl_pmds_values;
  		for(i=0; i < npmds; i++) {
  			*e++ = *val++;
  		}
  	}
  
  	/*
  	 * update position for next entry
  	 */
  	hdr->hdr_cur_offs += entry_size;
  	cur               += entry_size;
  
  	/*
  	 * post check to avoid losing the last sample
  	 */
  	if ((last - cur) < PFM_DEFAULT_MAX_ENTRY_SIZE) goto full;
  
  	/*
  	 * keep same ovfl_pmds, ovfl_notify
  	 */
  	arg->ovfl_ctrl.bits.notify_user     = 0;
  	arg->ovfl_ctrl.bits.block_task      = 0;
  	arg->ovfl_ctrl.bits.mask_monitoring = 0;
  	arg->ovfl_ctrl.bits.reset_ovfl_pmds = 1; /* reset before returning from interrupt handler */
  
  	return 0;
  full:
  	DPRINT_ovfl(("sampling buffer full free=%lu, count=%lu, ovfl_notify=%d
  ", last-cur, hdr->hdr_count, ovfl_notify));
  
  	/*
  	 * increment number of buffer overflow.
  	 * important to detect duplicate set of samples.
  	 */
  	hdr->hdr_overflows++;
  
  	/*
  	 * if no notification requested, then we saturate the buffer
  	 */
  	if (ovfl_notify == 0) {
  		arg->ovfl_ctrl.bits.notify_user     = 0;
  		arg->ovfl_ctrl.bits.block_task      = 0;
  		arg->ovfl_ctrl.bits.mask_monitoring = 1;
  		arg->ovfl_ctrl.bits.reset_ovfl_pmds = 0;
  	} else {
  		arg->ovfl_ctrl.bits.notify_user     = 1;
  		arg->ovfl_ctrl.bits.block_task      = 1; /* ignored for non-blocking context */
  		arg->ovfl_ctrl.bits.mask_monitoring = 1;
  		arg->ovfl_ctrl.bits.reset_ovfl_pmds = 0; /* no reset now */
  	}
  	return -1; /* we are full, sorry */
  }
  
  static int
  default_restart(struct task_struct *task, pfm_ovfl_ctrl_t *ctrl, void *buf, struct pt_regs *regs)
  {
  	pfm_default_smpl_hdr_t *hdr;
  
  	hdr = (pfm_default_smpl_hdr_t *)buf;
  
  	hdr->hdr_count    = 0UL;
  	hdr->hdr_cur_offs = sizeof(*hdr);
  
  	ctrl->bits.mask_monitoring = 0;
  	ctrl->bits.reset_ovfl_pmds = 1; /* uses long-reset values */
  
  	return 0;
  }
  
  static int
  default_exit(struct task_struct *task, void *buf, struct pt_regs *regs)
  {

  	DPRINT(("[%d] exit(%p)
  ", task_pid_nr(task), buf));

  	return 0;
  }
  
  static pfm_buffer_fmt_t default_fmt={
   	.fmt_name 	    = "default_format",
   	.fmt_uuid	    = PFM_DEFAULT_SMPL_UUID,
   	.fmt_arg_size	    = sizeof(pfm_default_smpl_arg_t),
   	.fmt_validate	    = default_validate,
   	.fmt_getsize	    = default_get_size,
   	.fmt_init	    = default_init,
   	.fmt_handler	    = default_handler,
   	.fmt_restart	    = default_restart,
   	.fmt_restart_active = default_restart,
   	.fmt_exit	    = default_exit,
  };
  
  static int __init
  pfm_default_smpl_init_module(void)
  {
  	int ret;
  
  	ret = pfm_register_buffer_fmt(&default_fmt);
  	if (ret == 0) {
  		printk("perfmon_default_smpl: %s v%u.%u registered
  ",
  			default_fmt.fmt_name,
  			PFM_DEFAULT_SMPL_VERSION_MAJ,
  			PFM_DEFAULT_SMPL_VERSION_MIN);
  	} else {
  		printk("perfmon_default_smpl: %s cannot register ret=%d
  ",
  			default_fmt.fmt_name,
  			ret);
  	}
  
  	return ret;
  }
  
  static void __exit
  pfm_default_smpl_cleanup_module(void)
  {
  	int ret;
  	ret = pfm_unregister_buffer_fmt(default_fmt.fmt_uuid);
  
  	printk("perfmon_default_smpl: unregister %s=%d
  ", default_fmt.fmt_name, ret);
  }
  
  module_init(pfm_default_smpl_init_module);
  module_exit(pfm_default_smpl_cleanup_module);