common/tnf/trace_funcs.c

	trace_funcs.c revision 7c478bd95313f5f23a4c958a745db2134aa03244
/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 *  Copyright (c) 1994, by Sun Microsytems, Inc.
 */

#pragma ident   "%Z%%M% %I% %E% SMI"

/*
 * Includes
 */
#include <sys/param.h>
#include <sys/time.h>
#include <sys/debug.h>
#include <sys/cmn_err.h>
#include <sys/tnf.h>

#include "tnf_buf.h"
#include "tnf_types.h"
#include "tnf_trace.h"

/*
 * Defines
 */

#define ENCODED_TAG(tag, tagarg)        \
    ((tag) | ((tagarg) & 0xfffc) | TNF_REF32_T_PAIR)

/*
 * CAUTION: halfword_accessible assumes that the pointer is to a reclaimable
 *      block - i.e. negative offsets have a 0 in high bit
 */
#define HALFWORD_ACCESSIBLE(x)          \
    ((((x) & 0xffff8000) == 0) || (((x) & 0xffff8000) == 0x7fff8000))

/*
 * Check that x can be encoded in tagarg slot
 * Same as above, but operates on ints (no space bit)
 */
#define TAGARG_CHECK(x)             \
    (((x) < 32767) && ((x) > -32768))

/*
 * Check that hit 32 bits of hrtime are zero
 */
#define TIME_CHECK(x)           \
    (((x) >> 32) == 0)

/*
 * CAUTION: Use the following macro only when doing a self relative pointer
 *      to a target in the same block
 */
#define PTR_DIFF(item, ref)         \
    ((tnf_ref32_t)((tnf_record_p)(item) - (tnf_record_p)(ref)))

/*
 * Typedefs
 */

typedef struct {
    tnf_probe_event_t       probe_event;
    tnf_time_delta_t        time_delta;
} probe_event_prototype_t;

/*
 * Declarations
 */

/*
 * tnf_trace_alloc
 *  the probe allocation function
 */

void *
tnf_trace_alloc(tnf_ops_t *ops, tnf_probe_control_t *probe_p,
    tnf_probe_setup_t *set_p)
{
    TNFW_B_WCB      *wcb;
    uintptr_t       probe_index;
    tnf_record_p        sched_record_p;
    tnf_reference_t     sched_offset, tag_disp;
    tnf_block_header_t  *block;
    tnf_uint32_t        shift;
    probe_event_prototype_t *buffer;
    hrtime_t        curr_time, time_diff;
    tnf_schedule_t      *sched;
    tnf_ref32_t     *fwd_p;
    size_t          size, asize;

    /*
     * Check the "tracing active" flag after setting the busy bit;
     * this avoids a race in which we check the "tracing active"
     * flag, then it gets turned off, and the buffer gets
     * deallocated, before we've set the busy bit.
     */
    if (!lock_try(&ops->busy)) /* atomic op flushes WB */
        return (NULL);
    if (!tnf_tracing_active)
        goto null_ret;

    /*
     * Write probe tag if needed
     */
    probe_index = probe_p->index;
    if (probe_index == 0) {
        if ((probe_index = tnf_probe_tag(ops, probe_p)) == 0)
            goto null_ret;
    }

    /*
     * Determine how much memory is required
     */
    size = probe_p->tnf_event_size;
    asize = size + sizeof (tnf_ref32_t); /* one fwd ptr */

    if (PROBE_IS_FILE_PTR(probe_index))
        /* common case - probe_index is a file ptr */
        /* LINTED assignment of 64-bit integer to 32-bit integer */
        tag_disp = probe_index & PROBE_INDEX_LOW_MASK;
    else
        /* rare case -- get an extra fwd ptr */
        asize += sizeof (tnf_ref32_t);

    /*
     * Allocate memory
     */
    wcb = &ops->wcb;
    /* LINTED assignment of 64-bit integer to 16-bit integer */
    TNFW_B_ALLOC(wcb, asize, buffer, probe_event_prototype_t *);
    if (buffer == NULL)
        goto null_ret;

    /* LINTED pointer cast may result in improper alignment */
    fwd_p = (tnf_ref32_t *)((char *)buffer + size);

    /*
     * Check if the probe tag needs more work
     */
    if (!PROBE_IS_FILE_PTR(probe_index)) {
        /* use up first fwd ptr */
        /* LINTED assignment of 64-bit integer to 32-bit integer */
        *fwd_p = TNF_REF32_MAKE_PERMANENT(
            (tnf_record_p)probe_index - tnf_buf);
        /* LINTED cast from 64-bit integer to 32-bit integer */
        tag_disp = PTR_DIFF(fwd_p, buffer);
        tag_disp |= TNF_TAG16_T_REL;
        tag_disp = tag_disp << TNF_REF32_TAG16_SHIFT;
        fwd_p++;
    }

    /*
     * Get timestamp
     */
    curr_time = gethrtime();

    /*
     * Write schedule record if needed
     */
    sched = &ops->schedule;

    /* LINTED pointer cast */
    shift = ((tnf_buf_file_header_t *)tnf_buf)->com.file_log_size;
    block = (tnf_block_header_t *)((uintptr_t)buffer & TNF_BLOCK_MASK);

    if ((sched_record_p = sched->record_p) == NULL)
        /* No record written yet */
        goto new_schedule;

    /*
     * Note: Don't bother about space bit here, because we'll
     * only use bits 15:2 anyway
     */
#if defined(_LP64)
    /* LINTED  assignment of 64-bit integer to 32-bit integer */
    sched_offset = ((sched->record_gen - block->generation) << shift) +
        (sched_record_p - (caddr_t)buffer);
#else
    sched_offset = ((sched->record_gen - block->generation) << shift) +
        (sched_record_p - (caddr_t)buffer);
#endif
    if (!TAGARG_CHECK(sched_offset))
        /* Record too far away to reference */
        goto new_schedule;

    time_diff = curr_time - sched->time_base;
    if (!TIME_CHECK(time_diff))
        /* Time delta can't fit in 32 bits */
        goto new_schedule;

    if (sched->cpuid != CPU->cpu_id)
        /* CPU information is invalid */
        goto new_schedule;

    /*
     * Can reuse existing schedule record
     * Since we did not allocate any more space, can giveback
     */
#if defined(_LP64)
    /* LINTED warning: assignment of 64-bit integer to 16-bit integer */
    TNFW_B_GIVEBACK(wcb, fwd_p);
#else
    TNFW_B_GIVEBACK(wcb, fwd_p);
#endif

good_ret:
    /*
     * Store return params and two common event members, return buffer
     */
    set_p->tpd_p = ops;
    set_p->buffer_p = buffer;
    set_p->probe_p = probe_p;
    buffer->probe_event = ENCODED_TAG(tag_disp, sched_offset);
#if defined(_LP64)
    /* LINTED assignment of 64-bit integer to 32-bit integer */
    buffer->time_delta = tnf_time_delta(ops, (unsigned long)time_diff,
        &buffer->probe_time_delta);
#else
    buffer->time_delta = tnf_time_delta(ops, (unsigned long)time_diff,
        &buffer->probe_time_delta);
#endif
    return (buffer);

new_schedule:
    /*
     * Write a new schedule record for this thread
     */
    sched->cpuid = CPU->cpu_id;
    sched->time_base = curr_time;
    time_diff = 0;
    if ((sched_record_p = tnf_kernel_schedule(ops, sched)) != NULL) {
        /* use one of the extra alloced words for the forwarding ptr */
#if defined(_LP64)
        /* LINTED assignment of 64-bit integer to 32-bit integer */
        *fwd_p = TNF_REF32_MAKE_RECLAIMABLE(
            ((sched->record_gen - block->generation) << shift) +
                /* LINTED */
                (sched_record_p - (tnf_record_p)fwd_p));
        /* LINTED cast from 64-bit integer to 32-bit integer */
        sched_offset = PTR_DIFF(fwd_p, buffer);
#else
        *fwd_p = TNF_REF32_MAKE_RECLAIMABLE(
            ((sched->record_gen - block->generation) << shift) +
            (sched_record_p - (tnf_record_p)fwd_p));
        sched_offset = PTR_DIFF(fwd_p, buffer);
#endif
    } else {
        /* Allocation failed (tracing may have been stopped) */
        sched_offset = 0;
        *fwd_p = TNF_NULL;
    }
    goto good_ret;

null_ret:
    /*
     * Clear busy flag and return null
     */
    LOCK_INIT_CLEAR(&ops->busy);    /* XXX save a call */
    return (NULL);
}

/*
 * tnf_trace_commit
 */
void
tnf_trace_commit(tnf_probe_setup_t *set_p)
{
    tnf_ops_t   *ops;
    TNFW_B_WCB  *wcb;
    TNFW_B_POS  *pos;

    ops = set_p->tpd_p;
    wcb = &ops->wcb;

    /* commit reusable bytes */
    pos = &wcb->tnfw_w_pos;
    TNFW_B_COMMIT(pos);

    /* commit tag bytes */
    pos = &wcb->tnfw_w_tag_pos;
    TNFW_B_COMMIT(pos);

    /* clear busy flag */
    LOCK_INIT_CLEAR(&ops->busy);    /* XXX save a call */
}

/*
 * tnf_trace_rollback
 */
void
tnf_trace_rollback(tnf_probe_setup_t *set_p)
{
    tnf_ops_t   *ops;
    TNFW_B_WCB  *wcb;
    TNFW_B_POS  *pos;

    ops = set_p->tpd_p;
    wcb = &ops->wcb;

    /* rollback data bytes */
    pos = &wcb->tnfw_w_pos;
    TNFW_B_ROLLBACK(pos);

    /* commit tag bytes */
    pos = &wcb->tnfw_w_tag_pos;
    TNFW_B_COMMIT(pos);

    /* zap schedule record, since it is in uncommitted store */
    ops->schedule.record_p = NULL;

    /* clear busy flag */
    LOCK_INIT_CLEAR(&ops->busy);    /* XXX save a call */
}

/*
 * tnf_allocate
 *  exported interface for allocating trace memory
 */

void *
tnf_allocate(tnf_ops_t *ops, size_t size)
{
    return (tnfw_b_alloc(&ops->wcb, size, ops->mode));
}