Archipelago » qemu

/*

 * Simple trace backend

 *

 * Copyright IBM, Corp. 2010

 *

 * This work is licensed under the terms of the GNU GPL, version 2.  See

 * the COPYING file in the top-level directory.

 *

 */

#include <stdlib.h>

#include <stdint.h>

#include <stdio.h>

#include <time.h>

#include "trace.h"

/** Trace file header event ID */

#define HEADER_EVENT_ID (~(uint64_t)0) /* avoids conflicting with TraceEventIDs */

/** Trace file magic number */

#define HEADER_MAGIC 0xf2b177cb0aa429b4ULL

/** Trace file version number, bump if format changes */

#define HEADER_VERSION 0

/** Trace buffer entry */

typedef struct {

    uint64_t event;

    uint64_t timestamp_ns;

    uint64_t x1;

    uint64_t x2;

    uint64_t x3;

    uint64_t x4;

    uint64_t x5;

    uint64_t x6;

} TraceRecord;

enum {

    TRACE_BUF_LEN = 64 * 1024 / sizeof(TraceRecord),

};

static TraceRecord trace_buf[TRACE_BUF_LEN];

static unsigned int trace_idx;

static FILE *trace_fp;

static bool write_header(FILE *fp)

{

    static const TraceRecord header = {

        .event = HEADER_EVENT_ID,

        .timestamp_ns = HEADER_MAGIC,

        .x1 = HEADER_VERSION,

    };

    return fwrite(&header, sizeof header, 1, fp) == 1;

}

static void flush_trace_buffer(void)

{

    if (!trace_fp) {

        trace_fp = fopen("trace.log", "w");

        if (trace_fp) {

            write_header(trace_fp);

        }

    }

    if (trace_fp) {

        size_t unused; /* for when fwrite(3) is declared warn_unused_result */

        unused = fwrite(trace_buf, trace_idx * sizeof(trace_buf[0]), 1, trace_fp);

    }

    /* Discard written trace records */

    trace_idx = 0;

}

void st_set_trace_file_enabled(bool enable)

{

    if (enable == trace_file_enabled) {

        return; /* no change */

    }

    /* Flush/discard trace buffer */

    st_flush_trace_buffer();

    /* To disable, close trace file */

    if (!enable) {

        fclose(trace_fp);

        trace_fp = NULL;

    }

    trace_file_enabled = enable;

}

static void trace(TraceEventID event, uint64_t x1, uint64_t x2, uint64_t x3,

                  uint64_t x4, uint64_t x5, uint64_t x6)

{

    TraceRecord *rec = &trace_buf[trace_idx];

    struct timespec ts;

    /* TODO Windows?  It would be good to use qemu-timer here but that isn't

     * linked into qemu-tools.  Also we should avoid recursion in the tracing

     * code, therefore it is useful to be self-contained.

     */

    clock_gettime(CLOCK_MONOTONIC, &ts);

    rec->event = event;

    rec->timestamp_ns = ts.tv_sec * 1000000000LL + ts.tv_nsec;

    rec->x1 = x1;

    rec->x2 = x2;

    rec->x3 = x3;

    rec->x4 = x4;

    rec->x5 = x5;

    rec->x6 = x6;

    if (++trace_idx == TRACE_BUF_LEN) {

        flush_trace_buffer();

    }

}

void trace0(TraceEventID event)

{

    trace(event, 0, 0, 0, 0, 0, 0);

}

void trace1(TraceEventID event, uint64_t x1)

{

    trace(event, x1, 0, 0, 0, 0, 0);

}

void trace2(TraceEventID event, uint64_t x1, uint64_t x2)

{

    trace(event, x1, x2, 0, 0, 0, 0);

}

void trace3(TraceEventID event, uint64_t x1, uint64_t x2, uint64_t x3)

{

    trace(event, x1, x2, x3, 0, 0, 0);

}

void trace4(TraceEventID event, uint64_t x1, uint64_t x2, uint64_t x3, uint64_t x4)

{

    trace(event, x1, x2, x3, x4, 0, 0);

}

void trace5(TraceEventID event, uint64_t x1, uint64_t x2, uint64_t x3, uint64_t x4, uint64_t x5)

{

    trace(event, x1, x2, x3, x4, x5, 0);

}

void trace6(TraceEventID event, uint64_t x1, uint64_t x2, uint64_t x3, uint64_t x4, uint64_t x5, uint64_t x6)

{

    trace(event, x1, x2, x3, x4, x5, x6);

}

/**

 * Flush the trace buffer on exit

 */

static void __attribute__((constructor)) st_init(void)

{

    atexit(st_flush_trace_buffer);

}