[apple/xnu.git] / libkern / os / log.c

#include <stddef.h>
#undef offset

#include <kern/cpu_data.h>
#include <os/base.h>
#include <os/object.h>
#include <os/log.h>
#include <stdbool.h>
#include <stdint.h>

#include <vm/vm_kern.h>
#include <mach/vm_statistics.h>
#include <kern/debug.h>
#include <libkern/libkern.h>
#include <libkern/kernel_mach_header.h>
#include <pexpert/pexpert.h>
#include <uuid/uuid.h>
#include <sys/msgbuf.h>

#include <mach/mach_time.h>
#include <kern/thread.h>
#include <kern/simple_lock.h>
#include <kern/kalloc.h>
#include <kern/clock.h>
#include <kern/assert.h>

#include <firehose/tracepoint_private.h>
#include <firehose/chunk_private.h>
#include <os/firehose_buffer_private.h>
#include <os/firehose.h>

#include <os/log_private.h>
#include "trace_internal.h"

#include "log_encode.h"

/* on embedded, with no kext loading or unloads,
 * make the kernel use the libtrace shared cache path for logging
 */
#define FIREHOSE_USES_SHARED_CACHE NO_KEXTD

#if FIREHOSE_USES_SHARED_CACHE
extern vm_offset_t   segLOWESTTEXT;
#endif

struct os_log_s {
	int a;
};

struct os_log_s _os_log_default;
struct os_log_s _os_log_replay;
extern vm_offset_t kernel_firehose_addr;
extern firehose_chunk_t firehose_boot_chunk;

extern void bsd_log_lock(void);
extern void bsd_log_unlock(void);
extern void logwakeup(struct msgbuf *);

decl_lck_spin_data(extern, oslog_stream_lock)
#define stream_lock() lck_spin_lock(&oslog_stream_lock)
#define stream_unlock() lck_spin_unlock(&oslog_stream_lock)

extern void oslog_streamwakeup(void);
void oslog_streamwrite_locked(firehose_tracepoint_id_u ftid,
    uint64_t stamp, const void *pubdata, size_t publen);
extern void oslog_streamwrite_metadata_locked(oslog_stream_buf_entry_t m_entry);

extern int oslog_stream_open;

extern void *OSKextKextForAddress(const void *);

/* Counters for persistence mode */
uint32_t oslog_p_total_msgcount = 0;
uint32_t oslog_p_metadata_saved_msgcount = 0;
uint32_t oslog_p_metadata_dropped_msgcount = 0;
uint32_t oslog_p_error_count = 0;
uint32_t oslog_p_saved_msgcount = 0;
uint32_t oslog_p_dropped_msgcount = 0;
uint32_t oslog_p_boot_dropped_msgcount = 0;

/* Counters for streaming mode */
uint32_t oslog_s_total_msgcount = 0;
uint32_t oslog_s_error_count = 0;
uint32_t oslog_s_metadata_msgcount = 0;

static bool oslog_boot_done = false;
extern boolean_t early_boot_complete;

#ifdef XNU_KERNEL_PRIVATE
bool startup_serial_logging_active = true;
uint64_t startup_serial_num_procs = 300;
#endif /* XNU_KERNEL_PRIVATE */

// XXX
firehose_tracepoint_id_t
firehose_debug_trace(firehose_stream_t stream, firehose_tracepoint_id_t trace_id,
    uint64_t timestamp, const char *format, const void *pubdata, size_t publen);

static inline firehose_tracepoint_id_t
_firehose_trace(firehose_stream_t stream, firehose_tracepoint_id_u ftid,
    uint64_t stamp, const void *pubdata, size_t publen);

static oslog_stream_buf_entry_t
oslog_stream_create_buf_entry(oslog_stream_link_type_t type, firehose_tracepoint_id_u ftid,
    uint64_t stamp, const void* pubdata, size_t publen);

static void
_os_log_with_args_internal(os_log_t oslog __unused, os_log_type_t type __unused,
    const char *format, va_list args, void *addr, void *dso);

static void
_os_log_to_msgbuf_internal(const char *format, va_list args, bool safe, bool logging);

static void
_os_log_to_log_internal(os_log_t oslog, os_log_type_t type,
    const char *format, va_list args, void *addr, void *dso);


static void
_os_log_actual(os_log_t oslog, os_log_type_t type, const char *format, void
    *dso, void *addr, os_log_buffer_context_t context);

bool
os_log_info_enabled(os_log_t log __unused)
{
	return true;
}

bool
os_log_debug_enabled(os_log_t log __unused)
{
	return true;
}

os_log_t
os_log_create(const char *subsystem __unused, const char *category __unused)
{
	return &_os_log_default;
}

bool
_os_log_string_is_public(const char *str __unused)
{
	return true;
}

__attribute__((noinline, not_tail_called)) void
_os_log_internal(void *dso, os_log_t log, uint8_t type, const char *message, ...)
{
	va_list args;
	void *addr = __builtin_return_address(0);

	va_start(args, message);

	_os_log_with_args_internal(log, type, message, args, addr, dso);

	va_end(args);

	return;
}

#pragma mark - shim functions

__attribute__((noinline, not_tail_called)) void
os_log_with_args(os_log_t oslog, os_log_type_t type, const char *format, va_list args, void *addr)
{
	// if no address passed, look it up
	if (addr == NULL) {
		addr = __builtin_return_address(0);
	}

	_os_log_with_args_internal(oslog, type, format, args, addr, NULL);
}

static void
_os_log_with_args_internal(os_log_t oslog, os_log_type_t type,
    const char *format, va_list args, void *addr, void *dso)
{
	uint32_t  logging_config = atm_get_diagnostic_config();
	boolean_t safe;
	boolean_t logging;

	if (format[0] == '\0') {
		return;
	}

	/* early boot can log to dmesg for later replay (27307943) */
	safe = (!early_boot_complete || oslog_is_safe());

	if (logging_config & ATM_TRACE_DISABLE || logging_config & ATM_TRACE_OFF) {
		logging = false;
	} else {
		logging = true;
	}

	if (oslog != &_os_log_replay) {
		_os_log_to_msgbuf_internal(format, args, safe, logging);
	}

	if (safe && logging) {
		_os_log_to_log_internal(oslog, type, format, args, addr, dso);
	}
}

static void
_os_log_to_msgbuf_internal(const char *format, va_list args, bool safe, bool logging)
{
	static int msgbufreplay = -1;
	va_list args_copy;

#if DEVELOPMENT || DEBUG
	if (safe) {
		bsd_log_lock();
	}
#else
	bsd_log_lock();
#endif

	if (!safe) {
		if (-1 == msgbufreplay) {
			msgbufreplay = msgbufp->msg_bufx;
		}
	} else if (logging && (-1 != msgbufreplay)) {
		uint32_t i;
		uint32_t localbuff_size;
		int newl, position;
		char *localbuff, *p, *s, *next, ch;

		position = msgbufreplay;
		msgbufreplay = -1;
		localbuff_size = (msgbufp->msg_size + 2); /* + '\n' + '\0' */
		/* Size for non-blocking */
		if (localbuff_size > 4096) {
			localbuff_size = 4096;
		}
		bsd_log_unlock();
		/* Allocate a temporary non-circular buffer */
		if ((localbuff = (char *)kalloc_noblock(localbuff_size))) {
			/* in between here, the log could become bigger, but that's fine */
			bsd_log_lock();
			/*
			 * The message buffer is circular; start at the replay pointer, and
			 * make one loop up to write pointer - 1.
			 */
			p = msgbufp->msg_bufc + position;
			for (i = newl = 0; p != msgbufp->msg_bufc + msgbufp->msg_bufx - 1; ++p) {
				if (p >= msgbufp->msg_bufc + msgbufp->msg_size) {
					p = msgbufp->msg_bufc;
				}
				ch = *p;
				if (ch == '\0') {
					continue;
				}
				newl = (ch == '\n');
				localbuff[i++] = ch;
				if (i >= (localbuff_size - 2)) {
					break;
				}
			}
			bsd_log_unlock();

			if (!newl) {
				localbuff[i++] = '\n';
			}
			localbuff[i++] = 0;

			s = localbuff;
			while ((next = strchr(s, '\n'))) {
				next++;
				ch = next[0];
				next[0] = 0;
				os_log(&_os_log_replay, "%s", s);
				next[0] = ch;
				s = next;
			}
			kfree(localbuff, localbuff_size);
		}
		bsd_log_lock();
	}

	va_copy(args_copy, args);
	vprintf_log_locked(format, args_copy);
	va_end(args_copy);

#if DEVELOPMENT || DEBUG
	if (safe) {
		bsd_log_unlock();
		logwakeup(msgbufp);
	}
#else
	bsd_log_unlock();
	if (safe) {
		logwakeup(msgbufp);
	}
#endif
}

static void
_os_log_to_log_internal(os_log_t oslog, os_log_type_t type,
    const char *format, va_list args, void *addr, void *dso)
{
	struct os_log_buffer_context_s context;
	unsigned char buffer_data[OS_LOG_BUFFER_MAX_SIZE] __attribute__((aligned(8)));
	os_log_buffer_t buffer = (os_log_buffer_t)buffer_data;
	uint8_t pubdata[OS_LOG_BUFFER_MAX_SIZE];
	va_list args_copy;

	if (addr == NULL) {
		return;
	}

#if FIREHOSE_USES_SHARED_CACHE
	dso = (void *) segLOWESTTEXT;
#else /* FIREHOSE_USES_SHARED_CACHE */
	if (dso == NULL) {
		dso = (void *) OSKextKextForAddress(format);
		if (dso == NULL) {
			return;
		}
	}

	if (!_os_trace_addr_in_text_segment(dso, format)) {
		return;
	}

	void *dso_addr = (void *) OSKextKextForAddress(addr);
	if (dso != dso_addr) {
		return;
	}
#endif /* FIREHOSE_USES_SHARED_CACHE */

	memset(&context, 0, sizeof(context));
	memset(buffer, 0, OS_LOG_BUFFER_MAX_SIZE);

	context.shimmed = true;
	context.buffer = buffer;
	context.content_sz = OS_LOG_BUFFER_MAX_SIZE - sizeof(*buffer);
	context.pubdata = pubdata;
	context.pubdata_sz = sizeof(pubdata);

	va_copy(args_copy, args);

	(void)hw_atomic_add(&oslog_p_total_msgcount, 1);
	if (_os_log_encode(format, args_copy, 0, &context)) {
		_os_log_actual(oslog, type, format, dso, addr, &context);
	} else {
		(void)hw_atomic_add(&oslog_p_error_count, 1);
	}

	va_end(args_copy);
}

static inline size_t
_os_trace_write_location_for_address(uint8_t buf[static sizeof(uint64_t)],
    void *dso, const void *address, firehose_tracepoint_flags_t *flags)
{
#if FIREHOSE_USES_SHARED_CACHE
	*flags = _firehose_tracepoint_flags_pc_style_shared_cache;
	memcpy(buf, (uint32_t[]){ (uintptr_t)address - (uintptr_t)dso },
	    sizeof(uint32_t));
	return sizeof(uint32_t);

#else /* FIREHOSE_USES_SHARED_CACHE */
	kernel_mach_header_t *mh = dso;

	if (mh->filetype == MH_EXECUTE) {
		*flags = _firehose_tracepoint_flags_pc_style_main_exe;

		memcpy(buf, (uint32_t[]){ (uintptr_t)address - (uintptr_t)dso },
		    sizeof(uint32_t));
		return sizeof(uint32_t);
	} else {
		*flags = _firehose_tracepoint_flags_pc_style_absolute;
		memcpy(buf, (uintptr_t[]){ VM_KERNEL_UNSLIDE(address) }, sizeof(uintptr_t));
#if __LP64__
		return 6; // 48 bits are enough
#else
		return sizeof(uintptr_t);
#endif
	}
#endif /* !FIREHOSE_USES_SHARED_CACHE */
}


OS_ALWAYS_INLINE
static inline size_t
_os_log_buffer_pack(uint8_t *buffdata, size_t buffdata_sz,
    os_log_buffer_context_t ctx)
{
	os_log_buffer_t buffer = ctx->buffer;
	size_t buffer_sz = sizeof(*ctx->buffer) + ctx->content_sz;
	size_t total_sz  = buffer_sz + ctx->pubdata_sz;

	if (total_sz > buffdata_sz) {
		return 0;
	}

	memcpy(buffdata, buffer, buffer_sz);
	memcpy(&buffdata[buffer_sz], ctx->pubdata, ctx->pubdata_sz);
	return total_sz;
}

static void
_os_log_actual(os_log_t oslog __unused, os_log_type_t type, const char *format,
    void *dso, void *addr, os_log_buffer_context_t context)
{
	firehose_stream_t stream;
	firehose_tracepoint_flags_t flags = 0;
	firehose_tracepoint_id_u trace_id;
	uint8_t buffdata[OS_LOG_BUFFER_MAX_SIZE];
	size_t addr_len = 0, buffdata_sz;
	uint64_t timestamp;
	uint64_t thread_id;

	// dso == the start of the binary that was loaded
	addr_len = _os_trace_write_location_for_address(buffdata, dso, addr, &flags);
	buffdata_sz = _os_log_buffer_pack(buffdata + addr_len,
	    sizeof(buffdata) - addr_len, context);
	if (buffdata_sz == 0) {
		return;
	}
	buffdata_sz += addr_len;

	timestamp = firehose_tracepoint_time(firehose_activity_flags_default);
	thread_id = thread_tid(current_thread());

	// create trace_id after we've set additional flags
	trace_id.ftid_value = FIREHOSE_TRACE_ID_MAKE(firehose_tracepoint_namespace_log,
	    type, flags, _os_trace_offset(dso, format, flags));

	if (FALSE) {
		firehose_debug_trace(stream, trace_id.ftid_value, timestamp,
		    format, buffdata, buffdata_sz);
	}
	if (type == OS_LOG_TYPE_INFO || type == OS_LOG_TYPE_DEBUG) {
		stream = firehose_stream_memory;
	} else {
		stream = firehose_stream_persist;
	}
	_firehose_trace(stream, trace_id, timestamp, buffdata, buffdata_sz);
}

static inline firehose_tracepoint_id_t
_firehose_trace(firehose_stream_t stream, firehose_tracepoint_id_u ftid,
    uint64_t stamp, const void *pubdata, size_t publen)
{
	const uint16_t ft_size = offsetof(struct firehose_tracepoint_s, ft_data);
	const size_t _firehose_chunk_payload_size =
	    sizeof(((struct firehose_chunk_s *)0)->fc_data);

	firehose_tracepoint_t ft;

	if (slowpath(ft_size + publen > _firehose_chunk_payload_size)) {
		// We'll need to have some handling here. For now - return 0
		(void)hw_atomic_add(&oslog_p_error_count, 1);
		return 0;
	}

	if (oslog_stream_open && (stream != firehose_stream_metadata)) {
		stream_lock();
		if (!oslog_stream_open) {
			stream_unlock();
			goto out;
		}

		oslog_s_total_msgcount++;
		oslog_streamwrite_locked(ftid, stamp, pubdata, publen);
		stream_unlock();
		oslog_streamwakeup();
	}

out:
	ft = __firehose_buffer_tracepoint_reserve(stamp, stream, (uint16_t)publen, 0, NULL);
	if (!fastpath(ft)) {
		if (oslog_boot_done) {
			if (stream == firehose_stream_metadata) {
				(void)hw_atomic_add(&oslog_p_metadata_dropped_msgcount, 1);
			} else {
				// If we run out of space in the persistence buffer we're
				// dropping the message.
				(void)hw_atomic_add(&oslog_p_dropped_msgcount, 1);
			}
			return 0;
		}
		firehose_chunk_t fbc = firehose_boot_chunk;
		long offset;

		//only stream available during boot is persist
		offset = firehose_chunk_tracepoint_try_reserve(fbc, stamp,
		    firehose_stream_persist, 0, publen, 0, NULL);
		if (offset <= 0) {
			(void)hw_atomic_add(&oslog_p_boot_dropped_msgcount, 1);
			return 0;
		}

		ft = firehose_chunk_tracepoint_begin(fbc, stamp, publen,
		    thread_tid(current_thread()), offset);
		memcpy(ft->ft_data, pubdata, publen);
		firehose_chunk_tracepoint_end(fbc, ft, ftid);
		(void)hw_atomic_add(&oslog_p_saved_msgcount, 1);
		return ftid.ftid_value;
	}
	if (!oslog_boot_done) {
		oslog_boot_done = true;
	}
	memcpy(ft->ft_data, pubdata, publen);

	__firehose_buffer_tracepoint_flush(ft, ftid);
	if (stream == firehose_stream_metadata) {
		(void)hw_atomic_add(&oslog_p_metadata_saved_msgcount, 1);
	} else {
		(void)hw_atomic_add(&oslog_p_saved_msgcount, 1);
	}
	return ftid.ftid_value;
}

static oslog_stream_buf_entry_t
oslog_stream_create_buf_entry(oslog_stream_link_type_t type, firehose_tracepoint_id_u ftid,
    uint64_t stamp, const void* pubdata, size_t publen)
{
	oslog_stream_buf_entry_t m_entry = NULL;
	firehose_tracepoint_t ft = NULL;
	size_t m_entry_len = 0;

	if (!pubdata) {
		return NULL;
	}

	m_entry_len = sizeof(struct oslog_stream_buf_entry_s) +
	    sizeof(struct firehose_tracepoint_s) + publen;
	m_entry = (oslog_stream_buf_entry_t) kalloc(m_entry_len);
	if (!m_entry) {
		return NULL;
	}

	m_entry->type = type;
	m_entry->timestamp = stamp;
	m_entry->size = sizeof(struct firehose_tracepoint_s) + publen;

	ft = m_entry->metadata;
	ft->ft_thread = thread_tid(current_thread());
	ft->ft_id.ftid_value = ftid.ftid_value;
	ft->ft_length = publen;
	memcpy(ft->ft_data, pubdata, publen);

	return m_entry;
}

#ifdef KERNEL
void
firehose_trace_metadata(firehose_stream_t stream, firehose_tracepoint_id_u ftid,
    uint64_t stamp, const void *pubdata, size_t publen)
{
	oslog_stream_buf_entry_t m_entry = NULL;

	// If streaming mode is not on, only log  the metadata
	// in the persistence buffer

	stream_lock();
	if (!oslog_stream_open) {
		stream_unlock();
		goto finish;
	}
	stream_unlock();

	// Setup and write the stream metadata entry
	m_entry = oslog_stream_create_buf_entry(oslog_stream_link_type_metadata, ftid,
	    stamp, pubdata, publen);
	if (!m_entry) {
		(void)hw_atomic_add(&oslog_s_error_count, 1);
		goto finish;
	}

	stream_lock();
	if (!oslog_stream_open) {
		stream_unlock();
		kfree(m_entry, sizeof(struct oslog_stream_buf_entry_s) +
		    sizeof(struct firehose_tracepoint_s) + publen);
		goto finish;
	}
	oslog_s_metadata_msgcount++;
	oslog_streamwrite_metadata_locked(m_entry);
	stream_unlock();

finish:
	_firehose_trace(stream, ftid, stamp, pubdata, publen);
}
#endif

firehose_tracepoint_id_t
firehose_debug_trace(firehose_stream_t stream, firehose_tracepoint_id_t trace_id,
    uint64_t timestamp, const char *format, const void *pubdata, size_t publen)
{
	kprintf("[os_log stream 0x%x trace_id 0x%llx timestamp %llu format '%s' data %p len %lu]\n",
	    (unsigned int)stream, (unsigned long long)trace_id, timestamp,
	    format, pubdata, publen);
	size_t i;
	const unsigned char *cdata = (const unsigned char *)pubdata;
	for (i = 0; i < publen; i += 8) {
		kprintf(">oslog 0x%08x: 0x%02x 0x%02x 0x%02x 0x%02x 0x%02x 0x%02x 0x%02x 0x%02x\n",
		    (unsigned int)i,
		    (i + 0) < publen ? cdata[i + 0] : 0,
		    (i + 1) < publen ? cdata[i + 1] : 0,
		    (i + 2) < publen ? cdata[i + 2] : 0,
		    (i + 3) < publen ? cdata[i + 3] : 0,
		    (i + 4) < publen ? cdata[i + 4] : 0,
		    (i + 5) < publen ? cdata[i + 5] : 0,
		    (i + 6) < publen ? cdata[i + 6] : 0,
		    (i + 7) < publen ? cdata[i + 7] : 0
		    );
	}
	return trace_id;
}

void
__firehose_buffer_push_to_logd(firehose_buffer_t fb __unused, bool for_io __unused)
{
	oslogwakeup();
	return;
}

void
__firehose_allocate(vm_offset_t *addr, vm_size_t size __unused)
{
	firehose_chunk_t kernel_buffer = (firehose_chunk_t)kernel_firehose_addr;

	if (kernel_firehose_addr) {
		*addr = kernel_firehose_addr;
	} else {
		*addr = 0;
		return;
	}
	// Now that we are done adding logs to this chunk, set the number of writers to 0
	// Without this, logd won't flush when the page is full
	firehose_boot_chunk->fc_pos.fcp_refcnt = 0;
	memcpy(&kernel_buffer[FIREHOSE_BUFFER_KERNEL_CHUNK_COUNT - 1], (const void *)firehose_boot_chunk, FIREHOSE_CHUNK_SIZE);
	return;
}
// There isnt a lock held in this case.
void
__firehose_critical_region_enter(void)
{
	disable_preemption();
	return;
}

void
__firehose_critical_region_leave(void)
{
	enable_preemption();
	return;
}

#ifdef CONFIG_XNUPOST

#include <tests/xnupost.h>
#define TESTOSLOGFMT(fn_name) "%u^%llu/%llu^kernel^0^test^" fn_name
#define TESTOSLOGPFX "TESTLOG:%u#"
#define TESTOSLOG(fn_name) TESTOSLOGPFX TESTOSLOGFMT(fn_name "#")

extern u_int32_t RandomULong(void);
extern uint32_t find_pattern_in_buffer(char * pattern, uint32_t len, int expected_count);
void test_oslog_default_helper(uint32_t uniqid, uint64_t count);
void test_oslog_info_helper(uint32_t uniqid, uint64_t count);
void test_oslog_debug_helper(uint32_t uniqid, uint64_t count);
void test_oslog_error_helper(uint32_t uniqid, uint64_t count);
void test_oslog_fault_helper(uint32_t uniqid, uint64_t count);
void _test_log_loop(void * arg __unused, wait_result_t wres __unused);
void test_oslog_handleOSLogCtl(int32_t * in, int32_t * out, int32_t len);
kern_return_t test_stresslog_dropmsg(uint32_t uniqid);

kern_return_t test_os_log(void);
kern_return_t test_os_log_parallel(void);

#define GENOSLOGHELPER(fname, ident, callout_f)                                                            \
    void fname(uint32_t uniqid, uint64_t count)                                                            \
    {                                                                                                      \
	int32_t datalen = 0;                                                                               \
	uint32_t checksum = 0;                                                                             \
	char databuffer[256];                                                                              \
	T_LOG("Doing os_log of %llu TESTLOG msgs for fn " ident, count);                                   \
	for (uint64_t i = 0; i < count; i++)                                                               \
	{                                                                                                  \
	    datalen = snprintf(databuffer, sizeof(databuffer), TESTOSLOGFMT(ident), uniqid, i + 1, count); \
	    checksum = crc32(0, databuffer, datalen);                                                      \
	    callout_f(OS_LOG_DEFAULT, TESTOSLOG(ident), checksum, uniqid, i + 1, count);                   \
	/*T_LOG(TESTOSLOG(ident), checksum, uniqid, i + 1, count);*/                                   \
	}                                                                                                  \
    }

GENOSLOGHELPER(test_oslog_info_helper, "oslog_info_helper", os_log_info);
GENOSLOGHELPER(test_oslog_fault_helper, "oslog_fault_helper", os_log_fault);
GENOSLOGHELPER(test_oslog_debug_helper, "oslog_debug_helper", os_log_debug);
GENOSLOGHELPER(test_oslog_error_helper, "oslog_error_helper", os_log_error);
GENOSLOGHELPER(test_oslog_default_helper, "oslog_default_helper", os_log);

kern_return_t
test_os_log()
{
	char databuffer[256];
	uint32_t uniqid = RandomULong();
	uint32_t match_count = 0;
	uint32_t checksum = 0;
	uint32_t total_msg = 0;
	uint32_t saved_msg = 0;
	uint32_t dropped_msg = 0;
	int datalen = 0;
	uint64_t a = mach_absolute_time();
	uint64_t seqno = 1;
	uint64_t total_seqno = 2;

	os_log_t log_handle = os_log_create("com.apple.xnu.test.t1", "kpost");

	T_ASSERT_EQ_PTR(&_os_log_default, log_handle, "os_log_create returns valid value.");
	T_ASSERT_EQ_INT(TRUE, os_log_info_enabled(log_handle), "os_log_info is enabled");
	T_ASSERT_EQ_INT(TRUE, os_log_debug_enabled(log_handle), "os_log_debug is enabled");
	T_ASSERT_EQ_PTR(&_os_log_default, OS_LOG_DEFAULT, "ensure OS_LOG_DEFAULT is _os_log_default");

	total_msg = oslog_p_total_msgcount;
	saved_msg = oslog_p_saved_msgcount;
	dropped_msg = oslog_p_dropped_msgcount;
	T_LOG("oslog internal counters total %u , saved %u, dropped %u", total_msg, saved_msg, dropped_msg);

	T_LOG("Validating with uniqid %u u64 %llu", uniqid, a);
	T_ASSERT_NE_UINT(0, uniqid, "random number should not be zero");
	T_ASSERT_NE_ULLONG(0, a, "absolute time should not be zero");

	datalen = snprintf(databuffer, sizeof(databuffer), TESTOSLOGFMT("printf_only"), uniqid, seqno, total_seqno);
	checksum = crc32(0, databuffer, datalen);
	printf(TESTOSLOG("printf_only") "mat%llu\n", checksum, uniqid, seqno, total_seqno, a);

	seqno += 1;
	datalen = snprintf(databuffer, sizeof(databuffer), TESTOSLOGFMT("printf_only"), uniqid, seqno, total_seqno);
	checksum = crc32(0, databuffer, datalen);
	printf(TESTOSLOG("printf_only") "mat%llu\n", checksum, uniqid, seqno, total_seqno, a);

	datalen = snprintf(databuffer, sizeof(databuffer), "kernel^0^test^printf_only#mat%llu", a);
	match_count = find_pattern_in_buffer(databuffer, datalen, total_seqno);
	T_EXPECT_EQ_UINT(match_count, 2, "verify printf_only goes to systemlog buffer");

	uint32_t logging_config = atm_get_diagnostic_config();
	T_LOG("checking atm_diagnostic_config 0x%X", logging_config);

	if ((logging_config & ATM_TRACE_OFF) || (logging_config & ATM_TRACE_DISABLE)) {
		T_LOG("ATM_TRACE_OFF / ATM_TRACE_DISABLE is set. Would not see oslog messages. skipping the rest of test.");
		return KERN_SUCCESS;
	}

	/* for enabled logging printfs should be saved in oslog as well */
	T_EXPECT_GE_UINT((oslog_p_total_msgcount - total_msg), 2, "atleast 2 msgs should be seen by oslog system");

	a = mach_absolute_time();
	total_seqno = 1;
	seqno = 1;
	total_msg = oslog_p_total_msgcount;
	saved_msg = oslog_p_saved_msgcount;
	dropped_msg = oslog_p_dropped_msgcount;
	datalen = snprintf(databuffer, sizeof(databuffer), TESTOSLOGFMT("oslog_info"), uniqid, seqno, total_seqno);
	checksum = crc32(0, databuffer, datalen);
	os_log_info(log_handle, TESTOSLOG("oslog_info") "mat%llu", checksum, uniqid, seqno, total_seqno, a);
	T_EXPECT_GE_UINT((oslog_p_total_msgcount - total_msg), 1, "total message count in buffer");

	datalen = snprintf(databuffer, sizeof(databuffer), "kernel^0^test^oslog_info#mat%llu", a);
	match_count = find_pattern_in_buffer(databuffer, datalen, total_seqno);
	T_EXPECT_EQ_UINT(match_count, 1, "verify oslog_info does not go to systemlog buffer");

	total_msg = oslog_p_total_msgcount;
	test_oslog_info_helper(uniqid, 10);
	T_EXPECT_GE_UINT(oslog_p_total_msgcount - total_msg, 10, "test_oslog_info_helper: Should have seen 10 msgs");

	total_msg = oslog_p_total_msgcount;
	test_oslog_debug_helper(uniqid, 10);
	T_EXPECT_GE_UINT(oslog_p_total_msgcount - total_msg, 10, "test_oslog_debug_helper:Should have seen 10 msgs");

	total_msg = oslog_p_total_msgcount;
	test_oslog_error_helper(uniqid, 10);
	T_EXPECT_GE_UINT(oslog_p_total_msgcount - total_msg, 10, "test_oslog_error_helper:Should have seen 10 msgs");

	total_msg = oslog_p_total_msgcount;
	test_oslog_default_helper(uniqid, 10);
	T_EXPECT_GE_UINT(oslog_p_total_msgcount - total_msg, 10, "test_oslog_default_helper:Should have seen 10 msgs");

	total_msg = oslog_p_total_msgcount;
	test_oslog_fault_helper(uniqid, 10);
	T_EXPECT_GE_UINT(oslog_p_total_msgcount - total_msg, 10, "test_oslog_fault_helper:Should have seen 10 msgs");

	T_LOG("oslog internal counters total %u , saved %u, dropped %u", oslog_p_total_msgcount, oslog_p_saved_msgcount,
	    oslog_p_dropped_msgcount);

	return KERN_SUCCESS;
}

static uint32_t _test_log_loop_count = 0;
void
_test_log_loop(void * arg __unused, wait_result_t wres __unused)
{
	uint32_t uniqid = RandomULong();
	test_oslog_debug_helper(uniqid, 100);
	(void)hw_atomic_add(&_test_log_loop_count, 100);
}

kern_return_t
test_os_log_parallel(void)
{
	thread_t thread[2];
	kern_return_t kr;
	uint32_t uniqid = RandomULong();

	printf("oslog internal counters total %u , saved %u, dropped %u", oslog_p_total_msgcount, oslog_p_saved_msgcount,
	    oslog_p_dropped_msgcount);

	kr = kernel_thread_start(_test_log_loop, NULL, &thread[0]);
	T_ASSERT_EQ_INT(kr, KERN_SUCCESS, "kernel_thread_start returned successfully");

	kr = kernel_thread_start(_test_log_loop, NULL, &thread[1]);
	T_ASSERT_EQ_INT(kr, KERN_SUCCESS, "kernel_thread_start returned successfully");

	test_oslog_info_helper(uniqid, 100);

	/* wait until other thread has also finished */
	while (_test_log_loop_count < 200) {
		delay(1000);
	}

	thread_deallocate(thread[0]);
	thread_deallocate(thread[1]);

	T_LOG("oslog internal counters total %u , saved %u, dropped %u", oslog_p_total_msgcount, oslog_p_saved_msgcount,
	    oslog_p_dropped_msgcount);
	T_PASS("parallel_logging tests is now complete");

	return KERN_SUCCESS;
}

void
test_oslog_handleOSLogCtl(int32_t * in, int32_t * out, int32_t len)
{
	if (!in || !out || len != 4) {
		return;
	}
	switch (in[0]) {
	case 1:
	{
		/* send out counters */
		out[1] = oslog_p_total_msgcount;
		out[2] = oslog_p_saved_msgcount;
		out[3] = oslog_p_dropped_msgcount;
		out[0] = KERN_SUCCESS;
		break;
	}
	case 2:
	{
		/* mini stress run */
		out[0] = test_os_log_parallel();
		break;
	}
	case 3:
	{
		/* drop msg tests */
		out[1] = RandomULong();
		out[0] = test_stresslog_dropmsg(out[1]);
		break;
	}
	case 4:
	{
		/* invoke log helpers */
		uint32_t uniqid = in[3];
		int32_t msgcount = in[2];
		if (uniqid == 0 || msgcount == 0) {
			out[0] = KERN_INVALID_VALUE;
			return;
		}

		switch (in[1]) {
		case OS_LOG_TYPE_INFO: test_oslog_info_helper(uniqid, msgcount); break;
		case OS_LOG_TYPE_DEBUG: test_oslog_debug_helper(uniqid, msgcount); break;
		case OS_LOG_TYPE_ERROR: test_oslog_error_helper(uniqid, msgcount); break;
		case OS_LOG_TYPE_FAULT: test_oslog_fault_helper(uniqid, msgcount); break;
		case OS_LOG_TYPE_DEFAULT:
		default: test_oslog_default_helper(uniqid, msgcount); break;
		}
		out[0] = KERN_SUCCESS;
		break;
		/* end of case 4 */
	}
	default:
	{
		out[0] = KERN_INVALID_VALUE;
		break;
	}
	}
	return;
}

kern_return_t
test_stresslog_dropmsg(uint32_t uniqid)
{
	uint32_t total, saved, dropped;
	total = oslog_p_total_msgcount;
	saved = oslog_p_saved_msgcount;
	dropped = oslog_p_dropped_msgcount;
	uniqid = RandomULong();
	test_oslog_debug_helper(uniqid, 100);
	while ((oslog_p_dropped_msgcount - dropped) == 0) {
		test_oslog_debug_helper(uniqid, 100);
	}
	printf("test_stresslog_dropmsg: logged %u msgs, saved %u and caused a drop of %u msgs. \n", oslog_p_total_msgcount - total,
	    oslog_p_saved_msgcount - saved, oslog_p_dropped_msgcount - dropped);
	return KERN_SUCCESS;
}

#endif