/*

 * smpl_nhm_lbr.c - Intel Nehalem LBR sampling

 *

 * Copyright (c) 2008 Google, Inc

 * Contributed by Stephane Eranian <eranian@gmail.com>

 *

 * Permission is hereby granted, free of charge, to any person obtaining a copy

 * of this software and associated documentation files (the "Software"), to deal

 * in the Software without restriction, including without limitation the rights

 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies

 * of the Software, and to permit persons to whom the Software is furnished to do so,

 * subject to the following conditions:

 *

 * The above copyright notice and this permission notice shall be included in all

 * copies or substantial portions of the Software.

 *

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,

 * INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A

 * PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT

 * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF

 * CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE

 * OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

 */

#include <sys/types.h>

#include <stdio.h>

#include <stdlib.h>

#include <stdarg.h>

#include <errno.h>

#include <unistd.h>

#include <string.h>

#include <signal.h>

#include <stdarg.h>

#include <stdint.h>

#include <sys/ptrace.h>

#include <sys/wait.h>

#include <sys/mman.h>

#include <sys/resource.h>

#include <setjmp.h>

#include <perfmon/pfmlib.h>

#include <perfmon/pfmlib_intel_nhm.h>

#include <perfmon/perfmon.h>

#include <perfmon/perfmon_dfl_smpl.h>

#include "../detect_pmcs.h"

#define SAMPLING_PERIOD	100000

#define EVENT_NAME	"br_inst_retired:all_branches"

typedef pfm_dfl_smpl_arg_t		smpl_fmt_arg_t;

typedef pfm_dfl_smpl_hdr_t		smpl_hdr_t;

typedef pfm_dfl_smpl_entry_t		smpl_entry_t;

typedef pfm_dfl_smpl_arg_t		smpl_arg_t;

#define FMT_NAME			PFM_DFL_SMPL_NAME

#define NUM_PMCS PFMLIB_MAX_PMCS

#define NUM_PMDS PFMLIB_MAX_PMDS

static jmp_buf jbuf;

static uint64_t collected_samples, collected_partial, ovfl_count;

static void fatal_error(char *fmt,...) __attribute__((noreturn));

#define BPL (sizeof(uint64_t)<<3)

#define LBPL	6

static void handler (int n)

{

	longjmp(jbuf, 1);

}

static inline void pfm_bv_set(uint64_t *bv, uint16_t rnum)

{

	bv[rnum>>LBPL] |= 1UL << (rnum&(BPL-1));

}

static void

warning(char *fmt, ...)

{

	va_list ap;

	va_start(ap, fmt);

	vfprintf(stderr, fmt, ap);

	va_end(ap);

}

static void

fatal_error(char *fmt, ...)

{

	va_list ap;

	va_start(ap, fmt);

	vfprintf(stderr, fmt, ap);

	va_end(ap);

	exit(1);

}

int

child(char **arg)

{

	/*

	 * force the task to stop before executing the first

	 * user level instruction

	 */

	ptrace(PTRACE_TRACEME, 0, NULL, NULL);

	execvp(arg[0], arg);

	/* not reached */

	exit(1);

}

static void

process_smpl_buf(smpl_hdr_t *hdr)

{

	static uint64_t last_overflow = ~0; /* initialize to biggest value possible */

	static uint64_t last_count;

	smpl_entry_t *ent;

	size_t pos, count, entry_size;

	uint64_t entry, *reg;

	uint64_t tos, i;

	if (hdr->hdr_overflows == last_overflow && hdr->hdr_count == last_count) {

		warning("skipping identical set of samples %"PRIu64" = %"PRIu64"\n",

			hdr->hdr_overflows, last_overflow);

		return;	

	}

	/*

 	 * 33 = 32 LBR registers + LBR_TOS

 	 */

	entry_size = sizeof(smpl_entry_t) + 33 * sizeof(uint64_t);

	count = hdr->hdr_count;

	ent   = (smpl_entry_t *)(hdr+1);

	pos   = (unsigned long)ent;

	entry = collected_samples;

	while(count--) {

		printf("entry %"PRIu64" PID:%d TID:%d CPU:%d LAST_VAL:%"PRIu64" OVFL:%u IIP:0x%llx\n",

			entry,

			ent->tgid,

			ent->pid,

			ent->cpu,

			-ent->last_reset_val,

			ent->ovfl_pmd,

			(unsigned long long)ent->ip);

		/*

		 * TOS is pmd31 and comes first

		 * TOs points to most recent entry

		 */

		reg = (uint64_t *)(ent+1);

		tos = reg[0] * 2;

		/*

 		 * i points to oldest entry, the one to print first

 		 */

		i = (tos + 2) % 32;

		/*

 		 * iterate over the 16 branches printing src -> dst

 		 */

		while (i != tos) {

			printf("0x%016"PRIx64" -> 0x%016"PRIx64"\n",

				reg[1+i],

				reg[1+i+1]);

			i = (i + 2) % 32;

		}

		pos += entry_size;

		ent = (smpl_entry_t *)pos;

		entry++;

	}

	collected_samples = entry;

	last_overflow = hdr->hdr_overflows;

	if (last_count != hdr->hdr_count && (last_count || last_overflow == 0))

		collected_partial += hdr->hdr_count;

	last_count = hdr->hdr_count;

}

int

mainloop(char **arg)

{

	smpl_hdr_t *hdr;

	pfarg_ctx_t ctx;

	smpl_arg_t buf_arg;

	pfmlib_input_param_t inp;

	pfmlib_nhm_input_param_t mod_inp;

	pfmlib_output_param_t outp;

	pfarg_pmd_t pd[NUM_PMDS];

	pfarg_pmc_t pc[NUM_PMCS];

	pfarg_load_t load_args;

	pfarg_msg_t msg;

	void *buf_addr;

	pid_t pid;

	int i, status, ret, fd;

	/*

	 * intialize all locals

	 */

	memset(&ctx, 0, sizeof(ctx));

	memset(&buf_arg, 0, sizeof(buf_arg));

	memset(&inp,0, sizeof(inp));

	memset(&outp,0, sizeof(outp));

	memset(pd, 0, sizeof(pd));

	memset(pc, 0, sizeof(pc));

	memset(&load_args, 0, sizeof(load_args));

	memset(&mod_inp, 0, sizeof(mod_inp));

	ret = pfm_find_full_event(EVENT_NAME, &inp.pfp_events[0]);

	if (ret != PFMLIB_SUCCESS)

		fatal_error("cannot find event %s\n", EVENT_NAME);

	/*

	 * set the privilege mode:

	 * 	PFM_PLM3 : user level

	 * 	PFM_PLM0 : kernel level

	 */

	inp.pfp_dfl_plm   = PFM_PLM3;

	/*

	 * how many counters we use

	 */

	inp.pfp_event_count = 1;

	mod_inp.pfp_nhm_lbr.lbr_used = 1;

	mod_inp.pfp_nhm_lbr.lbr_plm = 0; /* inherit from pfp_dfl_plm */

	/*

	 * setup LBR filter

	 *

	 * By default all types of branches are captured

	 *

	 * it is possible to filter out some types of branches using

	 * the macros in pfmlib_intel_nhm.c.

	 *

	 * for instance, to only capture nears calls, you do:

	 *

	 * lbr_filter = PFM_NHM_LBR_NEAR_REL_CALL

	 */

	mod_inp.pfp_nhm_lbr.lbr_filter = 0;

	/*

	 * the size of the buffer is indicated in bytes (not entries).

	 *

	 * The kernel will record into the buffer up to a certain point.

	 * No partial samples are ever recorded.

	 */

	buf_arg.buf_size = 4 * getpagesize();

	/*

	 * now create our perfmon context.

	 */

	fd = pfm_create_context(&ctx, FMT_NAME, &buf_arg, sizeof(buf_arg));

	if (fd == -1) {

		if (errno == ENOSYS)

			fatal_error("Your kernel does not have performance monitoring support!\n");

		fatal_error("cannot create PFM context %s\n", strerror(errno));

	}

	detect_unavail_pmcs(fd, &inp.pfp_unavail_pmcs);

	/*

	 * let the library figure out the values for the PMCS

	 */

	if ((ret=pfm_dispatch_events(&inp, &mod_inp, &outp, NULL)) != PFMLIB_SUCCESS)

		fatal_error("cannot configure events: %s\n", pfm_strerror(ret));

	for (i=0; i < outp.pfp_pmc_count; i++) {

		pc[i].reg_num   = outp.pfp_pmcs[i].reg_num;

		pc[i].reg_value = outp.pfp_pmcs[i].reg_value;

	}

	/*

 	 * we use only one counter

 	 */

	pd[0].reg_num = outp.pfp_pmds[0].reg_num;

	pd[0].reg_flags = PFM_REGFL_OVFL_NOTIFY;

	/*

 	 * add 2 x 16 LBR entries + LBR_TOS to smpl_pmds

 	 */

	for(i=31; i < 64; i++)

		pfm_bv_set(pd[0].reg_smpl_pmds, i);

	/*

 	 * we need to reset LBR after each sample to be able to determine

 	 * whether or not we get new data

 	 *

 	 * LBR_TOS(PMD31) is read-only, it is not included in reset_pmds

	 */

	for(i=32; i < 64; i++)

		pfm_bv_set(pd[0].reg_reset_pmds, i);

	/*

	 * set sampling periods

	 */

	pd[0].reg_value       = - SAMPLING_PERIOD;

	pd[0].reg_short_reset = - SAMPLING_PERIOD;

	pd[0].reg_long_reset  = - SAMPLING_PERIOD;

	/*

	 * prepare context structure.

	 */

	/*

	 * retrieve the virtual address at which the sampling

	 * buffer has been mapped

	 */

	buf_addr = mmap(NULL, (size_t)buf_arg.buf_size, PROT_READ, MAP_PRIVATE, fd, 0);

	if (buf_addr == MAP_FAILED)

		fatal_error("cannot mmap sampling buffer: %s\n", strerror(errno));

	printf("buffer mapped @%p\n", buf_addr);

	hdr = (smpl_hdr_t *)buf_addr;

	printf("hdr_cur_offs=%llu version=%u.%u\n",

		(unsigned long long)hdr->hdr_cur_offs,

		PFM_VERSION_MAJOR(hdr->hdr_version),

		PFM_VERSION_MINOR(hdr->hdr_version));

	if (PFM_VERSION_MAJOR(hdr->hdr_version) < 1)

		fatal_error("invalid buffer format version\n");

	/*

	 * program the PMCs

	 */

	if (pfm_write_pmcs(fd, pc, outp.pfp_pmc_count))

		fatal_error("pfm_write_pmcs error errno %d\n",errno);

	/*

	 *  program our counter

	 */

	if (pfm_write_pmds(fd, pd, 1))

		fatal_error("pfm_write_pmds error errno %d\n",errno);

	/*

	 * create the child task

	 */

	if ((pid=fork()) == -1)

		fatal_error("Cannot fork process\n");

	/*

	 * create child

	 * make sure child does not inherit the file descriptor

	 */

	if (pid == 0) {

		close(fd);

		child(arg);

	}

	/*

	 * wait for the child to exec

	 */

	waitpid(pid, &status, WUNTRACED);

	/*

	 * process is stopped at this point

	 */

	if (WIFEXITED(status)) {

		warning("task %s [%d] exited already status %d\n", arg[0], pid, WEXITSTATUS(status));

		goto terminate_session;

	}

	/*

	 * attach context to stopped task

	 */

	load_args.load_pid = pid;

	if (pfm_load_context (fd, &load_args))

		fatal_error("pfm_load_context error errno %d\n",errno);

	/*

	 * activate monitoring for stopped task.

	 * (nothing will be measured at this point

	 */

	if (pfm_start(fd, NULL))

		fatal_error("pfm_start error errno %d\n",errno);

	/*

	 * detach child. Side effect includes

	 * activation of monitoring.

	 */

	ptrace(PTRACE_DETACH, pid, NULL, 0);

	signal(SIGCHLD, handler);

	if (setjmp(jbuf) == 1)

		goto terminate_session;

	/*

	 * core loop

	 */

	for(;;) {

		ret = read(fd, &msg, sizeof(msg));

		if (ret == -1) {

			if(ret == -1 && errno == EINTR) {

				warning("read interrupted, retrying\n");

				continue;

			}

			fatal_error("cannot read perfmon msg: %s\n", strerror(errno));

		}

		if (msg.type == PFM_MSG_OVFL) {

			process_smpl_buf(hdr);

			ovfl_count++;

			/*

			 * reactivate monitoring once we are done with the samples

			 *

			 * Note that this call can fail with EBUSY in non-blocking mode

			 * as the task may have disappeared while we were processing

			 * the samples.

			 */

			if (pfm_restart(fd)) {

				if (errno != EBUSY)

					fatal_error("pfm_restart error errno %d\n",errno);

			}

		}

	}

terminate_session:

	/*

	 * cleanup child

	 */

	wait4(pid, &status, 0, NULL);

	/*

	 * check for any leftover samples

	 */

	process_smpl_buf(hdr);

	close(fd);

	ret = munmap(hdr, (size_t)buf_arg.buf_size);

	if (ret)

		fatal_error("cannot unmap buffer: %s\n", strerror(errno));

	printf("%"PRIu64" samples (%"PRIu64" in partial buffer) collected in %"PRIu64" buffer overflows\n",

		collected_samples,

		collected_partial,

		ovfl_count);

	return 0;

}

int

main(int argc, char **argv)

{

	pfmlib_options_t pfmlib_options;

	int ret;

	if (argc == 1)

		fatal_error("You must specify a command to execute\n");

	/*

	 * pass options to library (optional)

	 */

	memset(&pfmlib_options, 0, sizeof(pfmlib_options));

	pfmlib_options.pfm_debug   = 0; /* set to 1 for debug */

	pfmlib_options.pfm_verbose = 1; /* set to 1 for verbose */

	pfm_set_options(&pfmlib_options);

	/*

	 * Initialize pfm library (required before we can use it)

	 */

	ret = pfm_initialize();

	if (ret != PFMLIB_SUCCESS)

		fatal_error("Cannot initialize library: %s\n", pfm_strerror(ret));

	return mainloop(argv+1);

}