/*
 * Tests for prctl(PR_GET_TSC, ...) / prctl(PR_SET_TSC, ...)
 *
 * Tests if the control register is updated correctly
 * at context switches
 *
 * Warning: this test will cause a very high load for a few seconds
 *
 */

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <signal.h>
#include <inttypes.h>
#include <wait.h>


#include <sys/prctl.h>
#include <linux/prctl.h>

/* Get/set the process' ability to use the timestamp counter instruction */
#ifndef PR_GET_TSC
#define PR_GET_TSC 25
#define PR_SET_TSC 26
# define PR_TSC_ENABLE		1   /* allow the use of the timestamp counter */
# define PR_TSC_SIGSEGV		2   /* throw a SIGSEGV instead of reading the TSC */
#endif

static uint64_t rdtsc(void)
{
uint32_t lo, hi;
/* We cannot use "=A", since this would use %rax on x86_64 */
__asm__ __volatile__ ("rdtsc" : "=a" (lo), "=d" (hi));
return (uint64_t)hi << 32 | lo;
}

static void sigsegv_expect(int sig)
{
	/* */
}

static void segvtask(void)
{
	if (prctl(PR_SET_TSC, PR_TSC_SIGSEGV) < 0)
	{
		perror("prctl");
		exit(0);
	}
	signal(SIGSEGV, sigsegv_expect);
	alarm(10);
	rdtsc();
	fprintf(stderr, "FATAL ERROR, rdtsc() succeeded while disabled\n");
	exit(0);
}


static void sigsegv_fail(int sig)
{
	fprintf(stderr, "FATAL ERROR, rdtsc() failed while enabled\n");
	exit(0);
}

static void rdtsctask(void)
{
	if (prctl(PR_SET_TSC, PR_TSC_ENABLE) < 0)
	{
		perror("prctl");
		exit(0);
	}
	signal(SIGSEGV, sigsegv_fail);
	alarm(10);
	for(;;) rdtsc();
}


int main(void)
{
	int n_tasks = 100, i;

	fprintf(stderr, "[No further output means we're allright]\n");

	for (i=0; i<n_tasks; i++)
		if (fork() == 0)
		{
			if (i & 1)
				segvtask();
			else
				rdtsctask();
		}

	for (i=0; i<n_tasks; i++)
		wait(NULL);

	exit(0);
}

/gadget/epautoconf.c'>log</a><a href='/cgit.cgi/linux/net-next.git/tree/drivers/usb/gadget/epautoconf.c?id=c92816275674c1491ce228ee49aa030a5fa1be04'>tree</a><a class='active' href='/cgit.cgi/linux/net-next.git/commit/drivers/usb/gadget/epautoconf.c?id=c92816275674c1491ce228ee49aa030a5fa1be04'>commit</a><a href='/cgit.cgi/linux/net-next.git/diff/drivers/usb/gadget/epautoconf.c?id=c92816275674c1491ce228ee49aa030a5fa1be04'>diff</a></td><td class='form'><form class='right' method='get' action='/cgit.cgi/linux/net-next.git/log/drivers/usb/gadget/epautoconf.c'>
<input type='hidden' name='id' value='c92816275674c1491ce228ee49aa030a5fa1be04'/><select name='qt'>
<option value='grep'>log msg</option>
<option value='author'>author</option>
<option value='committer'>committer</option>
<option value='range'>range</option>
</select>
<input class='txt' type='search' size='10' name='q' value=''/>
<input type='submit' value='search'/>
</form>
</td></tr></table>
<div class='path'>path: <a href='/cgit.cgi/linux/net-next.git/commit/?id=c92816275674c1491ce228ee49aa030a5fa1be04'>root</a>/<a href='/cgit.cgi/linux/net-next.git/commit/drivers?id=c92816275674c1491ce228ee49aa030a5fa1be04'>drivers</a>/<a href='/cgit.cgi/linux/net-next.git/commit/drivers/usb?id=c92816275674c1491ce228ee49aa030a5fa1be04'>usb</a>/<a href='/cgit.cgi/linux/net-next.git/commit/drivers/usb/gadget?id=c92816275674c1491ce228ee49aa030a5fa1be04'>gadget</a>/<a href='/cgit.cgi/linux/net-next.git/commit/drivers/usb/gadget/epautoconf.c?id=c92816275674c1491ce228ee49aa030a5fa1be04'>epautoconf.c</a></div><div class='content'><div class='cgit-panel'><b>diff options</b><form method='get'><input type='hidden' name='id' value='c92816275674c1491ce228ee49aa030a5fa1be04'/><table><tr><td colspan='2'/></tr><tr><td class='label'>context:</td><td class='ctrl'><select name='context' onchange='this.form.submit();'><option value='1'>1</option><option value='2'>2</option><option value='3' selected='selected'>3</option><option value='4'>4</option><option value='5'>5</option><option value='6'>6</option><option value='7'>7</option><option value='8'>8</option><option value='9'>9</option><option value='10'>10</option><option value='15'>15</option><option value='20'>20</option><option value='25'>25</option><option value='30'>30</option><option value='35'>35</option><option value='40'>40</option></select></td></tr><tr><td class='label'>space:</td><td class='ctrl'><select name='ignorews' onchange='this.form.submit();'><option value='0' selected='selected'>include</option><option value='1'>ignore</option></select></td></tr><tr><td class='label'>mode:</td><td class='ctrl'><select name='dt' onchange='this.form.submit();'><option value='0' selected='selected'>unified</option><option value='1'>ssdiff</option><option value='2'>stat only</option></select></td></tr><tr><td/><td class='ctrl'><noscript><input type='submit' value='reload'/></noscript></td></tr></table></form></div><table summary='commit info' class='commit-info'>
<tr><th>author</th><td>Linus Torvalds &lt;torvalds@linux-foundation.org&gt;</td><td class='right'>2017-01-15 12:40:53 -0800</td></tr>
<tr><th>committer</th><td>Linus Torvalds &lt;torvalds@linux-foundation.org&gt;</td><td class='right'>2017-01-15 12:40:53 -0800</td></tr>
<tr><th>commit</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/drivers/usb/gadget/epautoconf.c?id=c92816275674c1491ce228ee49aa030a5fa1be04'>c92816275674c1491ce228ee49aa030a5fa1be04</a> (<a href='/cgit.cgi/linux/net-next.git/patch/drivers/usb/gadget/epautoconf.c?id=c92816275674c1491ce228ee49aa030a5fa1be04'>patch</a>)</td></tr>
<tr><th>tree</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/tree/?id=c92816275674c1491ce228ee49aa030a5fa1be04'>97deb97f282c6b9f4f58e45a60ea78d1fe31df4e</a> /<a href='/cgit.cgi/linux/net-next.git/tree/drivers/usb/gadget/epautoconf.c?id=c92816275674c1491ce228ee49aa030a5fa1be04'>drivers/usb/gadget/epautoconf.c</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/drivers/usb/gadget/epautoconf.c?id=2d5a7101a140adcf7a5d8677649847fbb2dd5a2f'>2d5a7101a140adcf7a5d8677649847fbb2dd5a2f</a> (<a href='/cgit.cgi/linux/net-next.git/diff/drivers/usb/gadget/epautoconf.c?id=c92816275674c1491ce228ee49aa030a5fa1be04&amp;id2=2d5a7101a140adcf7a5d8677649847fbb2dd5a2f'>diff</a>)</td></tr><tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/drivers/usb/gadget/epautoconf.c?id=c8a6a09c1c617402cc9254b2bc8da359a0347d75'>c8a6a09c1c617402cc9254b2bc8da359a0347d75</a> (<a href='/cgit.cgi/linux/net-next.git/diff/drivers/usb/gadget/epautoconf.c?id=c92816275674c1491ce228ee49aa030a5fa1be04&amp;id2=c8a6a09c1c617402cc9254b2bc8da359a0347d75'>diff</a>)</td></tr></table>
<div class='commit-subject'>Merge tag 'char-misc-4.10-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc</div><div class='commit-msg'>Pull char/misc driver fixes from Greg KH:
 "Here are some small char/misc driver fixes for 4.10-rc4 that resolve
  some reported issues.

  The MEI driver issue resolves a lot of problems that people have been
  having, as does the mem driver fix. The other minor fixes resolve
  other reported issues.

  All of these have been in linux-next for a while"

* tag 'char-misc-4.10-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc:
  vme: Fix wrong pointer utilization in ca91cx42_slave_get
  auxdisplay: fix new ht16k33 build errors
  ppdev: don't print a free'd string
  extcon: return error code on failure
  drivers: char: mem: Fix thinkos in kmem address checks
  mei: bus: enable OS version only for SPT and newer
</div><div class='diffstat-header'><a href='/cgit.cgi/linux/net-next.git/diff/?id=c92816275674c1491ce228ee49aa030a5fa1be04'>Diffstat</a> (limited to 'drivers/usb/gadget/epautoconf.c')</div><table summary='diffstat' class='diffstat'>