/*
 * syscall_nt.c - checks syscalls with NT set
 * Copyright (c) 2014-2015 Andrew Lutomirski
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * Some obscure user-space code requires the ability to make system calls
 * with FLAGS.NT set.  Make sure it works.
 */

#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <signal.h>
#include <err.h>
#include <sys/syscall.h>
#include <asm/processor-flags.h>

#ifdef __x86_64__
# define WIDTH "q"
#else
# define WIDTH "l"
#endif

static unsigned int nerrs;

static unsigned long get_eflags(void)
{
	unsigned long eflags;
	asm volatile ("pushf" WIDTH "\n\tpop" WIDTH " %0" : "=rm" (eflags));
	return eflags;
}

static void set_eflags(unsigned long eflags)
{
	asm volatile ("push" WIDTH " %0\n\tpopf" WIDTH
		      : : "rm" (eflags) : "flags");
}

static void sethandler(int sig, void (*handler)(int, siginfo_t *, void *),
		       int flags)
{
	struct sigaction sa;
	memset(&sa, 0, sizeof(sa));
	sa.sa_sigaction = handler;
	sa.sa_flags = SA_SIGINFO | flags;
	sigemptyset(&sa.sa_mask);
	if (sigaction(sig, &sa, 0))
		err(1, "sigaction");
}

static void sigtrap(int sig, siginfo_t *si, void *ctx_void)
{
}

static void do_it(unsigned long extraflags)
{
	unsigned long flags;

	set_eflags(get_eflags() | extraflags);
	syscall(SYS_getpid);
	flags = get_eflags();
	if ((flags & extraflags) == extraflags) {
		printf("[OK]\tThe syscall worked and flags are still set\n");
	} else {
		printf("[FAIL]\tThe syscall worked but flags were cleared (flags = 0x%lx but expected 0x%lx set)\n",
		       flags, extraflags);
		nerrs++;
	}
}

int main(void)
{
	printf("[RUN]\tSet NT and issue a syscall\n");
	do_it(X86_EFLAGS_NT);

	/*
	 * Now try it again with TF set -- TF forces returns via IRET in all
	 * cases except non-ptregs-using 64-bit full fast path syscalls.
	 */

	sethandler(SIGTRAP, sigtrap, 0);

	printf("[RUN]\tSet NT|TF and issue a syscall\n");
	do_it(X86_EFLAGS_NT | X86_EFLAGS_TF);

	return nerrs == 0 ? 0 : 1;
}
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<div class='path'>path: <a href='/cgit.cgi/linux/net-next.git/commit/?id=fc6f41ba8b2e705f91324db158c3cc28209a15b1'>root</a>/<a href='/cgit.cgi/linux/net-next.git/commit/drivers?id=fc6f41ba8b2e705f91324db158c3cc28209a15b1'>drivers</a>/<a href='/cgit.cgi/linux/net-next.git/commit/drivers/usb?id=fc6f41ba8b2e705f91324db158c3cc28209a15b1'>usb</a>/<a href='/cgit.cgi/linux/net-next.git/commit/drivers/usb/serial?id=fc6f41ba8b2e705f91324db158c3cc28209a15b1'>serial</a>/<a href='/cgit.cgi/linux/net-next.git/commit/drivers/usb/serial/usb-wwan.h?id=fc6f41ba8b2e705f91324db158c3cc28209a15b1'>usb-wwan.h</a></div><div class='content'><div class='cgit-panel'><b>diff options</b><form method='get'><input type='hidden' name='id' value='fc6f41ba8b2e705f91324db158c3cc28209a15b1'/><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'>2017-02-10 14:35:22 -0800</td></tr>
<tr><th>committer</th><td>Linus Torvalds &lt;torvalds@linux-foundation.org&gt;</td><td class='right'>2017-02-10 14:35:22 -0800</td></tr>
<tr><th>commit</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/drivers/usb/serial/usb-wwan.h?id=fc6f41ba8b2e705f91324db158c3cc28209a15b1'>fc6f41ba8b2e705f91324db158c3cc28209a15b1</a> (<a href='/cgit.cgi/linux/net-next.git/patch/drivers/usb/serial/usb-wwan.h?id=fc6f41ba8b2e705f91324db158c3cc28209a15b1'>patch</a>)</td></tr>
<tr><th>tree</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/tree/?id=fc6f41ba8b2e705f91324db158c3cc28209a15b1'>567bede1cc6bd9f2dec3a3dc85e908e02557da2e</a> /<a href='/cgit.cgi/linux/net-next.git/tree/drivers/usb/serial/usb-wwan.h?id=fc6f41ba8b2e705f91324db158c3cc28209a15b1'>drivers/usb/serial/usb-wwan.h</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/drivers/usb/serial/usb-wwan.h?id=1f369d1655c1de415a186c6ce9004e40ca790989'>1f369d1655c1de415a186c6ce9004e40ca790989</a> (<a href='/cgit.cgi/linux/net-next.git/diff/drivers/usb/serial/usb-wwan.h?id=fc6f41ba8b2e705f91324db158c3cc28209a15b1&amp;id2=1f369d1655c1de415a186c6ce9004e40ca790989'>diff</a>)</td></tr><tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/drivers/usb/serial/usb-wwan.h?id=5cad24d835772f9f709971a8d6fcf12afe53b2a7'>5cad24d835772f9f709971a8d6fcf12afe53b2a7</a> (<a href='/cgit.cgi/linux/net-next.git/diff/drivers/usb/serial/usb-wwan.h?id=fc6f41ba8b2e705f91324db158c3cc28209a15b1&amp;id2=5cad24d835772f9f709971a8d6fcf12afe53b2a7'>diff</a>)</td></tr></table>
<div class='commit-subject'>Merge tag 'mmc-v4.10-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/ulfh/mmc</div><div class='commit-msg'>Pull MMC host fix from Ulf Hansson:
 "mmci: Fix hang while waiting for busy-end interrupt"

* tag 'mmc-v4.10-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/ulfh/mmc:
  mmc: mmci: avoid clearing ST Micro busy end interrupt mistakenly
</div><div class='diffstat-header'><a href='/cgit.cgi/linux/net-next.git/diff/?id=fc6f41ba8b2e705f91324db158c3cc28209a15b1'>Diffstat</a> (limited to 'drivers/usb/serial/usb-wwan.h')</div><table summary='diffstat' class='diffstat'>