203 lines
		
	
	
		
			6.0 KiB
		
	
	
	
		
			C
		
	
	
	
			
		
		
	
	
			203 lines
		
	
	
		
			6.0 KiB
		
	
	
	
		
			C
		
	
	
	
| /*
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|  * Copyright (c) 2000 Silicon Graphics, Inc.  All Rights Reserved.
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|  * Portions Copyright (c) 2000 Ulrich Drepper
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|  *
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|  * This program is free software; you can redistribute it and/or modify it
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|  * under the terms of version 2 of the GNU General Public License as
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|  * published by the Free Software Foundation.
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|  *
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|  * This program is distributed in the hope that it would be useful, but
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|  * WITHOUT ANY WARRANTY; without even the implied warranty of
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|  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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|  *
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|  * Further, this software is distributed without any warranty that it is
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|  * free of the rightful claim of any third person regarding infringement
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|  * or the like.  Any license provided herein, whether implied or
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|  * otherwise, applies only to this software file.  Patent licenses, if
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|  * any, provided herein do not apply to combinations of this program with
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|  * other software, or any other product whatsoever.
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|  *
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|  * You should have received a copy of the GNU General Public License along
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|  * with this program; if not, write the Free Software Foundation, Inc.,
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|  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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|  *
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|  * Contact information: Silicon Graphics, Inc., 1600 Amphitheatre Pkwy,
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|  * Mountain View, CA  94043, or:
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|  *
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|  * http://www.sgi.com$
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|  *
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|  * For further information regarding this notice, see:$
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|  *
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|  * http://oss.sgi.com/projects/GenInfo/NoticeExplan/
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|  *
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|  *
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|  *    Linux Test Project - Silicon Graphics, Inc.
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|  *    TEST IDENTIFIER	: fork05
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|  *    EXECUTED BY	: anyone
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|  *    TEST TITLE	: Make sure LDT is propagated correctly
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|  *    TEST CASE TOTAL	: 1
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|  *    CPU TYPES		: i386
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|  *    AUTHORS		: Ulrich Drepper
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|  *			  Nate Straz
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|  *
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|  *On Friday, May 2, 2003 at 09:47:00AM MST, Ulrich Drepper wrote:
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|  *>Robert Williamson wrote:
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|  *>
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|  *>>   I'm getting a SIGSEGV with one of our tests, fork05.c, that apparently
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|  *>> you wrote (attached below).  The test passes on my 2.5.68 machine running
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|  *>> SuSE 8.0 (glibc 2.2.5 and Linuxthreads), however it segmentation faults on
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|  *>> RedHat 9 running 2.5.68.  The test seems to "break" when it attempts to run
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|  *>> the assembly code....could you take a look at it?
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|  *>
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|  *>There is no need to look at it, I know it cannot work anymore on recent
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|  *>systems.  Either change all uses of %gs to %fs or skip the entire patch
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|  *>if %gs has a nonzero value.
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|  *>
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|  *>- --
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|  *>- --------------.                        ,-.            444 Castro Street
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|  *>Ulrich Drepper \    ,-----------------'   \ Mountain View, CA 94041 USA
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|  *>Red Hat         `--' drepper at redhat.com `---------------------------
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|  *
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|  *
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|  *
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|  *On Sat, Aug 12, 2000 at 12:47:31PM -0700, Ulrich Drepper wrote:
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|  *> Ever since the %gs handling was fixed in the 2.3.99 series the
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|  *> appended test program worked.  Now with 2.4.0-test6 it's not working
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|  *> again.  Looking briefly over the patch from test5 to test6 I haven't
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|  *> seen an immediate candidate for the breakage.  It could be missing
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|  *> propagation of the LDT to the new process (and therefore an invalid
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|  *> segment descriptor) or simply clearing %gs.
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|  *>
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|  *> Anyway, this is what you should see and what you get with test5:
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|  *>
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|  *> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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|  *> a = 42
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|  *> %gs = 0x0007
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|  *> %gs = 0x0007
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|  *> a = 99
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|  *> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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|  *>
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|  *> This is what you get with test6:
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|  *>
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|  *> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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|  *> a = 42
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|  *> %gs = 0x0007
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|  *> %gs = 0x0000
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|  *> <SEGFAULT>
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|  *> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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|  *>
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|  *> If somebody is actually creating a test suite for the kernel, please
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|  *> add this program.  It's mostly self-contained.  The correct handling
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|  *> of %gs is really important since glibc 2.2 will make heavy use of it.
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|  *>
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|  *> - --
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|  *> - ---------------.                          ,-.   1325 Chesapeake Terrace
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|  *> Ulrich Drepper  \    ,-------------------'   \  Sunnyvale, CA 94089 USA
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|  *> Red Hat          `--' drepper at redhat.com   `------------------------
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|  *>
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|  *> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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|  *
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|  */
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| 
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| #include <stdio.h>
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| #include <fcntl.h>
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| #include <unistd.h>
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| #include <stdlib.h>
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| #include <sys/wait.h>
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| #include "lapi/syscalls.h"
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| #include "test.h"
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| 
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| char *TCID = "fork05";
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| 
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| static char *environ_list[] = { "TERM", "NoTSetzWq", "TESTPROG" };
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| 
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| #define NUMBER_OF_ENVIRON (sizeof(environ_list)/sizeof(char *))
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| int TST_TOTAL = NUMBER_OF_ENVIRON;
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| 
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| #if defined(linux) && defined(__i386__)
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| 
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| struct modify_ldt_ldt_s {
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| 	unsigned int entry_number;
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| 	unsigned long int base_addr;
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| 	unsigned int limit;
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| 	unsigned int seg_32bit:1;
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| 	unsigned int contents:2;
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| 	unsigned int read_exec_only:1;
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| 	unsigned int limit_in_pages:1;
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| 	unsigned int seg_not_present:1;
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| 	unsigned int useable:1;
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| 	unsigned int empty:25;
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| };
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| 
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| static int a = 42;
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| 
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| static void modify_ldt(int func, struct modify_ldt_ldt_s *ptr, int bytecount)
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| {
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| 	ltp_syscall(__NR_modify_ldt, func, ptr, bytecount);
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| }
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| 
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| int main(void)
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| {
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| 	struct modify_ldt_ldt_s ldt0;
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| 	int lo;
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| 	pid_t pid;
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| 	int res;
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| 
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| 	ldt0.entry_number = 0;
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| 	ldt0.base_addr = (long)&a;
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| 	ldt0.limit = 4;
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| 	ldt0.seg_32bit = 1;
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| 	ldt0.contents = 0;
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| 	ldt0.read_exec_only = 0;
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| 	ldt0.limit_in_pages = 0;
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| 	ldt0.seg_not_present = 0;
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| 	ldt0.useable = 1;
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| 	ldt0.empty = 0;
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| 
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| 	modify_ldt(1, &ldt0, sizeof(ldt0));
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| 
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| 	asm volatile ("movw %w0, %%fs"::"q" (7));
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| 
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| 	asm volatile ("movl %%fs:0, %0":"=r" (lo));
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| 	tst_resm(TINFO, "a = %d", lo);
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| 
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| 	asm volatile ("pushl %%fs; popl %0":"=q" (lo));
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| 	tst_resm(TINFO, "%%fs = %#06hx", lo);
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| 
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| 	asm volatile ("movl %0, %%fs:0"::"r" (99));
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| 
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| 	pid = fork();
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| 
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| 	if (pid == 0) {
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| 		asm volatile ("pushl %%fs; popl %0":"=q" (lo));
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| 		tst_resm(TINFO, "%%fs = %#06hx", lo);
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| 
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| 		asm volatile ("movl %%fs:0, %0":"=r" (lo));
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| 		tst_resm(TINFO, "a = %d", lo);
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| 
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| 		if (lo != 99)
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| 			tst_resm(TFAIL, "Test failed");
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| 		else
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| 			tst_resm(TPASS, "Test passed");
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| 		exit(lo != 99);
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| 	} else {
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| 		waitpid(pid, &res, 0);
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| 	}
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| 
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| 	return WIFSIGNALED(res);
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| }
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| 
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| #else /* if defined(linux) && defined(__i386__) */
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| 
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| int main(void)
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| {
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| 	tst_resm(TINFO, "%%fs test only for ix86");
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| 
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| 	/*
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| 	 * should be successful on all non-ix86 platforms.
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| 	 */
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| 	tst_exit();
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| }
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| 
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| #endif /* if defined(linux) && defined(__i386__) */
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