xref: /openbmc/linux/arch/um/kernel/skas/clone.c (revision 64c70b1c)
1 #include <sched.h>
2 #include <signal.h>
3 #include <sys/mman.h>
4 #include <sys/time.h>
5 #include <asm/unistd.h>
6 #include <asm/page.h>
7 #include "ptrace_user.h"
8 #include "skas.h"
9 #include "stub-data.h"
10 #include "uml-config.h"
11 #include "sysdep/stub.h"
12 #include "kern_constants.h"
13 
14 /* This is in a separate file because it needs to be compiled with any
15  * extraneous gcc flags (-pg, -fprofile-arcs, -ftest-coverage) disabled
16  *
17  * Use UM_KERN_PAGE_SIZE instead of PAGE_SIZE because that calls getpagesize
18  * on some systems.
19  */
20 
21 void __attribute__ ((__section__ (".__syscall_stub")))
22 stub_clone_handler(void)
23 {
24 	struct stub_data *data = (struct stub_data *) UML_CONFIG_STUB_DATA;
25 	long err;
26 
27 	err = stub_syscall2(__NR_clone, CLONE_PARENT | CLONE_FILES | SIGCHLD,
28 			    UML_CONFIG_STUB_DATA + UM_KERN_PAGE_SIZE / 2 -
29 			    sizeof(void *));
30 	if(err != 0)
31 		goto out;
32 
33 	err = stub_syscall4(__NR_ptrace, PTRACE_TRACEME, 0, 0, 0);
34 	if(err)
35 		goto out;
36 
37 	err = stub_syscall3(__NR_setitimer, ITIMER_VIRTUAL,
38 			    (long) &data->timer, 0);
39 	if(err)
40 		goto out;
41 
42 	remap_stack(data->fd, data->offset);
43 	goto done;
44 
45  out:
46 	/* save current result.
47 	 * Parent: pid;
48 	 * child: retcode of mmap already saved and it jumps around this
49 	 * assignment
50 	 */
51 	data->err = err;
52  done:
53 	trap_myself();
54 }
55