[deliverable/linux.git] / arch / um / os-Linux / start_up.c

/*
 * Copyright (C) 2000, 2001, 2002 Jeff Dike (jdike@karaya.com)
 * Licensed under the GPL
 */

#include <pty.h>
#include <stdio.h>
#include <stddef.h>
#include <stdarg.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <signal.h>
#include <sched.h>
#include <fcntl.h>
#include <errno.h>
#include <sys/time.h>
#include <sys/wait.h>
#include <sys/mman.h>
#include <sys/resource.h>
#include <asm/unistd.h>
#include <sys/types.h>
#include "kern_util.h"
#include "user.h"
#include "signal_kern.h"
#include "sysdep/ptrace.h"
#include "sysdep/sigcontext.h"
#include "irq_user.h"
#include "ptrace_user.h"
#include "mem_user.h"
#include "init.h"
#include "os.h"
#include "uml-config.h"
#include "tempfile.h"
#include "kern_constants.h"
#include "skas.h"
#include "skas_ptrace.h"
#include "registers.h"

static int ptrace_child(void *arg)
{
	int ret;
	int pid = os_getpid(), ppid = getppid();
	int sc_result;

	change_sig(SIGWINCH, 0);
	if(ptrace(PTRACE_TRACEME, 0, 0, 0) < 0){
		perror("ptrace");
		os_kill_process(pid, 0);
	}
	kill(pid, SIGSTOP);

	/*This syscall will be intercepted by the parent. Don't call more than
	 * once, please.*/
	sc_result = os_getpid();

	if (sc_result == pid)
		ret = 1; /*Nothing modified by the parent, we are running
			   normally.*/
	else if (sc_result == ppid)
		ret = 0; /*Expected in check_ptrace and check_sysemu when they
			   succeed in modifying the stack frame*/
	else
		ret = 2; /*Serious trouble! This could be caused by a bug in
			   host 2.6 SKAS3/2.6 patch before release -V6, together
			   with a bug in the UML code itself.*/
	_exit(ret);
}

static void fatal_perror(char *str)
{
	perror(str);
	exit(1);
}

static void fatal(char *fmt, ...)
{
	va_list list;

	va_start(list, fmt);
	vprintf(fmt, list);
	va_end(list);
	fflush(stdout);

	exit(1);
}

static void non_fatal(char *fmt, ...)
{
	va_list list;

	va_start(list, fmt);
	vprintf(fmt, list);
	va_end(list);
	fflush(stdout);
}

static int start_ptraced_child(void **stack_out)
{
	void *stack;
	unsigned long sp;
	int pid, n, status;

	stack = mmap(NULL, UM_KERN_PAGE_SIZE,
		     PROT_READ | PROT_WRITE | PROT_EXEC,
		     MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
	if(stack == MAP_FAILED)
		fatal_perror("check_ptrace : mmap failed");
	sp = (unsigned long) stack + UM_KERN_PAGE_SIZE - sizeof(void *);
	pid = clone(ptrace_child, (void *) sp, SIGCHLD, NULL);
	if(pid < 0)
		fatal_perror("start_ptraced_child : clone failed");
	CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
	if(n < 0)
		fatal_perror("check_ptrace : clone failed");
	if(!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGSTOP))
		fatal("check_ptrace : expected SIGSTOP, got status = %d",
		      status);

	*stack_out = stack;
	return pid;
}

/* When testing for SYSEMU support, if it is one of the broken versions, we
 * must just avoid using sysemu, not panic, but only if SYSEMU features are
 * broken.
 * So only for SYSEMU features we test mustpanic, while normal host features
 * must work anyway!
 */
static int stop_ptraced_child(int pid, void *stack, int exitcode,
			      int mustexit)
{
	int status, n, ret = 0;

	if(ptrace(PTRACE_CONT, pid, 0, 0) < 0)
		fatal_perror("stop_ptraced_child : ptrace failed");
	CATCH_EINTR(n = waitpid(pid, &status, 0));
	if(!WIFEXITED(status) || (WEXITSTATUS(status) != exitcode)) {
		int exit_with = WEXITSTATUS(status);
		if (exit_with == 2)
			non_fatal("check_ptrace : child exited with status 2. "
				  "\nDisabling SYSEMU support.\n");
		non_fatal("check_ptrace : child exited with exitcode %d, while "
			  "expecting %d; status 0x%x\n", exit_with,
			  exitcode, status);
		if (mustexit)
			exit(1);
		ret = -1;
	}

	if(munmap(stack, UM_KERN_PAGE_SIZE) < 0)
		fatal_perror("check_ptrace : munmap failed");
	return ret;
}

/* Changed only during early boot */
int ptrace_faultinfo = 1;
int ptrace_ldt = 1;
int proc_mm = 1;
int skas_needs_stub = 0;

static int __init skas0_cmd_param(char *str, int* add)
{
	ptrace_faultinfo = proc_mm = 0;
	return 0;
}

/* The two __uml_setup would conflict, without this stupid alias. */

static int __init mode_skas0_cmd_param(char *str, int* add)
	__attribute__((alias("skas0_cmd_param")));

__uml_setup("skas0", skas0_cmd_param,
		"skas0\n"
		"    Disables SKAS3 usage, so that SKAS0 is used, unless \n"
	        "    you specify mode=tt.\n\n");

__uml_setup("mode=skas0", mode_skas0_cmd_param,
		"mode=skas0\n"
		"    Disables SKAS3 usage, so that SKAS0 is used, unless you \n"
		"    specify mode=tt. Note that this was recently added - on \n"
		"    older kernels you must use simply \"skas0\".\n\n");

/* Changed only during early boot */
static int force_sysemu_disabled = 0;

static int __init nosysemu_cmd_param(char *str, int* add)
{
	force_sysemu_disabled = 1;
	return 0;
}

__uml_setup("nosysemu", nosysemu_cmd_param,
"nosysemu\n"
"    Turns off syscall emulation patch for ptrace (SYSEMU) on.\n"
"    SYSEMU is a performance-patch introduced by Laurent Vivier. It changes\n"
"    behaviour of ptrace() and helps reducing host context switch rate.\n"
"    To make it working, you need a kernel patch for your host, too.\n"
"    See http://perso.wanadoo.fr/laurent.vivier/UML/ for further \n"
"    information.\n\n");

static void __init check_sysemu(void)
{
	void *stack;
	unsigned long regs[MAX_REG_NR];
	int pid, n, status, count=0;

	non_fatal("Checking syscall emulation patch for ptrace...");
	sysemu_supported = 0;
	pid = start_ptraced_child(&stack);

	if(ptrace(PTRACE_SYSEMU, pid, 0, 0) < 0)
		goto fail;

	CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
	if (n < 0)
		fatal_perror("check_sysemu : wait failed");
	if(!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGTRAP))
		fatal("check_sysemu : expected SIGTRAP, got status = %d",
		      status);

	if(ptrace(PTRACE_GETREGS, pid, 0, regs) < 0)
		fatal_perror("check_sysemu : PTRACE_GETREGS failed");
	if(PT_SYSCALL_NR(regs) != __NR_getpid){
		non_fatal("check_sysemu got system call number %d, "
			  "expected %d...", PT_SYSCALL_NR(regs), __NR_getpid);
		goto fail;
	}

	n = ptrace(PTRACE_POKEUSR, pid, PT_SYSCALL_RET_OFFSET, os_getpid());
	if(n < 0){
		non_fatal("check_sysemu : failed to modify system call "
			  "return");
		goto fail;
	}

	if (stop_ptraced_child(pid, stack, 0, 0) < 0)
		goto fail_stopped;

	sysemu_supported = 1;
	non_fatal("OK\n");
	set_using_sysemu(!force_sysemu_disabled);

	non_fatal("Checking advanced syscall emulation patch for ptrace...");
	pid = start_ptraced_child(&stack);

	if((ptrace(PTRACE_OLDSETOPTIONS, pid, 0,
		   (void *) PTRACE_O_TRACESYSGOOD) < 0))
		fatal_perror("check_ptrace: PTRACE_OLDSETOPTIONS failed");

	while(1){
		count++;
		if(ptrace(PTRACE_SYSEMU_SINGLESTEP, pid, 0, 0) < 0)
			goto fail;
		CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
		if(n < 0)
			fatal_perror("check_ptrace : wait failed");

		if(WIFSTOPPED(status) && (WSTOPSIG(status) == (SIGTRAP|0x80))){
			if (!count)
				fatal("check_ptrace : SYSEMU_SINGLESTEP "
				      "doesn't singlestep");
			n = ptrace(PTRACE_POKEUSR, pid, PT_SYSCALL_RET_OFFSET,
				   os_getpid());
			if(n < 0)
				fatal_perror("check_sysemu : failed to modify "
					     "system call return");
			break;
		}
		else if(WIFSTOPPED(status) && (WSTOPSIG(status) == SIGTRAP))
			count++;
		else
			fatal("check_ptrace : expected SIGTRAP or "
			      "(SIGTRAP | 0x80), got status = %d", status);
	}
	if (stop_ptraced_child(pid, stack, 0, 0) < 0)
		goto fail_stopped;

	sysemu_supported = 2;
	non_fatal("OK\n");

	if ( !force_sysemu_disabled )
		set_using_sysemu(sysemu_supported);
	return;

fail:
	stop_ptraced_child(pid, stack, 1, 0);
fail_stopped:
	non_fatal("missing\n");
}

static void __init check_ptrace(void)
{
	void *stack;
	int pid, syscall, n, status;

	non_fatal("Checking that ptrace can change system call numbers...");
	pid = start_ptraced_child(&stack);

	if((ptrace(PTRACE_OLDSETOPTIONS, pid, 0,
		   (void *) PTRACE_O_TRACESYSGOOD) < 0))
		fatal_perror("check_ptrace: PTRACE_OLDSETOPTIONS failed");

	while(1){
		if(ptrace(PTRACE_SYSCALL, pid, 0, 0) < 0)
			fatal_perror("check_ptrace : ptrace failed");

		CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
		if(n < 0)
			fatal_perror("check_ptrace : wait failed");

		if(!WIFSTOPPED(status) ||
		   (WSTOPSIG(status) != (SIGTRAP | 0x80)))
			fatal("check_ptrace : expected (SIGTRAP|0x80), "
			       "got status = %d", status);

		syscall = ptrace(PTRACE_PEEKUSR, pid, PT_SYSCALL_NR_OFFSET,
				 0);
		if(syscall == __NR_getpid){
			n = ptrace(PTRACE_POKEUSR, pid, PT_SYSCALL_NR_OFFSET,
				   __NR_getppid);
			if(n < 0)
				fatal_perror("check_ptrace : failed to modify "
					     "system call");
			break;
		}
	}
	stop_ptraced_child(pid, stack, 0, 1);
	non_fatal("OK\n");
	check_sysemu();
}

extern void check_tmpexec(void);

static void __init check_coredump_limit(void)
{
	struct rlimit lim;
	int err = getrlimit(RLIMIT_CORE, &lim);

	if(err){
		perror("Getting core dump limit");
		return;
	}

	printf("Core dump limits :\n\tsoft - ");
	if(lim.rlim_cur == RLIM_INFINITY)
		printf("NONE\n");
	else printf("%lu\n", lim.rlim_cur);

	printf("\thard - ");
	if(lim.rlim_max == RLIM_INFINITY)
		printf("NONE\n");
	else printf("%lu\n", lim.rlim_max);
}

void __init os_early_checks(void)
{
	/* Print out the core dump limits early */
	check_coredump_limit();

	check_ptrace();

	/* Need to check this early because mmapping happens before the
	 * kernel is running.
	 */
	check_tmpexec();
}

static int __init noprocmm_cmd_param(char *str, int* add)
{
	proc_mm = 0;
	return 0;
}

__uml_setup("noprocmm", noprocmm_cmd_param,
"noprocmm\n"
"    Turns off usage of /proc/mm, even if host supports it.\n"
"    To support /proc/mm, the host needs to be patched using\n"
"    the current skas3 patch.\n\n");

static int __init noptracefaultinfo_cmd_param(char *str, int* add)
{
	ptrace_faultinfo = 0;
	return 0;
}

__uml_setup("noptracefaultinfo", noptracefaultinfo_cmd_param,
"noptracefaultinfo\n"
"    Turns off usage of PTRACE_FAULTINFO, even if host supports\n"
"    it. To support PTRACE_FAULTINFO, the host needs to be patched\n"
"    using the current skas3 patch.\n\n");

static int __init noptraceldt_cmd_param(char *str, int* add)
{
	ptrace_ldt = 0;
	return 0;
}

__uml_setup("noptraceldt", noptraceldt_cmd_param,
"noptraceldt\n"
"    Turns off usage of PTRACE_LDT, even if host supports it.\n"
"    To support PTRACE_LDT, the host needs to be patched using\n"
"    the current skas3 patch.\n\n");

static inline void check_skas3_ptrace_faultinfo(void)
{
	struct ptrace_faultinfo fi;
	void *stack;
	int pid, n;

	non_fatal("  - PTRACE_FAULTINFO...");
	pid = start_ptraced_child(&stack);

	n = ptrace(PTRACE_FAULTINFO, pid, 0, &fi);
	if (n < 0) {
		ptrace_faultinfo = 0;
		if(errno == EIO)
			non_fatal("not found\n");
		else
			perror("not found");
	}
	else {
		if (!ptrace_faultinfo)
			non_fatal("found but disabled on command line\n");
		else
			non_fatal("found\n");
	}

	init_registers(pid);
	stop_ptraced_child(pid, stack, 1, 1);
}

static inline void check_skas3_ptrace_ldt(void)
{
#ifdef PTRACE_LDT
	void *stack;
	int pid, n;
	unsigned char ldtbuf[40];
	struct ptrace_ldt ldt_op = (struct ptrace_ldt) {
		.func = 2, /* read default ldt */
		.ptr = ldtbuf,
		.bytecount = sizeof(ldtbuf)};

	non_fatal("  - PTRACE_LDT...");
	pid = start_ptraced_child(&stack);

	n = ptrace(PTRACE_LDT, pid, 0, (unsigned long) &ldt_op);
	if (n < 0) {
		if(errno == EIO)
			non_fatal("not found\n");
		else {
			perror("not found");
		}
		ptrace_ldt = 0;
	}
	else {
		if(ptrace_ldt)
			non_fatal("found\n");
		else
			non_fatal("found, but use is disabled\n");
	}

	stop_ptraced_child(pid, stack, 1, 1);
#else
	/* PTRACE_LDT might be disabled via cmdline option.
	 * We want to override this, else we might use the stub
	 * without real need
	 */
	ptrace_ldt = 1;
#endif
}

static inline void check_skas3_proc_mm(void)
{
	non_fatal("  - /proc/mm...");
	if (access("/proc/mm", W_OK) < 0) {
		proc_mm = 0;
		perror("not found");
	}
	else {
		if (!proc_mm)
			non_fatal("found but disabled on command line\n");
		else
			non_fatal("found\n");
	}
}

int can_do_skas(void)
{
	non_fatal("Checking for the skas3 patch in the host:\n");

	check_skas3_proc_mm();
	check_skas3_ptrace_faultinfo();
	check_skas3_ptrace_ldt();

	if(!proc_mm || !ptrace_faultinfo || !ptrace_ldt)
		skas_needs_stub = 1;

	return 1;
}

int __init parse_iomem(char *str, int *add)
{
	struct iomem_region *new;
	struct stat64 buf;
	char *file, *driver;
	int fd, size;

	driver = str;
	file = strchr(str,',');
	if(file == NULL){
		printf("parse_iomem : failed to parse iomem\n");
		goto out;
	}
	*file = '\0';
	file++;
	fd = open(file, O_RDWR, 0);
	if(fd < 0){
		os_print_error(fd, "parse_iomem - Couldn't open io file");
		goto out;
	}

	if(fstat64(fd, &buf) < 0){
		perror("parse_iomem - cannot stat_fd file");
		goto out_close;
	}

	new = malloc(sizeof(*new));
	if(new == NULL){
		perror("Couldn't allocate iomem_region struct");
		goto out_close;
	}

	size = (buf.st_size + UM_KERN_PAGE_SIZE) & ~(UM_KERN_PAGE_SIZE - 1);

	*new = ((struct iomem_region) { .next		= iomem_regions,
					.driver		= driver,
					.fd		= fd,
					.size		= size,
					.phys		= 0,
					.virt		= 0 });
	iomem_regions = new;
	iomem_size += new->size + UM_KERN_PAGE_SIZE;

	return 0;
 out_close:
	close(fd);
 out:
	return 1;
}
Commit	Line	Data
60d339f6	1	/*
1da177e4 LT	2	* Copyright (C) 2000, 2001, 2002 Jeff Dike (jdike@karaya.com)
	3	* Licensed under the GPL
	4	*/
	5
8e367065	6	#include <pty.h>
1da177e4	7	#include <stdio.h>
0f80bc85 JD	8	#include <stddef.h>
	9	#include <stdarg.h>
	10	#include <stdlib.h>
	11	#include <string.h>
1da177e4 LT	12	#include <unistd.h>
	13	#include <signal.h>
	14	#include <sched.h>
0f80bc85	15	#include <fcntl.h>
1da177e4	16	#include <errno.h>
1da177e4 LT	17	#include <sys/time.h>
	18	#include <sys/wait.h>
	19	#include <sys/mman.h>
1d94cda0	20	#include <sys/resource.h>
1da177e4	21	#include <asm/unistd.h>
0f80bc85	22	#include <sys/types.h>
1da177e4 LT	23	#include "kern_util.h"
1da177e4 LT	24	#include "user.h"
1da177e4	25	#include "signal_kern.h"
1da177e4 LT	26	#include "sysdep/ptrace.h"
	27	#include "sysdep/sigcontext.h"
	28	#include "irq_user.h"
	29	#include "ptrace_user.h"
0f80bc85	30	#include "mem_user.h"
1da177e4 LT	31	#include "init.h"
	32	#include "os.h"
	33	#include "uml-config.h"
d67b569f	34	#include "tempfile.h"
0f80bc85	35	#include "kern_constants.h"
1da177e4 LT	36	#include "skas.h"
	37	#include "skas_ptrace.h"
	38	#include "registers.h"
1da177e4	39
b85e9680	40	static int ptrace_child(void *arg)
1da177e4 LT	41	{
	42	int ret;
	43	int pid = os_getpid(), ppid = getppid();
	44	int sc_result;
	45
43b00fdb	46	change_sig(SIGWINCH, 0);
1da177e4 LT	47	if(ptrace(PTRACE_TRACEME, 0, 0, 0) < 0){
	48	perror("ptrace");
	49	os_kill_process(pid, 0);
	50	}
73c8f444	51	kill(pid, SIGSTOP);
1da177e4 LT	52
	53	/*This syscall will be intercepted by the parent. Don't call more than
	54	* once, please.*/
	55	sc_result = os_getpid();
	56
	57	if (sc_result == pid)
	58	ret = 1; /*Nothing modified by the parent, we are running
	59	normally.*/
	60	else if (sc_result == ppid)
	61	ret = 0; /*Expected in check_ptrace and check_sysemu when they
	62	succeed in modifying the stack frame*/
	63	else
	64	ret = 2; /*Serious trouble! This could be caused by a bug in
	65	host 2.6 SKAS3/2.6 patch before release -V6, together
	66	with a bug in the UML code itself.*/
	67	_exit(ret);
	68	}
	69
3a150e1d JD	70	static void fatal_perror(char *str)
	71	{
	72	perror(str);
	73	exit(1);
	74	}
	75
	76	static void fatal(char *fmt, ...)
	77	{
	78	va_list list;
	79
	80	va_start(list, fmt);
	81	vprintf(fmt, list);
	82	va_end(list);
	83	fflush(stdout);
	84
	85	exit(1);
	86	}
	87
	88	static void non_fatal(char *fmt, ...)
	89	{
	90	va_list list;
	91
	92	va_start(list, fmt);
	93	vprintf(fmt, list);
	94	va_end(list);
	95	fflush(stdout);
	96	}
	97
b85e9680	98	static int start_ptraced_child(void **stack_out)
1da177e4	99	{
b85e9680 JD	100	void *stack;
b85e9680 JD	101	unsigned long sp;
1da177e4	102	int pid, n, status;
60d339f6	103
c539ab73 JD	104	stack = mmap(NULL, UM_KERN_PAGE_SIZE,
c539ab73 JD	105	PROT_READ \| PROT_WRITE \| PROT_EXEC,
b85e9680 JD	106	MAP_PRIVATE \| MAP_ANONYMOUS, -1, 0);
b85e9680 JD	107	if(stack == MAP_FAILED)
3a150e1d	108	fatal_perror("check_ptrace : mmap failed");
c539ab73	109	sp = (unsigned long) stack + UM_KERN_PAGE_SIZE - sizeof(void *);
b85e9680	110	pid = clone(ptrace_child, (void *) sp, SIGCHLD, NULL);
1da177e4	111	if(pid < 0)
3a150e1d	112	fatal_perror("start_ptraced_child : clone failed");
1da177e4 LT	113	CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
1da177e4 LT	114	if(n < 0)
3a150e1d	115	fatal_perror("check_ptrace : clone failed");
1da177e4	116	if(!WIFSTOPPED(status) \|\| (WSTOPSIG(status) != SIGSTOP))
3a150e1d	117	fatal("check_ptrace : expected SIGSTOP, got status = %d",
1da177e4 LT	118	status);
1da177e4 LT	119
b85e9680	120	*stack_out = stack;
9eae9b13	121	return pid;
1da177e4 LT	122	}
1da177e4 LT	123
60d339f6 GS	124	/* When testing for SYSEMU support, if it is one of the broken versions, we
	125	* must just avoid using sysemu, not panic, but only if SYSEMU features are
	126	* broken.
1da177e4	127	* So only for SYSEMU features we test mustpanic, while normal host features
60d339f6 GS	128	* must work anyway!
	129	*/
	130	static int stop_ptraced_child(int pid, void *stack, int exitcode,
3a150e1d	131	int mustexit)
1da177e4 LT	132	{
	133	int status, n, ret = 0;
	134
	135	if(ptrace(PTRACE_CONT, pid, 0, 0) < 0)
3a150e1d	136	fatal_perror("stop_ptraced_child : ptrace failed");
1da177e4 LT	137	CATCH_EINTR(n = waitpid(pid, &status, 0));
	138	if(!WIFEXITED(status) \|\| (WEXITSTATUS(status) != exitcode)) {
	139	int exit_with = WEXITSTATUS(status);
	140	if (exit_with == 2)
3a150e1d	141	non_fatal("check_ptrace : child exited with status 2. "
cf6acedb	142	"\nDisabling SYSEMU support.\n");
3a150e1d JD	143	non_fatal("check_ptrace : child exited with exitcode %d, while "
	144	"expecting %d; status 0x%x\n", exit_with,
	145	exitcode, status);
	146	if (mustexit)
	147	exit(1);
1da177e4 LT	148	ret = -1;
	149	}
	150
c539ab73	151	if(munmap(stack, UM_KERN_PAGE_SIZE) < 0)
3a150e1d	152	fatal_perror("check_ptrace : munmap failed");
1da177e4 LT	153	return ret;
	154	}
	155
7242a400	156	/* Changed only during early boot */
cb66504d	157	int ptrace_faultinfo = 1;
858259cf	158	int ptrace_ldt = 1;
cb66504d	159	int proc_mm = 1;
858259cf	160	int skas_needs_stub = 0;
cb66504d PBG	161
	162	static int __init skas0_cmd_param(char str, int add)
	163	{
	164	ptrace_faultinfo = proc_mm = 0;
	165	return 0;
	166	}
	167
9e3d862e PBG	168	/* The two __uml_setup would conflict, without this stupid alias. */
	169
	170	static int __init mode_skas0_cmd_param(char str, int add)
	171	__attribute__((alias("skas0_cmd_param")));
	172
60d339f6 GS	173	__uml_setup("skas0", skas0_cmd_param,
	174	"skas0\n"
	175	" Disables SKAS3 usage, so that SKAS0 is used, unless \n"
	176	" you specify mode=tt.\n\n");
	177
9e3d862e PBG	178	__uml_setup("mode=skas0", mode_skas0_cmd_param,
	179	"mode=skas0\n"
	180	" Disables SKAS3 usage, so that SKAS0 is used, unless you \n"
	181	" specify mode=tt. Note that this was recently added - on \n"
	182	" older kernels you must use simply \"skas0\".\n\n");
	183
7242a400	184	/* Changed only during early boot */
60d339f6 GS	185	static int force_sysemu_disabled = 0;
60d339f6 GS	186
1da177e4 LT	187	static int __init nosysemu_cmd_param(char str, int add)
	188	{
	189	force_sysemu_disabled = 1;
	190	return 0;
	191	}
	192
	193	__uml_setup("nosysemu", nosysemu_cmd_param,
60d339f6 GS	194	"nosysemu\n"
	195	" Turns off syscall emulation patch for ptrace (SYSEMU) on.\n"
	196	" SYSEMU is a performance-patch introduced by Laurent Vivier. It changes\n"
	197	" behaviour of ptrace() and helps reducing host context switch rate.\n"
	198	" To make it working, you need a kernel patch for your host, too.\n"
	199	" See http://perso.wanadoo.fr/laurent.vivier/UML/ for further \n"
	200	" information.\n\n");
1da177e4 LT	201
	202	static void __init check_sysemu(void)
	203	{
b85e9680	204	void *stack;
cf6acedb	205	unsigned long regs[MAX_REG_NR];
9eae9b13	206	int pid, n, status, count=0;
1da177e4	207
3a150e1d	208	non_fatal("Checking syscall emulation patch for ptrace...");
1da177e4	209	sysemu_supported = 0;
b85e9680	210	pid = start_ptraced_child(&stack);
1da177e4 LT	211
	212	if(ptrace(PTRACE_SYSEMU, pid, 0, 0) < 0)
	213	goto fail;
	214
	215	CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
	216	if (n < 0)
3a150e1d	217	fatal_perror("check_sysemu : wait failed");
1da177e4	218	if(!WIFSTOPPED(status) \|\| (WSTOPSIG(status) != SIGTRAP))
3a150e1d JD	219	fatal("check_sysemu : expected SIGTRAP, got status = %d",
3a150e1d JD	220	status);
1da177e4	221
cf6acedb JD	222	if(ptrace(PTRACE_GETREGS, pid, 0, regs) < 0)
	223	fatal_perror("check_sysemu : PTRACE_GETREGS failed");
	224	if(PT_SYSCALL_NR(regs) != __NR_getpid){
	225	non_fatal("check_sysemu got system call number %d, "
	226	"expected %d...", PT_SYSCALL_NR(regs), __NR_getpid);
	227	goto fail;
	228	}
	229
	230	n = ptrace(PTRACE_POKEUSR, pid, PT_SYSCALL_RET_OFFSET, os_getpid());
	231	if(n < 0){
	232	non_fatal("check_sysemu : failed to modify system call "
	233	"return");
	234	goto fail;
	235	}
1da177e4	236
b85e9680	237	if (stop_ptraced_child(pid, stack, 0, 0) < 0)
1da177e4 LT	238	goto fail_stopped;
	239
	240	sysemu_supported = 1;
3a150e1d	241	non_fatal("OK\n");
1da177e4 LT	242	set_using_sysemu(!force_sysemu_disabled);
1da177e4 LT	243
3a150e1d	244	non_fatal("Checking advanced syscall emulation patch for ptrace...");
b85e9680	245	pid = start_ptraced_child(&stack);
f9dfefe4	246
3a150e1d JD	247	if((ptrace(PTRACE_OLDSETOPTIONS, pid, 0,
	248	(void *) PTRACE_O_TRACESYSGOOD) < 0))
	249	fatal_perror("check_ptrace: PTRACE_OLDSETOPTIONS failed");
f9dfefe4	250
1da177e4 LT	251	while(1){
	252	count++;
	253	if(ptrace(PTRACE_SYSEMU_SINGLESTEP, pid, 0, 0) < 0)
	254	goto fail;
	255	CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
	256	if(n < 0)
3a150e1d JD	257	fatal_perror("check_ptrace : wait failed");
3a150e1d JD	258
f9dfefe4	259	if(WIFSTOPPED(status) && (WSTOPSIG(status) == (SIGTRAP\|0x80))){
1da177e4	260	if (!count)
3a150e1d	261	fatal("check_ptrace : SYSEMU_SINGLESTEP "
f9dfefe4	262	"doesn't singlestep");
1da177e4 LT	263	n = ptrace(PTRACE_POKEUSR, pid, PT_SYSCALL_RET_OFFSET,
	264	os_getpid());
	265	if(n < 0)
3a150e1d JD	266	fatal_perror("check_sysemu : failed to modify "
3a150e1d JD	267	"system call return");
1da177e4 LT	268	break;
1da177e4 LT	269	}
f9dfefe4 BS	270	else if(WIFSTOPPED(status) && (WSTOPSIG(status) == SIGTRAP))
	271	count++;
	272	else
3a150e1d JD	273	fatal("check_ptrace : expected SIGTRAP or "
3a150e1d JD	274	"(SIGTRAP \| 0x80), got status = %d", status);
1da177e4	275	}
b85e9680	276	if (stop_ptraced_child(pid, stack, 0, 0) < 0)
1da177e4 LT	277	goto fail_stopped;
	278
	279	sysemu_supported = 2;
3a150e1d	280	non_fatal("OK\n");
1da177e4 LT	281
	282	if ( !force_sysemu_disabled )
	283	set_using_sysemu(sysemu_supported);
	284	return;
	285
	286	fail:
b85e9680	287	stop_ptraced_child(pid, stack, 1, 0);
1da177e4	288	fail_stopped:
3a150e1d	289	non_fatal("missing\n");
1da177e4 LT	290	}
1da177e4 LT	291
60d339f6	292	static void __init check_ptrace(void)
1da177e4	293	{
b85e9680	294	void *stack;
1da177e4 LT	295	int pid, syscall, n, status;
1da177e4 LT	296
3a150e1d	297	non_fatal("Checking that ptrace can change system call numbers...");
b85e9680	298	pid = start_ptraced_child(&stack);
1da177e4	299
3a150e1d JD	300	if((ptrace(PTRACE_OLDSETOPTIONS, pid, 0,
	301	(void *) PTRACE_O_TRACESYSGOOD) < 0))
	302	fatal_perror("check_ptrace: PTRACE_OLDSETOPTIONS failed");
1da177e4 LT	303
	304	while(1){
	305	if(ptrace(PTRACE_SYSCALL, pid, 0, 0) < 0)
3a150e1d JD	306	fatal_perror("check_ptrace : ptrace failed");
3a150e1d JD	307
1da177e4 LT	308	CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
1da177e4 LT	309	if(n < 0)
3a150e1d JD	310	fatal_perror("check_ptrace : wait failed");
	311
	312	if(!WIFSTOPPED(status) \|\|
	313	(WSTOPSIG(status) != (SIGTRAP \| 0x80)))
	314	fatal("check_ptrace : expected (SIGTRAP\|0x80), "
	315	"got status = %d", status);
60d339f6	316
1da177e4 LT	317	syscall = ptrace(PTRACE_PEEKUSR, pid, PT_SYSCALL_NR_OFFSET,
	318	0);
	319	if(syscall == __NR_getpid){
	320	n = ptrace(PTRACE_POKEUSR, pid, PT_SYSCALL_NR_OFFSET,
	321	__NR_getppid);
	322	if(n < 0)
3a150e1d JD	323	fatal_perror("check_ptrace : failed to modify "
3a150e1d JD	324	"system call");
1da177e4 LT	325	break;
	326	}
	327	}
b85e9680	328	stop_ptraced_child(pid, stack, 0, 1);
3a150e1d	329	non_fatal("OK\n");
1da177e4 LT	330	check_sysemu();
	331	}
	332
966a082f	333	extern void check_tmpexec(void);
0f80bc85	334
36e45463	335	static void __init check_coredump_limit(void)
1d94cda0 JD	336	{
	337	struct rlimit lim;
	338	int err = getrlimit(RLIMIT_CORE, &lim);
	339
	340	if(err){
	341	perror("Getting core dump limit");
	342	return;
	343	}
	344
	345	printf("Core dump limits :\n\tsoft - ");
	346	if(lim.rlim_cur == RLIM_INFINITY)
	347	printf("NONE\n");
	348	else printf("%lu\n", lim.rlim_cur);
	349
	350	printf("\thard - ");
	351	if(lim.rlim_max == RLIM_INFINITY)
	352	printf("NONE\n");
	353	else printf("%lu\n", lim.rlim_max);
	354	}
	355
36e45463	356	void __init os_early_checks(void)
1da177e4	357	{
1d94cda0 JD	358	/* Print out the core dump limits early */
	359	check_coredump_limit();
	360
60d339f6	361	check_ptrace();
0f80bc85 JD	362
	363	/* Need to check this early because mmapping happens before the
	364	* kernel is running.
	365	*/
	366	check_tmpexec();
1da177e4 LT	367	}
1da177e4 LT	368
d9838d86 BS	369	static int __init noprocmm_cmd_param(char str, int add)
	370	{
	371	proc_mm = 0;
	372	return 0;
	373	}
	374
	375	__uml_setup("noprocmm", noprocmm_cmd_param,
	376	"noprocmm\n"
	377	" Turns off usage of /proc/mm, even if host supports it.\n"
	378	" To support /proc/mm, the host needs to be patched using\n"
	379	" the current skas3 patch.\n\n");
	380
	381	static int __init noptracefaultinfo_cmd_param(char str, int add)
	382	{
	383	ptrace_faultinfo = 0;
	384	return 0;
	385	}
	386
	387	__uml_setup("noptracefaultinfo", noptracefaultinfo_cmd_param,
	388	"noptracefaultinfo\n"
	389	" Turns off usage of PTRACE_FAULTINFO, even if host supports\n"
	390	" it. To support PTRACE_FAULTINFO, the host needs to be patched\n"
	391	" using the current skas3 patch.\n\n");
	392
858259cf BS	393	static int __init noptraceldt_cmd_param(char str, int add)
	394	{
	395	ptrace_ldt = 0;
	396	return 0;
	397	}
	398
	399	__uml_setup("noptraceldt", noptraceldt_cmd_param,
	400	"noptraceldt\n"
	401	" Turns off usage of PTRACE_LDT, even if host supports it.\n"
	402	" To support PTRACE_LDT, the host needs to be patched using\n"
	403	" the current skas3 patch.\n\n");
	404
858259cf	405	static inline void check_skas3_ptrace_faultinfo(void)
1da177e4 LT	406	{
1da177e4 LT	407	struct ptrace_faultinfo fi;
b85e9680	408	void *stack;
d67b569f	409	int pid, n;
1da177e4	410
3a150e1d	411	non_fatal(" - PTRACE_FAULTINFO...");
b85e9680	412	pid = start_ptraced_child(&stack);
1da177e4 LT	413
	414	n = ptrace(PTRACE_FAULTINFO, pid, 0, &fi);
	415	if (n < 0) {
cb66504d	416	ptrace_faultinfo = 0;
1da177e4	417	if(errno == EIO)
3a150e1d	418	non_fatal("not found\n");
60d339f6	419	else
1da177e4	420	perror("not found");
d67b569f JD	421	}
d67b569f JD	422	else {
cb66504d	423	if (!ptrace_faultinfo)
3a150e1d	424	non_fatal("found but disabled on command line\n");
cb66504d	425	else
3a150e1d	426	non_fatal("found\n");
1da177e4 LT	427	}
	428
	429	init_registers(pid);
b85e9680	430	stop_ptraced_child(pid, stack, 1, 1);
1da177e4 LT	431	}
1da177e4 LT	432
858259cf BS	433	static inline void check_skas3_ptrace_ldt(void)
	434	{
	435	#ifdef PTRACE_LDT
	436	void *stack;
	437	int pid, n;
	438	unsigned char ldtbuf[40];
	439	struct ptrace_ldt ldt_op = (struct ptrace_ldt) {
	440	.func = 2, /* read default ldt */
	441	.ptr = ldtbuf,
	442	.bytecount = sizeof(ldtbuf)};
	443
3a150e1d	444	non_fatal(" - PTRACE_LDT...");
858259cf BS	445	pid = start_ptraced_child(&stack);
	446
	447	n = ptrace(PTRACE_LDT, pid, 0, (unsigned long) &ldt_op);
	448	if (n < 0) {
	449	if(errno == EIO)
3a150e1d	450	non_fatal("not found\n");
858259cf BS	451	else {
	452	perror("not found");
	453	}
	454	ptrace_ldt = 0;
	455	}
	456	else {
	457	if(ptrace_ldt)
3a150e1d	458	non_fatal("found\n");
858259cf	459	else
3a150e1d	460	non_fatal("found, but use is disabled\n");
858259cf BS	461	}
	462
	463	stop_ptraced_child(pid, stack, 1, 1);
	464	#else
	465	/* PTRACE_LDT might be disabled via cmdline option.
	466	* We want to override this, else we might use the stub
	467	* without real need
	468	*/
	469	ptrace_ldt = 1;
	470	#endif
	471	}
	472
	473	static inline void check_skas3_proc_mm(void)
1da177e4	474	{
3a150e1d	475	non_fatal(" - /proc/mm...");
73c8f444	476	if (access("/proc/mm", W_OK) < 0) {
9eae9b13	477	proc_mm = 0;
3a150e1d	478	perror("not found");
60d339f6 GS	479	}
60d339f6 GS	480	else {
cb66504d	481	if (!proc_mm)
3a150e1d	482	non_fatal("found but disabled on command line\n");
cb66504d	483	else
3a150e1d	484	non_fatal("found\n");
1da177e4	485	}
858259cf BS	486	}
	487
	488	int can_do_skas(void)
	489	{
3a150e1d	490	non_fatal("Checking for the skas3 patch in the host:\n");
858259cf BS	491
	492	check_skas3_proc_mm();
	493	check_skas3_ptrace_faultinfo();
	494	check_skas3_ptrace_ldt();
	495
	496	if(!proc_mm \|\| !ptrace_faultinfo \|\| !ptrace_ldt)
	497	skas_needs_stub = 1;
1da177e4	498
d67b569f	499	return 1;
1da177e4	500	}
0f80bc85	501
0f80bc85 JD	502	int __init parse_iomem(char str, int add)
	503	{
	504	struct iomem_region *new;
73c8f444	505	struct stat64 buf;
0f80bc85	506	char file, driver;
73c8f444	507	int fd, size;
0f80bc85 JD	508
	509	driver = str;
	510	file = strchr(str,',');
	511	if(file == NULL){
	512	printf("parse_iomem : failed to parse iomem\n");
	513	goto out;
	514	}
	515	*file = '\0';
	516	file++;
73c8f444	517	fd = open(file, O_RDWR, 0);
0f80bc85 JD	518	if(fd < 0){
	519	os_print_error(fd, "parse_iomem - Couldn't open io file");
	520	goto out;
	521	}
	522
73c8f444 JD	523	if(fstat64(fd, &buf) < 0){
73c8f444 JD	524	perror("parse_iomem - cannot stat_fd file");
0f80bc85 JD	525	goto out_close;
	526	}
	527
	528	new = malloc(sizeof(*new));
	529	if(new == NULL){
	530	perror("Couldn't allocate iomem_region struct");
	531	goto out_close;
	532	}
	533
73c8f444	534	size = (buf.st_size + UM_KERN_PAGE_SIZE) & ~(UM_KERN_PAGE_SIZE - 1);
0f80bc85 JD	535
	536	*new = ((struct iomem_region) { .next = iomem_regions,
	537	.driver = driver,
	538	.fd = fd,
	539	.size = size,
	540	.phys = 0,
	541	.virt = 0 });
	542	iomem_regions = new;
	543	iomem_size += new->size + UM_KERN_PAGE_SIZE;
	544
9eae9b13	545	return 0;
0f80bc85	546	out_close:
73c8f444	547	close(fd);
0f80bc85	548	out:
9eae9b13	549	return 1;
0f80bc85	550	}