[mirror_ubuntu-zesty-kernel.git] / arch / s390 / kernel / signal.c

/*
 *    Copyright IBM Corp. 1999, 2006
 *    Author(s): Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com)
 *
 *    Based on Intel version
 * 
 *  Copyright (C) 1991, 1992  Linus Torvalds
 *
 *  1997-11-28  Modified for POSIX.1b signals by Richard Henderson
 */

#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/kernel.h>
#include <linux/signal.h>
#include <linux/errno.h>
#include <linux/wait.h>
#include <linux/ptrace.h>
#include <linux/unistd.h>
#include <linux/stddef.h>
#include <linux/tty.h>
#include <linux/personality.h>
#include <linux/binfmts.h>
#include <linux/tracehook.h>
#include <linux/syscalls.h>
#include <linux/compat.h>
#include <asm/ucontext.h>
#include <asm/uaccess.h>
#include <asm/lowcore.h>
#include <asm/switch_to.h>
#include "entry.h"

typedef struct 
{
	__u8 callee_used_stack[__SIGNAL_FRAMESIZE];
	struct sigcontext sc;
	_sigregs sregs;
	int signo;
	__u8 retcode[S390_SYSCALL_SIZE];
} sigframe;

typedef struct 
{
	__u8 callee_used_stack[__SIGNAL_FRAMESIZE];
	__u8 retcode[S390_SYSCALL_SIZE];
	struct siginfo info;
	struct ucontext uc;
} rt_sigframe;

/* Returns non-zero on fault. */
static int save_sigregs(struct pt_regs *regs, _sigregs __user *sregs)
{
	_sigregs user_sregs;

	save_access_regs(current->thread.acrs);

	/* Copy a 'clean' PSW mask to the user to avoid leaking
	   information about whether PER is currently on.  */
	user_sregs.regs.psw.mask = PSW_USER_BITS |
		(regs->psw.mask & (PSW_MASK_USER | PSW_MASK_RI));
	user_sregs.regs.psw.addr = regs->psw.addr;
	memcpy(&user_sregs.regs.gprs, &regs->gprs, sizeof(sregs->regs.gprs));
	memcpy(&user_sregs.regs.acrs, current->thread.acrs,
	       sizeof(user_sregs.regs.acrs));
	/* 
	 * We have to store the fp registers to current->thread.fp_regs
	 * to merge them with the emulated registers.
	 */
	save_fp_ctl(&current->thread.fp_regs.fpc);
	save_fp_regs(current->thread.fp_regs.fprs);
	memcpy(&user_sregs.fpregs, &current->thread.fp_regs,
	       sizeof(user_sregs.fpregs));
	if (__copy_to_user(sregs, &user_sregs, sizeof(_sigregs)))
		return -EFAULT;
	return 0;
}

static int restore_sigregs(struct pt_regs *regs, _sigregs __user *sregs)
{
	_sigregs user_sregs;

	/* Alwys make any pending restarted system call return -EINTR */
	current_thread_info()->restart_block.fn = do_no_restart_syscall;

	if (__copy_from_user(&user_sregs, sregs, sizeof(user_sregs)))
		return -EFAULT;

	if (!is_ri_task(current) && (user_sregs.regs.psw.mask & PSW_MASK_RI))
		return -EINVAL;

	/* Loading the floating-point-control word can fail. Do that first. */
	if (restore_fp_ctl(&user_sregs.fpregs.fpc))
		return -EINVAL;

	/* Use regs->psw.mask instead of PSW_USER_BITS to preserve PER bit. */
	regs->psw.mask = (regs->psw.mask & ~PSW_MASK_USER) |
		(user_sregs.regs.psw.mask & (PSW_MASK_USER | PSW_MASK_RI));
	/* Check for invalid user address space control. */
	if ((regs->psw.mask & PSW_MASK_ASC) == PSW_ASC_HOME)
		regs->psw.mask = PSW_ASC_PRIMARY |
			(regs->psw.mask & ~PSW_MASK_ASC);
	/* Check for invalid amode */
	if (regs->psw.mask & PSW_MASK_EA)
		regs->psw.mask |= PSW_MASK_BA;
	regs->psw.addr = user_sregs.regs.psw.addr;
	memcpy(&regs->gprs, &user_sregs.regs.gprs, sizeof(sregs->regs.gprs));
	memcpy(&current->thread.acrs, &user_sregs.regs.acrs,
	       sizeof(current->thread.acrs));
	restore_access_regs(current->thread.acrs);

	memcpy(&current->thread.fp_regs, &user_sregs.fpregs,
	       sizeof(current->thread.fp_regs));

	restore_fp_regs(current->thread.fp_regs.fprs);
	clear_thread_flag(TIF_SYSCALL);	/* No longer in a system call */
	return 0;
}

SYSCALL_DEFINE0(sigreturn)
{
	struct pt_regs *regs = task_pt_regs(current);
	sigframe __user *frame = (sigframe __user *)regs->gprs[15];
	sigset_t set;

	if (__copy_from_user(&set.sig, &frame->sc.oldmask, _SIGMASK_COPY_SIZE))
		goto badframe;
	set_current_blocked(&set);
	if (restore_sigregs(regs, &frame->sregs))
		goto badframe;
	return regs->gprs[2];
badframe:
	force_sig(SIGSEGV, current);
	return 0;
}

SYSCALL_DEFINE0(rt_sigreturn)
{
	struct pt_regs *regs = task_pt_regs(current);
	rt_sigframe __user *frame = (rt_sigframe __user *)regs->gprs[15];
	sigset_t set;

	if (__copy_from_user(&set.sig, &frame->uc.uc_sigmask, sizeof(set)))
		goto badframe;
	set_current_blocked(&set);
	if (restore_sigregs(regs, &frame->uc.uc_mcontext))
		goto badframe;
	if (restore_altstack(&frame->uc.uc_stack))
		goto badframe;
	return regs->gprs[2];
badframe:
	force_sig(SIGSEGV, current);
	return 0;
}

/*
 * Set up a signal frame.
 */


/*
 * Determine which stack to use..
 */
static inline void __user *
get_sigframe(struct k_sigaction *ka, struct pt_regs * regs, size_t frame_size)
{
	unsigned long sp;

	/* Default to using normal stack */
	sp = regs->gprs[15];

	/* Overflow on alternate signal stack gives SIGSEGV. */
	if (on_sig_stack(sp) && !on_sig_stack((sp - frame_size) & -8UL))
		return (void __user *) -1UL;

	/* This is the X/Open sanctioned signal stack switching.  */
	if (ka->sa.sa_flags & SA_ONSTACK) {
		if (! sas_ss_flags(sp))
			sp = current->sas_ss_sp + current->sas_ss_size;
	}

	return (void __user *)((sp - frame_size) & -8ul);
}

static inline int map_signal(int sig)
{
	if (current_thread_info()->exec_domain
	    && current_thread_info()->exec_domain->signal_invmap
	    && sig < 32)
		return current_thread_info()->exec_domain->signal_invmap[sig];
	else
		return sig;
}

static int setup_frame(int sig, struct k_sigaction *ka,
		       sigset_t *set, struct pt_regs * regs)
{
	sigframe __user *frame;

	frame = get_sigframe(ka, regs, sizeof(sigframe));

	if (frame == (void __user *) -1UL)
		goto give_sigsegv;

	if (__copy_to_user(&frame->sc.oldmask, &set->sig, _SIGMASK_COPY_SIZE))
		goto give_sigsegv;

	if (save_sigregs(regs, &frame->sregs))
		goto give_sigsegv;
	if (__put_user(&frame->sregs, &frame->sc.sregs))
		goto give_sigsegv;

	/* Set up to return from userspace.  If provided, use a stub
	   already in userspace.  */
	if (ka->sa.sa_flags & SA_RESTORER) {
                regs->gprs[14] = (unsigned long)
			ka->sa.sa_restorer | PSW_ADDR_AMODE;
	} else {
                regs->gprs[14] = (unsigned long)
			frame->retcode | PSW_ADDR_AMODE;
		if (__put_user(S390_SYSCALL_OPCODE | __NR_sigreturn,
	                       (u16 __user *)(frame->retcode)))
			goto give_sigsegv;
	}

	/* Set up backchain. */
	if (__put_user(regs->gprs[15], (addr_t __user *) frame))
		goto give_sigsegv;

	/* Set up registers for signal handler */
	regs->gprs[15] = (unsigned long) frame;
	/* Force default amode and default user address space control. */
	regs->psw.mask = PSW_MASK_EA | PSW_MASK_BA |
		(PSW_USER_BITS & PSW_MASK_ASC) |
		(regs->psw.mask & ~PSW_MASK_ASC);
	regs->psw.addr = (unsigned long) ka->sa.sa_handler | PSW_ADDR_AMODE;

	regs->gprs[2] = map_signal(sig);
	regs->gprs[3] = (unsigned long) &frame->sc;

	/* We forgot to include these in the sigcontext.
	   To avoid breaking binary compatibility, they are passed as args. */
	if (sig == SIGSEGV || sig == SIGBUS || sig == SIGILL ||
	    sig == SIGTRAP || sig == SIGFPE) {
		/* set extra registers only for synchronous signals */
		regs->gprs[4] = regs->int_code & 127;
		regs->gprs[5] = regs->int_parm_long;
		regs->gprs[6] = task_thread_info(current)->last_break;
	}

	/* Place signal number on stack to allow backtrace from handler.  */
	if (__put_user(regs->gprs[2], (int __user *) &frame->signo))
		goto give_sigsegv;
	return 0;

give_sigsegv:
	force_sigsegv(sig, current);
	return -EFAULT;
}

static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
			   sigset_t *set, struct pt_regs * regs)
{
	int err = 0;
	rt_sigframe __user *frame;

	frame = get_sigframe(ka, regs, sizeof(rt_sigframe));

	if (frame == (void __user *) -1UL)
		goto give_sigsegv;

	if (copy_siginfo_to_user(&frame->info, info))
		goto give_sigsegv;

	/* Create the ucontext.  */
	err |= __put_user(0, &frame->uc.uc_flags);
	err |= __put_user(NULL, &frame->uc.uc_link);
	err |= __save_altstack(&frame->uc.uc_stack, regs->gprs[15]);
	err |= save_sigregs(regs, &frame->uc.uc_mcontext);
	err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
	if (err)
		goto give_sigsegv;

	/* Set up to return from userspace.  If provided, use a stub
	   already in userspace.  */
	if (ka->sa.sa_flags & SA_RESTORER) {
                regs->gprs[14] = (unsigned long)
			ka->sa.sa_restorer | PSW_ADDR_AMODE;
	} else {
                regs->gprs[14] = (unsigned long)
			frame->retcode | PSW_ADDR_AMODE;
		if (__put_user(S390_SYSCALL_OPCODE | __NR_rt_sigreturn,
			       (u16 __user *)(frame->retcode)))
			goto give_sigsegv;
	}

	/* Set up backchain. */
	if (__put_user(regs->gprs[15], (addr_t __user *) frame))
		goto give_sigsegv;

	/* Set up registers for signal handler */
	regs->gprs[15] = (unsigned long) frame;
	/* Force default amode and default user address space control. */
	regs->psw.mask = PSW_MASK_EA | PSW_MASK_BA |
		(PSW_USER_BITS & PSW_MASK_ASC) |
		(regs->psw.mask & ~PSW_MASK_ASC);
	regs->psw.addr = (unsigned long) ka->sa.sa_handler | PSW_ADDR_AMODE;

	regs->gprs[2] = map_signal(sig);
	regs->gprs[3] = (unsigned long) &frame->info;
	regs->gprs[4] = (unsigned long) &frame->uc;
	regs->gprs[5] = task_thread_info(current)->last_break;
	return 0;

give_sigsegv:
	force_sigsegv(sig, current);
	return -EFAULT;
}

static void handle_signal(unsigned long sig, struct k_sigaction *ka,
			 siginfo_t *info, sigset_t *oldset,
			 struct pt_regs *regs)
{
	int ret;

	/* Set up the stack frame */
	if (ka->sa.sa_flags & SA_SIGINFO)
		ret = setup_rt_frame(sig, ka, info, oldset, regs);
	else
		ret = setup_frame(sig, ka, oldset, regs);
	if (ret)
		return;
	signal_delivered(sig, info, ka, regs,
				 test_thread_flag(TIF_SINGLE_STEP));
}

/*
 * Note that 'init' is a special process: it doesn't get signals it doesn't
 * want to handle. Thus you cannot kill init even with a SIGKILL even by
 * mistake.
 *
 * Note that we go through the signals twice: once to check the signals that
 * the kernel can handle, and then we build all the user-level signal handling
 * stack-frames in one go after that.
 */
void do_signal(struct pt_regs *regs)
{
	siginfo_t info;
	int signr;
	struct k_sigaction ka;
	sigset_t *oldset = sigmask_to_save();

	/*
	 * Get signal to deliver. When running under ptrace, at this point
	 * the debugger may change all our registers, including the system
	 * call information.
	 */
	current_thread_info()->system_call =
		test_thread_flag(TIF_SYSCALL) ? regs->int_code : 0;
	signr = get_signal_to_deliver(&info, &ka, regs, NULL);

	if (signr > 0) {
		/* Whee!  Actually deliver the signal.  */
		if (current_thread_info()->system_call) {
			regs->int_code = current_thread_info()->system_call;
			/* Check for system call restarting. */
			switch (regs->gprs[2]) {
			case -ERESTART_RESTARTBLOCK:
			case -ERESTARTNOHAND:
				regs->gprs[2] = -EINTR;
				break;
			case -ERESTARTSYS:
				if (!(ka.sa.sa_flags & SA_RESTART)) {
					regs->gprs[2] = -EINTR;
					break;
				}
			/* fallthrough */
			case -ERESTARTNOINTR:
				regs->gprs[2] = regs->orig_gpr2;
				regs->psw.addr =
					__rewind_psw(regs->psw,
						     regs->int_code >> 16);
				break;
			}
		}
		/* No longer in a system call */
		clear_thread_flag(TIF_SYSCALL);

		if (is_compat_task())
			handle_signal32(signr, &ka, &info, oldset, regs);
		else
			handle_signal(signr, &ka, &info, oldset, regs);
		return;
	}

	/* No handlers present - check for system call restart */
	clear_thread_flag(TIF_SYSCALL);
	if (current_thread_info()->system_call) {
		regs->int_code = current_thread_info()->system_call;
		switch (regs->gprs[2]) {
		case -ERESTART_RESTARTBLOCK:
			/* Restart with sys_restart_syscall */
			regs->int_code = __NR_restart_syscall;
		/* fallthrough */
		case -ERESTARTNOHAND:
		case -ERESTARTSYS:
		case -ERESTARTNOINTR:
			/* Restart system call with magic TIF bit. */
			regs->gprs[2] = regs->orig_gpr2;
			set_thread_flag(TIF_SYSCALL);
			if (test_thread_flag(TIF_SINGLE_STEP))
				set_thread_flag(TIF_PER_TRAP);
			break;
		}
	}

	/*
	 * If there's no signal to deliver, we just put the saved sigmask back.
	 */
	restore_saved_sigmask();
}

void do_notify_resume(struct pt_regs *regs)
{
	clear_thread_flag(TIF_NOTIFY_RESUME);
	tracehook_notify_resume(regs);
}
Commit	Line	Data
1da177e4	1	/*
a53c8fab	2	* Copyright IBM Corp. 1999, 2006
1da177e4 LT	3	* Author(s): Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com)
	4	*
	5	* Based on Intel version
	6	*
	7	* Copyright (C) 1991, 1992 Linus Torvalds
	8	*
	9	* 1997-11-28 Modified for POSIX.1b signals by Richard Henderson
	10	*/
	11
1da177e4 LT	12	#include <linux/sched.h>
	13	#include <linux/mm.h>
	14	#include <linux/smp.h>
1da177e4 LT	15	#include <linux/kernel.h>
	16	#include <linux/signal.h>
	17	#include <linux/errno.h>
	18	#include <linux/wait.h>
	19	#include <linux/ptrace.h>
	20	#include <linux/unistd.h>
	21	#include <linux/stddef.h>
	22	#include <linux/tty.h>
	23	#include <linux/personality.h>
	24	#include <linux/binfmts.h>
753c4dd6	25	#include <linux/tracehook.h>
26689452	26	#include <linux/syscalls.h>
7757591a	27	#include <linux/compat.h>
1da177e4 LT	28	#include <asm/ucontext.h>
	29	#include <asm/uaccess.h>
	30	#include <asm/lowcore.h>
a0616cde	31	#include <asm/switch_to.h>
a806170e	32	#include "entry.h"
1da177e4	33
1da177e4 LT	34	typedef struct
	35	{
	36	__u8 callee_used_stack[__SIGNAL_FRAMESIZE];
	37	struct sigcontext sc;
	38	_sigregs sregs;
	39	int signo;
	40	__u8 retcode[S390_SYSCALL_SIZE];
	41	} sigframe;
	42
	43	typedef struct
	44	{
	45	__u8 callee_used_stack[__SIGNAL_FRAMESIZE];
	46	__u8 retcode[S390_SYSCALL_SIZE];
	47	struct siginfo info;
	48	struct ucontext uc;
	49	} rt_sigframe;
	50
1da177e4 LT	51	/* Returns non-zero on fault. */
	52	static int save_sigregs(struct pt_regs regs, _sigregs __user sregs)
	53	{
6837a8c3 GS	54	_sigregs user_sregs;
6837a8c3 GS	55
1da177e4 LT	56	save_access_regs(current->thread.acrs);
	57
	58	/* Copy a 'clean' PSW mask to the user to avoid leaking
	59	information about whether PER is currently on. */
e258d719	60	user_sregs.regs.psw.mask = PSW_USER_BITS \|
5ebf250d	61	(regs->psw.mask & (PSW_MASK_USER \| PSW_MASK_RI));
b05e3703 MS	62	user_sregs.regs.psw.addr = regs->psw.addr;
b05e3703 MS	63	memcpy(&user_sregs.regs.gprs, &regs->gprs, sizeof(sregs->regs.gprs));
6837a8c3	64	memcpy(&user_sregs.regs.acrs, current->thread.acrs,
4725c860	65	sizeof(user_sregs.regs.acrs));
1da177e4 LT	66	/*
	67	* We have to store the fp registers to current->thread.fp_regs
	68	* to merge them with the emulated registers.
	69	*/
4725c860 MS	70	save_fp_ctl(&current->thread.fp_regs.fpc);
4725c860 MS	71	save_fp_regs(current->thread.fp_regs.fprs);
6837a8c3	72	memcpy(&user_sregs.fpregs, &current->thread.fp_regs,
4725c860	73	sizeof(user_sregs.fpregs));
f8544ec4 HC	74	if (__copy_to_user(sregs, &user_sregs, sizeof(_sigregs)))
	75	return -EFAULT;
	76	return 0;
1da177e4 LT	77	}
1da177e4 LT	78
1da177e4 LT	79	static int restore_sigregs(struct pt_regs regs, _sigregs __user sregs)
1da177e4 LT	80	{
6837a8c3	81	_sigregs user_sregs;
1da177e4 LT	82
	83	/* Alwys make any pending restarted system call return -EINTR */
	84	current_thread_info()->restart_block.fn = do_no_restart_syscall;
	85
4725c860	86	if (__copy_from_user(&user_sregs, sregs, sizeof(user_sregs)))
f8544ec4	87	return -EFAULT;
4725c860	88
5ebf250d HC	89	if (!is_ri_task(current) && (user_sregs.regs.psw.mask & PSW_MASK_RI))
	90	return -EINVAL;
	91
4725c860 MS	92	/* Loading the floating-point-control word can fail. Do that first. */
	93	if (restore_fp_ctl(&user_sregs.fpregs.fpc))
	94	return -EINVAL;
	95
e258d719	96	/* Use regs->psw.mask instead of PSW_USER_BITS to preserve PER bit. */
b50511e4	97	regs->psw.mask = (regs->psw.mask & ~PSW_MASK_USER) \|
5ebf250d	98	(user_sregs.regs.psw.mask & (PSW_MASK_USER \| PSW_MASK_RI));
fa968ee2	99	/* Check for invalid user address space control. */
e258d719 MS	100	if ((regs->psw.mask & PSW_MASK_ASC) == PSW_ASC_HOME)
e258d719 MS	101	regs->psw.mask = PSW_ASC_PRIMARY \|
fa968ee2	102	(regs->psw.mask & ~PSW_MASK_ASC);
d4e81b35 MS	103	/* Check for invalid amode */
	104	if (regs->psw.mask & PSW_MASK_EA)
	105	regs->psw.mask \|= PSW_MASK_BA;
	106	regs->psw.addr = user_sregs.regs.psw.addr;
b05e3703	107	memcpy(&regs->gprs, &user_sregs.regs.gprs, sizeof(sregs->regs.gprs));
6837a8c3	108	memcpy(&current->thread.acrs, &user_sregs.regs.acrs,
4725c860	109	sizeof(current->thread.acrs));
1da177e4 LT	110	restore_access_regs(current->thread.acrs);
1da177e4 LT	111
6837a8c3	112	memcpy(&current->thread.fp_regs, &user_sregs.fpregs,
4725c860	113	sizeof(current->thread.fp_regs));
1da177e4	114
4725c860	115	restore_fp_regs(current->thread.fp_regs.fprs);
b6ef5bb3	116	clear_thread_flag(TIF_SYSCALL); /* No longer in a system call */
1da177e4 LT	117	return 0;
	118	}
	119
26689452	120	SYSCALL_DEFINE0(sigreturn)
1da177e4	121	{
03ff9a23	122	struct pt_regs *regs = task_pt_regs(current);
1da177e4 LT	123	sigframe __user frame = (sigframe __user )regs->gprs[15];
	124	sigset_t set;
	125
1da177e4 LT	126	if (__copy_from_user(&set.sig, &frame->sc.oldmask, _SIGMASK_COPY_SIZE))
1da177e4 LT	127	goto badframe;
391c62fe	128	set_current_blocked(&set);
1da177e4 LT	129	if (restore_sigregs(regs, &frame->sregs))
1da177e4 LT	130	goto badframe;
1da177e4	131	return regs->gprs[2];
1da177e4 LT	132	badframe:
	133	force_sig(SIGSEGV, current);
	134	return 0;
	135	}
	136
26689452	137	SYSCALL_DEFINE0(rt_sigreturn)
1da177e4	138	{
03ff9a23	139	struct pt_regs *regs = task_pt_regs(current);
1da177e4 LT	140	rt_sigframe __user frame = (rt_sigframe __user )regs->gprs[15];
	141	sigset_t set;
	142
1da177e4 LT	143	if (__copy_from_user(&set.sig, &frame->uc.uc_sigmask, sizeof(set)))
1da177e4 LT	144	goto badframe;
391c62fe	145	set_current_blocked(&set);
1da177e4 LT	146	if (restore_sigregs(regs, &frame->uc.uc_mcontext))
1da177e4 LT	147	goto badframe;
e214125a	148	if (restore_altstack(&frame->uc.uc_stack))
4e3df37e	149	goto badframe;
1da177e4	150	return regs->gprs[2];
1da177e4 LT	151	badframe:
	152	force_sig(SIGSEGV, current);
	153	return 0;
	154	}
	155
	156	/*
	157	* Set up a signal frame.
	158	*/
	159
	160
	161	/*
	162	* Determine which stack to use..
	163	*/
	164	static inline void __user *
	165	get_sigframe(struct k_sigaction ka, struct pt_regs regs, size_t frame_size)
	166	{
	167	unsigned long sp;
	168
	169	/* Default to using normal stack */
	170	sp = regs->gprs[15];
	171
de553438 HC	172	/* Overflow on alternate signal stack gives SIGSEGV. */
	173	if (on_sig_stack(sp) && !on_sig_stack((sp - frame_size) & -8UL))
	174	return (void __user *) -1UL;
	175
1da177e4 LT	176	/* This is the X/Open sanctioned signal stack switching. */
	177	if (ka->sa.sa_flags & SA_ONSTACK) {
	178	if (! sas_ss_flags(sp))
	179	sp = current->sas_ss_sp + current->sas_ss_size;
	180	}
	181
1da177e4 LT	182	return (void __user *)((sp - frame_size) & -8ul);
	183	}
	184
	185	static inline int map_signal(int sig)
	186	{
	187	if (current_thread_info()->exec_domain
	188	&& current_thread_info()->exec_domain->signal_invmap
	189	&& sig < 32)
	190	return current_thread_info()->exec_domain->signal_invmap[sig];
	191	else
	192	return sig;
	193	}
	194
54dfe5dd HC	195	static int setup_frame(int sig, struct k_sigaction *ka,
54dfe5dd HC	196	sigset_t set, struct pt_regs regs)
1da177e4 LT	197	{
	198	sigframe __user *frame;
	199
	200	frame = get_sigframe(ka, regs, sizeof(sigframe));
1da177e4	201
de553438 HC	202	if (frame == (void __user *) -1UL)
	203	goto give_sigsegv;
	204
1da177e4 LT	205	if (__copy_to_user(&frame->sc.oldmask, &set->sig, _SIGMASK_COPY_SIZE))
	206	goto give_sigsegv;
	207
	208	if (save_sigregs(regs, &frame->sregs))
	209	goto give_sigsegv;
	210	if (__put_user(&frame->sregs, &frame->sc.sregs))
	211	goto give_sigsegv;
	212
	213	/* Set up to return from userspace. If provided, use a stub
	214	already in userspace. */
	215	if (ka->sa.sa_flags & SA_RESTORER) {
	216	regs->gprs[14] = (unsigned long)
	217	ka->sa.sa_restorer \| PSW_ADDR_AMODE;
	218	} else {
	219	regs->gprs[14] = (unsigned long)
	220	frame->retcode \| PSW_ADDR_AMODE;
	221	if (__put_user(S390_SYSCALL_OPCODE \| __NR_sigreturn,
	222	(u16 __user *)(frame->retcode)))
	223	goto give_sigsegv;
	224	}
	225
	226	/* Set up backchain. */
	227	if (__put_user(regs->gprs[15], (addr_t __user *) frame))
	228	goto give_sigsegv;
	229
	230	/* Set up registers for signal handler */
	231	regs->gprs[15] = (unsigned long) frame;
fa968ee2 MS	232	/* Force default amode and default user address space control. */
fa968ee2 MS	233	regs->psw.mask = PSW_MASK_EA \| PSW_MASK_BA \|
e258d719	234	(PSW_USER_BITS & PSW_MASK_ASC) \|
fa968ee2	235	(regs->psw.mask & ~PSW_MASK_ASC);
1da177e4 LT	236	regs->psw.addr = (unsigned long) ka->sa.sa_handler \| PSW_ADDR_AMODE;
	237
	238	regs->gprs[2] = map_signal(sig);
	239	regs->gprs[3] = (unsigned long) &frame->sc;
	240
	241	/* We forgot to include these in the sigcontext.
	242	To avoid breaking binary compatibility, they are passed as args. */
aa33c8cb MS	243	if (sig == SIGSEGV \|\| sig == SIGBUS \|\| sig == SIGILL \|\|
	244	sig == SIGTRAP \|\| sig == SIGFPE) {
	245	/* set extra registers only for synchronous signals */
	246	regs->gprs[4] = regs->int_code & 127;
	247	regs->gprs[5] = regs->int_parm_long;
	248	regs->gprs[6] = task_thread_info(current)->last_break;
	249	}
1da177e4 LT	250
	251	/* Place signal number on stack to allow backtrace from handler. */
	252	if (__put_user(regs->gprs[2], (int __user *) &frame->signo))
	253	goto give_sigsegv;
54dfe5dd	254	return 0;
1da177e4 LT	255
	256	give_sigsegv:
	257	force_sigsegv(sig, current);
54dfe5dd	258	return -EFAULT;
1da177e4 LT	259	}
1da177e4 LT	260
54dfe5dd	261	static int setup_rt_frame(int sig, struct k_sigaction ka, siginfo_t info,
1da177e4 LT	262	sigset_t set, struct pt_regs regs)
	263	{
	264	int err = 0;
	265	rt_sigframe __user *frame;
	266
	267	frame = get_sigframe(ka, regs, sizeof(rt_sigframe));
1da177e4	268
de553438 HC	269	if (frame == (void __user *) -1UL)
	270	goto give_sigsegv;
	271
1da177e4 LT	272	if (copy_siginfo_to_user(&frame->info, info))
	273	goto give_sigsegv;
	274
	275	/* Create the ucontext. */
	276	err \|= __put_user(0, &frame->uc.uc_flags);
c2814476	277	err \|= __put_user(NULL, &frame->uc.uc_link);
e214125a	278	err \|= __save_altstack(&frame->uc.uc_stack, regs->gprs[15]);
1da177e4 LT	279	err \|= save_sigregs(regs, &frame->uc.uc_mcontext);
	280	err \|= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
	281	if (err)
	282	goto give_sigsegv;
	283
	284	/* Set up to return from userspace. If provided, use a stub
	285	already in userspace. */
	286	if (ka->sa.sa_flags & SA_RESTORER) {
	287	regs->gprs[14] = (unsigned long)
	288	ka->sa.sa_restorer \| PSW_ADDR_AMODE;
	289	} else {
	290	regs->gprs[14] = (unsigned long)
	291	frame->retcode \| PSW_ADDR_AMODE;
b44df334 HC	292	if (__put_user(S390_SYSCALL_OPCODE \| __NR_rt_sigreturn,
	293	(u16 __user *)(frame->retcode)))
	294	goto give_sigsegv;
1da177e4 LT	295	}
	296
	297	/* Set up backchain. */
	298	if (__put_user(regs->gprs[15], (addr_t __user *) frame))
	299	goto give_sigsegv;
	300
	301	/* Set up registers for signal handler */
	302	regs->gprs[15] = (unsigned long) frame;
fa968ee2 MS	303	/* Force default amode and default user address space control. */
fa968ee2 MS	304	regs->psw.mask = PSW_MASK_EA \| PSW_MASK_BA \|
e258d719	305	(PSW_USER_BITS & PSW_MASK_ASC) \|
fa968ee2	306	(regs->psw.mask & ~PSW_MASK_ASC);
1da177e4 LT	307	regs->psw.addr = (unsigned long) ka->sa.sa_handler \| PSW_ADDR_AMODE;
	308
	309	regs->gprs[2] = map_signal(sig);
	310	regs->gprs[3] = (unsigned long) &frame->info;
	311	regs->gprs[4] = (unsigned long) &frame->uc;
86f2552b	312	regs->gprs[5] = task_thread_info(current)->last_break;
54dfe5dd	313	return 0;
1da177e4 LT	314
	315	give_sigsegv:
	316	force_sigsegv(sig, current);
54dfe5dd	317	return -EFAULT;
1da177e4 LT	318	}
1da177e4 LT	319
a610d6e6	320	static void handle_signal(unsigned long sig, struct k_sigaction *ka,
391c62fe HC	321	siginfo_t info, sigset_t oldset,
391c62fe HC	322	struct pt_regs *regs)
1da177e4	323	{
54dfe5dd HC	324	int ret;
54dfe5dd HC	325
1da177e4 LT	326	/* Set up the stack frame */
1da177e4 LT	327	if (ka->sa.sa_flags & SA_SIGINFO)
54dfe5dd	328	ret = setup_rt_frame(sig, ka, info, oldset, regs);
1da177e4	329	else
54dfe5dd	330	ret = setup_frame(sig, ka, oldset, regs);
391c62fe	331	if (ret)
a610d6e6	332	return;
efee984c	333	signal_delivered(sig, info, ka, regs,
a610d6e6	334	test_thread_flag(TIF_SINGLE_STEP));
1da177e4 LT	335	}
	336
	337	/*
	338	* Note that 'init' is a special process: it doesn't get signals it doesn't
	339	* want to handle. Thus you cannot kill init even with a SIGKILL even by
	340	* mistake.
	341	*
	342	* Note that we go through the signals twice: once to check the signals that
	343	* the kernel can handle, and then we build all the user-level signal handling
	344	* stack-frames in one go after that.
	345	*/
54dfe5dd	346	void do_signal(struct pt_regs *regs)
1da177e4	347	{
1da177e4 LT	348	siginfo_t info;
	349	int signr;
	350	struct k_sigaction ka;
b7f9a11a	351	sigset_t *oldset = sigmask_to_save();
1da177e4	352
20b40a79 MS	353	/*
	354	* Get signal to deliver. When running under ptrace, at this point
	355	* the debugger may change all our registers, including the system
	356	* call information.
	357	*/
b6ef5bb3	358	current_thread_info()->system_call =
aa33c8cb	359	test_thread_flag(TIF_SYSCALL) ? regs->int_code : 0;
1da177e4	360	signr = get_signal_to_deliver(&info, &ka, regs, NULL);
1da177e4 LT	361
	362	if (signr > 0) {
	363	/* Whee! Actually deliver the signal. */
b6ef5bb3	364	if (current_thread_info()->system_call) {
aa33c8cb	365	regs->int_code = current_thread_info()->system_call;
20b40a79 MS	366	/* Check for system call restarting. */
	367	switch (regs->gprs[2]) {
	368	case -ERESTART_RESTARTBLOCK:
	369	case -ERESTARTNOHAND:
	370	regs->gprs[2] = -EINTR;
	371	break;
	372	case -ERESTARTSYS:
	373	if (!(ka.sa.sa_flags & SA_RESTART)) {
	374	regs->gprs[2] = -EINTR;
	375	break;
	376	}
	377	/* fallthrough */
	378	case -ERESTARTNOINTR:
	379	regs->gprs[2] = regs->orig_gpr2;
ccf45caf MS	380	regs->psw.addr =
ccf45caf MS	381	__rewind_psw(regs->psw,
aa33c8cb	382	regs->int_code >> 16);
20b40a79 MS	383	break;
20b40a79 MS	384	}
20b40a79	385	}
d9ae6772 MS	386	/* No longer in a system call */
d9ae6772 MS	387	clear_thread_flag(TIF_SYSCALL);
20b40a79	388
a610d6e6 AV	389	if (is_compat_task())
	390	handle_signal32(signr, &ka, &info, oldset, regs);
	391	else
	392	handle_signal(signr, &ka, &info, oldset, regs);
54dfe5dd HC	393	return;
	394	}
	395
20b40a79	396	/* No handlers present - check for system call restart */
d9ae6772	397	clear_thread_flag(TIF_SYSCALL);
b6ef5bb3	398	if (current_thread_info()->system_call) {
aa33c8cb	399	regs->int_code = current_thread_info()->system_call;
20b40a79 MS	400	switch (regs->gprs[2]) {
	401	case -ERESTART_RESTARTBLOCK:
	402	/* Restart with sys_restart_syscall */
aa33c8cb	403	regs->int_code = __NR_restart_syscall;
20b40a79 MS	404	/* fallthrough */
	405	case -ERESTARTNOHAND:
	406	case -ERESTARTSYS:
	407	case -ERESTARTNOINTR:
	408	/* Restart system call with magic TIF bit. */
	409	regs->gprs[2] = regs->orig_gpr2;
b6ef5bb3	410	set_thread_flag(TIF_SYSCALL);
39efd4ec MS	411	if (test_thread_flag(TIF_SINGLE_STEP))
39efd4ec MS	412	set_thread_flag(TIF_PER_TRAP);
b6ef5bb3	413	break;
20b40a79 MS	414	}
	415	}
	416
54dfe5dd HC	417	/*
	418	* If there's no signal to deliver, we just put the saved sigmask back.
	419	*/
51a7b448	420	restore_saved_sigmask();
1da177e4	421	}
753c4dd6 MS	422
	423	void do_notify_resume(struct pt_regs *regs)
	424	{
	425	clear_thread_flag(TIF_NOTIFY_RESUME);
	426	tracehook_notify_resume(regs);
	427	}