1 files changed, 169 insertions, 268 deletions

diff --git a/arch/s390/kernel/signal.c b/arch/s390/kernel/signal.c
index 6ae4a77270b..42b49f9e19b 100644
--- a/arch/s390/kernel/signal.c
+++ b/arch/s390/kernel/signal.c
@@ -1,8 +1,5 @@
 /*
- *  arch/s390/kernel/signal.c
- *
- *  S390 version
- *    Copyright (C) 1999,2000 IBM Deutschland Entwicklung GmbH, IBM Corporation
+ *    Copyright IBM Corp. 1999, 2006
  *    Author(s): Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com)
  *
  *    Based on Intel version
@@ -12,11 +9,9 @@
  *  1997-11-28  Modified for POSIX.1b signals by Richard Henderson
  */
 
-#include <linux/config.h>
 #include <linux/sched.h>
 #include <linux/mm.h>
 #include <linux/smp.h>
-#include <linux/smp_lock.h>
 #include <linux/kernel.h>
 #include <linux/signal.h>
 #include <linux/errno.h>
@@ -27,12 +22,14 @@
 #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>
-
-#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
-
+#include <asm/switch_to.h>
+#include "entry.h"
 
 typedef struct 
 {
@@ -51,214 +48,106 @@ typedef struct
 	struct ucontext uc;
 } rt_sigframe;
 
-int do_signal(struct pt_regs *regs, sigset_t *oldset);
-
-/*
- * Atomically swap in the new signal mask, and wait for a signal.
- */
-asmlinkage int
-sys_sigsuspend(struct pt_regs * regs, int history0, int history1,
-	       old_sigset_t mask)
-{
-	sigset_t saveset;
-
-	mask &= _BLOCKABLE;
-	spin_lock_irq(&current->sighand->siglock);
-	saveset = current->blocked;
-	siginitset(&current->blocked, mask);
-	recalc_sigpending();
-	spin_unlock_irq(&current->sighand->siglock);
-	regs->gprs[2] = -EINTR;
-
-	while (1) {
-		set_current_state(TASK_INTERRUPTIBLE);
-		schedule();
-		if (do_signal(regs, &saveset))
-			return -EINTR;
-	}
-}
-
-asmlinkage long
-sys_rt_sigsuspend(struct pt_regs *regs, sigset_t __user *unewset,
-						size_t sigsetsize)
-{
-	sigset_t saveset, newset;
-
-	/* XXX: Don't preclude handling different sized sigset_t's.  */
-	if (sigsetsize != sizeof(sigset_t))
-		return -EINVAL;
-
-	if (copy_from_user(&newset, unewset, sizeof(newset)))
-		return -EFAULT;
-	sigdelsetmask(&newset, ~_BLOCKABLE);
-
-	spin_lock_irq(&current->sighand->siglock);
-	saveset = current->blocked;
-	current->blocked = newset;
-	recalc_sigpending();
-	spin_unlock_irq(&current->sighand->siglock);
-	regs->gprs[2] = -EINTR;
-
-	while (1) {
-		set_current_state(TASK_INTERRUPTIBLE);
-		schedule();
-		if (do_signal(regs, &saveset))
-			return -EINTR;
-	}
-}
-
-asmlinkage long
-sys_sigaction(int sig, const struct old_sigaction __user *act,
-	      struct old_sigaction __user *oact)
-{
-	struct k_sigaction new_ka, old_ka;
-	int ret;
-
-	if (act) {
-		old_sigset_t mask;
-		if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
-		    __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
-		    __get_user(new_ka.sa.sa_restorer, &act->sa_restorer))
-			return -EFAULT;
-		__get_user(new_ka.sa.sa_flags, &act->sa_flags);
-		__get_user(mask, &act->sa_mask);
-		siginitset(&new_ka.sa.sa_mask, mask);
-	}
-
-	ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
-
-	if (!ret && oact) {
-		if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
-		    __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
-		    __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer))
-			return -EFAULT;
-		__put_user(old_ka.sa.sa_flags, &oact->sa_flags);
-		__put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask);
-	}
-
-	return ret;
-}
-
-asmlinkage long
-sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss,
-					struct pt_regs *regs)
-{
-	return do_sigaltstack(uss, uoss, regs->gprs[15]);
-}
-
-
-
 /* Returns non-zero on fault. */
 static int save_sigregs(struct pt_regs *regs, _sigregs __user *sregs)
 {
-	unsigned long old_mask = regs->psw.mask;
-	int err;
-  
+	_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.  */
-	regs->psw.mask = PSW_MASK_MERGE(PSW_USER_BITS, regs->psw.mask);
-	err = __copy_to_user(&sregs->regs.psw, &regs->psw,
-			     sizeof(sregs->regs.psw)+sizeof(sregs->regs.gprs));
-	regs->psw.mask = old_mask;
-	if (err != 0)
-		return err;
-	err = __copy_to_user(&sregs->regs.acrs, current->thread.acrs,
-			     sizeof(sregs->regs.acrs));
-	if (err != 0)
-		return err;
+	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_regs(&current->thread.fp_regs);
-	return __copy_to_user(&sregs->fpregs, &current->thread.fp_regs,
-			      sizeof(s390_fp_regs));
+	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;
 }
 
-/* Returns positive number on error */
 static int restore_sigregs(struct pt_regs *regs, _sigregs __user *sregs)
 {
-	unsigned long old_mask = regs->psw.mask;
-	int err;
+	_sigregs user_sregs;
 
 	/* Alwys make any pending restarted system call return -EINTR */
 	current_thread_info()->restart_block.fn = do_no_restart_syscall;
 
-	err = __copy_from_user(&regs->psw, &sregs->regs.psw,
-			       sizeof(sregs->regs.psw)+sizeof(sregs->regs.gprs));
-	regs->psw.mask = PSW_MASK_MERGE(old_mask, regs->psw.mask);
-	regs->psw.addr |= PSW_ADDR_AMODE;
-	if (err)
-		return err;
-	err = __copy_from_user(&current->thread.acrs, &sregs->regs.acrs,
-			       sizeof(sregs->regs.acrs));
-	if (err)
-		return err;
+	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 | PSW_MASK_RI)) |
+		(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);
 
-	err = __copy_from_user(&current->thread.fp_regs, &sregs->fpregs,
-			       sizeof(s390_fp_regs));
-	current->thread.fp_regs.fpc &= FPC_VALID_MASK;
-	if (err)
-		return err;
+	memcpy(&current->thread.fp_regs, &user_sregs.fpregs,
+	       sizeof(current->thread.fp_regs));
 
-	restore_fp_regs(&current->thread.fp_regs);
-	regs->trap = -1;	/* disable syscall checks */
+	restore_fp_regs(current->thread.fp_regs.fprs);
+	clear_pt_regs_flag(regs, PIF_SYSCALL); /* No longer in a system call */
 	return 0;
 }
 
-asmlinkage long sys_sigreturn(struct pt_regs *regs)
+SYSCALL_DEFINE0(sigreturn)
 {
+	struct pt_regs *regs = task_pt_regs(current);
 	sigframe __user *frame = (sigframe __user *)regs->gprs[15];
 	sigset_t set;
 
-	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
-		goto badframe;
 	if (__copy_from_user(&set.sig, &frame->sc.oldmask, _SIGMASK_COPY_SIZE))
 		goto badframe;
-
-	sigdelsetmask(&set, ~_BLOCKABLE);
-	spin_lock_irq(&current->sighand->siglock);
-	current->blocked = set;
-	recalc_sigpending();
-	spin_unlock_irq(&current->sighand->siglock);
-
+	set_current_blocked(&set);
 	if (restore_sigregs(regs, &frame->sregs))
 		goto badframe;
-
 	return regs->gprs[2];
-
 badframe:
 	force_sig(SIGSEGV, current);
 	return 0;
 }
 
-asmlinkage long sys_rt_sigreturn(struct pt_regs *regs)
+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 (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
-		goto badframe;
 	if (__copy_from_user(&set.sig, &frame->uc.uc_sigmask, sizeof(set)))
 		goto badframe;
-
-	sigdelsetmask(&set, ~_BLOCKABLE);
-	spin_lock_irq(&current->sighand->siglock);
-	current->blocked = set;
-	recalc_sigpending();
-	spin_unlock_irq(&current->sighand->siglock);
-
+	set_current_blocked(&set);
 	if (restore_sigregs(regs, &frame->uc.uc_mcontext))
 		goto badframe;
-
-	if (do_sigaltstack(&frame->uc.uc_stack, NULL,
-			   regs->gprs[15]) == -EFAULT)
+	if (restore_altstack(&frame->uc.uc_stack))
 		goto badframe;
 	return regs->gprs[2];
-
 badframe:
 	force_sig(SIGSEGV, current);
 	return 0;
@@ -280,19 +169,16 @@ get_sigframe(struct k_sigaction *ka, struct pt_regs * regs, size_t frame_size)
 	/* 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;
 	}
 
-	/* This is the legacy signal stack switching. */
-	else if (!user_mode(regs) &&
-		 !(ka->sa.sa_flags & SA_RESTORER) &&
-		 ka->sa.sa_restorer) {
-		sp = (unsigned long) ka->sa.sa_restorer;
-	}
-
 	return (void __user *)((sp - frame_size) & -8ul);
 }
 
@@ -306,13 +192,14 @@ static inline int map_signal(int sig)
 		return sig;
 }
 
-static void setup_frame(int sig, struct k_sigaction *ka,
-			sigset_t *set, struct pt_regs * regs)
+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 (!access_ok(VERIFY_WRITE, frame, sizeof(sigframe)))
+
+	if (frame == (void __user *) -1UL)
 		goto give_sigsegv;
 
 	if (__copy_to_user(&frame->sc.oldmask, &set->sig, _SIGMASK_COPY_SIZE))
@@ -342,6 +229,10 @@ static void setup_frame(int sig, struct k_sigaction *ka,
 
 	/* 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);
@@ -349,26 +240,33 @@ static void setup_frame(int sig, struct k_sigaction *ka,
 
 	/* We forgot to include these in the sigcontext.
 	   To avoid breaking binary compatibility, they are passed as args. */
-	regs->gprs[4] = current->thread.trap_no;
-	regs->gprs[5] = current->thread.prot_addr;
+	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;
+	return 0;
 
 give_sigsegv:
 	force_sigsegv(sig, current);
+	return -EFAULT;
 }
 
-static void setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
+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 (!access_ok(VERIFY_WRITE, frame, sizeof(rt_sigframe)))
+
+	if (frame == (void __user *) -1UL)
 		goto give_sigsegv;
 
 	if (copy_siginfo_to_user(&frame->info, info))
@@ -377,10 +275,7 @@ static void setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 	/* Create the ucontext.  */
 	err |= __put_user(0, &frame->uc.uc_flags);
 	err |= __put_user(NULL, &frame->uc.uc_link);
-	err |= __put_user((void __user *)current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
-	err |= __put_user(sas_ss_flags(regs->gprs[15]),
-			  &frame->uc.uc_stack.ss_flags);
-	err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
+	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)
@@ -394,8 +289,9 @@ static void setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 	} else {
                 regs->gprs[14] = (unsigned long)
 			frame->retcode | PSW_ADDR_AMODE;
-		err |= __put_user(S390_SYSCALL_OPCODE | __NR_rt_sigreturn,
-	                          (u16 __user *)(frame->retcode));
+		if (__put_user(S390_SYSCALL_OPCODE | __NR_rt_sigreturn,
+			       (u16 __user *)(frame->retcode)))
+			goto give_sigsegv;
 	}
 
 	/* Set up backchain. */
@@ -404,37 +300,38 @@ static void setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 
 	/* 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;
-	return;
+	regs->gprs[5] = task_thread_info(current)->last_break;
+	return 0;
 
 give_sigsegv:
 	force_sigsegv(sig, current);
+	return -EFAULT;
 }
 
-/*
- * OK, we're invoking a handler
- */	
-
-static void
-handle_signal(unsigned long sig, struct k_sigaction *ka,
-	      siginfo_t *info, sigset_t *oldset, struct pt_regs * regs)
+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)
-		setup_rt_frame(sig, ka, info, oldset, regs);
+		ret = setup_rt_frame(sig, ka, info, oldset, regs);
 	else
-		setup_frame(sig, ka, oldset, regs);
-
-	spin_lock_irq(&current->sighand->siglock);
-	sigorsets(&current->blocked,&current->blocked,&ka->sa.sa_mask);
-	if (!(ka->sa.sa_flags & SA_NODEFER))
-		sigaddset(&current->blocked,sig);
-	recalc_sigpending();
-	spin_unlock_irq(&current->sighand->siglock);
+		ret = setup_frame(sig, ka, oldset, regs);
+	if (ret)
+		return;
+	signal_delivered(sig, info, ka, regs,
+				 test_thread_flag(TIF_SINGLE_STEP));
 }
 
 /*
@@ -446,81 +343,85 @@ handle_signal(unsigned long sig, struct k_sigaction *ka,
  * the kernel can handle, and then we build all the user-level signal handling
  * stack-frames in one go after that.
  */
-int do_signal(struct pt_regs *regs, sigset_t *oldset)
+void do_signal(struct pt_regs *regs)
 {
-	unsigned long retval = 0, continue_addr = 0, restart_addr = 0;
 	siginfo_t info;
 	int signr;
 	struct k_sigaction ka;
+	sigset_t *oldset = sigmask_to_save();
 
 	/*
-	 * We want the common case to go fast, which
-	 * is why we may in certain cases get here from
-	 * kernel mode. Just return without doing anything
-	 * if so.
+	 * Get signal to deliver. When running under ptrace, at this point
+	 * the debugger may change all our registers, including the system
+	 * call information.
 	 */
-	if (!user_mode(regs))
-		return 1;
-
-	if (!oldset)
-		oldset = &current->blocked;
-
-	/* Are we from a system call? */
-	if (regs->trap == __LC_SVC_OLD_PSW) {
-		continue_addr = regs->psw.addr;
-		restart_addr = continue_addr - regs->ilc;
-		retval = regs->gprs[2];
-
-		/* Prepare for system call restart.  We do this here so that a
-		   debugger will see the already changed PSW. */
-		if (retval == -ERESTARTNOHAND ||
-		    retval == -ERESTARTSYS ||
-		    retval == -ERESTARTNOINTR) {
-			regs->gprs[2] = regs->orig_gpr2;
-			regs->psw.addr = restart_addr;
-		} else if (retval == -ERESTART_RESTARTBLOCK) {
-			regs->gprs[2] = -EINTR;
-		}
-	}
-
-	/* Get signal to deliver.  When running under ptrace, at this point
-	   the debugger may change all our registers ... */
+	current_thread_info()->system_call =
+		test_pt_regs_flag(regs, PIF_SYSCALL) ? regs->int_code : 0;
 	signr = get_signal_to_deliver(&info, &ka, regs, NULL);
 
-	/* Depending on the signal settings we may need to revert the
-	   decision to restart the system call. */
-	if (signr > 0 && regs->psw.addr == restart_addr) {
-		if (retval == -ERESTARTNOHAND
-		    || (retval == -ERESTARTSYS
-			 && !(current->sighand->action[signr-1].sa.sa_flags
-			      & SA_RESTART))) {
-			regs->gprs[2] = -EINTR;
-			regs->psw.addr = continue_addr;
-		}
-	}
-
 	if (signr > 0) {
 		/* Whee!  Actually deliver the signal.  */
-#ifdef CONFIG_COMPAT
-		if (test_thread_flag(TIF_31BIT)) {
-			extern void handle_signal32(unsigned long sig,
-						    struct k_sigaction *ka,
-						    siginfo_t *info,
-						    sigset_t *oldset,
-						    struct pt_regs *regs);
+		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_pt_regs_flag(regs, PIF_SYSCALL);
+
+		if (is_compat_task())
 			handle_signal32(signr, &ka, &info, oldset, regs);
-			return 1;
-	        }
-#endif
-		handle_signal(signr, &ka, &info, oldset, regs);
-		return 1;
+		else
+			handle_signal(signr, &ka, &info, oldset, regs);
+		return;
 	}
 
-	/* Restart a different system call. */
-	if (retval == -ERESTART_RESTARTBLOCK
-	    && regs->psw.addr == continue_addr) {
-		regs->gprs[2] = __NR_restart_syscall;
-		set_thread_flag(TIF_RESTART_SVC);
+	/* No handlers present - check for system call restart */
+	clear_pt_regs_flag(regs, PIF_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_pt_regs_flag(regs, PIF_SYSCALL);
+			if (test_thread_flag(TIF_SINGLE_STEP))
+				clear_pt_regs_flag(regs, PIF_PER_TRAP);
+			break;
+		}
 	}
-	return 0;
+
+	/*
+	 * 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);
 }