diff --git a/arch/csky/abiv1/inc/abi/entry.h b/arch/csky/abiv1/inc/abi/entry.h
index f041299..fa26461 100644
--- a/arch/csky/abiv1/inc/abi/entry.h
+++ b/arch/csky/abiv1/inc/abi/entry.h
@@ -16,9 +16,6 @@
 #define LSAVE_A4	40
 #define LSAVE_A5	44
 
-#define EPC_INCREASE	2
-#define EPC_KEEP	0
-
 .macro USPTOKSP
 	mtcr	sp, ss1
 	mfcr	sp, ss0
@@ -29,10 +26,6 @@
 	mfcr	sp, ss1
 .endm
 
-.macro INCTRAP	rx
-	addi	\rx, EPC_INCREASE
-.endm
-
 .macro	SAVE_ALL epc_inc
 	mtcr    r13, ss2
 	mfcr    r13, epsr
diff --git a/arch/csky/abiv1/inc/abi/regdef.h b/arch/csky/abiv1/inc/abi/regdef.h
index 9e7e692..729b1c3 100644
--- a/arch/csky/abiv1/inc/abi/regdef.h
+++ b/arch/csky/abiv1/inc/abi/regdef.h
@@ -21,4 +21,6 @@
 
 #define SYSTRACE_SAVENUM	2
 
+#define TRAP0_SIZE		2
+
 #endif /* __ASM_CSKY_REGDEF_H */
diff --git a/arch/csky/abiv2/inc/abi/entry.h b/arch/csky/abiv2/inc/abi/entry.h
index b4232c3..31d0aa9 100644
--- a/arch/csky/abiv2/inc/abi/entry.h
+++ b/arch/csky/abiv2/inc/abi/entry.h
@@ -14,18 +14,11 @@
 #define LSAVE_A2	32
 #define LSAVE_A3	36
 
-#define EPC_INCREASE	4
-#define EPC_KEEP	0
-
 #define KSPTOUSP
 #define USPTOKSP
 
 #define usp cr<14, 1>
 
-.macro INCTRAP	rx
-	addi	\rx, EPC_INCREASE
-.endm
-
 .macro SAVE_ALL epc_inc
 	subi    sp, 152
 	stw	tls, (sp, 0)
diff --git a/arch/csky/abiv2/inc/abi/regdef.h b/arch/csky/abiv2/inc/abi/regdef.h
index 652f5ce..77cb178 100644
--- a/arch/csky/abiv2/inc/abi/regdef.h
+++ b/arch/csky/abiv2/inc/abi/regdef.h
@@ -21,4 +21,6 @@
 
 #define SYSTRACE_SAVENUM	5
 
+#define TRAP0_SIZE		4
+
 #endif /* __ASM_CSKY_REGDEF_H */
diff --git a/arch/csky/kernel/atomic.S b/arch/csky/kernel/atomic.S
index d2357c8..5b84f11 100644
--- a/arch/csky/kernel/atomic.S
+++ b/arch/csky/kernel/atomic.S
@@ -12,11 +12,10 @@
  * If *ptr != oldval && return 1,
  * else *ptr = newval return 0.
  */
-#ifdef CONFIG_CPU_HAS_LDSTEX
 ENTRY(csky_cmpxchg)
 	USPTOKSP
 	mfcr	a3, epc
-	INCTRAP	a3
+	addi	a3, TRAP0_SIZE
 
 	subi    sp, 8
 	stw     a3, (sp, 0)
@@ -24,6 +23,7 @@ ENTRY(csky_cmpxchg)
 	stw     a3, (sp, 4)
 
 	psrset	ee
+#ifdef CONFIG_CPU_HAS_LDSTEX
 1:
 	ldex	a3, (a2)
 	cmpne	a0, a3
@@ -33,27 +33,7 @@ ENTRY(csky_cmpxchg)
 	bez	a3, 1b
 2:
 	sync.is
-	mvc	a0
-	ldw	a3, (sp, 0)
-	mtcr	a3, epc
-	ldw     a3, (sp, 4)
-	mtcr	a3, epsr
-	addi	sp, 8
-	KSPTOUSP
-	rte
-END(csky_cmpxchg)
 #else
-ENTRY(csky_cmpxchg)
-	USPTOKSP
-	mfcr	a3, epc
-	INCTRAP	a3
-
-	subi    sp, 8
-	stw     a3, (sp, 0)
-	mfcr    a3, epsr
-	stw     a3, (sp, 4)
-
-	psrset	ee
 1:
 	ldw	a3, (a2)
 	cmpne	a0, a3
@@ -61,6 +41,7 @@ ENTRY(csky_cmpxchg)
 2:
 	stw	a1, (a2)
 3:
+#endif
 	mvc	a0
 	ldw	a3, (sp, 0)
 	mtcr	a3, epc
@@ -71,6 +52,7 @@ ENTRY(csky_cmpxchg)
 	rte
 END(csky_cmpxchg)
 
+#ifndef CONFIG_CPU_HAS_LDSTEX
 /*
  * Called from tlbmodified exception
  */
diff --git a/arch/csky/kernel/entry.S b/arch/csky/kernel/entry.S
index d40fbd5..efcd7a1 100644
--- a/arch/csky/kernel/entry.S
+++ b/arch/csky/kernel/entry.S
@@ -2,19 +2,19 @@
 // Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
 
 #include <linux/linkage.h>
-#include <abi/entry.h>
-#include <abi/pgtable-bits.h>
-#include <asm/errno.h>
-#include <asm/setup.h>
-#include <asm/unistd.h>
-#include <asm/asm-offsets.h>
 #include <linux/threads.h>
-#include <asm/setup.h>
+
+#include <asm/asm-offsets.h>
+#include <asm/errno.h>
 #include <asm/page.h>
+#include <asm/setup.h>
 #include <asm/thread_info.h>
+#include <asm/unistd.h>
 
-.macro tlbop_begin
-	SAVE_ALL EPC_KEEP
+#include <abi/entry.h>
+
+.macro TLBOP_PREPARE
+	SAVE_ALL 0
 #ifdef CONFIG_CPU_HAS_TLBI
 	RD_MEH	a1
 	tlbi.vaas a1
@@ -27,67 +27,66 @@
 #endif
 .endm
 
-.macro tlbop_end
-	mov     a0, sp
+.macro TLBOP_FINISH
+	mov	a0, sp
 	RD_MEH	a1
-	psrset  ee, ie
-	jbsr    do_page_fault
-	jmpi    ret_from_exception
+	psrset	ee, ie
+	jbsr	do_page_fault
+	br	ret_from_exception
 .endm
 
 .text
-
 ENTRY(csky_tlbinvalidl)
-	tlbop_begin
-	tlbop_end
+	TLBOP_PREPARE
+	TLBOP_FINISH
 
 ENTRY(csky_tlbinvalids)
-	tlbop_begin
-	tlbop_end
+	TLBOP_PREPARE
+	TLBOP_FINISH
 
 ENTRY(csky_tlbmodified)
-	tlbop_begin
+	TLBOP_PREPARE
 #ifndef CONFIG_CPU_HAS_LDSTEX
-	jbsr csky_cmpxchg_fixup
+	jbsr	csky_cmpxchg_fixup
 #endif
-	tlbop_end
+	TLBOP_FINISH
 
 ENTRY(csky_systemcall)
-	SAVE_ALL EPC_INCREASE
+	SAVE_ALL TRAP0_SIZE
 
-	psrset  ee, ie
+	psrset	ee, ie
 
-	lrw     r11, __NR_syscalls
-	cmphs   syscallid, r11		/* Check nr of syscall */
-	bt      ret_from_exception
+	lrw	r11, __NR_syscalls
+	cmphs	syscallid, r11		/* Check nr of syscall */
+	bt	ret_from_exception
 
-	lrw     r13, sys_call_table
-	ixw     r13, syscallid
-	ldw     r11, (r13)
-	cmpnei  r11, 0
-	bf      ret_from_exception
+	lrw	r13, sys_call_table
+	ixw	r13, syscallid
+	ldw	r11, (r13)
+	cmpnei	r11, 0
+	bf	ret_from_exception
 
-	mov     r9, sp
-	bmaski  r10, THREAD_SHIFT
-	andn    r9, r10
-	ldw     r8, (r9, TINFO_FLAGS)
+	mov	r9, sp
+	bmaski	r10, THREAD_SHIFT
+	andn	r9, r10
+	ldw	r8, (r9, TINFO_FLAGS)
 	ANDI_R3	r8, (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_TRACEPOINT | _TIF_SYSCALL_AUDIT)
 	cmpnei	r8, 0
-	bt      csky_syscall_trace
+	bt	csky_syscall_trace
 #if defined(__CSKYABIV2__)
-	subi    sp, 8
-	stw  	r5, (sp, 0x4)
-	stw  	r4, (sp, 0x0)
-	jsr     r11                      /* Do system call */
-	addi 	sp, 8
+	subi	sp, 8
+	stw	r5, (sp, 0x4)
+	stw	r4, (sp, 0x0)
+	jsr	r11
+	addi	sp, 8
 #else
-	jsr     r11
+	jsr	r11
 #endif
-	stw     a0, (sp, LSAVE_A0)      /* Save return value */
-	jmpi    ret_from_exception
+	stw	a0, (sp, LSAVE_A0)	/* Save return value */
+	br	ret_from_exception
 
 csky_syscall_trace:
-	mov	a0, sp                  /* sp = pt_regs pointer */
+	mov	a0, sp			/* a0 = pt_regs pointer */
 	jbsr	syscall_trace_enter
 	/* Prepare args before do system call */
 	ldw	a0, (sp, LSAVE_A0)
@@ -102,21 +101,21 @@ csky_syscall_trace:
 	ldw	r6, (sp, LSAVE_A4)
 	ldw	r7, (sp, LSAVE_A5)
 #endif
-	jsr	r11                     /* Do system call */
+	jsr	r11
 #if defined(__CSKYABIV2__)
 	addi	sp, 8
 #endif
 	stw	a0, (sp, LSAVE_A0)	/* Save return value */
 
-	mov     a0, sp                  /* right now, sp --> pt_regs */
-	jbsr    syscall_trace_exit
+	mov	a0, sp			/* a0 = pt_regs pointer */
+	jbsr	syscall_trace_exit
 	br	ret_from_exception
 
 ENTRY(ret_from_kernel_thread)
 	jbsr	schedule_tail
 	mov	a0, r8
 	jsr	r9
-	jbsr	ret_from_exception
+	br	ret_from_exception
 
 ENTRY(ret_from_fork)
 	jbsr	schedule_tail
@@ -126,16 +125,14 @@ ENTRY(ret_from_fork)
 	ldw	r8, (r9, TINFO_FLAGS)
 	ANDI_R3	r8, (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_TRACEPOINT | _TIF_SYSCALL_AUDIT)
 	cmpnei	r8, 0
-	bf	3f
-	mov	a0, sp			/* sp = pt_regs pointer */
+	bf	ret_from_exception
+	mov	a0, sp			/* a0 = pt_regs pointer */
 	jbsr	syscall_trace_exit
-3:
-	jbsr	ret_from_exception
 
 ret_from_exception:
 	ld	syscallid, (sp, LSAVE_PSR)
 	btsti	syscallid, 31
-	bt	1f
+	bt	1f			/* return to kernel */
 
 	/*
 	 * Load address of current->thread_info, Then get address of task_struct
@@ -145,38 +142,33 @@ ret_from_exception:
 	bmaski	r10, THREAD_SHIFT
 	andn	r9, r10
 
-resume_userspace:
 	ldw	r8, (r9, TINFO_FLAGS)
 	andi	r8, (_TIF_SIGPENDING | _TIF_NOTIFY_RESUME | _TIF_NEED_RESCHED)
 	cmpnei	r8, 0
 	bt	exit_work
-1:  RESTORE_ALL
+1:
+	RESTORE_ALL
 
 exit_work:
+	lrw	syscallid, ret_from_exception
+	mov	lr, syscallid		/* Return address in link */
+
 	btsti	r8, TIF_NEED_RESCHED
 	bt	work_resched
-	/* If thread_info->flag is empty, RESTORE_ALL */
-	cmpnei	r8, 0
-	bf	1b
-	mov	a0, r8
-	mov	a1, sp
-	jbsr	do_notify_resume	/* do signals */
-	br	resume_userspace
+
+	mov	a0, sp
+	mov	a1, r8
+	jmpi	do_notify_resume
 
 work_resched:
-	lrw	syscallid, ret_from_exception
-	mov	r15, syscallid		/* Return address in link */
 	jmpi	schedule
 
-ENTRY(sys_rt_sigreturn)
-	jmpi	do_rt_sigreturn
-
 ENTRY(csky_trap)
-	SAVE_ALL EPC_KEEP
+	SAVE_ALL 0
 	psrset	ee
-	mov	a0, sp                 /* Push Stack pointer arg */
-	jbsr	trap_c                 /* Call C-level trap handler */
-	jmpi	ret_from_exception
+	mov	a0, sp
+	jbsr	trap_c
+	br	ret_from_exception
 
 /*
  * Prototype from libc for abiv1:
@@ -188,7 +180,7 @@ ENTRY(csky_get_tls)
 
 	/* increase epc for continue */
 	mfcr	a0, epc
-	INCTRAP	a0
+	addi	a0, TRAP0_SIZE
 	mtcr	a0, epc
 
 	/* get current task thread_info with kernel 8K stack */
@@ -205,7 +197,7 @@ ENTRY(csky_get_tls)
 	rte
 
 ENTRY(csky_irq)
-	SAVE_ALL EPC_KEEP
+	SAVE_ALL 0
 	psrset	ee
 
 #ifdef CONFIG_PREEMPT
@@ -240,12 +232,12 @@ ENTRY(csky_irq)
 	bt	1b			/* go again */
 #endif
 2:
-	jmpi	ret_from_exception
+	br	ret_from_exception
 
 /*
- * a0 =  prev task_struct *
- * a1 =  next task_struct *
- * a0 =  return next
+ * a0 = prev task_struct *
+ * a1 = next task_struct *
+ * a0 = return next
  */
 ENTRY(__switch_to)
 	lrw	a3, TASK_THREAD
@@ -269,7 +261,7 @@ ENTRY(__switch_to)
 	ldw	a2, (a3, THREAD_SR)	/* Set next PSR */
 	mtcr	a2, psr
 
-#if  defined(__CSKYABIV2__)
+#if defined(__CSKYABIV2__)
 	addi	r7, a1, TASK_THREAD_INFO
 	ldw	tls, (r7, TINFO_TP_VALUE)
 #endif
diff --git a/arch/csky/kernel/signal.c b/arch/csky/kernel/signal.c
index 5a18940..2c613b9 100644
--- a/arch/csky/kernel/signal.c
+++ b/arch/csky/kernel/signal.c
@@ -1,138 +1,129 @@
 // SPDX-License-Identifier: GPL-2.0
-// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
 
-#include <linux/sched.h>
-#include <linux/mm.h>
-#include <linux/kernel.h>
 #include <linux/signal.h>
+#include <linux/uaccess.h>
 #include <linux/syscalls.h>
-#include <linux/errno.h>
-#include <linux/wait.h>
-#include <linux/ptrace.h>
-#include <linux/unistd.h>
-#include <linux/stddef.h>
-#include <linux/highuid.h>
-#include <linux/personality.h>
-#include <linux/tty.h>
-#include <linux/binfmts.h>
 #include <linux/tracehook.h>
-#include <linux/freezer.h>
-#include <linux/uaccess.h>
 
-#include <asm/setup.h>
-#include <asm/pgtable.h>
 #include <asm/traps.h>
 #include <asm/ucontext.h>
 #include <asm/vdso.h>
 
+#include <abi/fpu.h>
 #include <abi/regdef.h>
 
-#ifdef CONFIG_CPU_HAS_FPU
-#include <abi/fpu.h>
+struct rt_sigframe {
+	struct siginfo info;
+	struct ucontext uc;
+};
 
-static int restore_fpu_state(struct sigcontext *sc)
+#ifdef CONFIG_CPU_HAS_FPU
+static int restore_fpu_state(struct sigcontext __user *sc)
 {
 	int err = 0;
 	struct user_fp user_fp;
 
-	err = copy_from_user(&user_fp, &sc->sc_user_fp, sizeof(user_fp));
+	err = __copy_from_user(&user_fp, &sc->sc_user_fp, sizeof(user_fp));
 
 	restore_from_user_fp(&user_fp);
 
 	return err;
 }
 
-static int save_fpu_state(struct sigcontext *sc)
+static int save_fpu_state(struct sigcontext __user *sc)
 {
 	struct user_fp user_fp;
 
 	save_to_user_fp(&user_fp);
 
-	return copy_to_user(&sc->sc_user_fp, &user_fp, sizeof(user_fp));
+	return __copy_to_user(&sc->sc_user_fp, &user_fp, sizeof(user_fp));
 }
 #else
-static inline int restore_fpu_state(struct sigcontext *sc) { return 0; }
-static inline int save_fpu_state(struct sigcontext *sc) { return 0; }
+#define restore_fpu_state(sigcontext)	(0)
+#define save_fpu_state(sigcontext)	(0)
 #endif
 
-struct rt_sigframe {
-	int sig;
-	struct siginfo *pinfo;
-	void *puc;
-	struct siginfo info;
-	struct ucontext uc;
-};
-
-static int
-restore_sigframe(struct pt_regs *regs,
-		 struct sigcontext *sc, int *pr2)
+static long restore_sigcontext(struct pt_regs *regs,
+	struct sigcontext __user *sc)
 {
 	int err = 0;
 
-	/* Always make any pending restarted system calls return -EINTR */
-	current_thread_info()->task->restart_block.fn = do_no_restart_syscall;
-
-	err |= copy_from_user(regs, &sc->sc_pt_regs, sizeof(struct pt_regs));
+	/* sc_pt_regs is structured the same as the start of pt_regs */
+	err |= __copy_from_user(regs, &sc->sc_pt_regs, sizeof(struct pt_regs));
 
+	/* Restore the floating-point state. */
 	err |= restore_fpu_state(sc);
 
-	*pr2 = regs->a0;
 	return err;
 }
 
-asmlinkage int
-do_rt_sigreturn(void)
+SYSCALL_DEFINE0(rt_sigreturn)
 {
-	sigset_t set;
-	int a0;
 	struct pt_regs *regs = current_pt_regs();
-	struct rt_sigframe *frame = (struct rt_sigframe *)(regs->usp);
+	struct rt_sigframe __user *frame;
+	struct task_struct *task;
+	sigset_t set;
+
+	/* Always make any pending restarted system calls return -EINTR */
+	current->restart_block.fn = do_no_restart_syscall;
+
+	frame = (struct rt_sigframe __user *)regs->usp;
 
 	if (!access_ok(frame, sizeof(*frame)))
 		goto badframe;
+
 	if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
 		goto badframe;
 
-	sigdelsetmask(&set, (sigmask(SIGKILL) | sigmask(SIGSTOP)));
-	spin_lock_irq(&current->sighand->siglock);
-	current->blocked = set;
-	recalc_sigpending();
-	spin_unlock_irq(&current->sighand->siglock);
+	set_current_blocked(&set);
 
-	if (restore_sigframe(regs, &frame->uc.uc_mcontext, &a0))
+	if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
 		goto badframe;
 
-	return a0;
+	if (restore_altstack(&frame->uc.uc_stack))
+		goto badframe;
+
+	return regs->a0;
 
 badframe:
-	force_sig(SIGSEGV, current);
+	task = current;
+	force_sig(SIGSEGV, task);
 	return 0;
 }
 
-static int setup_sigframe(struct sigcontext *sc, struct pt_regs *regs)
+static int setup_sigcontext(struct rt_sigframe __user *frame,
+	struct pt_regs *regs)
 {
+	struct sigcontext __user *sc = &frame->uc.uc_mcontext;
 	int err = 0;
 
-	err |= copy_to_user(&sc->sc_pt_regs, regs, sizeof(struct pt_regs));
+	err |= __copy_to_user(&sc->sc_pt_regs, regs, sizeof(struct pt_regs));
 	err |= save_fpu_state(sc);
 
 	return err;
 }
 
-static inline void *
-get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size)
+static inline void __user *get_sigframe(struct ksignal *ksig,
+	struct pt_regs *regs, size_t framesize)
 {
-	unsigned long usp;
+	unsigned long sp;
+	/* Default to using normal stack */
+	sp = regs->usp;
+
+	/*
+	 * If we are on the alternate signal stack and would overflow it, don't.
+	 * Return an always-bogus address instead so we will die with SIGSEGV.
+	 */
+	if (on_sig_stack(sp) && !likely(on_sig_stack(sp - framesize)))
+		return (void __user __force *)(-1UL);
 
-	/* Default to using normal stack.  */
-	usp = regs->usp;
+	/* This is the X/Open sanctioned signal stack switching. */
+	sp = sigsp(sp, ksig) - framesize;
 
-	/* This is the X/Open sanctioned signal stack switching.  */
-	if ((ka->sa.sa_flags & SA_ONSTACK) && !sas_ss_flags(usp)) {
-		if (!on_sig_stack(usp))
-			usp = current->sas_ss_sp + current->sas_ss_size;
-	}
-	return (void *)((usp - frame_size) & -8UL);
+	/* Align the stack frame. */
+	sp &= -8UL;
+
+	return (void __user *)sp;
 }
 
 static int
@@ -140,208 +131,128 @@ setup_rt_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs)
 {
 	struct rt_sigframe *frame;
 	int err = 0;
-
 	struct csky_vdso *vdso = current->mm->context.vdso;
 
-	frame = get_sigframe(&ksig->ka, regs, sizeof(*frame));
-	if (!frame)
-		return 1;
+	frame = get_sigframe(ksig, regs, sizeof(*frame));
+	if (!access_ok(frame, sizeof(*frame)))
+		return -EFAULT;
 
-	err |= __put_user(ksig->sig, &frame->sig);
-	err |= __put_user(&frame->info, &frame->pinfo);
-	err |= __put_user(&frame->uc, &frame->puc);
 	err |= copy_siginfo_to_user(&frame->info, &ksig->info);
 
-	/* Create the ucontext.  */
+	/* Create the ucontext. */
 	err |= __put_user(0, &frame->uc.uc_flags);
-	err |= __put_user(0, &frame->uc.uc_link);
-	err |= __put_user((void *)current->sas_ss_sp,
-			&frame->uc.uc_stack.ss_sp);
-	err |= __put_user(sas_ss_flags(regs->usp),
-			&frame->uc.uc_stack.ss_flags);
-	err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
-	err |= setup_sigframe(&frame->uc.uc_mcontext, regs);
-	err |= copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
-
+	err |= __put_user(NULL, &frame->uc.uc_link);
+	err |= __save_altstack(&frame->uc.uc_stack, regs->usp);
+	err |= setup_sigcontext(frame, regs);
+	err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
 	if (err)
-		goto give_sigsegv;
+		return -EFAULT;
 
-	/* Set up registers for signal handler */
-	regs->usp = (unsigned long)frame;
-	regs->pc = (unsigned long)ksig->ka.sa.sa_handler;
-	regs->lr = (unsigned long)vdso->rt_signal_retcode;
+	/* Set up to return from userspace. */
+	regs->lr = (unsigned long)(vdso->rt_signal_retcode);
 
-adjust_stack:
-	regs->a0 = ksig->sig; /* first arg is signo */
-	regs->a1 = (unsigned long)(&(frame->info));
-	regs->a2 = (unsigned long)(&(frame->uc));
-	return err;
+	/*
+	 * Set up registers for signal handler.
+	 * Registers that we don't modify keep the value they had from
+	 * user-space at the time we took the signal.
+	 * We always pass siginfo and mcontext, regardless of SA_SIGINFO,
+	 * since some things rely on this (e.g. glibc's debug/segfault.c).
+	 */
+	regs->pc  = (unsigned long)ksig->ka.sa.sa_handler;
+	regs->usp = (unsigned long)frame;
+	regs->a0  = ksig->sig;				/* a0: signal number */
+	regs->a1  = (unsigned long)(&(frame->info));	/* a1: siginfo pointer */
+	regs->a2  = (unsigned long)(&(frame->uc));	/* a2: ucontext pointer */
 
-give_sigsegv:
-	if (ksig->sig == SIGSEGV)
-		ksig->ka.sa.sa_handler = SIG_DFL;
-	force_sig(SIGSEGV, current);
-	goto adjust_stack;
+	return 0;
 }
 
-/*
- * OK, we're invoking a handler
- */
-static int
-handle_signal(struct ksignal *ksig, struct pt_regs *regs)
+static void handle_signal(struct ksignal *ksig, struct pt_regs *regs)
 {
-	int ret;
 	sigset_t *oldset = sigmask_to_save();
+	int ret;
 
-	/*
-	 * set up the stack frame, regardless of SA_SIGINFO,
-	 * and pass info anyway.
-	 */
-	ret = setup_rt_frame(ksig, oldset, regs);
+	/* Are we from a system call? */
+	if (in_syscall(regs)) {
+		/* Avoid additional syscall restarting via ret_from_exception */
+		forget_syscall(regs);
+
+		/* If so, check system call restarting.. */
+		switch (regs->a0) {
+		case -ERESTART_RESTARTBLOCK:
+		case -ERESTARTNOHAND:
+			regs->a0 = -EINTR;
+			break;
 
-	if (ret != 0) {
-		force_sigsegv(ksig->sig, current);
-		return ret;
+		case -ERESTARTSYS:
+			if (!(ksig->ka.sa.sa_flags & SA_RESTART)) {
+				regs->a0 = -EINTR;
+				break;
+			}
+			/* fallthrough */
+		case -ERESTARTNOINTR:
+			regs->a0 = regs->orig_a0;
+			regs->pc -= TRAP0_SIZE;
+			break;
+		}
 	}
 
-	/* Block the signal if we were successful. */
-	spin_lock_irq(&current->sighand->siglock);
-	sigorsets(&current->blocked, &current->blocked, &ksig->ka.sa.sa_mask);
-	if (!(ksig->ka.sa.sa_flags & SA_NODEFER))
-		sigaddset(&current->blocked, ksig->sig);
-	recalc_sigpending();
-	spin_unlock_irq(&current->sighand->siglock);
+	/* Set up the stack frame */
+	ret = setup_rt_frame(ksig, oldset, regs);
 
-	return 0;
+	signal_setup_done(ret, ksig, 0);
 }
 
-/*
- * 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.
- */
 static void do_signal(struct pt_regs *regs)
 {
-	unsigned int retval = 0, continue_addr = 0, restart_addr = 0;
 	struct ksignal ksig;
 
-	/*
-	 * 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.
-	 */
-	if (!user_mode(regs))
+	if (get_signal(&ksig)) {
+		/* Actually deliver the signal */
+		handle_signal(&ksig, regs);
 		return;
+	}
 
-	/*
-	 * If we were from a system call, check for system call restarting...
-	 */
+	/* Did we come from a system call? */
 	if (in_syscall(regs)) {
+		/* Avoid additional syscall restarting via ret_from_exception */
 		forget_syscall(regs);
 
-		continue_addr = regs->pc;
-#if defined(__CSKYABIV2__)
-		restart_addr = continue_addr - 4;
-#else
-		restart_addr = continue_addr - 2;
-#endif
-		retval = regs->a0;
-		/*
-		 * Prepare for system call restart.  We do this here so that a
-		 * debugger will see the already changed.
-		 */
-		switch (retval) {
+		/* Restart the system call - no handlers present */
+		switch (regs->a0) {
 		case -ERESTARTNOHAND:
 		case -ERESTARTSYS:
 		case -ERESTARTNOINTR:
 			regs->a0 = regs->orig_a0;
-			regs->pc = restart_addr;
+			regs->pc -= TRAP0_SIZE;
 			break;
 		case -ERESTART_RESTARTBLOCK:
-			regs->a0 = -EINTR;
+			regs->a0 = regs->orig_a0;
+			regs_syscallid(regs) = __NR_restart_syscall;
+			regs->pc -= TRAP0_SIZE;
 			break;
 		}
 	}
 
-	if (try_to_freeze())
-		goto no_signal;
-
 	/*
-	 * Get the signal to deliver.  When running under ptrace, at this
-	 * point the debugger may change all our registers ...
+	 * If there is no signal to deliver, we just put the saved
+	 * sigmask back.
 	 */
-	if (get_signal(&ksig)) {
-		/*
-		 * Depending on the signal settings we may need to revert the
-		 * decision to restart the system call.  But skip this if a
-		 * debugger has chosen to restart at a different PC.
-		 */
-		if (regs->pc == restart_addr) {
-			if (retval == -ERESTARTNOHAND ||
-			    (retval == -ERESTARTSYS &&
-			     !(ksig.ka.sa.sa_flags & SA_RESTART))) {
-				regs->a0 = -EINTR;
-				regs->pc = continue_addr;
-			}
-		}
-
-		/* Whee!  Actually deliver the signal.  */
-		if (handle_signal(&ksig, regs) == 0) {
-			/*
-			 * A signal was successfully delivered; the saved
-			 * sigmask will have been stored in the signal frame,
-			 * and will be restored by sigreturn, so we can simply
-			 * clear the TIF_RESTORE_SIGMASK flag.
-			 */
-			if (test_thread_flag(TIF_RESTORE_SIGMASK))
-				clear_thread_flag(TIF_RESTORE_SIGMASK);
-		}
-		return;
-	}
-
-no_signal:
-	if (in_syscall(regs)) {
-		forget_syscall(regs);
-
-		/*
-		 * Handle restarting a different system call.  As above,
-		 * if a debugger has chosen to restart at a different PC,
-		 * ignore the restart.
-		 */
-		if (retval == -ERESTART_RESTARTBLOCK
-				&& regs->pc == continue_addr) {
-#if defined(__CSKYABIV2__)
-			regs->regs[3] = __NR_restart_syscall;
-			regs->pc -= 4;
-#else
-			regs->regs[9] = __NR_restart_syscall;
-			regs->pc -= 2;
-#endif
-		}
-
-		/*
-		 * If there's no signal to deliver, we just put the saved
-		 * sigmask back.
-		 */
-		if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
-			clear_thread_flag(TIF_RESTORE_SIGMASK);
-			sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
-		}
-	}
+	restore_saved_sigmask();
 }
 
-asmlinkage void
-do_notify_resume(unsigned int thread_flags, struct pt_regs *regs)
+/*
+ * notification of userspace execution resumption
+ * - triggered by the _TIF_WORK_MASK flags
+ */
+asmlinkage void do_notify_resume(struct pt_regs *regs,
+	unsigned long thread_info_flags)
 {
-	if (thread_flags & _TIF_SIGPENDING)
+	/* Handle pending signal delivery */
+	if (thread_info_flags & _TIF_SIGPENDING)
 		do_signal(regs);
 
-	if (thread_flags & _TIF_NOTIFY_RESUME) {
+	if (thread_info_flags & _TIF_NOTIFY_RESUME) {
 		clear_thread_flag(TIF_NOTIFY_RESUME);
 		tracehook_notify_resume(regs);
 	}
