sh: Tidy up NEFF-based sign extension for SH-5.

This consolidates all of the NEFF-based sign extension for SH-5.
In the future the other SH code will need to make use of this as well,
so make it generic in preparation for more 32/64 consolidation.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

2 files changed, 23 insertions, 39 deletions

diff --git a/arch/sh/kernel/process_64.c b/arch/sh/kernel/process_64.c
index 24de74214940..1192398ef582 100644
--- a/arch/sh/kernel/process_64.c
+++ b/arch/sh/kernel/process_64.c
@@ -425,7 +425,6 @@ int copy_thread(unsigned long clone_flags, unsigned long usp,
 		struct task_struct *p, struct pt_regs *regs)
 {
 	struct pt_regs *childregs;
-	unsigned long long se;			/* Sign extension */
 
 #ifdef CONFIG_SH_FPU
 	if(last_task_used_math == current) {
@@ -441,11 +440,19 @@ int copy_thread(unsigned long clone_flags, unsigned long usp,
 
 	*childregs = *regs;
 
+	/*
+	 * Sign extend the edited stack.
+	 * Note that thread.pc and thread.pc will stay
+	 * 32-bit wide and context switch must take care
+	 * of NEFF sign extension.
+	 */
 	if (user_mode(regs)) {
-		childregs->regs[15] = usp;
+		childregs->regs[15] = neff_sign_extend(usp);
 		p->thread.uregs = childregs;
 	} else {
-		childregs->regs[15] = (unsigned long)task_stack_page(p) + THREAD_SIZE;
+		childregs->regs[15] =
+			neff_sign_extend((unsigned long)task_stack_page(p) +
+					 THREAD_SIZE);
 	}
 
 	childregs->regs[9] = 0; /* Set return value for child */
@@ -454,17 +461,6 @@ int copy_thread(unsigned long clone_flags, unsigned long usp,
 	p->thread.sp = (unsigned long) childregs;
 	p->thread.pc = (unsigned long) ret_from_fork;
 
-	/*
-	 * Sign extend the edited stack.
-         * Note that thread.pc and thread.pc will stay
-	 * 32-bit wide and context switch must take care
-	 * of NEFF sign extension.
-	 */
-
-	se = childregs->regs[15];
-	se = (se & NEFF_SIGN) ? (se | NEFF_MASK) : se;
-	childregs->regs[15] = se;
-
 	return 0;
 }
 
diff --git a/arch/sh/kernel/signal_64.c b/arch/sh/kernel/signal_64.c
index 0663a0ee6021..026fd1cfe17d 100644
--- a/arch/sh/kernel/signal_64.c
+++ b/arch/sh/kernel/signal_64.c
@@ -561,13 +561,11 @@ static int setup_frame(int sig, struct k_sigaction *ka,
 	/* Set up to return from userspace.  If provided, use a stub
 	   already in userspace.  */
 	if (ka->sa.sa_flags & SA_RESTORER) {
-		DEREF_REG_PR = (unsigned long) ka->sa.sa_restorer | 0x1;
-
 		/*
 		 * On SH5 all edited pointers are subject to NEFF
 		 */
-		DEREF_REG_PR = (DEREF_REG_PR & NEFF_SIGN) ?
-			(DEREF_REG_PR | NEFF_MASK) : DEREF_REG_PR;
+		DEREF_REG_PR = neff_sign_extend((unsigned long)
+			ka->sa.sa_restorer | 0x1);
 	} else {
 		/*
 		 * Different approach on SH5.
@@ -580,9 +578,8 @@ static int setup_frame(int sig, struct k_sigaction *ka,
 		 * . being code, linker turns ShMedia bit on, always
 		 *   dereference index -1.
 		 */
-		DEREF_REG_PR = (unsigned long) frame->retcode | 0x01;
-		DEREF_REG_PR = (DEREF_REG_PR & NEFF_SIGN) ?
-			(DEREF_REG_PR | NEFF_MASK) : DEREF_REG_PR;
+		DEREF_REG_PR = neff_sign_extend((unsigned long)
+			frame->retcode | 0x01);
 
 		if (__copy_to_user(frame->retcode,
 			(void *)((unsigned long)sa_default_restorer & (~1)), 16) != 0)
@@ -596,9 +593,7 @@ static int setup_frame(int sig, struct k_sigaction *ka,
 	 * Set up registers for signal handler.
 	 * All edited pointers are subject to NEFF.
 	 */
-	regs->regs[REG_SP] = (unsigned long) frame;
-	regs->regs[REG_SP] = (regs->regs[REG_SP] & NEFF_SIGN) ?
-		 (regs->regs[REG_SP] | NEFF_MASK) : regs->regs[REG_SP];
+	regs->regs[REG_SP] = neff_sign_extend((unsigned long)frame);
 	regs->regs[REG_ARG1] = signal; /* Arg for signal handler */
 
         /* FIXME:
@@ -613,8 +608,7 @@ static int setup_frame(int sig, struct k_sigaction *ka,
 	regs->regs[REG_ARG2] = (unsigned long long)(unsigned long)(signed long)&frame->sc;
 	regs->regs[REG_ARG3] = (unsigned long long)(unsigned long)(signed long)&frame->sc;
 
-	regs->pc = (unsigned long) ka->sa.sa_handler;
-	regs->pc = (regs->pc & NEFF_SIGN) ? (regs->pc | NEFF_MASK) : regs->pc;
+	regs->pc = neff_sign_extend((unsigned long)ka->sa.sa_handler);
 
 	set_fs(USER_DS);
 
@@ -676,13 +670,11 @@ static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 	/* Set up to return from userspace.  If provided, use a stub
 	   already in userspace.  */
 	if (ka->sa.sa_flags & SA_RESTORER) {
-		DEREF_REG_PR = (unsigned long) ka->sa.sa_restorer | 0x1;
-
 		/*
 		 * On SH5 all edited pointers are subject to NEFF
 		 */
-		DEREF_REG_PR = (DEREF_REG_PR & NEFF_SIGN) ?
-			(DEREF_REG_PR | NEFF_MASK) : DEREF_REG_PR;
+		DEREF_REG_PR = neff_sign_extend((unsigned long)
+			ka->sa.sa_restorer | 0x1);
 	} else {
 		/*
 		 * Different approach on SH5.
@@ -695,15 +687,14 @@ static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 		 * . being code, linker turns ShMedia bit on, always
 		 *   dereference index -1.
 		 */
-
-		DEREF_REG_PR = (unsigned long) frame->retcode | 0x01;
-		DEREF_REG_PR = (DEREF_REG_PR & NEFF_SIGN) ?
-			(DEREF_REG_PR | NEFF_MASK) : DEREF_REG_PR;
+		DEREF_REG_PR = neff_sign_extend((unsigned long)
+			frame->retcode | 0x01);
 
 		if (__copy_to_user(frame->retcode,
 			(void *)((unsigned long)sa_default_rt_restorer & (~1)), 16) != 0)
 			goto give_sigsegv;
 
+		/* Cohere the trampoline with the I-cache. */
 		flush_icache_range(DEREF_REG_PR-1, DEREF_REG_PR-1+15);
 	}
 
@@ -711,14 +702,11 @@ static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 	 * Set up registers for signal handler.
 	 * All edited pointers are subject to NEFF.
 	 */
-	regs->regs[REG_SP] = (unsigned long) frame;
-	regs->regs[REG_SP] = (regs->regs[REG_SP] & NEFF_SIGN) ?
-		 (regs->regs[REG_SP] | NEFF_MASK) : regs->regs[REG_SP];
+	regs->regs[REG_SP] = neff_sign_extend((unsigned long)frame);
 	regs->regs[REG_ARG1] = signal; /* Arg for signal handler */
 	regs->regs[REG_ARG2] = (unsigned long long)(unsigned long)(signed long)&frame->info;
 	regs->regs[REG_ARG3] = (unsigned long long)(unsigned long)(signed long)&frame->uc.uc_mcontext;
-	regs->pc = (unsigned long) ka->sa.sa_handler;
-	regs->pc = (regs->pc & NEFF_SIGN) ? (regs->pc | NEFF_MASK) : regs->pc;
+	regs->pc = neff_sign_extend((unsigned long)ka->sa.sa_handler);
 
 	set_fs(USER_DS);