MIPS: Clean up notify_die() usage.

The sixth argument of notify_die() is a signal number, the fifth is a
trap number.

Instead of passing a signal number in a randomly selected argument,
pass it in the sixth.  Extract the exception code from regs and pass
that as the trap number.

Get rid of redundant cast, and remove some gratuitous spaces.

Nobody actually does anything with the signal number or trap number,
but we might as well populate them with sensible values.

Signed-off-by: David Daney <ddaney@caviumnetworks.com>
To: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/1532/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/kernel/traps.c

@@ -357,17 +357,22 @@ void show_registers(struct pt_regs *regs)
 	printk("\n");
 }
 
+static int regs_to_trapnr(struct pt_regs *regs)
+{
+	return (regs->cp0_cause >> 2) & 0x1f;
+}
+
 static DEFINE_SPINLOCK(die_lock);
 
-void __noreturn die(const char * str, struct pt_regs * regs)
+void __noreturn die(const char *str, struct pt_regs *regs)
 {
 	static int die_counter;
 	int sig = SIGSEGV;
 #ifdef CONFIG_MIPS_MT_SMTC
 	unsigned long dvpret = dvpe();
 #endif /* CONFIG_MIPS_MT_SMTC */
 
-	notify_die(DIE_OOPS, str, (struct pt_regs *)regs, SIGSEGV, 0, 0);
+	notify_die(DIE_OOPS, str, regs, 0, regs_to_trapnr(regs), SIGSEGV);
 
 	console_verbose();
 	spin_lock_irq(&die_lock);
@@ -376,7 +381,7 @@ void __noreturn die(const char * str, struct pt_regs * regs)
 	mips_mt_regdump(dvpret);
 #endif /* CONFIG_MIPS_MT_SMTC */
 
-	if (notify_die(DIE_OOPS, str, regs, 0, 0, SIGSEGV) == NOTIFY_STOP)
+	if (notify_die(DIE_OOPS, str, regs, 0, regs_to_trapnr(regs), SIGSEGV) == NOTIFY_STOP)
 		sig = 0;
 
 	printk("%s[#%d]:\n", str, ++die_counter);
@@ -450,7 +455,7 @@ asmlinkage void do_be(struct pt_regs *regs)
 	printk(KERN_ALERT "%s bus error, epc == %0*lx, ra == %0*lx\n",
 	       data ? "Data" : "Instruction",
 	       field, regs->cp0_epc, field, regs->regs[31]);
-	if (notify_die(DIE_OOPS, "bus error", regs, SIGBUS, 0, 0)
+	if (notify_die(DIE_OOPS, "bus error", regs, 0, regs_to_trapnr(regs), SIGBUS)
 	    == NOTIFY_STOP)
 		return;
 
@@ -651,7 +656,7 @@ asmlinkage void do_fpe(struct pt_regs *regs, unsigned long fcr31)
 {
 	siginfo_t info;
 
-	if (notify_die(DIE_FP, "FP exception", regs, SIGFPE, 0, 0)
+	if (notify_die(DIE_FP, "FP exception", regs, 0, regs_to_trapnr(regs), SIGFPE)
 	    == NOTIFY_STOP)
 		return;
 	die_if_kernel("FP exception in kernel code", regs);
@@ -714,11 +719,11 @@ static void do_trap_or_bp(struct pt_regs *regs, unsigned int code,
 	char b[40];
 
 #ifdef CONFIG_KGDB_LOW_LEVEL_TRAP
-	if (kgdb_ll_trap(DIE_TRAP, str, regs, code, 0, 0) == NOTIFY_STOP)
+	if (kgdb_ll_trap(DIE_TRAP, str, regs, code, regs_to_trapnr(regs), SIGTRAP) == NOTIFY_STOP)
 		return;
 #endif /* CONFIG_KGDB_LOW_LEVEL_TRAP */
 
-	if (notify_die(DIE_TRAP, str, regs, code, 0, 0) == NOTIFY_STOP)
+	if (notify_die(DIE_TRAP, str, regs, code, regs_to_trapnr(regs), SIGTRAP) == NOTIFY_STOP)
 		return;
 
 	/*
@@ -790,12 +795,12 @@ asmlinkage void do_bp(struct pt_regs *regs)
 	 */
 	switch (bcode) {
 	case BRK_KPROBE_BP:
-		if (notify_die(DIE_BREAK, "debug", regs, bcode, 0, 0) == NOTIFY_STOP)
+		if (notify_die(DIE_BREAK, "debug", regs, bcode, regs_to_trapnr(regs), SIGTRAP) == NOTIFY_STOP)
 			return;
 		else
 			break;
 	case BRK_KPROBE_SSTEPBP:
-		if (notify_die(DIE_SSTEPBP, "single_step", regs, bcode, 0, 0) == NOTIFY_STOP)
+		if (notify_die(DIE_SSTEPBP, "single_step", regs, bcode, regs_to_trapnr(regs), SIGTRAP) == NOTIFY_STOP)
 			return;
 		else
 			break;
@@ -835,7 +840,7 @@ asmlinkage void do_ri(struct pt_regs *regs)
 	unsigned int opcode = 0;
 	int status = -1;
 
-	if (notify_die(DIE_RI, "RI Fault", regs, SIGSEGV, 0, 0)
+	if (notify_die(DIE_RI, "RI Fault", regs, 0, regs_to_trapnr(regs), SIGILL)
 	    == NOTIFY_STOP)
 		return;