x86-64: honor notify_die() returning NOTIFY_STOP

This requires making die() return a value, making its callers honor
this (and be prepared that it may return), and making oops_end() have
two additional parameters.
Signed-off-by: NJan Beulich <jbeulich@novell.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

arch/x86/kernel/cpu/mcheck/mce_64.c

@@ -192,10 +192,10 @@ void do_machine_check(struct pt_regs * regs, long error_code)
 
 	atomic_inc(&mce_entry);
 
-	if (regs)
-		notify_die(DIE_NMI, "machine check", regs, error_code, 18,
-			   SIGKILL);
-	if (!banks)
+	if ((regs
+	     && notify_die(DIE_NMI, "machine check", regs, error_code,
+			   18, SIGKILL) == NOTIFY_STOP)
+	    || !banks)
 		goto out2;
 
 	memset(&m, 0, sizeof(struct mce));

arch/x86/kernel/traps_64.c

@@ -488,7 +488,7 @@ unsigned __kprobes long oops_begin(void)
 	return flags;
 }
 
-void __kprobes oops_end(unsigned long flags)
+void __kprobes oops_end(unsigned long flags, struct pt_regs *regs, int signr)
 { 
 	die_owner = -1;
 	bust_spinlocks(0);
@@ -497,12 +497,17 @@ void __kprobes oops_end(unsigned long flags)
 		/* Nest count reaches zero, release the lock. */
 		__raw_spin_unlock(&die_lock);
 	raw_local_irq_restore(flags);
+	if (!regs) {
+		oops_exit();
+		return;
+	}
 	if (panic_on_oops)
 		panic("Fatal exception");
 	oops_exit();
+	do_exit(signr);
 }
 
-void __kprobes __die(const char * str, struct pt_regs * regs, long err)
+int __kprobes __die(const char * str, struct pt_regs * regs, long err)
 {
 	static int die_counter;
 	printk(KERN_EMERG "%s: %04lx [%u] ", str, err & 0xffff,++die_counter);
@@ -516,7 +521,8 @@ void __kprobes __die(const char * str, struct pt_regs * regs, long err)
 	printk("DEBUG_PAGEALLOC");
 #endif
 	printk("\n");
-	notify_die(DIE_OOPS, str, regs, err, current->thread.trap_no, SIGSEGV);
+	if (notify_die(DIE_OOPS, str, regs, err, current->thread.trap_no, SIGSEGV) == NOTIFY_STOP)
+		return 1;
 	show_registers(regs);
 	add_taint(TAINT_DIE);
 	/* Executive summary in case the oops scrolled away */
@@ -525,6 +531,7 @@ void __kprobes __die(const char * str, struct pt_regs * regs, long err)
 	printk(" RSP <%016lx>\n", regs->sp);
 	if (kexec_should_crash(current))
 		crash_kexec(regs);
+	return 0;
 }
 
 void die(const char * str, struct pt_regs * regs, long err)
@@ -534,9 +541,9 @@ void die(const char * str, struct pt_regs * regs, long err)
 	if (!user_mode(regs))
 		report_bug(regs->ip, regs);
 
-	__die(str, regs, err);
-	oops_end(flags);
-	do_exit(SIGSEGV); 
+	if (__die(str, regs, err))
+		regs = NULL;
+	oops_end(flags, regs, SIGSEGV);
 }
 
 void __kprobes die_nmi(char *str, struct pt_regs *regs, int do_panic)
@@ -553,10 +560,10 @@ void __kprobes die_nmi(char *str, struct pt_regs *regs, int do_panic)
 		crash_kexec(regs);
 	if (do_panic || panic_on_oops)
 		panic("Non maskable interrupt");
-	oops_end(flags);
+	oops_end(flags, NULL, SIGBUS);
 	nmi_exit();
 	local_irq_enable();
-	do_exit(SIGSEGV);
+	do_exit(SIGBUS);
 }
 
 static void __kprobes do_trap(int trapnr, int signr, char *str,

arch/x86/mm/fault_64.c

@@ -227,9 +227,9 @@ static noinline void pgtable_bad(unsigned long address, struct pt_regs *regs,
 	tsk->thread.cr2 = address;
 	tsk->thread.trap_no = 14;
 	tsk->thread.error_code = error_code;
-	__die("Bad pagetable", regs, error_code);
-	oops_end(flags);
-	do_exit(SIGKILL);
+	if (__die("Bad pagetable", regs, error_code))
+		regs = NULL;
+	oops_end(flags, regs, SIGKILL);
 }
 
 /*
@@ -541,11 +541,11 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
 	tsk->thread.cr2 = address;
 	tsk->thread.trap_no = 14;
 	tsk->thread.error_code = error_code;
-	__die("Oops", regs, error_code);
+	if (__die("Oops", regs, error_code))
+		regs = NULL;
 	/* Executive summary in case the body of the oops scrolled away */
 	printk(KERN_EMERG "CR2: %016lx\n", address);
-	oops_end(flags);
-	do_exit(SIGKILL);
+	oops_end(flags, regs, SIGKILL);
 
 /*
  * We ran out of memory, or some other thing happened to us that made

include/asm-x86/kdebug.h

@@ -25,7 +25,7 @@ enum die_val {
 extern void early_printk(const char *fmt, ...) __attribute__((format(printf,1,2)));
 extern void printk_address(unsigned long address);
 extern void die(const char *,struct pt_regs *,long);
-extern void __die(const char *,struct pt_regs *,long);
+extern int __must_check __die(const char *, struct pt_regs *, long);
 extern void show_registers(struct pt_regs *regs);
 extern void __show_registers(struct pt_regs *, int all);
 extern void show_trace(struct task_struct *, struct pt_regs *, unsigned long *);
@@ -33,6 +33,6 @@ extern void __show_regs(struct pt_regs *regs);
 extern void show_regs(struct pt_regs *regs);
 extern void dump_pagetable(unsigned long);
 extern unsigned long oops_begin(void);
-extern void oops_end(unsigned long);
+extern void oops_end(unsigned long, struct pt_regs *, int signr);
 
 #endif