MIPS: die() does not call die notifier chain

The MIPS implementation of die() forgets to call notify_die() and thus notifiers
registered via register_die_notifier() are not called.  This results in kgdb not
being activated on exceptions.

The only subtlety is that notify_die declares its regs argument w/o const, so
the const had to be removed from mips die() as well.

[Ralf: Fixed build error for SGI IP22 and IP28 platforms.]

Signed-off-by: Yury Polyanskiy <ypolyans@princeton.edu>
Cc: linux-mips@linux-mips.org
Patchworks: http://patchwork.linux-mips.org/patch/1142/
Acked-by: Jason Wessel <jason.wessel@windriver.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

---

4 files changed, 11 insertions, 6 deletions

diff --git a/arch/mips/include/asm/ptrace.h b/arch/mips/include/asm/ptrace.h
index ce47118e52b7..cdc6a46efd98 100644
--- a/arch/mips/include/asm/ptrace.h
+++ b/arch/mips/include/asm/ptrace.h
@@ -142,9 +142,9 @@ extern int ptrace_set_watch_regs(struct task_struct *child,
 
 extern asmlinkage void do_syscall_trace(struct pt_regs *regs, int entryexit);
 
-extern NORET_TYPE void die(const char *, const struct pt_regs *) ATTRIB_NORET;
+extern NORET_TYPE void die(const char *, struct pt_regs *) ATTRIB_NORET;
 
-static inline void die_if_kernel(const char *str, const struct pt_regs *regs)
+static inline void die_if_kernel(const char *str, struct pt_regs *regs)
 {
         if (unlikely(!user_mode(regs)))
                 die(str, regs);
diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c
index 1a4dd657ccb9..36460c7b7cc8 100644
--- a/arch/mips/kernel/traps.c
+++ b/arch/mips/kernel/traps.c
@@ -352,9 +352,10 @@ void show_registers(const struct pt_regs *regs)
 
 static DEFINE_SPINLOCK(die_lock);
 
-void __noreturn die(const char * str, const 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 */
@@ -365,6 +366,10 @@ void __noreturn die(const char * str, const struct pt_regs * regs)
 #ifdef CONFIG_MIPS_MT_SMTC
         mips_mt_regdump(dvpret);
 #endif /* CONFIG_MIPS_MT_SMTC */
+
+        if (notify_die(DIE_OOPS, str, regs, 0, current->thread.trap_no, SIGSEGV) == NOTIFY_STOP)
+                sig = 0;
+
         printk("%s[#%d]:\n", str, ++die_counter);
         show_registers(regs);
         add_taint(TAINT_DIE);
@@ -379,7 +384,7 @@ void __noreturn die(const char * str, const struct pt_regs * regs)
                 panic("Fatal exception");
         }
 
-        do_exit(SIGSEGV);
+        do_exit(sig);
 }
 
 extern struct exception_table_entry __start___dbe_table[];
diff --git a/arch/mips/sgi-ip22/ip22-berr.c b/arch/mips/sgi-ip22/ip22-berr.c
index de6a0cc32fea..911d3999c0c7 100644
--- a/arch/mips/sgi-ip22/ip22-berr.c
+++ b/arch/mips/sgi-ip22/ip22-berr.c
@@ -89,7 +89,7 @@ static void print_buserr(void)
 void ip22_be_interrupt(int irq)
 {
         const int field = 2 * sizeof(unsigned long);
-        const struct pt_regs *regs = get_irq_regs();
+        struct pt_regs *regs = get_irq_regs();
 
         save_and_clear_buserr();
         print_buserr();
diff --git a/arch/mips/sgi-ip22/ip28-berr.c b/arch/mips/sgi-ip22/ip28-berr.c
index 30e12e2ec4b5..88c684e05a3d 100644
--- a/arch/mips/sgi-ip22/ip28-berr.c
+++ b/arch/mips/sgi-ip22/ip28-berr.c
@@ -453,7 +453,7 @@ mips_be_fatal:
 
 void ip22_be_interrupt(int irq)
 {
-        const struct pt_regs *regs = get_irq_regs();
+        struct pt_regs *regs = get_irq_regs();
 
         count_be_interrupt++;