Merge branch 'core-debug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull core debug changes from Ingo Molnar:
 "Currently there are two methods to set the panic_timeout: via
  'panic=X' boot commandline option, or via /proc/sys/kernel/panic.

  This tree adds a third panic_timeout configuration method:
  configuration via Kconfig, via CONFIG_PANIC_TIMEOUT=X - useful to
  distros that generally want their kernel defaults to come with the
  .config.

  CONFIG_PANIC_TIMEOUT defaults to 0, which was the previous default
  value of panic_timeout.

  Doing that unearthed a few arch trickeries regarding arch-special
  panic_timeout values and related complications - hopefully all
  resolved to the satisfaction of everyone"

* 'core-debug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  powerpc: Clean up panic_timeout usage
  MIPS: Remove panic_timeout settings
  panic: Make panic_timeout configurable

13 files changed, 25 insertions, 16 deletions

diff --git a/arch/mips/ar7/setup.c b/arch/mips/ar7/setup.c
index 9a357fffcfbe..820b7a313d9b 100644
--- a/arch/mips/ar7/setup.c
+++ b/arch/mips/ar7/setup.c
@@ -92,7 +92,6 @@ void __init plat_mem_setup(void)
         _machine_restart = ar7_machine_restart;
         _machine_halt = ar7_machine_halt;
         pm_power_off = ar7_machine_power_off;
-        panic_timeout = 3;
 
         io_base = (unsigned long)ioremap(AR7_REGS_BASE, 0x10000);
         if (!io_base)
diff --git a/arch/mips/emma/markeins/setup.c b/arch/mips/emma/markeins/setup.c
index d71005835c00..9100122e5cef 100644
--- a/arch/mips/emma/markeins/setup.c
+++ b/arch/mips/emma/markeins/setup.c
@@ -111,9 +111,6 @@ void __init plat_mem_setup(void)
         iomem_resource.start = EMMA2RH_IO_BASE;
         iomem_resource.end = EMMA2RH_ROM_BASE - 1;
 
-        /* Reboot on panic */
-        panic_timeout = 180;
-
         markeins_sio_setup();
 }
 
diff --git a/arch/mips/netlogic/xlp/setup.c b/arch/mips/netlogic/xlp/setup.c
index 6d981bb337ec..54e75c77184b 100644
--- a/arch/mips/netlogic/xlp/setup.c
+++ b/arch/mips/netlogic/xlp/setup.c
@@ -92,7 +92,6 @@ static void __init xlp_init_mem_from_bars(void)
 
 void __init plat_mem_setup(void)
 {
-        panic_timeout   = 5;
         _machine_restart = (void (*)(char *))nlm_linux_exit;
         _machine_halt   = nlm_linux_exit;
         pm_power_off    = nlm_linux_exit;
diff --git a/arch/mips/netlogic/xlr/setup.c b/arch/mips/netlogic/xlr/setup.c
index 214d123b79fa..921be5f77797 100644
--- a/arch/mips/netlogic/xlr/setup.c
+++ b/arch/mips/netlogic/xlr/setup.c
@@ -92,7 +92,6 @@ static void nlm_linux_exit(void)
 
 void __init plat_mem_setup(void)
 {
-        panic_timeout   = 5;
         _machine_restart = (void (*)(char *))nlm_linux_exit;
         _machine_halt   = nlm_linux_exit;
         pm_power_off    = nlm_linux_exit;
diff --git a/arch/mips/sibyte/swarm/setup.c b/arch/mips/sibyte/swarm/setup.c
index 41707a245dea..3462c831d0ea 100644
--- a/arch/mips/sibyte/swarm/setup.c
+++ b/arch/mips/sibyte/swarm/setup.c
@@ -134,8 +134,6 @@ void __init plat_mem_setup(void)
 #error invalid SiByte board configuration
 #endif
 
-        panic_timeout = 5;  /* For debug.  */
-
         board_be_handler = swarm_be_handler;
 
         if (xicor_probe())
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index b44b52c0a8f0..b2be8e8cb5c7 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -147,6 +147,10 @@ config EARLY_PRINTK
         bool
         default y
 
+config PANIC_TIMEOUT
+        int
+        default 180
+
 config COMPAT
         bool
         default y if PPC64
diff --git a/arch/powerpc/include/asm/setup.h b/arch/powerpc/include/asm/setup.h
index 703a8412dac2..11ba86e17631 100644
--- a/arch/powerpc/include/asm/setup.h
+++ b/arch/powerpc/include/asm/setup.h
@@ -26,6 +26,7 @@ extern void reloc_got2(unsigned long);
 void check_for_initrd(void);
 void do_init_bootmem(void);
 void setup_panic(void);
+#define ARCH_PANIC_TIMEOUT 180
 
 #endif /* !__ASSEMBLY__ */
 
diff --git a/arch/powerpc/kernel/setup_32.c b/arch/powerpc/kernel/setup_32.c
index b903dc5cf944..2b0da27eaee4 100644
--- a/arch/powerpc/kernel/setup_32.c
+++ b/arch/powerpc/kernel/setup_32.c
@@ -296,9 +296,6 @@ void __init setup_arch(char **cmdline_p)
         if (cpu_has_feature(CPU_FTR_UNIFIED_ID_CACHE))
                 ucache_bsize = icache_bsize = dcache_bsize;
 
-        /* reboot on panic */
-        panic_timeout = 180;
-
         if (ppc_md.panic)
                 setup_panic();
 
diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c
index 4085aaa9478f..856dd4e99bfe 100644
--- a/arch/powerpc/kernel/setup_64.c
+++ b/arch/powerpc/kernel/setup_64.c
@@ -588,9 +588,6 @@ void __init setup_arch(char **cmdline_p)
         dcache_bsize = ppc64_caches.dline_size;
         icache_bsize = ppc64_caches.iline_size;
 
-        /* reboot on panic */
-        panic_timeout = 180;
-
         if (ppc_md.panic)
                 setup_panic();
 
diff --git a/arch/powerpc/platforms/pseries/setup.c b/arch/powerpc/platforms/pseries/setup.c
index c1f190858701..6f76ae417f47 100644
--- a/arch/powerpc/platforms/pseries/setup.c
+++ b/arch/powerpc/platforms/pseries/setup.c
@@ -470,7 +470,7 @@ static long pseries_little_endian_exceptions(void)
 
 static void __init pSeries_setup_arch(void)
 {
-        panic_timeout = 10;
+        set_arch_panic_timeout(10, ARCH_PANIC_TIMEOUT);
 
         /* Discover PIC type and setup ppc_md accordingly */
         pseries_discover_pic();
diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index ecb87544cc5d..2aa3d4b000e6 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -394,6 +394,15 @@ extern int panic_on_oops;
 extern int panic_on_unrecovered_nmi;
 extern int panic_on_io_nmi;
 extern int sysctl_panic_on_stackoverflow;
+/*
+ * Only to be used by arch init code. If the user over-wrote the default
+ * CONFIG_PANIC_TIMEOUT, honor it.
+ */
+static inline void set_arch_panic_timeout(int timeout, int arch_default_timeout)
+{
+        if (panic_timeout == arch_default_timeout)
+                panic_timeout = timeout;
+}
 extern const char *print_tainted(void);
 enum lockdep_ok {
         LOCKDEP_STILL_OK,
diff --git a/kernel/panic.c b/kernel/panic.c
index c00b4ceb39e8..6d6300375090 100644
--- a/kernel/panic.c
+++ b/kernel/panic.c
@@ -33,7 +33,7 @@ static int pause_on_oops;
 static int pause_on_oops_flag;
 static DEFINE_SPINLOCK(pause_on_oops_lock);
 
-int panic_timeout;
+int panic_timeout = CONFIG_PANIC_TIMEOUT;
 EXPORT_SYMBOL_GPL(panic_timeout);
 
 ATOMIC_NOTIFIER_HEAD(panic_notifier_list);
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index db25707aa41b..6982094a7e74 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -761,6 +761,15 @@ config PANIC_ON_OOPS_VALUE
         default 0 if !PANIC_ON_OOPS
         default 1 if PANIC_ON_OOPS
 
+config PANIC_TIMEOUT
+        int "panic timeout"
+        default 0
+        help
+          Set the timeout value (in seconds) until a reboot occurs when the
+          the kernel panics. If n = 0, then we wait forever. A timeout
+          value n > 0 will wait n seconds before rebooting, while a timeout
+          value n < 0 will reboot immediately.
+
 config SCHED_DEBUG
         bool "Collect scheduler debugging info"
         depends on DEBUG_KERNEL && PROC_FS