powerpc: Clean up panic_timeout usage

Default CONFIG_PANIC_TIMEOUT to 180 seconds on powerpc. The
pSeries continue to set the timeout to 10 seconds at run-time.

Thus, there's a small window where we don't have the correct
value on pSeries, but if this is only run-time discoverable we
don't have a better option. In any case, if the user changes the
default setting of 180 seconds, we honor that user setting.

Signed-off-by: Jason Baron <jbaron@akamai.com>
Cc: benh@kernel.crashing.org
Cc: paulus@samba.org
Cc: ralf@linux-mips.org
Cc: mpe@ellerman.id.au
Cc: felipe.contreras@gmail.com
Cc: linuxppc-dev@lists.ozlabs.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/705bbe0f70fb20759151642ba0176a6414ec9f7a.1385418410.git.jbaron@akamai.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

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

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__ */
 

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();
 

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();
 

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();