sparc-2.6.git sparc32

sparc-2.6.git sparc32

[Raymond Burns]

[-- Attachment #1: Type: TEXT/PLAIN, Size: 698 bytes --]

Hi

Working with a June 29th pull of davem's tree I found a sequence of
events which poses a problem causing BUG and then Oops.

This impacts platforms with the mostek clock 

kernel/main.c calls out time_init() which ultimatly leads to a call
of clock_init() which calls of_register_driver() for the mostek clock.

This occurs prior to the kobject, klist and friends being initialized
which occurs as postcore_initcall(of_bus_driver_init), This leads to
the BUGs and oops.

The clock initialization is needed prior to local_irq_enable

I have not found reasons for the postcore_initcall calls timing but
assume they're concrete for other platforms.

I have not found a work around.

Thanx
  Ray



[-- Attachment #2: log of boot --]
[-- Type: TEXT/PLAIN, Size: 2110 bytes --]

SILO boot: sm
Using /dev/ttya as console.
TYPE: SPARCserver 1000E
Ethernet address: 8:0:20:7e:19:ee
Boot time fixup v1.6. 4/Mar/98 Jakub Jelinek (jj@ultra.linux.cz). Patching kerne
l for srmmu[TI Viking/MXCC]/io-unit
318MB HIGHMEM available.
PROM: Built device tree with 14005 bytes of memory.
Booting Linux...
Built 1 zonelists.  Total pages: 130066
Kernel command line: root=/dev/sdc3 console=ttya
PID hash table entries: 1024 (order: 10, 4096 bytes)
BUG: warning at lib/kref.c:32/kref_get()
[f013df38 : get_bus+0x20/0x50 ] [f013dd04 : bus_add_driver+0x8/0xa8 ] [f025bc74
: sbus_setup_arch_props+0x30/0x54 ] [f02560a4 : found_version+0x5c/0x68 ] [f0255
7c8 : _etext+0x76c20/0x77458 ] [00000000 : __stext+0xfffc000/0x10 ]
BUG: warning at lib/kref.c:32/kref_get()
[f0109d7c : kobject_init+0x38/0x70 ] [f0109f64 : kobject_register+0x10/0x44 ] [f
013dd44 : bus_add_driver+0x48/0xa8 ] [f025bc74 : sbus_setup_arch_props+0x30/0x54
 ] [f02560a4 : found_version+0x5c/0x68 ] [f02557c8 : _etext+0x76c20/0x77458 ] [0
0000000 : __stext+0xfffc000/0x10 ]
Unable to handle kernel NULL pointer dereference
tsk->{mm,active_mm}->context = ffffffff
tsk->{mm,active_mm}->pgd = fc000000
swapper(0): Oops [#1]
PSR: 40401fc2 PC: f0109ef4 NPC: f0109ef8 Y: 00000000    Not tainted
PC: <kobject_add+0xec/0x14c>
%G: f02177d8 f0110db8  404010e1 40401fe6  f003af34 f027ec00  f0012000 00000100
%O: f02177e0 f0217260  00000000 00000073  ffffffff ffffffff  f0013d90 f0109f10
RPC: <kobject_add+0x108/0x14c>
%L: 00000000 f02177ec  fffffffd f0217248  00000040 00000000  0000001f f0013d08
%I: f0217244 00000014  f01e8582 f0013eb0  f027f5e0 ffffffff  f0013df8 f0109f6c
Caller[f0109f6c]: kobject_register+0x18/0x44
Caller[f013dd44]: bus_add_driver+0x48/0xa8
Caller[f025bc74]: sbus_setup_arch_props+0x30/0x54
Caller[f02560a4]: found_version+0x5c/0x68
Caller[f02557c8]: _etext+0x76c20/0x77458
Caller[00000000]: __stext+0xfffc000/0x10
Instruction DUMP: d4022004  d026201c  d2222004 <d2228000> d4226004  d0062028  90
022010  c02a0000  10bfffd5
Program terminated
Type  help  for more information
<#0> ok

Re: sparc-2.6.git sparc32

[Bob Breuer]

[-- Attachment #1: Type: text/plain, Size: 1148 bytes --]

Raymond Burns wrote:
> Hi
> 
> Working with a June 29th pull of davem's tree I found a sequence of
> events which poses a problem causing BUG and then Oops.
> 
> This impacts platforms with the mostek clock 
> 
> kernel/main.c calls out time_init() which ultimatly leads to a call
> of clock_init() which calls of_register_driver() for the mostek clock.
> 
> This occurs prior to the kobject, klist and friends being initialized
> which occurs as postcore_initcall(of_bus_driver_init), This leads to
> the BUGs and oops.
> 
> The clock initialization is needed prior to local_irq_enable
> 
> I have not found reasons for the postcore_initcall calls timing but
> assume they're concrete for other platforms.
> 
> I have not found a work around.

I'm seeing the same thing.

Based on sparc64, it should be possible to defer the initialization of
the mostek clock until later.

The attached patch gets me past the clock driver, but it ends up with a
watchdog reset after switching to malloc:

  io scheduler cfq registered (default)
  ioremap: done with statics, switching to malloc

  Watchdog Reset
  Type  help  for more information
  <#0> ok

Bob

[-- Attachment #2: sparc32-delayed-clock_init.txt --]
[-- Type: text/plain, Size: 3624 bytes --]

diff --git a/arch/sparc/kernel/time.c b/arch/sparc/kernel/time.c
index 04eb1ea..845081b 100644
--- a/arch/sparc/kernel/time.c
+++ b/arch/sparc/kernel/time.c
@@ -225,6 +225,32 @@ static __inline__ int has_low_battery(vo
 	return (data1 == data2);	/* Was the write blocked? */
 }
 
+static void __init mostek_set_system_time(void)
+{
+	unsigned int year, mon, day, hour, min, sec;
+	struct mostek48t02 *mregs;
+
+	mregs = (struct mostek48t02 *)mstk48t02_regs;
+	if(!mregs) {
+		prom_printf("Something wrong, clock regs not mapped yet.\n");
+		prom_halt();
+	}		
+	spin_lock_irq(&mostek_lock);
+	mregs->creg |= MSTK_CREG_READ;
+	sec = MSTK_REG_SEC(mregs);
+	min = MSTK_REG_MIN(mregs);
+	hour = MSTK_REG_HOUR(mregs);
+	day = MSTK_REG_DOM(mregs);
+	mon = MSTK_REG_MONTH(mregs);
+	year = MSTK_CVT_YEAR( MSTK_REG_YEAR(mregs) );
+	xtime.tv_sec = mktime(year, mon, day, hour, min, sec);
+	xtime.tv_nsec = (INITIAL_JIFFIES % HZ) * (NSEC_PER_SEC / HZ);
+        set_normalized_timespec(&wall_to_monotonic,
+                                -xtime.tv_sec, -xtime.tv_nsec);
+	mregs->creg &= ~MSTK_CREG_READ;
+	spin_unlock_irq(&mostek_lock);
+}
+
 /* Probe for the real time clock chip on Sun4 */
 static __inline__ void sun4_clock_probe(void)
 {
@@ -273,6 +299,7 @@ #ifdef CONFIG_SUN4
 #endif
 }
 
+#ifndef CONFIG_SUN4
 static int __devinit clock_probe(struct of_device *op, const struct of_device_id *match)
 {
 	struct device_node *dp = op->node;
@@ -307,6 +334,8 @@ static int __devinit clock_probe(struct 
 	if (mostek_read(mstk48t02_regs + MOSTEK_SEC) & MSTK_STOP)
 		kick_start_clock();
 
+	mostek_set_system_time();
+
 	return 0;
 }
 
@@ -325,56 +354,37 @@ static struct of_platform_driver clock_d
 
 
 /* Probe for the mostek real time clock chip. */
-static void clock_init(void)
+static int __init clock_init(void)
 {
-	of_register_driver(&clock_driver, &of_bus_type);
+	return of_register_driver(&clock_driver, &of_bus_type);
 }
 
+/* Must be after subsys_initcall() so that busses are probed.  Must
+ * be before device_initcall() because things like the RTC driver
+ * need to see the clock registers.
+ */
+fs_initcall(clock_init);
+#endif /* !CONFIG_SUN4 */
+
 void __init sbus_time_init(void)
 {
-	unsigned int year, mon, day, hour, min, sec;
-	struct mostek48t02 *mregs;
-
-#ifdef CONFIG_SUN4
-	int temp;
-	struct intersil *iregs;
-#endif
 
 	BTFIXUPSET_CALL(bus_do_settimeofday, sbus_do_settimeofday, BTFIXUPCALL_NORM);
 	btfixup();
 
 	if (ARCH_SUN4)
 		sun4_clock_probe();
-	else
-		clock_init();
 
 	sparc_init_timers(timer_interrupt);
 	
 #ifdef CONFIG_SUN4
 	if(idprom->id_machtype == (SM_SUN4 | SM_4_330)) {
-#endif
-	mregs = (struct mostek48t02 *)mstk48t02_regs;
-	if(!mregs) {
-		prom_printf("Something wrong, clock regs not mapped yet.\n");
-		prom_halt();
-	}		
-	spin_lock_irq(&mostek_lock);
-	mregs->creg |= MSTK_CREG_READ;
-	sec = MSTK_REG_SEC(mregs);
-	min = MSTK_REG_MIN(mregs);
-	hour = MSTK_REG_HOUR(mregs);
-	day = MSTK_REG_DOM(mregs);
-	mon = MSTK_REG_MONTH(mregs);
-	year = MSTK_CVT_YEAR( MSTK_REG_YEAR(mregs) );
-	xtime.tv_sec = mktime(year, mon, day, hour, min, sec);
-	xtime.tv_nsec = (INITIAL_JIFFIES % HZ) * (NSEC_PER_SEC / HZ);
-        set_normalized_timespec(&wall_to_monotonic,
-                                -xtime.tv_sec, -xtime.tv_nsec);
-	mregs->creg &= ~MSTK_CREG_READ;
-	spin_unlock_irq(&mostek_lock);
-#ifdef CONFIG_SUN4
+		mostek_set_system_time();
 	} else if(idprom->id_machtype == (SM_SUN4 | SM_4_260) ) {
 		/* initialise the intersil on sun4 */
+		unsigned int year, mon, day, hour, min, sec;
+		int temp;
+		struct intersil *iregs;
 
 		iregs=intersil_clock;
 		if(!iregs) {

Re: sparc-2.6.git sparc32

[Raymond Burns]

[-- Attachment #1: Type: TEXT/PLAIN, Size: 666 bytes --]

Hi

Your patch worked well, Thank You

For the sun4d I had to remove the arc specific local_irq_enable() to
allow the mainline initialization to occur, which seems to work.


On Sat, 8 Jul 2006, Bob Breuer wrote:

> I'm seeing the same thing.
> 
> Based on sparc64, it should be possible to defer the initialization of
> the mostek clock until later.
> 
> The attached patch gets me past the clock driver, but it ends up with a
> watchdog reset after switching to malloc:
> 
>   io scheduler cfq registered (default)
>   ioremap: done with statics, switching to malloc
> 
>   Watchdog Reset
>   Type  help  for more information
>   <#0> ok
> 
> Bob
> 

Thanx
  Ray


[-- Attachment #2: patch remove arch local_irq_enable --]
[-- Type: TEXT/PLAIN, Size: 246 bytes --]

--- time.c.orig	Mon Jul 10 17:47:28 2006
+++ time.c	Mon Jul 10 17:47:34 2006
@@ -421,7 +421,6 @@
 #endif
 
 	/* Now that OBP ticker has been silenced, it is safe to enable IRQ. */
-	local_irq_enable();
 }
 
 void __init time_init(void)