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arch-specific callout in panic()

PATCH In review Mike Strosaker 4 participants 5 messages Feb 23, 2004 – Feb 24, 2004

Subsystems (9)
Arm (32-bit) MIPS s390 SuperH +5 more subsystems
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Mike Strosaker

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#0 lore raw

PATCH 1/1 arch-specific callout in panic()

Hello, All:

There are some ppc64-specific actions that should be taken upon a kernel panic. Rather than adding a new #ifdef in panic(), it seems to me that it would be worthwhile to add a single callout, and move the arch-specific code out to the arch subtrees. Does this seem reasonable, or should another #ifdef be added in panic() to perform the ppc64- specific actions?

Please cc me on any replies.

Thanks,
Mike

arch/alpha/kernel/process.c +7 -0
diff -Nru a/arch/alpha/kernel/process.c b/arch/alpha/kernel/process.c
@@ -183,6 +183,13 @@
 
 EXPORT_SYMBOL(machine_power_off);
 
+void
+machine_panic(void)
+{
+}
+
+EXPORT_SYMBOL(machine_panic);
+
 /* Used by sysrq-p, among others.  I don't believe r9-r15 are ever
    saved in the context it's used.  */
arch/arm/kernel/process.c +6 -0
diff -Nru a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c
@@ -163,6 +163,12 @@
 
 EXPORT_SYMBOL(machine_restart);
 
+void machine_panic(void)
+{
+}
+
+EXPORT_SYMBOL(machine_panic);
+
 void show_regs(struct pt_regs * regs)
 {
 	unsigned long flags;
arch/arm26/kernel/process.c +6 -0
diff -Nru a/arch/arm26/kernel/process.c b/arch/arm26/kernel/process.c
@@ -163,6 +163,12 @@
 
 EXPORT_SYMBOL(machine_restart);
 
+void machine_panic(void)
+{
+}
+
+EXPORT_SYMBOL(machine_panic);
+
 void show_regs(struct pt_regs * regs)
 {
 	unsigned long flags;
arch/cris/kernel/process.c +6 -0
diff -Nru a/arch/cris/kernel/process.c b/arch/cris/kernel/process.c
@@ -222,6 +222,12 @@
 
 EXPORT_SYMBOL(machine_power_off);
 
+void machine_panic(void)
+{
+}
+
+EXPORT_SYMBOL(machine_panic);
+
 /*
  * When a process does an "exec", machine state like FPU and debug
  * registers need to be reset.  This is a hook function for that.
arch/h8300/kernel/process.c +6 -0
diff -Nru a/arch/h8300/kernel/process.c b/arch/h8300/kernel/process.c
@@ -110,6 +110,12 @@
 
 EXPORT_SYMBOL(machine_power_off);
 
+void machine_panic(void)
+{
+}
+
+EXPORT_SYMBOL(machine_panic);
+
 void show_regs(struct pt_regs * regs)
 {
 	printk("\n");
arch/i386/kernel/reboot.c +7 -0
diff -Nru a/arch/i386/kernel/reboot.c b/arch/i386/kernel/reboot.c
@@ -303,3 +303,10 @@
 
 EXPORT_SYMBOL(machine_power_off);
 
+void machine_panic(void)
+{
+}
+
+EXPORT_SYMBOL(machine_panic);
+
+
arch/ia64/kernel/process.c +7 -0
diff -Nru a/arch/ia64/kernel/process.c b/arch/ia64/kernel/process.c
@@ -713,3 +713,10 @@
 }
 
 EXPORT_SYMBOL(machine_power_off);
+
+void
+machine_panic (void)
+{
+}
+
+EXPORT_SYMBOL(machine_panic);
arch/m68k/kernel/process.c +6 -0
diff -Nru a/arch/m68k/kernel/process.c b/arch/m68k/kernel/process.c
@@ -135,6 +135,12 @@
 
 EXPORT_SYMBOL(machine_power_off);
 
+void machine_panic(void)
+{
+}
+
+EXPORT_SYMBOL(machine_panic);
+
 void show_regs(struct pt_regs * regs)
 {
 	printk("\n");
arch/m68knommu/kernel/process.c +6 -0
diff -Nru a/arch/m68knommu/kernel/process.c b/arch/m68knommu/kernel/process.c
@@ -93,6 +93,12 @@
 
 EXPORT_SYMBOL(machine_power_off);
 
+void machine_panic(void)
+{
+}
+
+EXPORT_SYMBOL(machine_panic);
+
 void show_regs(struct pt_regs * regs)
 {
 	printk("\n");
arch/mips/kernel/reset.c +6 -0
diff -Nru a/arch/mips/kernel/reset.c b/arch/mips/kernel/reset.c
@@ -41,3 +41,9 @@
 }
 
 EXPORT_SYMBOL(machine_power_off);
+
+void machine_panic(void)
+{
+}
+
+EXPORT_SYMBOL(machine_panic);
arch/parisc/kernel/process.c +6 -0
diff -Nru a/arch/parisc/kernel/process.c b/arch/parisc/kernel/process.c
@@ -161,6 +161,12 @@
 
 EXPORT_SYMBOL(machine_halt);
 
+void machine_panic(void)
+{
+}
+
+EXPORT_SYMBOL(machine_panic);
+
 
 /*
  * This routine is called from sys_reboot to actually turn off the
arch/ppc/kernel/setup.c +6 -0
diff -Nru a/arch/ppc/kernel/setup.c b/arch/ppc/kernel/setup.c
@@ -140,6 +140,12 @@
 
 EXPORT_SYMBOL(machine_halt);
 
+void machine_panic(void)
+{
+}
+
+EXPORT_SYMBOL(machine_panic);
+
 void (*pm_power_off)(void) = machine_power_off;
 
 #ifdef CONFIG_TAU
arch/ppc64/kernel/chrp_setup.c +1 -0
diff -Nru a/arch/ppc64/kernel/chrp_setup.c b/arch/ppc64/kernel/chrp_setup.c
@@ -271,6 +271,7 @@
 	ppc_md.restart        = rtas_restart;
 	ppc_md.power_off      = rtas_power_off;
 	ppc_md.halt           = rtas_halt;
+	ppc_md.panic          = rtas_os_term;
 
 	ppc_md.get_boot_time  = pSeries_get_boot_time;
 	ppc_md.get_rtc_time   = pSeries_get_rtc_time;
arch/ppc64/kernel/iSeries_setup.c +8 -0
diff -Nru a/arch/ppc64/kernel/iSeries_setup.c b/arch/ppc64/kernel/iSeries_setup.c
@@ -324,6 +324,7 @@
 	ppc_md.restart = iSeries_restart;
 	ppc_md.power_off = iSeries_power_off;
 	ppc_md.halt = iSeries_halt;
+	ppc_md.panic = iSeries_panic;
 
 	ppc_md.get_boot_time = iSeries_get_boot_time;
 	ppc_md.set_rtc_time = iSeries_set_rtc_time;

@@ -791,6 +792,13 @@
 void iSeries_halt(void)
 {
 	mf_powerOff();
+}
+
+/*
+ * Document and implement me.
+ */
+void iSeries_panic(void)
+{
 }
 
 /* JDH Hack */
arch/ppc64/kernel/rtas.c +11 -0
diff -Nru a/arch/ppc64/kernel/rtas.c b/arch/ppc64/kernel/rtas.c
@@ -386,6 +386,17 @@
         rtas_power_off();
 }
 
+void
+rtas_os_term(void)
+{
+	long status;
+	char *str = "OS panic";
+
+	status = rtas_call(rtas_token("ibm,os-term"), 1, 1, NULL, __pa(str));
+	if (status != 0)
+		printk(KERN_EMERG "ibm,os-term call failed %d\n", status);
+}
+
 unsigned long rtas_rmo_buf = 0;
 
 asmlinkage int ppc_rtas(struct rtas_args __user *uargs)
arch/ppc64/kernel/setup.c +10 -1
diff -Nru a/arch/ppc64/kernel/setup.c b/arch/ppc64/kernel/setup.c
@@ -315,6 +315,13 @@
 
 EXPORT_SYMBOL(machine_halt);
 
+void machine_panic(void)
+{
+	ppc_md.panic();
+}
+
+EXPORT_SYMBOL(machine_panic);
+
 unsigned long ppc_proc_freq;
 unsigned long ppc_tb_freq;
 

@@ -611,8 +618,10 @@
 	dcache_bsize = systemcfg->dCacheL1LineSize;
 	icache_bsize = systemcfg->iCacheL1LineSize;
 
-	/* reboot on panic */
+	/* reboot on panic
 	panic_timeout = 180;
+	*/
+	panic_timeout = 0;
 
 	init_mm.start_code = PAGE_OFFSET;
 	init_mm.end_code = (unsigned long) _etext;
arch/s390/kernel/setup.c +8 -0
diff -Nru a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c
@@ -53,6 +53,7 @@
 unsigned int console_irq = -1;
 unsigned long memory_size = 0;
 unsigned long machine_flags = 0;
+unsigned long panic_caller = 0;
 struct { unsigned long addr, size, type; } memory_chunk[16] = { { 0 } };
 #define CHUNK_READ_WRITE 0
 #define CHUNK_READ_ONLY 1

@@ -310,6 +311,13 @@
 }
 
 EXPORT_SYMBOL(machine_power_off);
+
+void machine_panic(void)
+{
+	disabled_wait(panic_caller);
+}
+
+EXPORT_SYMBOL(machine_panic);
 
 /*
  * Setup function called from init/main.c just after the banner
arch/sh/kernel/process.c +6 -0
diff -Nru a/arch/sh/kernel/process.c b/arch/sh/kernel/process.c
@@ -85,6 +85,12 @@
 
 EXPORT_SYMBOL(machine_power_off);
 
+void machine_panic(void)
+{
+}
+
+EXPORT_SYMBOL(machine_panic);
+
 void show_regs(struct pt_regs * regs)
 {
 	printk("\n");
arch/sparc/kernel/process.c +10 -0
diff -Nru a/arch/sparc/kernel/process.c b/arch/sparc/kernel/process.c
@@ -195,6 +195,16 @@
 
 EXPORT_SYMBOL(machine_power_off);
 
+void machine_panic(void)
+{
+	extern int stop_a_enabled;
+	/* Make sure the user can actually press L1-A */
+	stop_a_enabled = 1;
+	printk(KERN_EMERG "Press L1-A to return to the boot prom\n");
+}
+
+EXPORT_SYMBOL(machine_panic);
+
 static spinlock_t sparc_backtrace_lock = SPIN_LOCK_UNLOCKED;
 
 void __show_backtrace(unsigned long fp)
arch/sparc64/kernel/process.c +10 -0
diff -Nru a/arch/sparc64/kernel/process.c b/arch/sparc64/kernel/process.c
@@ -158,6 +158,16 @@
 
 EXPORT_SYMBOL(machine_restart);
 
+void machine_panic(void)
+{
+	extern int stop_a_enabled;
+	/* Make sure the user can actually press L1-A */
+	stop_a_enabled = 1;
+	printk(KERN_EMERG "Press L1-A to return to the boot prom\n");
+}
+
+EXPORT_SYMBOL(machine_panic);
+
 static void show_regwindow32(struct pt_regs *regs)
 {
 	struct reg_window32 *rw;
arch/um/kernel/reboot.c +6 -0
diff -Nru a/arch/um/kernel/reboot.c b/arch/um/kernel/reboot.c
@@ -65,6 +65,12 @@
 
 EXPORT_SYMBOL(machine_halt);
 
+void machine_panic(void)
+{
+}
+
+EXPORT_SYMBOL(machine_panic);
+
 /*
  * Overrides for Emacs so that we follow Linus's tabbing style.
  * Emacs will notice this stuff at the end of the file and automatically
arch/v850/kernel/anna.c +6 -0
diff -Nru a/arch/v850/kernel/anna.c b/arch/v850/kernel/anna.c
@@ -154,6 +154,12 @@
 
 EXPORT_SYMBOL(machine_power_off);
 
+void machine_panic (void)
+{
+}
+
+EXPORT_SYMBOL(machine_panic);
+
 /* Called before configuring an on-chip UART.  */
 void anna_uart_pre_configure (unsigned chan, unsigned cflags, unsigned baud)
 {
arch/v850/kernel/as85ep1.c +6 -0
diff -Nru a/arch/v850/kernel/as85ep1.c b/arch/v850/kernel/as85ep1.c
@@ -182,6 +182,12 @@
 
 EXPORT_SYMBOL(machine_power_off);
 
+void machine_panic (void)
+{
+}
+
+EXPORT_SYMBOL(machine_panic);
+
 /* Called before configuring an on-chip UART.  */
 void as85ep1_uart_pre_configure (unsigned chan, unsigned cflags, unsigned baud)
 {
arch/v850/kernel/fpga85e2c.c +6 -0
diff -Nru a/arch/v850/kernel/fpga85e2c.c b/arch/v850/kernel/fpga85e2c.c
@@ -138,6 +138,12 @@
 
 EXPORT_SYMBOL(machine_power_off);
 
+void machine_panic (void)
+{
+}
+
+EXPORT_SYMBOL(machine_panic);
+
 
 /* Interrupts */
arch/v850/kernel/rte_cb.c +6 -0
diff -Nru a/arch/v850/kernel/rte_cb.c b/arch/v850/kernel/rte_cb.c
@@ -98,6 +98,12 @@
 
 EXPORT_SYMBOL(machine_power_off);
 
+void machine_panic (void)
+{
+}
+
+EXPORT_SYMBOL(machine_panic);
+
 
 /* Animated LED display for timer tick.  */
arch/v850/kernel/sim.c +6 -0
diff -Nru a/arch/v850/kernel/sim.c b/arch/v850/kernel/sim.c
@@ -122,6 +122,12 @@
 
 EXPORT_SYMBOL(machine_power_off);
 
+void machine_panic (void)
+{
+}
+
+EXPORT_SYMBOL(machine_panic);
+
 
 /* Load data from a file called NAME into ram.  The address and length
    of the data image are returned in ADDR and LEN.  */
arch/v850/kernel/sim85e2.c +6 -0
diff -Nru a/arch/v850/kernel/sim85e2.c b/arch/v850/kernel/sim85e2.c
@@ -201,3 +201,9 @@
 }
 
 EXPORT_SYMBOL(machine_power_off);
+
+void machine_panic (void)
+{
+}
+
+EXPORT_SYMBOL(machine_panic);
arch/x86_64/kernel/reboot.c +6 -0
diff -Nru a/arch/x86_64/kernel/reboot.c b/arch/x86_64/kernel/reboot.c
@@ -185,3 +185,9 @@
 }
 
 EXPORT_SYMBOL(machine_power_off);
+
+void machine_panic(void)
+{
+}
+
+EXPORT_SYMBOL(machine_panic);
include/asm-ppc64/machdep.h +1 -0
diff -Nru a/include/asm-ppc64/machdep.h b/include/asm-ppc64/machdep.h
@@ -78,6 +78,7 @@
 	void		(*restart)(char *cmd);
 	void		(*power_off)(void);
 	void		(*halt)(void);
+	void		(*panic)(void);
 
 	int		(*set_rtc_time)(struct rtc_time *);
 	void		(*get_rtc_time)(struct rtc_time *);
include/asm-ppc64/rtas.h +1 -0
diff -Nru a/include/asm-ppc64/rtas.h b/include/asm-ppc64/rtas.h
@@ -175,6 +175,7 @@
 extern void rtas_restart(char *cmd);
 extern void rtas_power_off(void);
 extern void rtas_halt(void);
+extern void rtas_os_term(void);
 extern int rtas_get_sensor(int sensor, int index, int *state);
 extern int rtas_get_power_level(int powerdomain, int *level);
 extern int rtas_set_indicator(int indicator, int index, int new_value);
include/linux/reboot.h +1 -0
diff -Nru a/include/linux/reboot.h b/include/linux/reboot.h
@@ -48,6 +48,7 @@
 extern void machine_restart(char *cmd);
 extern void machine_halt(void);
 extern void machine_power_off(void);
+extern void machine_panic(void);
 
 #endif
kernel/panic.c +8 -12
diff -Nru a/kernel/panic.c b/kernel/panic.c
@@ -53,7 +53,8 @@
 	static char buf[1024];
 	va_list args;
 #if defined(CONFIG_ARCH_S390)
-        unsigned long caller = (unsigned long) __builtin_return_address(0);
+	extern unsigned long panic_caller;
+        panic_caller = (unsigned long) __builtin_return_address(0);
 #endif
 
 	bust_spinlocks(1);

@@ -94,17 +95,12 @@
 		 */
 		machine_restart(NULL);
 	}
-#ifdef __sparc__
-	{
-		extern int stop_a_enabled;
-		/* Make sure the user can actually press L1-A */
-		stop_a_enabled = 1;
-		printk(KERN_EMERG "Press L1-A to return to the boot prom\n");
-	}
-#endif
-#if defined(CONFIG_ARCH_S390)
-        disabled_wait(caller);
-#endif
+
+	/*
+	 * Machine specific callout; might not return
+	 */
+	machine_panic();
+
 	local_irq_enable();
 	for (;;)
 		;
#1 lore raw
Quoted 7 lines · Mike Strosaker

There are some ppc64-specific actions that should be taken upon a
kernel panic. Rather than adding a new #ifdef in panic(), it seems to me that it would be worthwhile to add a single callout, and move the arch-specific code out to the arch subtrees. Does this seem reasonable, or should another #ifdef be added in panic() to perform the ppc64- specific actions?

We have the panic_notifier_list in there. Cannot you hook into that?

author
#2 lore raw
Quoted 2 lines · Andrew Morton

We have the panic_notifier_list in there. Cannot you hook into that?

panic_notifier_list is not used becasue we need to ensure that the actions in machine_panic are the last ones taken. machine_panic may not return (in the ppc64 case, it calls a firmware routine which does not return), so any other actions on the list need to be taken first.

Thanks,
Mike

#3 lore raw
Quoted 5 lines · Mike Strosaker
Quoted 1 line · Andrew Morton

We have the panic_notifier_list in there. Cannot you hook into that?

panic_notifier_list is not used becasue we need to ensure that the actions in machine_panic are the last ones taken.

panic_notifier_list, like all entries defined via notifier_chain_register, is run in priority order, with LIFO order within priority. Register machine_panic first with priority INT_MIN and it gets called last.

Which reduces your problem to "which one of the 57 initcall levels do I use for registering machine_panic first on the panic_notifier_list"?

#4 lore raw
In reply to Mike Strosaker
Quoted 8 lines · Mike Strosaker

Hello, All:

There are some ppc64-specific actions that should be taken upon a kernel panic. Rather than adding a new #ifdef in panic(), it seems to me that it would be worthwhile to add a single callout, and move the arch-specific code out to the arch subtrees. Does this seem reasonable, or should another #ifdef be added in panic() to perform the ppc64- specific actions?

Don't do it that way. Add a weak alias to empty function and override it on ppc64 by defining a function with the same name.

See how cond_syscall() is done - similar trick will work here. There's no need to mess with the architectures that do not use your hook.