Subject: [PATCH v2 1/3] powerpc: do not call ppc_md.panic in fadump panic notifier

From: Nicholas Piggin <[email-masked]>
Date: Wed, 5 Jul 2017 13:56:25 +1000

If fadump is not registered, and no other crash or debug handlers are
registered, the powerpc panic handler stops the guest before the generic
panic code can push out debug information to the console.

Currently, system reset injection causes the guest to silently
stop.

Stop calling ppc_md.panic in the panic notifier. crash_fadump already
does rtas_os_term() to terminate the guest if fadump is registered.

Remove ppc_md.panic. Move fadump panic notifier into fadump code.

Signed-off-by: Nicholas Piggin <[email-masked]>
---
 arch/powerpc/include/asm/machdep.h     |  1 -
 arch/powerpc/include/asm/setup.h       |  1 -
 arch/powerpc/kernel/fadump.c           | 22 ++++++++++++++++++++++
 arch/powerpc/kernel/setup-common.c     | 27 ---------------------------
 arch/powerpc/platforms/ps3/setup.c     | 15 ---------------
 arch/powerpc/platforms/pseries/setup.c |  1 -
 6 files changed, 22 insertions(+), 45 deletions(-)

diff --git a/arch/powerpc/include/asm/machdep.h b/arch/powerpc/include/asm/machdep.h
index cd2fc1cc1cc7..73b92017b6d7 100644
--- a/arch/powerpc/include/asm/machdep.h
+++ b/arch/powerpc/include/asm/machdep.h
@@ -76,7 +76,6 @@ struct machdep_calls {
 
 	void __noreturn	(*restart)(char *cmd);
 	void __noreturn (*halt)(void);
-	void		(*panic)(char *str);
 	void		(*cpu_die)(void);
 
 	long		(*time_init)(void); /* Optional, may be NULL */
diff --git a/arch/powerpc/include/asm/setup.h b/arch/powerpc/include/asm/setup.h
index 654d64c9f3ac..3a3fb0ca68f5 100644
--- a/arch/powerpc/include/asm/setup.h
+++ b/arch/powerpc/include/asm/setup.h
@@ -23,7 +23,6 @@ extern void reloc_got2(unsigned long);
 
 void check_for_initrd(void);
 void initmem_init(void);
-void setup_panic(void);
 #define ARCH_PANIC_TIMEOUT 180
 
 #ifdef CONFIG_PPC_PSERIES
diff --git a/arch/powerpc/kernel/fadump.c b/arch/powerpc/kernel/fadump.c
index 3079518f2245..8f1a8bd8433c 100644
--- a/arch/powerpc/kernel/fadump.c
+++ b/arch/powerpc/kernel/fadump.c
@@ -1447,6 +1447,25 @@ static void fadump_init_files(void)
 	return;
 }
 
+static int fadump_panic_event(struct notifier_block *this,
+                             unsigned long event, void *ptr)
+{
+	/*
+	 * If firmware-assisted dump has been registered then trigger
+	 * firmware-assisted dump and let firmware handle everything
+	 * else. If this returns, then fadump was not registered, so
+	 * go through the rest of the panic path.
+	 */
+	crash_fadump(NULL, ptr);
+
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block fadump_panic_block = {
+	.notifier_call = fadump_panic_event,
+	.priority = INT_MIN /* may not return; must be done last */
+};
+
 /*
  * Prepare for firmware-assisted dump.
  */
@@ -1479,6 +1498,9 @@ int __init setup_fadump(void)
 		init_fadump_mem_struct(&fdm, fw_dump.reserve_dump_area_start);
 	fadump_init_files();
 
+	atomic_notifier_chain_register(&panic_notifier_list,
+					&fadump_panic_block);
+
 	return 1;
 }
 subsys_initcall(setup_fadump);
diff --git a/arch/powerpc/kernel/setup-common.c b/arch/powerpc/kernel/setup-common.c
index 94a948207cd2..b697530d9bdc 100644
--- a/arch/powerpc/kernel/setup-common.c
+++ b/arch/powerpc/kernel/setup-common.c
@@ -704,30 +704,6 @@ int check_legacy_ioport(unsigned long base_port)
 }
 EXPORT_SYMBOL(check_legacy_ioport);
 
-static int ppc_panic_event(struct notifier_block *this,
-                             unsigned long event, void *ptr)
-{
-	/*
-	 * If firmware-assisted dump has been registered then trigger
-	 * firmware-assisted dump and let firmware handle everything else.
-	 */
-	crash_fadump(NULL, ptr);
-	ppc_md.panic(ptr);  /* May not return */
-	return NOTIFY_DONE;
-}
-
-static struct notifier_block ppc_panic_block = {
-	.notifier_call = ppc_panic_event,
-	.priority = INT_MIN /* may not return; must be done last */
-};
-
-void __init setup_panic(void)
-{
-	if (!ppc_md.panic)
-		return;
-	atomic_notifier_chain_register(&panic_notifier_list, &ppc_panic_block);
-}
-
 #ifdef CONFIG_CHECK_CACHE_COHERENCY
 /*
  * For platforms that have configurable cache-coherency.  This function
@@ -872,9 +848,6 @@ void __init setup_arch(char **cmdline_p)
 	/* Probe the machine type, establish ppc_md. */
 	probe_machine();
 
-	/* Setup panic notifier if requested by the platform. */
-	setup_panic();
-
 	/*
 	 * Configure ppc_md.power_save (ppc32 only, 64-bit machines do
 	 * it from their respective probe() function.
diff --git a/arch/powerpc/platforms/ps3/setup.c b/arch/powerpc/platforms/ps3/setup.c
index 6244bc849469..9dabea6e1443 100644
--- a/arch/powerpc/platforms/ps3/setup.c
+++ b/arch/powerpc/platforms/ps3/setup.c
@@ -104,20 +104,6 @@ static void __noreturn ps3_halt(void)
 	ps3_sys_manager_halt(); /* never returns */
 }
 
-static void ps3_panic(char *str)
-{
-	DBG("%s:%d %s\n", __func__, __LINE__, str);
-
-	smp_send_stop();
-	printk("\n");
-	printk("   System does not reboot automatically.\n");
-	printk("   Please press POWER button.\n");
-	printk("\n");
-
-	while(1)
-		lv1_pause(1);
-}
-
 #if defined(CONFIG_FB_PS3) || defined(CONFIG_FB_PS3_MODULE) || \
     defined(CONFIG_PS3_FLASH) || defined(CONFIG_PS3_FLASH_MODULE)
 static void __init prealloc(struct ps3_prealloc *p)
@@ -269,7 +255,6 @@ define_machine(ps3) {
 	.probe				= ps3_probe,
 	.setup_arch			= ps3_setup_arch,
 	.init_IRQ			= ps3_init_IRQ,
-	.panic				= ps3_panic,
 	.get_boot_time			= ps3_get_boot_time,
 	.set_dabr			= ps3_set_dabr,
 	.calibrate_decr			= ps3_calibrate_decr,
diff --git a/arch/powerpc/platforms/pseries/setup.c b/arch/powerpc/platforms/pseries/setup.c
index b5d86426e97b..b5b650910cf5 100644
--- a/arch/powerpc/platforms/pseries/setup.c
+++ b/arch/powerpc/platforms/pseries/setup.c
@@ -722,7 +722,6 @@ define_machine(pseries) {
 	.pcibios_fixup		= pSeries_final_fixup,
 	.restart		= rtas_restart,
 	.halt			= rtas_halt,
-	.panic			= rtas_os_term,
 	.get_boot_time		= rtas_get_boot_time,
 	.get_rtc_time		= rtas_get_rtc_time,
 	.set_rtc_time		= rtas_set_rtc_time,
-- 
2.11.0