Revert "powerpc: Do not call ppc_md.panic in fadump panic notifier"

This reverts commit a3b2cb30f252b21a6f962e0dd107c8b897ca65e4.

That commit tried to fix problems with panic on powerpc in certain
circumstances, where some output from the generic panic code was being
dropped.

Unfortunately, it breaks things worse in other circumstances. In
particular when running a PAPR guest, it will now attempt to reboot
instead of informing the hypervisor (KVM or PowerVM) that the guest
has crashed. The crash notification is important to some
virtualization management layers.

Revert it for now until we can come up with a better solution.

Fixes: a3b2cb30f252 ("powerpc: Do not call ppc_md.panic in fadump panic notifier")
Cc: stable@vger.kernel.org # v4.14+
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
[mpe: Tweak change log a bit]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

6 files changed, 45 insertions, 22 deletions

diff --git a/arch/powerpc/include/asm/machdep.h b/arch/powerpc/include/asm/machdep.h
index 73b92017b6d7..cd2fc1cc1cc7 100644
--- a/arch/powerpc/include/asm/machdep.h
+++ b/arch/powerpc/include/asm/machdep.h
@@ -76,6 +76,7 @@ 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 257d23dbf55d..cf00ec26303a 100644
--- a/arch/powerpc/include/asm/setup.h
+++ b/arch/powerpc/include/asm/setup.h
@@ -24,6 +24,7 @@ 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 04ea5c04fd24..3c2c2688918f 100644
--- a/arch/powerpc/kernel/fadump.c
+++ b/arch/powerpc/kernel/fadump.c
@@ -1462,25 +1462,6 @@ 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.
  */
@@ -1513,9 +1494,6 @@ 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 2075322cd225..9d213542a48b 100644
--- a/arch/powerpc/kernel/setup-common.c
+++ b/arch/powerpc/kernel/setup-common.c
@@ -704,6 +704,30 @@ 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
@@ -848,6 +872,9 @@ 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 9dabea6e1443..6244bc849469 100644
--- a/arch/powerpc/platforms/ps3/setup.c
+++ b/arch/powerpc/platforms/ps3/setup.c
@@ -104,6 +104,20 @@ 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)
@@ -255,6 +269,7 @@ 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 5f1beb8367ac..a8531e012658 100644
--- a/arch/powerpc/platforms/pseries/setup.c
+++ b/arch/powerpc/platforms/pseries/setup.c
@@ -726,6 +726,7 @@ 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,